Fact-checked by Grok 2 weeks ago

Tree

A tree is a perennial woody plant characterized by a single main stem or trunk that supports branches and foliage, typically growing to a height of at least 13 feet (4 meters) with a crown of leaves or needles, distinguishing it from shrubs by its erect structure and capacity for substantial vertical growth.^[1]^[2] Trees exhibit a complex anatomy adapted for longevity and environmental interaction, consisting of roots for anchorage and nutrient absorption, a trunk with layers including outer bark for protection against pests and weather, inner bark (phloem) for transporting sugars, cambium for annual growth, sapwood for water conduction, and heartwood for structural support.^[3]^[2] Leaves or needles serve as the primary sites for photosynthesis, converting sunlight, carbon dioxide, and water into energy while releasing oxygen, with their surface area enabling vast food production—equivalent to several acres of chlorophyll exposure in species like Douglas fir.^[3] Trees are classified into broad categories such as deciduous (shedding leaves annually, e.g., maples) and evergreen (retaining foliage year-round, e.g., pines), with variations in growth forms including monocots like palms that lack typical annual rings.^[1]^[2] Ecologically, trees play a vital role in sustaining biodiversity and regulating Earth's systems. There are approximately 73,000 known tree species on Earth, with around 9,000 yet to be discovered.^[4] As of 2025, forests cover approximately 31% of the world's land area.^[5] They sequester carbon dioxide to mitigate climate change, produce oxygen, filter air pollutants, conserve water through reduced runoff and erosion control, and provide habitats for wildlife via symbiotic relationships like mycorrhizae with fungi.^[6]^[7]^[8] In urban and natural settings, they moderate temperatures by shading and transpiration, support pollination and food webs, and enhance human well-being through cleaner air, water, and recreational spaces.^[6]^[7]

Definition and Classification

Definition

In botany, a tree is a perennial woody plant featuring a single main self-supporting stem, known as the trunk, from which branches and leaves extend, typically achieving a mature height of at least 13 feet (4 meters). However, there is no universally accepted botanical definition of a tree, with criteria varying by context and including factors like height, stem structure, and growth form. This structure distinguishes trees as long-lived organisms capable of substantial vertical and radial growth, supported by specialized tissues that enable them to thrive in diverse environments.^[1]^[9] Key characteristics of trees include the presence of lignified tissues, such as wood formed from secondary xylem, which provide mechanical strength and allow the plant to support its canopy against gravity and wind. Secondary growth occurs through the activity of the vascular cambium, a thin layer of meristematic cells that divides to produce annual rings of new vascular tissue, increasing the diameter of the trunk over time. Trees often live for decades or centuries, with some species reaching ages exceeding 1,000 years, far outlasting many other plant forms due to their robust physiology.^[10]^[11] The term "tree" originates from the Old English word trēow, meaning something firm or hard, a descriptor that aptly captures the plant's durable, woody composition derived from Proto-Indo-European roots emphasizing solidity. Trees differ from shrubs, which are woody but multi-stemmed from the base and generally shorter, lacking a single dominant trunk. They also contrast with herbs, which possess soft, non-lignified stems without secondary growth, resulting in limited height and lifespan.^[12]^[13]^[14]

Types of Trees

Trees are primarily classified into two major botanical groups based on their reproductive structures: gymnosperms and angiosperms. Gymnosperms, meaning "naked seeds" in Greek, produce seeds that are not enclosed within an ovary or fruit, typically borne on cones or similar structures.^[15] This group includes conifers such as pines (Pinus spp.), which dominate many forested regions with their woody, perennial forms.^[16] In contrast, angiosperms, or flowering plants, enclose their seeds within fruits developed from ovaries, enabling more efficient protection and dispersal.^[15] Examples include oaks (Quercus spp.), which produce acorns as fruits containing seeds.^[17] Angiosperms include the vast majority (≈99%) of tree species, with approximately 72,000 angiosperm tree species out of a global total of ≈73,000 tree species (as of 2022).^[4] A common commercial and structural classification further divides trees into softwoods and hardwoods, which aligns closely with the gymnosperm-angiosperm divide but focuses on wood properties rather than botanical taxonomy. Softwoods, derived from gymnosperms, feature simple wood anatomy with tracheids for water conduction and lack vessels, resulting in lighter, more uniform timber often used in construction.^[18] These trees are typically needle-leaved conifers like spruces (Picea spp.) and firs (Abies spp.).^[19] Hardwoods, from angiosperms, have more complex wood with vessels for efficient water transport, leading to denser, varied timber suitable for furniture and flooring.^[18] Broad-leaved species such as maples (Acer spp.) and cherries (Prunus spp.) exemplify hardwoods.^[19] Notably, these terms do not strictly indicate the wood's hardness; some softwoods like yew are denser than certain hardwoods.^[20] Trees can also be categorized by leaf retention patterns: deciduous and evergreen. Deciduous trees shed their leaves annually, typically in response to seasonal changes, allowing adaptation to cold or dry periods by conserving resources.^[21] Common examples include maples and birches (Betula spp.), which display vibrant fall colors before leaf drop.^[22] Evergreen trees, conversely, retain foliage year-round, maintaining photosynthetic activity through varying conditions.^[21] Firs and pines are classic evergreens, though exceptions exist, such as deciduous conifers like larches (Larix spp.) that lose needles seasonally.^[23] This distinction often correlates with climate: deciduous species prevail in temperate zones, while evergreens are more common in boreal or tropical environments.^[24] Within angiosperms, trees are subdivided into monocots and dicots based on seed structure and vascular organization, influencing growth patterns. Monocot trees, with a single cotyledon in their seeds, feature scattered vascular bundles throughout the stem, lacking the secondary growth rings typical of woody forms.^[25] Palms (Arecaceae family), such as coconut palms (Cocos nucifera), represent the primary monocot trees, achieving height through primary growth alone.^[26] Dicot trees, with two cotyledons, arrange vascular bundles in a ring, enabling extensive secondary growth via cambium layers for thicker trunks.^[25] Most hardwood trees, like oaks and beeches (Fagus spp.), are dicots, supporting their dominance in diverse ecosystems.^[27] This vascular difference underscores why monocot trees are rarer and structurally distinct from the dicot majority.^[28]

Anatomy and Physiology

Roots

Tree roots form the below-ground portion of the vascular system, primarily serving to anchor the plant and facilitate the uptake of essential resources from the soil. Most trees develop either a taproot system or a fibrous root system. In a taproot system, a single, dominant primary root grows deeply into the soil, often branching into lateral roots that spread outward for absorption; this configuration is common in many dicotyledonous trees such as oaks and walnuts, providing strong anchorage and access to deep water sources.^[29]^[30] In contrast, a fibrous root system consists of numerous fine, branching roots of similar diameter that spread horizontally near the soil surface, maximizing contact area for nutrient capture; this is typical in some trees like maples and most monocots, though many mature trees exhibit a combination of both systems with extensive lateral roots emerging from the primary structure to enhance absorption efficiency.^[29]^[31] The primary functions of tree roots include the absorption of water and dissolved minerals, mechanical anchorage to withstand environmental stresses like wind, and the conduction of these resources upward to the stem. Water and mineral uptake occurs mainly through microscopic root hairs—extensions of epidermal cells that dramatically increase the root's surface area for osmosis and active transport processes.^[32]^[33] Anchorage is achieved through the structural integrity of larger roots, which interlock with soil particles to prevent uprooting, while symbiotic relationships with mycorrhizal fungi further augment these roles by extending the root network via fungal hyphae, improving phosphorus and nitrogen acquisition in nutrient-poor soils.^[32]^[34] These mutualistic associations, present in over 80% of tree species, involve the fungi receiving carbohydrates from the tree in exchange for enhanced mineral transport.^[35]^[36] Tree roots exhibit diverse adaptations to environmental challenges, particularly in challenging habitats. In tropical rainforests, where shallow, nutrient-rich soils predominate, many large trees develop buttress roots—plate-like, vertically oriented extensions from the trunk base that widen the anchorage area and provide stability against lateral forces from wind or uneven weight distribution, contributing up to 60% of the total uprooting resistance.^[37] In waterlogged coastal environments, mangrove trees produce pneumatophores, specialized vertical roots that protrude above the soil or water surface, equipped with lenticels (small pores) that facilitate aeration by allowing oxygen diffusion into the submerged root system, thereby preventing hypoxia in anaerobic mud.^[38]^[39] Root depth and spread vary significantly by species and habitat, reflecting adaptations to water availability. In arid regions, species like mesquite (Prosopis glandulosa) often feature shallow, extensive lateral roots that can spread up to 60 feet (18 m) horizontally to capture sporadic surface moisture from rainfall, while their taproots may penetrate deeply—sometimes exceeding 50 feet (15 m)—to reach groundwater aquifers.^[40] In contrast, trees in mesic environments may prioritize shallower fibrous networks for broad nutrient foraging, whereas those in dry or rocky soils invest in deeper penetrating roots for reliable water access, with overall depth influenced by soil texture, precipitation, and competition.^[40] These variations underscore the roots' role in resource optimization, connecting briefly to the vascular transport system in the trunk for upward flow.^[32]

Trunk and Bark

The trunk of a tree serves as the primary structural support, consisting of two main types of wood: heartwood and sapwood. Heartwood forms the inactive, central core, composed of dead xylem cells that provide mechanical strength and rigidity to the tree, often appearing darker due to extractives and lignins.^[3] Sapwood, the outer, lighter-colored layer, comprises living xylem cells responsible for conducting water and nutrients upward from the roots, with its width varying by species and age but typically encompassing the most recent growth rings.^[41] Annual rings in the trunk result from secondary growth, where seasonal variations in cell size create distinct bands of earlywood (larger, thinner-walled cells formed in spring) and latewood (smaller, thicker-walled cells formed in summer), allowing age estimation through ring counts.^[30] Secondary growth in the trunk is driven by the vascular cambium, a thin layer of meristematic cells between the xylem and phloem that divides to produce new xylem inward (adding to wood) and new phloem outward (contributing to inner bark), enabling radial expansion.^[3] The cork cambium, or phellogen, originates in the outer cortex or phloem and produces bark tissues, replacing the epidermis as the tree matures; it generates phellem (cork cells) outward for protection and phelloderm (living parenchyma) inward for storage and support.^[42] Bark is divided into inner bark (living phloem for nutrient transport) and outer bark, with the rhytidome forming the dead, protective outer layer through successive periderm formations that crack and slough off.^[43] Bark functions primarily to shield the trunk from environmental threats, including pathogens, physical damage, herbivores, and fire, with its layered structure acting as a barrier to water loss and gas exchange via lenticels.^[44] In fire-prone ecosystems, certain species exhibit adaptations like exceptionally thick bark; for instance, giant sequoias (Sequoiadendron giganteum) develop bark up to 60 cm thick, composed of fibrous, non-resinous tissue that insulates the cambium from lethal heat during wildfires.^[45] This thickness, combined with high tannin content, deters insects and fungi while allowing the tree to survive low- to moderate-intensity fires that promote seed release.^[46]

Leaves

Leaves are the primary photosynthetic organs of trees, consisting of a flattened blade, a petiole that connects the blade to the stem, and an internal network of veins that transport water, nutrients, and sugars. The blade, also known as the lamina, is the broad, expanded portion where most photosynthesis occurs, featuring a waxy cuticle on the upper surface to minimize water loss. Veins, formed by xylem and phloem tissues, provide structural support and facilitate the movement of resources throughout the leaf.^[47]^[48] Tree leaves are classified as simple or compound based on blade division. Simple leaves have a single, undivided blade attached to the petiole, as seen in oaks (Quercus spp.) and maples (Acer spp.), allowing for a continuous surface for light absorption. Compound leaves, in contrast, feature multiple leaflets arising from a single petiole, either pinnately (arranged along a central axis, like in ashes Fraxinus spp.) or palmately (radiating from one point, like in horse chestnuts Aesculus spp.), which can enhance flexibility and reduce wind damage in certain environments.^[49]^[50] Photosynthesis in tree leaves converts light energy into chemical energy, summarized by the equation:

$6\text{CO}_2 + 6\text{H}_2\text{O} + \text{light energy} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2

This process occurs in chloroplasts within mesophyll cells of the blade. The light-dependent reactions, taking place in the thylakoid membranes, capture photons to split water molecules, releasing oxygen and generating ATP and NADPH. These energy carriers then drive the light-independent Calvin cycle in the stroma, where carbon dioxide is fixed into glucose through a series of enzymatic reactions involving ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO).^[51]^[52] Leaf adaptations in trees reflect environmental pressures, particularly for water conservation and light capture. Conifers, such as pines (Pinus spp.) and spruces (Picea spp.), bear needle-like leaves with thick cuticles, sunken stomata, and reduced surface area to minimize transpiration in arid or cold climates, thereby conserving water during periods of low availability. In temperate regions, broad-leaved deciduous trees like birches (Betula spp.) and beeches (Fagus spp.) develop expansive, flat blades to maximize interception of diffuse sunlight, optimizing photosynthetic efficiency in moderate moisture conditions.^[53]^[54]^[55] Gas exchange in tree leaves occurs primarily through stomata, microscopic pores on the blade's underside regulated by guard cells. Stomata open to allow carbon dioxide influx for photosynthesis and close to prevent excessive water vapor loss via transpiration, balancing CO₂ uptake with hydration needs. Transpiration rates vary by species and conditions; for instance, conifer needles exhibit lower rates (around 0.5–2 mmol m⁻² s⁻¹) compared to broad leaves (up to 5–10 mmol m⁻² s⁻¹), aiding drought tolerance through controlled evaporation driven by leaf temperature and humidity gradients.^[56]^[57]^[58]

Reproductive Structures

Trees reproduce through specialized structures that facilitate pollination and fertilization, primarily cones in gymnosperms and flowers in angiosperms, leading to the development of fruits that enclose seeds.^[59]^[60] In gymnosperms, such as conifers, reproduction occurs via cones that bear exposed ovules on their scales, without enclosing structures like ovaries. Male cones produce pollen grains, which are typically dispersed by wind to reach the ovules in female cones, as seen in pine trees where pollen is released in large quantities during spring.^[61]^[15]^[62] Angiosperms, the dominant group of trees including species like oaks and maples, utilize flowers as their primary reproductive organs, consisting of sepals that protect the bud, petals that attract pollinators, stamens bearing pollen-producing anthers, and pistils containing the ovary with ovules. Pollination in these trees can occur via wind, as in many temperate species, or through animal vectors such as insects, birds, and bats, which transfer pollen from anthers to the stigma of the pistil.^[60]^[63]^[64] Following pollination, fertilization in angiosperms involves a unique process called double fertilization, where one sperm nucleus from the pollen tube fuses with the egg cell to form the diploid zygote that develops into the embryo, while the second sperm nucleus fuses with two polar nuclei in the central cell to produce the triploid endosperm, a nutritive tissue for the embryo.^[65]^[66] In gymnosperms, fertilization is simpler, with a single sperm fertilizing the egg without endosperm formation. Seed development proceeds post-fertilization within protective structures, as detailed in subsequent sections on growth. The fertilized ovules in angiosperms mature into seeds enclosed by fruits, which derive from the ovary and sometimes accessory parts, aiding in protection and dispersal preparation. Fruits are classified into types such as simple fruits, which develop from a single ovary—like the pome of an apple tree where the fleshy part forms from the floral tube—aggregate fruits from multiple ovaries of one flower, such as the raspberry's cluster of drupelets, and multiple fruits from the fusion of ovaries from many flowers, exemplified by the pineapple's composite structure.^[67]^[68]^[69]

Growth and Development

Buds and Seasonal Growth

Tree buds are embryonic structures that contain undeveloped shoots, leaves, or flowers, serving as the primary sites for new vegetative growth. Terminal buds, located at the apex of stems, promote vertical growth through apical dominance, where they inhibit the development of nearby lateral buds to maintain a centralized growth pattern. ^[41] Axillary buds, positioned in the leaf axils along stems, enable branching and lateral expansion when not suppressed. ^[70] These buds are typically protected by overlapping scales—modified leaves that shield the delicate inner tissues from desiccation and frost during unfavorable conditions. ^[68] Seasonal growth in trees follows distinct phases modulated by environmental cues. In spring, bud break initiates a flush of new shoots and leaves, fueled by carbohydrates stored in roots and stems from the previous season's photosynthesis. ^[71] Summer brings elongation of these shoots as temperatures rise and water availability supports cell expansion. ^[72] Autumn triggers dormancy, where shortening day lengths and cooling temperatures halt growth, allowing buds to form and harden for winter survival. ^[72] Hormonal regulation orchestrates these processes. Auxins, produced in terminal buds, enforce apical dominance by diffusing downward to suppress axillary bud outgrowth, ensuring efficient resource allocation for height gain. ^[73] Gibberellins, synthesized in growing tissues, drive stem and leaf elongation during active phases by promoting cell division and expansion. ^[74] Phenological patterns vary by climate. Temperate trees exhibit pronounced seasonal cycles, with synchronized bud break in spring and dormancy in winter, aligned to photoperiod and temperature shifts. ^[75] In contrast, tropical trees often display continuous or episodic growth, less dependent on temperature and more responsive to rainfall patterns, enabling multiple flushes year-round.

Seeds and Dispersal

Tree seeds typically consist of three primary components: the embryo, which develops into the new plant; the endosperm, a nutritive tissue that sustains early growth; and the seed coat, a protective outer layer that shields the internal structures from environmental stresses.^[76]^[77] The embryo itself comprises the radicle (embryonic root), the plumule (embryonic shoot), and one or two cotyledons, which serve as initial food storage organs in many species.^[78] In gymnosperms, the endosperm is often prominent and haploid-derived from the female gametophyte, while in angiosperms, it is triploid and forms post-fertilization to provide starch, proteins, and oils for the embryo.^[77] Many tree seeds exhibit dormancy, a temporary suspension of germination that ensures propagation occurs under favorable conditions, often due to a hard, impermeable seed coat that prevents water uptake—a condition known as physical dormancy.^[79] This impermeable coat, composed of lignified sclerenchyma cells, can require scarification—mechanical abrasion, chemical treatment, or exposure to fire—to break it down and allow imbibition.^[80] For instance, seeds of species like honey locust (Gleditsia triacanthos) possess such robust coats that scarification via animal digestion or sulfuric acid soaking is necessary to initiate viability.^[80] Germination in tree seeds begins with imbibition, the absorption of water that activates metabolic processes and causes the seed to swell, often rupturing the seed coat.^[81] Following this, the radicle emerges as the first visible structure, anchoring the seedling and beginning nutrient uptake from the soil.^[82] The cotyledons then expand, either remaining belowground (hypogeal germination, as in oaks) or emerging aboveground (epigeal, as in maples), utilizing stored reserves from the endosperm or cotyledons until photosynthesis commences.^[83] Environmental cues are critical: adequate moisture initiates imbibition, while temperatures typically between 15–25°C (59–77°F) promote enzyme activity, and oxygen availability supports respiration; light may inhibit or stimulate germination depending on the species.^[83] Tree seeds employ diverse dispersal strategies to promote propagation over distances, reducing competition with parent plants. Anemochory, or wind dispersal, involves lightweight structures like the winged samaras of maples (Acer spp.), which autorotate to extend flight time and travel up to several hundred meters.^[84]^[85] Zoochory relies on animals, with nuts such as acorns from oaks (Quercus spp.) cached by squirrels (Sciurus spp.), some of which are forgotten and germinate, facilitating dispersal up to kilometers away.^[84] Hydrochory uses water currents, as seen in mangroves (Rhizophora spp.), where buoyant propagules float and lodge in tidal zones to establish new stands.^[84]^[85] Seed viability varies widely among tree species, influencing regeneration success and forest dynamics. Short-lived seeds, such as those of European aspen (Populus tremula), lose viability within days to weeks under moist conditions at 15–40°C (59–104°F), necessitating rapid germination post-dispersal.^[86] In contrast, long-lived seeds like those of the date palm (Phoenix dactylifera) can remain viable for over 2,000 years under desiccated storage, as demonstrated by ancient seeds germinated from archaeological sites.^[87] This spectrum allows pioneer species with ephemeral seeds to quickly colonize disturbances, while orthodox seeds from long-lived types persist in soil seed banks for extended periods.^[86]^[87]

Evolutionary History

Origin of Trees

The origin of trees marks a pivotal transition in plant evolution during the Devonian Period, approximately 419 to 358 million years ago, when vascular plants first developed the capacity for significant height and structural support. Prior to this, land vegetation consisted primarily of small, herbaceous forms such as early ferns and horsetails, which lacked the rigidity to grow tall and were limited to a few meters in height. These early plants, including zosterophylls and trimerophytes from the Early Devonian, paved the way for more complex forms by establishing basic vascular systems for water and nutrient transport.^[88]^[89] The first true tree-like plants emerged in the Middle Devonian with the appearance of progymnosperms, a group of woody vascular plants that combined gymnosperm-like wood with fern-like reproduction via spores. A hallmark example is Archaeopteris, which by the Late Devonian formed large trees up to 10-30 meters tall with fern-like fronds and a global distribution, representing the earliest widespread arborescent vegetation. These progymnosperms, which became extinct by the Early Carboniferous, demonstrated the initial evolutionary shift toward perennial, upright growth that defined trees.^[88]^[90]^[91] A critical adaptation enabling this vertical growth was the development of secondary xylem, or true wood, produced by a vascular cambium that added layers of lignified tissue to stems, providing mechanical strength against gravity and wind. This innovation, first evident in Early Devonian euphyllophytes and refined in Middle Devonian trees, allowed plants to compete for sunlight by reaching heights unattainable by non-woody ancestors like ferns and horsetails. Lignification of stems thus facilitated the transition from prostrate or short-statured forms to towering structures, fundamentally altering terrestrial ecosystems.^[92]^[93]^[94] The earliest forests, appearing in the Middle to Late Devonian, were dominated by cladoxylopsids such as Wattieza (formerly Eospermatopteris), which formed dense stands of trees up to 10 meters tall with hollow, branching trunks supported by a unique aerenchyma-like tissue for stability. Fossil evidence from sites like Gilboa, New York, reveals in-situ stumps and root systems from these Middle Devonian forests, indicating organized woodland communities that stabilized soils and influenced early atmospheric conditions. By the Late Devonian, these ecosystems expanded, with cladoxylopsid-dominated forests giving way to more diverse assemblages including progymnosperms.^[95]^[96]

Major Evolutionary Developments

During the Carboniferous period (358–299 million years ago), seed ferns (pteridosperms) emerged as a significant group of seed-producing plants, bridging the evolutionary gap between ferns and later gymnosperms through their fern-like fronds and enclosed seeds borne on cupules derived from modified leaves or fertile appendages. These plants, alongside true ferns and other vascular flora, formed dense swamp forests that contributed to the accumulation of organic matter, which later compressed into extensive coal deposits under anaerobic conditions.^[97] Concurrently, primitive conifers began to appear, featuring scale-like leaves and naked seeds that allowed for taller growth forms and adaptation to varied terrestrial habitats, marking an early diversification within gymnosperms. In the Mesozoic era (252–66 million years ago), gymnosperms achieved dominance in global forests, with conifers and other groups like cycads and ginkgos forming extensive woodlands that shaped Mesozoic landscapes and supported diverse herbivorous faunas.^[98] This period saw gymnosperms as the primary seed plants, thriving in a range of climates from equatorial to polar regions, until the Cretaceous-Paleogene mass extinction event at 66 million years ago disrupted their hegemony.^[98] Angiosperms, which originated around 140 million years ago in the Early Cretaceous, underwent rapid radiation during the Late Cretaceous and accelerated in the early Cenozoic following the K-Pg extinction, with insect pollination emerging as a key driver by the mid-Cretaceous (~99 Ma); specialized floral traits attracted beetles, flies, and later bees, enabling efficient pollen transfer and accelerating angiosperm diversification.^[99] A hallmark innovation of angiosperms was the evolution of vessel elements in their xylem, short and wide cells that form continuous conduits for water transport, surpassing the efficiency of gymnosperm tracheids and allowing taller growth and faster water conduction in diverse environments.^[100] Complementing this, angiosperm leaves evolved broader laminae with elevated vein densities, optimizing light capture and CO2 diffusion to boost photosynthetic rates and support higher metabolic demands.^[101] Angiosperms also co-evolved with pollinators through floral syndromes tailored to specific insects, such as ultraviolet patterns and nectar rewards, fostering mutualistic relationships that enhanced reproductive success.^[99] Similarly, interactions with seed dispersers drove the proliferation of fruit types, from berries attracting birds to drupes suited for mammals, with fleshy, indehiscent structures evolving primarily in the Cenozoic to promote endozoochory and expand dispersal ranges.^[102] These co-evolutionary dynamics resulted in a diverse array of fruit types, reflecting adaptations to vertebrate and invertebrate partners and contributing to angiosperm ecological dominance.^[102]

Distribution and Ecology

Global Distribution

Trees are distributed across a wide range of biomes globally, with their presence and diversity shaped by climatic conditions, soil types, and geographical features. Tropical rainforests host the highest tree diversity, particularly in the Amazon Basin, which is estimated to contain around 16,000 tree species across nearly 400 billion individual trees. Boreal forests, spanning northern high latitudes in regions like Canada, Russia, and Scandinavia, are dominated by coniferous species such as black spruce (Picea mariana), white spruce (Picea glauca), balsam fir (Abies balsamea), jack pine (Pinus banksiana), and tamarack (Larix laricina).^[103] Temperate woodlands, found in mid-latitude zones of North America, Europe, and East Asia, feature a mix of deciduous and evergreen trees, including oaks (Quercus spp.), beeches (Fagus spp.), maples (Acer spp.), and pines (Pinus spp.), adapted to seasonal climates with moderate precipitation.^[104] Tree species diversity follows a pronounced latitudinal gradient, with richness peaking near the equator and steadily declining toward the poles due to variations in energy availability, habitat stability, and evolutionary history.^[105] This pattern is evident in forests worldwide, where tropical regions support thousands of species per plot, while polar and subpolar areas are limited to fewer, hardier types. In mountainous regions, trees occupy distinct altitudinal zones, transitioning from broadleaf species at lower elevations to conifers like Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) in montane and subalpine forests above 2,500 meters, where cooler temperatures and shorter growing seasons prevail.^[106] Human activities have significantly altered tree distributions through widespread deforestation, resulting in a total gross loss through deforestation of approximately 489 million hectares since 1990, though the annual deforestation rate has slowed to about 10.9 million hectares in 2015–2025, with net forest loss further reduced to 4.12 million hectares per year in the same period.^[107]^[108] This loss, concentrated in tropical areas like the Amazon and Southeast Asia, has fragmented habitats and shifted species ranges, with ongoing trends as of 2025 reflecting continued pressure from agriculture and logging despite global efforts to curb it.^[109]

Ecological Roles

Trees provide critical habitats that support high levels of biodiversity within ecosystems. Their multilayered canopies create vertical stratification, enabling epiphytes such as orchids, bromeliads, and ferns to colonize branches and trunks, which in turn offer food, shelter, and breeding sites for birds, insects, and other arthropods. For instance, in tropical forest fragments and agroforestry systems, epiphyte diversity can reach up to 58 species per site, sustaining associated fauna through nectar, pollen, and structural complexity.^[110] In tropical communities, fig trees (Ficus spp.) act as keystone species, producing fruit year-round that sustains diverse frugivores including primates, birds like toucans, and mammals, while relying on specific wasp pollinators for reproduction; a decline in fig populations below critical thresholds could collapse food webs for these taxa.^[111] Trees contribute significantly to global carbon sequestration, serving as a primary mechanism for mitigating atmospheric CO₂. Forests, largely composed of trees, function as a net carbon sink, absorbing approximately 3.6 billion metric tons of CO₂ annually (2021–2025) through photosynthesis and biomass accumulation, offsetting a substantial portion of anthropogenic emissions.^[108] This process is particularly pronounced in intact forest ecosystems, where long-lived tree species store carbon in wood, roots, and soil over decades. Through their structural and biochemical properties, trees regulate soil health and water dynamics essential for ecosystem stability. Root systems bind soil particles, preventing erosion on slopes and during heavy rainfall, while canopies intercept up to 30% of precipitation, reducing runoff velocity and soil detachment.^[112] Leaf litter accumulation forms a protective mulch layer that minimizes soil exposure to erosive forces, moderates temperature and moisture fluctuations, and promotes infiltration in watersheds, thereby enhancing water quality by filtering sediments and nutrients before they reach streams.^[113] This litter also drives nutrient cycling, as its decomposition by microbes and invertebrates releases nitrogen, phosphorus, and other elements back into the soil, sustaining forest productivity and understory growth.^[114] Trees engage in complex belowground interactions that shape community dynamics. Mycorrhizal networks, formed by fungal hyphae linking tree roots, facilitate the transfer of nutrients like phosphorus and nitrogen between plants, alleviating resource limitations in nutrient-poor soils and modulating competitive hierarchies by favoring connected kin over distant competitors.^[115] Complementing these mutualisms, some trees employ allelopathy, exuding chemicals such as phenolics or terpenoids from roots and leaves to inhibit seed germination and growth of neighboring plants, thereby reducing competition for light, water, and space in dense forest understories.^[116]

Human Interactions

Timber and Fuel Uses

Trees have been a primary source of timber for construction and other structural applications due to the inherent properties of wood, such as strength and durability. For instance, oak wood is renowned for its high density, exceptional mechanical strength, and resistance to fungal decay and rot, making it ideal for heavy-duty construction like framing and flooring.^[117] These qualities stem from the trunk's anatomical structure, where heartwood provides enhanced longevity and load-bearing capacity compared to sapwood.^[118] Global timber production reached approximately 4 billion cubic meters in 2022, with levels remaining stable into 2023, driven largely by demand for industrial roundwood used in building materials and furniture.^[119] Historically, timber played a crucial role in shipbuilding; ancient Roman galleys, for example, utilized oak for its robustness to construct hulls and frames capable of withstanding maritime stresses.^[120] This reliance on solid timber has evolved into modern engineered wood products, such as laminated veneer lumber (LVL) and cross-laminated timber (CLT), which combine wood strands or veneers under pressure and adhesives to achieve superior strength-to-weight ratios and dimensional stability for contemporary applications like high-rise buildings.^[121] Beyond structural uses, trees provide fuelwood essential for heating and cooking, with more than 2 billion people in developing regions depending on biomass such as wood and charcoal as their primary energy source.^[122] Wood processing begins with sawmilling, where logs are cut into lumber through operations like debarking, sawing, and drying to produce sawn timber for construction.^[123] Further refinement includes plywood production, involving peeling logs into thin veneers, gluing them in cross-grained layers, and pressing to create versatile panels resistant to warping.^[123] To promote sustainability, certifications like the Forest Stewardship Council (FSC) ensure timber harvesting adheres to environmental and social standards, verifying that wood originates from responsibly managed forests.^[124]

Food and Medicinal Uses

Trees provide a variety of edible fruits and nuts that serve as important sources of nutrition worldwide. Apples (Malus domestica), derived from the reproductive structures of apple trees, are a staple fruit rich in vitamins, particularly vitamin C, and dietary fiber, with one medium apple (182g) containing about 95 calories, 4.4g of fiber, and 10% of the daily recommended vitamin C intake.^[125] Global apple production reached approximately 84 million metric tons in 2023, led by major producers like China and the United States.^[126] Similarly, almonds (Prunus dulcis) from almond trees offer healthy fats, protein, and vitamin E; a 1-ounce (28g) serving provides 164 calories, 14g of fat (mostly monounsaturated), 6g of protein, and 7.3mg of vitamin E (48% of daily needs).^[127] World almond production exceeded 4 million metric tons in recent years, with the United States accounting for the majority.^[128] Tree saps and derived products also contribute to food and medicinal applications. Maple syrup, extracted from the sap of sugar maple trees (Acer saccharum), is boiled down to concentrate its natural sugars, yielding a sweetener with antioxidants and minerals like manganese and zinc; it takes about 40 gallons of sap to produce one gallon of syrup.^[129] Natural rubber latex from the rubber tree (Hevea brasiliensis) has biomedical uses, including as a biocompatible material that promotes tissue repair and wound healing by enhancing vasculogenesis and cell recruitment.^[130] Many tree-derived compounds form the basis of modern medicines. Aspirin, or acetylsalicylic acid, originated from salicylic acid in willow bark (Salix spp.), used traditionally for pain relief and fever reduction since ancient times; the bark's analgesic properties were documented over 3,500 years ago by Sumerians and Egyptians.^[131] Quinine, extracted from the bark of cinchona trees (Cinchona spp.), has been a key treatment for malaria since the 17th century, effectively targeting the Plasmodium parasite and reducing fever; it remains a standard therapy for severe cases resistant to other drugs.^[132] Traditional medicinal uses of tree parts persist, particularly among indigenous communities. Birch bark (Betula spp.) has been employed for wound healing due to its betulin content, which accelerates keratinocyte migration and tissue regeneration; clinical studies confirm its efficacy in promoting faster closure of skin wounds without toxicity.^[133]

Ornamental and Cultural Uses

Trees have been cultivated for ornamental purposes in urban and landscape settings to enhance aesthetics, provide shade, and improve environmental quality. In cities, species like the London plane tree (Platanus × acerifolia) are commonly planted along streets due to their tolerance for pollution, compacted soil, and pruning, offering substantial canopy cover in dense environments.^[134]^[135] In landscaping, flowering trees such as Japanese cherry (Prunus serrulata) are prized for their spring blossoms, creating seasonal displays that symbolize renewal and are integrated into parks and gardens for visual appeal.^[136]^[137] Tree shaping involves artistic manipulation of living trees through techniques like pleaching and espalier to form functional or decorative structures. Pleaching, an ancient method dating to medieval Europe, intertwines branches of young trees—often beech or hornbeam—to create living arbors, hedges, or tunnels that provide shaded walkways in gardens.^[138] Espalier uses grafting and pruning to train trees flat against walls or trellises, maximizing space in orchards or formal gardens while promoting fruit production in ornamental contexts.^[139]^[140] A notable modern example is the work of Axel Erlandson, who from the 1920s shaped willows and other species into fantastical forms like baskets and ladders for his "Tree Circus" in California, demonstrating the potential of grafting and bending for sculptural art.^[141] Bonsai, the Japanese art of miniaturizing trees, originated in the 14th century as a refinement of Chinese penjing practices, evolving into a cultural pursuit that mimics ancient, weathered landscapes in small pots. Techniques include selective pruning to control growth, wiring branches to guide shapes, and root reduction to maintain diminutive size, often evoking an aged appearance through careful styling over decades.^[142]^[143] In cultural contexts, trees hold revered status beyond aesthetics, influencing traditions worldwide. In India, sacred groves—forest patches protected as abodes of deities—preserve biodiversity through religious taboos against harm, with species like banyan (Ficus benghalensis) and peepal (Ficus religiosa) central to Hindu rituals and community identity.^[144]^[145] The Christmas tree tradition, rooted in 16th-century German Protestant customs, uses evergreens like firs to symbolize eternal life during winter solstice celebrations, now a global practice involving decorated conifers in homes and public spaces.^[146]^[147]

Threats and Conservation

Environmental Threats

Trees face numerous environmental threats that compromise individual health and entire populations, leading to widespread mortality and ecosystem disruption. Deforestation remains a primary anthropogenic driver, with approximately 10 million hectares of forest lost annually between 2020 and 2025, primarily due to agricultural expansion and commercial logging activities.^[148] This rate, while slightly slowed from previous decades, equates to the destruction of vast woodland areas, reducing habitat availability and carbon sequestration capacity.^[148] Invasive pests and diseases exacerbate these losses by targeting specific species with high lethality. Dutch elm disease, caused by the fungus Ophiostoma novo-ulmi, has killed millions of elm trees across North America and Europe since the 1970s, spreading via bark beetles and vascular blockage that leads to wilting and death.^[149] Similarly, the emerald ash borer (Agrilus planipennis), an invasive beetle from Asia, has destroyed hundreds of millions of ash trees in North America since its detection in 2002, with larvae feeding on inner bark and disrupting nutrient transport, threatening up to 8 billion ash trees overall.^[150] Climate change intensifies tree vulnerability through extreme weather events, particularly prolonged droughts that trigger widespread die-offs. In the U.S. Southwest, a severe drought from 2002 to 2003 caused high mortality in piñon pine (Pinus edulis) populations, with rates exceeding 90% in primary affected areas and 40-80% regionally, impacting more than 1.2 million hectares (12,000 km²) and killing an estimated hundreds of millions of trees.^[151] Additionally, climate change has amplified wildfire risks, with extreme events destroying millions of hectares of forest worldwide and exacerbating tree mortality through direct burning and post-fire effects.^[152] Ongoing effects include elevated mortality rates in drought-prone regions, as rising temperatures reduce water availability and stress tree physiology.^[153] Air and soil pollution further impair tree resilience by altering biochemical processes. Acid rain, resulting from sulfur and nitrogen emissions, damages foliage by leaching essential nutrients like calcium and magnesium, leading to leaf necrosis, reduced photosynthesis, and heightened susceptibility to secondary stressors in high-elevation forests.^[154] Heavy metal contamination in soils, from industrial runoff and mining, inhibits root growth and nutrient uptake in trees, causing stunted development and toxicity accumulation that disrupts enzymatic functions and overall vigor.^[155]

Conservation Strategies

Protected areas form a cornerstone of tree conservation by designating large expanses of land where natural forest processes can occur without human interference. National parks, for example, safeguard old-growth forests that represent mature ecosystems with high biodiversity value. In Yellowstone National Park, United States, approximately 80% of the 8,991 square kilometers is covered by forests, including old-growth stands of lodgepole pine (Pinus contorta) and other conifers, where natural succession and lightning-ignited fires are permitted to maintain ecological integrity.^[156]^[157] Reforestation efforts worldwide focus on reversing tree loss through ambitious planting campaigns. China's Three-North Shelterbelt Forest Program, commonly known as the Great Green Wall, launched in 1978, aims to establish a 4,500-kilometer tree belt across northern regions to combat desertification and soil erosion, with ongoing plantings contributing to increased forest cover from 12% to 18% of the country's land by the early 21st century.^[158] Global initiatives, such as the 1t.org platform coordinated by the World Economic Forum, unite governments, businesses, and organizations to conserve, restore, and grow one trillion trees by 2030, emphasizing sustainable practices to enhance carbon sequestration and habitat restoration across 60 countries.^[159] Legal frameworks provide international mechanisms to regulate trade and incentivize protection of threatened tree species. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) lists Brazilian rosewood (Dalbergia nigra) in Appendix I since 1992, prohibiting commercial international trade to prevent overexploitation for timber.^[160] Complementing this, the Reducing Emissions from Deforestation and Forest Degradation (REDD+) mechanism under the United Nations Framework Convention on Climate Change (UNFCCC) enables developing countries to receive payments through carbon credits for reducing forest emissions and enhancing carbon stocks, supporting sustainable forest management in tropical regions.^[161] Ex situ conservation complements in situ efforts by preserving genetic diversity outside natural habitats. Seed banks store viable seeds under controlled conditions for long-term viability and potential reintroduction. The Millennium Seed Bank at the Royal Botanic Gardens, Kew, United Kingdom, houses nearly 2.5 billion seeds from approximately 40,000 wild plant species, including many trees, as of 2025, facilitating research and restoration amid climate change pressures.^[162]

Cultural and Symbolic Aspects

Mythology and Symbolism

In Norse mythology, Yggdrasil serves as the central World Tree, an immense ash that connects the nine realms of the cosmos, sustaining the universe through its roots, trunk, and branches while embodying the interconnectedness of all existence.^[163] This sacred tree is depicted as alive and vulnerable, with its leaves nourished by a mystical well and its bark gnawed by creatures, symbolizing the fragile balance of cosmic order.^[164] Similarly, in Buddhist tradition, the Bodhi tree (Ficus religiosa) represents enlightenment, as Siddhartha Gautama meditated beneath it in Bodh Gaya, attaining awakening after years of spiritual seeking.^[165] The tree's heart-shaped leaves and serene presence have since been revered as a site of profound transformation, with descendants of the original propagated worldwide to honor this pivotal moment.^[166] Trees hold deep symbolic meanings across cultures, often representing enduring qualities like strength and harmony. In Celtic lore, the oak (Quercus spp.) symbolizes resilience and wisdom, revered by Druids as a sacred emblem of the thunder god Taranis, with its acorns and leaves used in rituals to invoke protection and vitality.^[167] The tree's longevity and sturdy form mirrored the Celts' view of nature's unyielding power, influencing their sacred groves where oaks served as oracles.^[168] In Mediterranean traditions, the olive tree (Olea europaea) embodies peace and reconciliation, its branch extended as a gesture of truce in ancient Greek and Roman customs, rooted in myths where Athena gifted the olive to Athens as a symbol of prosperity and non-violence.^[169] This association persists in religious narratives, including biblical accounts where the olive branch signals divine favor and renewal.^[170] Sacred trees feature prominently in indigenous folklore as conduits to the spiritual world. In various African traditions, the baobab (Adansonia spp.) is viewed as an ancestral dwelling, its massive, hollow trunk believed to house spirits of the departed, serving as a communal gathering site for rituals and storytelling that reinforce cultural identity.^[171] Communities in Senegal and Madagascar regard these ancient giants—some over 1,000 years old—as living histories, with taboos against harming them to preserve harmony with forebears.^[172] Among Native American peoples, particularly the Salish and other Pacific Northwest tribes, the cedar (Thuja plicata) holds sacred status in rituals for purification and protection, its aromatic branches burned as smudge to carry prayers and ward off malevolent forces.^[173] The tree's versatile wood and bark, used in ceremonies for healing and dream invocation, underscore its role as a generous life-giver, often personified in oral traditions as a benevolent guardian.^[173] In modern contexts, trees continue to inspire symbolic interpretations tied to spirituality and ecology. The Tree of Life (Etz Chaim) in Jewish Kabbalah diagrams the sefirot—ten emanations of divine energy—illustrating the flow from infinite potential to earthly reality, a meditative tool for understanding creation and ethical living.^[174] This glyph, drawn from Proverbs and mystical texts, represents interconnected wisdom and the soul's ascent toward unity with the divine.^[175] As an environmental icon, California's Lone Cypress (Cupressus macrocarpa) on the Monterey Peninsula symbolizes resilience against coastal erosion and climate challenges, its solitary stance amid crashing waves photographed millions of times since the 1880s to evoke stewardship of fragile ecosystems.^[176] Protected since 1990, it stands as a emblem of natural endurance, inspiring conservation efforts along the Pacific shoreline.^[177]

Superlative Trees

Trees achieve remarkable extremes in size, age, and form, showcasing the diverse adaptations that enable some species to dominate landscapes for millennia. Among these, certain individuals stand out as record-holders, protected in national parks and forests where their longevity and scale provide insights into environmental resilience. These superlative trees, often measured through rigorous scientific methods, highlight the upper limits of arboreal growth and survival. The tallest known living tree is Hyperion, a coast redwood (Sequoia sempervirens) standing at 115.92 meters in Redwood National Park, California. Discovered in 2006 by naturalists Chris Atkins and Michael Taylor, Hyperion's height surpasses other redwoods, with its crown reaching depths that challenge structural limits of wood and water transport.^[178] Its precise location remains undisclosed to prevent human impact, underscoring the vulnerability of such giants. For longevity, bristlecone pines (Pinus longaeva) in the arid White Mountains of California represent verified extremes among non-clonal trees, with Methuselah confirmed at approximately 4,855 years old via core samples taken in 1957 (initially dated over 4,789 years). Located in the Inyo National Forest, Methuselah's gnarled, resilient form endures extreme conditions through dense wood and minimal metabolic demands.^[179] A candidate for the oldest non-clonal tree is the Gran Abuelo (Alerce Milenario), a Patagonian cypress (Fitzroya cupressoides) in Chile, estimated at 5,000–5,500 years old based on partial core samples and modeling as of 2022, though not fully verified due to conservation concerns.^[180] By volume, the General Sherman giant sequoia (Sequoiadendron giganteum) in Sequoia National Park holds the record at 1,487 cubic meters, equivalent to 52,508 cubic feet of trunk wood. Measured using standardized dendrometric techniques, this tree's massive base—over 11 meters in diameter—continues to add volume at about 1 cubic meter annually, far outpacing other species in biomass accumulation. Planted around 2,300–2,700 years ago, General Sherman exemplifies sequoia growth in the Sierra Nevada's stable, fire-adapted ecosystems.^[181] Unique trees further illustrate extremes, such as baobabs (Adansonia digitata) with enormous trunks that store water in savanna environments. The Sunland Baobab in Limpopo Province, South Africa, featured a hollowed interior converted into a wine cellar and bar, accommodating up to 20 people within its 47-meter circumference and 22-meter height; estimated at 1,000–6,000 years old, it symbolized human adaptation to natural forms before structural damage led to its closure in 2013 and eventual death in 2017.^[182] In contrast, clonal colonies blur individual boundaries, as seen in Pando, a quaking aspen (Populus tremuloides) in Utah's Fishlake National Forest comprising about 47,000 genetically identical stems connected by a single root system across 106 acres, forming the world's largest organism by mass at over 6,000 metric tons. This clone, estimated at 16,000 to 80,000 years old based on a 2024 genetic study, demonstrates asexual reproduction's role in forest persistence amid disturbances.^[183]^[184]

References

[1]
What is a Tree? | Forestry - Utah State University Extension
Though no scientific definition exists to separate trees and shrubs, a useful definition for a tree is a woody plant having one erect perennial stem (trunk) at ...
[2]
Chapter 4: Botany of Trees – Tree Steward Manual
The definition of a tree is a woody perennial plant, typically having a single stem or trunk, growing to a considerable height and having lateral branches at ...
[3]
Anatomy of a tree | US Forest Service
Anatomy of a tree ... A: The outer bark is the tree's protection from the outside world. Continually renewed from within, it helps keep out moisture in the rain, ...
[4]
We need trees and here's why… | - Purdue University
Mar 18, 2020 · They improve our quality of life by providing food, cleaner air and water, regulating temperatures, supporting pollination and providing ...
[5]
Benefits of Trees and Vegetation | US EPA
May 27, 2025 · Reduced energy use and lower greenhouse gas emissions. Trees and vegetation that directly shade buildings decrease demand for air conditioning.
[6]
Chapter 7: Trees and Ecology – Tree Steward Manual
Trees are water regulators, intercepting and absorbing rainfall, removing particulates from rainfall, transpiring water back into the atmosphere, softening the ...
[7]
What is the botanical definition of a tree? - Biology Stack Exchange
Aug 4, 2021 · In botany, a tree is a perennial plant with an elongated stem, or trunk, supporting branches and leaves in most species. In some usages, the ...
[8]
Vascular Cambium: The Source of Wood Formation - PMC
Aug 18, 2021 · Wood (secondary xylem) is derived from vascular cambium, and its formation encompasses a series of developmental processes.
[9]
Maximum tree lifespans derived from public-domain ... - NIH
Feb 3, 2023 · Maximum tree ages exceeded 1,000 years for several species (22), all of them conifers, whereas angiosperm longevity peaked around 500 years.
[10]
Tree - Etymology, Origin & Meaning
Tree originates from Old English treo, meaning a perennial plant with a self-supporting stem; from Proto-Germanic *trewam and PIE *deru-, meaning firm or ...
[11]
Shrubs and trees - The Arboretum
A tree is a perennial woody plant with a single main stem. A shrub is a woody plant with multiple stems or is small. Examples include Ribes speciosum and ...
[12]
What Is a Shrub? Shrubs vs. Bushes, Trees, and More - The Spruce
May 6, 2025 · Trees have one trunk acting as a "stem" from which branches grow, while shrubs have multiple stems that originate from the same root base.<|control11|><|separator|>
[13]
Lab 9 - Gymnosperms and Angiosperms - Tulane University
Gymnosperms are seed plants with a seed coat, while angiosperms are flowering plants that rapidly dominated gymnosperms. Gymnosperms are a pale remnant, while ...
[14]
Chapter 5: Tree Taxonomy, Identification, and Measurement
At that point, plants are separated into gymnosperms (non-flowering plants that produce naked seeds not enclosed in an ovary) and angiosperms (flowering plants ...
[15]
Angiosperms vs Gymnosperms | The Garden Scoop - Illinois Extension
Jan 23, 2021 · Angiosperms have specialized seeds in flowers/fruits, while gymnosperms have naked seeds in cones. Angiosperms are more diverse, with 300,000- ...Missing: classification | Show results with:classification
[16]
[PDF] Beyond pine Cones: An Introduction to Gymnosperms
In compari- son, the angiosperms have ovules that are pro- tected by a layer of tissue called a carpel. The word gymnosperm comes from ancient Greek and means “ ...
[17]
Hardwood or Hard Wood? - Penn State Extension
Mar 31, 2025 · Hardwoods have a much more complex structure than softwoods but the main the difference is hardwood contains pores or vessels while softwoods do not.
[18]
[PDF] Wood Identification for Hardwood and Softwood Species Native to ...
Oaks, maples, birches and fruit trees are examples of hardwood trees. Softwood trees are conifers (evergreens), have needles or scale-like foliage and are not.
[19]
Forest Products Terminology - Ohioline - The Ohio State University
Jan 30, 2013 · Hardwood—wood containing vessels, or pores, produced from broad-leaved tree species. The term hardwood is not an indication of the hardness of ...<|control11|><|separator|>
[20]
Compare and Contrast deciduous and evergreen tree leaves to aid ...
Sep 8, 2008 · Deciduous leaves fall in the fall, while evergreen leaves stay green year-round. Deciduous leaves have different shapes, sizes, edges, and vein ...
[21]
[PDF] Tree and Leaf Identification | UGA Extension
Leaves are the best way to identify trees. Consider if leaves are simple or compound, margins smooth or rough, and if they are deciduous or evergreen.
[22]
Not All Conifers are Evergreen - Arnold Arboretum
Jan 6, 2016 · While most conifers are evergreen, some, like larches, bald cypress, golden larch, dawn redwood, and water pine, are deciduous, losing leaves ...
[23]
Winter Tree ID – Part 1 – Evergreens - BYGL (osu.edu)
Jan 21, 2022 · Obviously, evergreens are easier, since they retain their needles or leaves. Deciduous or woody ornamentals can present a greater challenge, ...Missing: classification | Show results with:classification
[24]
Monocot_vs_Dicot - Organismal Biology
Jul 21, 2017 · Monocots have a single cotyledon and long and narrow leaves with parallel veins. Their vascular bundles are scattered. Their petals or flower parts are in ...
[25]
5.2 Inside Stems – The Science of Plants
Dicots typically have a pith while monocots do not. Why? Could you distinguish between a monocot and dicot stem based on the arrangement of the vascular bundles ...
[26]
plants and their structure ii
Dicot stems have their vascular bundles in a ring arrangement. Monocot stems have most of their vascular bundles near the outside edge of the stem.
[27]
[PDF] The Shoot System I: The Stem - PLB Lab Websites
Dicot stems and monocot stems are usually different. Dicot stems tend to have vascular bundles distributed in a ring, whereas in monocot stems they tend to be.
[28]
3.3 Roots – The Science of Plants
Fibrous root systems begin the same as tap root systems…with a radicle growing from the seed. However, after a period of early growth, the radicle or primary ...
[29]
Tree Anatomy 101 - Natural Resources - Iowa State University
Mar 1, 2019 · Tree size ranges from a few feet in height and width to more than 100 feet tall and wide for the largest tree in Iowa. Tree tops are visible and appreciated.Missing: definition | Show results with:definition
[30]
The Tree Underground - Iowa State University Extension and Outreach
The roots of young seedling trees are often classified as either having a tap root (most oaks, walnut and hickory) or having a fibrous root system (maples, ash ...
[31]
[PDF] The Root System - PLB Lab Websites
The principal functions of roots are absorption of water and nutrients, conduction of absorbed materials into the plant body, and anchorage of the plant in the ...
[32]
Measuring plant root health by scanning leaves with X-ray device
Mar 25, 2024 · This absorption occurs primarily through root hairs, tiny extensions that increase the root's surface area and efficiency in nutrient uptake.<|control11|><|separator|>
[33]
Root morphology and mycorrhizal symbioses together shape ...
Jul 18, 2016 · Roots of nearly all plants cooperate with mycorrhizal fungi in nutrient acquisition. Most tree species form symbioses with either arbuscular ...
[34]
Mycorrhizal Fungi | Oklahoma State University - OSU Extension
Mycorrhiza, which means “fungus-root,” is defined as a beneficial, or symbiotic relationship between a fungus and the roots of its host plant. This relationship ...
[35]
[PDF] Mycorrhizae in forest tree nurseries
Mycorrhizae are symbiotic fungus root associations. The colonization of roots by mycorrhizal fungi can benefit the host by improving nutrient and water.
[36]
Root Systems Research for Bioinspired Resilient Design: A Concept ...
Apr 26, 2021 · Root systems are multifunctional, resilient, biological structures that offer promising strategies for the design of civil and coastal infrastructure.
[37]
Mangroves | Smithsonian Ocean
a closeup of many mangrove pneumatophores. Pneumatophores have small pores called lenticels that cover their surface and allow oxygen to enter the root system.
[38]
Adaptations – South Florida Aquatic Environments
Oct 3, 2018 · During low tides, air is taken up through open passages in the pneumatophores and transported to living root tissues. Mangrove seedlings © ...
[39]
Species: Prosopis glandulosa - USDA Forest Service
... system of lateral roots often extends up to 60 feet (18 m) away from the plant base [9,43,64,81,163]. Lateral roots of a 19.7 foot (6 m) tall honey mesquite ...
[40]
Plant Development II: Primary and Secondary Growth
This interior, nonfunctional xylem is called heartwood. The newer, functional xylem is called sapwood. A new layer of phloem is added each year toward the ...
[41]
How Trees Grow, Part II - UNH Extension
Jan 24, 2025 · The vascular cambium produces conductive material (xylem and phloem) that moves water and nutrients throughout the tree, and the cork cambium ...
[42]
[PDF] BARK STRUCfURE OF SOUTHERN UPLAND OAKS!
The innennost periderm is the boundary between inner and outer bark. In outer bark (rhytidome), areas of collapsed, dead phloem are enclosed by periderm layers.
[43]
The utilization of tree bark - BioResources
The tissue that characteristically splits and develops in this way, thickening over time, is called rhytidome. The most external layers can break off from the ...
[44]
Giant Sequoias and Fire - National Park Service
Their thick, spongy bark insulates most trees from heat injury, and the branches of large sequoias grow high enough to avoid the flames of most fires. Also, ...
[45]
Tracking resilience of giant sequoias after wildfires | US Forest Service
Aug 9, 2022 · Their fire-resistant bark grows upwards of two feet thick, helping to protect the inner core of the trunk that transports water and ...
[46]
3.1 Leaves – The Science of Plants
Simple leaves have uninterrupted leaf margins. The leaf may have lobes like the oak leaf, but the blade has one continuous margin. The venation differs in the ...
[47]
Identification of Common Trees of North Carolina
Dec 9, 2022 · The basic parts of a simple leaf include the blade, the petiole, margin, base, apex, mid-rib, and veins (Figure 1). A leaf that is a compound ...Missing: morphology | Show results with:morphology
[48]
Plant Identification
Leaves may have a single undivided blade or a blade that is divided into parts. Simple leaves have only one leaf blade, with or without a stalk or petiole.<|control11|><|separator|>
[49]
[PDF] Plant Structures: Leaves - Colorado Master Gardener
Leaf Types [Figure 3]. Simple – Leaf blade is one continuous unit (cherry, maple, and elm). Compound – Several leaflets arise from the same petiole.
[50]
[PDF] Overall equation for photosynthesis
Main concepts: •Overall equation for photosynthesis: 6 CO2 + 6 H2O --> C6H12O6 + 6 O2. •Photosynthetic organisms are autotrophs (also called producers), ...
[51]
The process of photosynthesis - Student Academic Success
In the Calvin cycle, ATP and NADPH are converted back to ADP +Pi and NADP+, respectively, which can be returned to the light-dependent reactions.
[52]
Coniferous Biome - Fullerton Arboretum | CSUF
Leaves. Tough, waxy surface to reduce water loss; Scale-like, awl-shaped, linear-shaped, single needles, bundled needles, and clustered needles ; Roots. Shallow ...
[53]
[PDF] Temperate Coniferous Forests
Conifers are well adapted to arid and cold conditions. The surfaces of needle-shaped leaves are protected by waxes and sunken stomata and a large proportion of ...
[54]
Temperate Forest Biome - KDE Santa Barbara
In the summer their broad green leaves capture sunlight and help the trees make food through photosynthesis. As temperatures cool in the fall, the ...Missing: light | Show results with:light
[55]
Gas exchange: Stomata & transpiration - csbsju
Jan 20, 2004 · Simply put, as the plant looses water, the turgidity of the leaf cells, including guard cells, decreases and this results in stomatal closure.Missing: tree | Show results with:tree
[56]
Water Transport in Plants: Xylem | Organismal Biology
Transpiration (evaporation) occurs because stomata in the leaves are open to allow gas exchange for photosynthesis. As transpiration occurs, evaporation of ...
[57]
11.1 Plants and Water – The Science of Plants
When these stomata are open, water vapor exits. We often refer to stomata as associated with gas exchange in the leaves because of the movement of these ...
[58]
Gymnosperms - OpenEd CUNY
Gymnosperms are heterosporous seed plants that produce naked seeds. They appeared in the Paleozoic period and were the dominant plant life during the Mesozoic.<|control11|><|separator|>
[59]
Seed Plants: Angiosperms – Introductory Biology
The vivid colors of flowers are an adaptation to pollination by insects and birds. ... flowers contain the same structures: sepals, petals, pistils, and stamens.
[60]
Gymnosperms – Biology - UH Pressbooks
Gymnosperms, meaning 'naked seeds,' are seed plants with exposed seeds, separate male and female gametes, and wind pollination. They are heterosporous.
[61]
Seed Plants: Gymnosperms – Introductory Biology
Pine trees are conifers and carry both male and female sporophylls on the same plant. Like all gymnosperms, pines are heterosporous and produce male microspores ...
[62]
Reproductive plant parts - OSU Extension Service
As a plant's reproductive part, a flower contains a stamen (male flower part) or pistil (female flower part), or both, plus accessory parts such as sepals, ...Missing: angiosperm | Show results with:angiosperm
[63]
Pollination Mechanisms and Plant-Pollinator Relationships
Mar 1, 2017 · Pollination is the first step in sexual reproduction of seed plants. Most angiosperms have perfect flowers, but some produce imperfect flowers.
[64]
Pollination and Fertilization - OpenEd CUNY
Double fertilization in angiosperms involves one sperm fertilizing the egg to form a zygote, and another fertilizing the central cell to form the endosperm.
[65]
Plant Reproduction | Organismal Biology
Double Fertilization: the Embryo and the Endosperm The phenomenon of double fertilization, or two fertilization events, is unique to angiosperms and does not ...
[66]
8.1 Fruit Morphology – The Science of Plants
An aggregate fruit is from one flower with many ovaries, and the multiple fruit is made up of multiple flowers. Fruit types. Fruits are also categorized ...
[67]
3. Botany | NC State Extension Publications
Feb 1, 2022 · In a monocot stem, the xylem and phloem are paired into discrete vascular bundles; these bundles are scattered throughout the stem like a ...
[68]
[PDF] Chapter 6 Plant Life Cycle: Fruits and Seeds
The apple, a simple, fleshy, accessory fruit. Page 18. The pineapple is an example of a multiple fruit: the fruit is derived from the fusion of an entire.
[69]
Chapter 3- Basic Botany, Plant Physiology, and Plant Classification
Monocots have bundles of vascular tissue containing both xylem and phloem throughout the root. Dicots have xylem surrounded by phloem with cambium in between.
[70]
The Chill-Out is over for our landscapes - Forestry - Purdue University
Mar 19, 2020 · The tree must rely on stored carbohydrate reserves in its woody parts such as stems and branches to grow. ... spring flush or during the summer ...
[71]
What Causes a Tree to Enter and Exit Dormancy?
Apr 7, 2023 · Dormancy begins with the shortening of days and the increased amount of time tree phytochromes remain inactive. Following this, the tree begins ...
[72]
Do Trees Have Hormones? - Penn State Extension
Apr 10, 2023 · Gibberellins are hormones that act in flowering and stem elongation as well, but also promote leaf elongation and phloem activity. Cytokines ...
[73]
Plant Hormones and Sensory Systems | Organismal Biology
Auxins are the main hormones responsible for cell elongation in phototropism (movement in response to light) and gravitropism (movement in response to gravity) ...
[74]
Insolation and photoperiodic control of tree development near the ...
At temperate latitudes, rising spring temperatures cause bud break of these species, but in subtropical Mexico their new leaves emerge concurrently with those ...
[75]
Chapter 14: The Development of Seeds – Inanimate Life
A seed consists of three components: an embryonic sporophyte plant, a tissue that provides nutrition to that embryo, and a 'seed coat', the container tissue in ...
[76]
[PDF] Seed Biology - USDA Forest Service
Endosperm tissue is triploid (3N) and functions as a source of nutrients available to the growing embryo and, in some species, to the young seedling that ...
[77]
[PDF] Seed Science
The seed coat is a protective covering over the entire seed to protect the embryo. The cotyledon is a “seed leaf ” that usually stores food for the embryo ...
[78]
Germination: Seed Dormancy | College of Agricultural Sciences
There are two different categories of seed dormancy: exogenous and endogenous (Scarification). Exogenous dormancy is caused by conditions outside of the seed's ...
[79]
Seed dormancy revisited: Dormancy‐release pathways and ...
Jan 13, 2023 · Digestion appears to scarify certain seeds via acid conditions in the gut, as inorganic acids may be effective in dormancy release among hard ...INTRODUCTION · DORMANCY CLASSES AND... · INTERACTIONS BETWEEN...
[80]
2.2 Introduction to Seed Germination – The Science of Plants
Germination begins with activation by water uptake. We call this imbibition, and sometimes the seed or fruit requires special treatment for water to get into ...
[81]
An Updated Overview on the Regulation of Seed Germination - PMC
Germination encompasses the events from imbibition to radicle protrusion through the seed coverings. In the field, the spatial pattern of seed dispersal depends ...
[82]
4.6.4: Germination - Biology LibreTexts
Jul 28, 2025 · Common environmental requirements include light, the proper temperature, presence of oxygen, and presence of water. Seeds of small-seeded ...
[83]
Seed dispersal: 5 ways trees spread their seeds - Woodland Trust
Aug 23, 2019 · Allochory: spreading seeds with outside help · By animals (known as zoochory) · By wind (known as anemochory) · By water (known as hydrochory).
[84]
Fruit & Seed Dispersal - Digital Atlas of Ancient Life
Mar 10, 2020 · Wind dispersal (anemochory) Fruits and seeds that are wind-dispersed frequently have modifications that help slow their descent to the ground ...Introduction · Animal Dispersal (zoochory) · Dispersal By Ingestion...
[85]
Global warming could shorten the seed lifespan of pioneer tree ...
Dec 2, 2023 · In the case of Populus tremula, complete loss of seed viability lasted 7 days (40 °C moist), 42 days (15 °C moist), and 63 days (25 °C moist).
[86]
Assessing Extreme Seed Longevity: The Value of Historic Botanical ...
The longest-lived example of a viable seed of known age is the date palm, Phoenix dactylifera L., of which an estimated 2000-year-old seed was germinated in ...
[87]
The Devonian Period
The progymnosperm Archaeopteris (see photo above) was a large tree with true wood. It was the oldest known tree until the 2007 identification of Wattieza in ...
[88]
The Origin and Early Evolution of Roots - PMC - PubMed Central - NIH
Roots were an early development in plant life, evolving on land during the Devonian Period, 416 to 360 million years ago.
[89]
Devonian Period: Climate, Animals & Plants | Live Science
Feb 22, 2014 · By the end of the Devonian, progymnosperms such as Archaeopteris were the first successful trees. Archaeopteris could grow up to 98 feet (30 ...
[90]
Archaeopteris trees at high southern latitudes in the late Devonian
Archaeopteris trees inferred to be in excess of 20 m height, the first demonstration of forest stature at high latitudes in the Devonian.
[91]
Unique growth strategy in the Earth's first trees revealed in silicified ...
Oct 23, 2017 · Below and above the dichotomies of primary xylem plates, normal concentric growth of secondary xylem around the primary xylem plates is observed ...
[92]
An early origin of secondary growth: Franhueberia gerriennei gen. et ...
Apr 1, 2013 · Secondary growth evolved in several lineages in the Devonian, but only two occurrences have been reported previously from the Early Devonian.
[93]
A Simple Type of Wood in Two Early Devonian Plants - ResearchGate
Aug 6, 2025 · The advent of wood (secondary xylem) is a major event of the Paleozoic Era, facilitating the evolution of large perennial plants.
[94]
Giant cladoxylopsid trees resolve the enigma of the Earth's earliest ...
Apr 19, 2007 · Late Middle Devonian fossil tree stumps, rooted and still in life position, discovered in the 1870s from Gilboa, New York, and later named Eospermatopteris.Missing: cladoxylopsids | Show results with:cladoxylopsids
[95]
A new phylogeny of the cladoxylopsid plexus
Oct 19, 2021 · Cladoxylopsids formed Earth's earliest forests and gave rise to the ancestors of sphenopsids and ferns. Lower Devonian (Emsian) strata of the ...
[96]
Carboniferous plant physiology breaks the mold - Wiley Online Library
Apr 8, 2020 · Recent work has suggested that biomes during the Carboniferous Period contained plants with extraordinary physiological capacity to shape their environment.
[97]
Angiosperms versus gymnosperms in the Cretaceous - PNAS
Nov 13, 2020 · However, conifers were a dominant and widespread component of the Earth's flora in the Mesozoic, especially in Triassic and Jurassic times (250 ...Angiosperms Versus... · Total Citations7 · Other Plant Groups
[98]
Pollination of Cretaceous flowers - PMC - NIH
Nov 11, 2019 · Since Darwin, insect pollination was thought to be a key contributor to the Cretaceous radiation of angiosperms. Both insects and angiosperms ...Discussion · Fig. 2 · Systematic Descriptions And...
[99]
Testing the benefits of early vessel evolution - PMC - NIH
Jun 28, 2019 · They showed that the vessel elements in angiosperms are unique in being short and wide, compared to the narrow tracheids of gymnosperms and ...Missing: broad | Show results with:broad
[100]
The Angiosperm Terrestrial Revolution and the origins of modern ...
Oct 26, 2021 · Insect pollination may have been widespread in Mesozoic seed plants based on diverse evidence such as fossil insects with long probosces ( ...
[101]
Evolution of angiosperm seed disperser mutualisms: the timing of ...
Dec 20, 2014 · This review synthesizes evidence pertaining to key events during the evolution of angiosperm–frugivore interactions and suggests some implications of this ...
[102]
https://onlinelibrary.wiley.com/doi/10.1111/brv.12164
[103]
Temperate Deciduous Forests - NatureWorks - New Hampshire PBS
Temperate deciduous forests can be found in the eastern part of the United States and Canada, most of Europe and parts of China and Japan.<|separator|>
[104]
Region effects influence local tree species diversity - PNAS
The local tree taxonomic diversity of the 47 plots included in this study showed a clear global pattern, exhibiting the typical latitudinal gradient of ...Abstract · Sign Up For Pnas Alerts · Results
[105]
Montane Forest Vegetation in the Southwest - National Park Service
Oct 5, 2016 · Similar to mixed conifer forest at low elevation, but primarily Engelmann spruce, subalpine fir, and blue spruce at high elevation. Quaking ...
[106]
UN report: Five charts showing how global deforestation is declining
Oct 24, 2025 · In total, around 489Mha of forest have been lost due to deforestation since 1990, the new report finds. Most of this – 88% – occurred in the ...
[107]
Global Forest Resources Assessment 2025
It finds that, although the rate of deforestation is slowing, forests are still being lost at nearly 11 million hectares per year. The area of planted forests ...
[108]
[PDF] Epiphyte Biodiversity in the Coffee Agricultural Matrix: Canopy ...
Epiphytes colonize canopy trees and provide resources for birds and insects and thus effects of agricultural production on epiphytes may affect other species.
[109]
[PDF] Considering Ecological Processes in Environmental Impact ...
In tropical communities, fig trees are keystone species. Each of the approximately 800 fig tree species depends on a unique tiny wasp for pollination. If ...
[110]
Quantifying Carbon Fluxes in Forests | Global Forest Watch Blog
Jan 21, 2021 · In other words, forests provide a “carbon sink” that absorbs a net 7.6 billion metric tonnes of CO2 per year, 1.5 times more carbon than the ...Missing: Gt | Show results with:Gt
[111]
[PDF] Stormwater to Street Trees: Engineering Urban Forests for ...
❖ Reduced Throughfall—Tree canopies reduce soil erosion by diminishing the volume and velocity of rainfall as it falls through the canopy, lessening the impact ...
[112]
https://www.epa.gov/sites/default/files/2015-11/documents/stormwater2streettrees.pdf
[113]
FS1369: Why Leave the Leaves and How to Do it (Rutgers NJAES)
Weed Suppression by leaf litter blocks sunlight from reaching weed seeds, thus reducing competition for resources like water and nutrients. Erosion control is ...
[114]
How mycorrhizal associations drive plant population and community ...
Feb 21, 2020 · Complex networks of mycorrhizal hyphae connect the root systems of individual plants, regulating nutrient flow and competitive interactions ...
[115]
Plant neighbor detection and allelochemical response are driven by ...
Sep 24, 2018 · These findings suggest that root-secreted (-)-loliolide and jasmonic acid are involved in plant neighbor detection and allelochemical response.
[116]
Hardwood Timber: Oak Wood Uses & Properties — W.L West & Sons
It is extremely strong, dense, durable and resistant to fungal attacks, which makes it less prone to decay and rotting. Oak is considered one of the finest and ...
[117]
[PDF] Mechanical Properties of Wood - Forest Products Laboratory
Many of the mechanical properties of wood tabulated in this chapter were derived from extensive sampling and analysis procedures. These properties are ...
[118]
Global wood production is at record levels, at about 4 billion m³ per ...
Global wood production is at record levels, about 4 billion m³ per year, with 4.01 billion cubic meters in 2022.
[119]
Boat Building - The Roman Seas
The timber used by the ancient races on the shores of the Mediterranean in the construction of their ships appears to have been chiefly fir and oak; but, in ...
[120]
Engineered Wood - an overview | ScienceDirect Topics
Engineered wood products such as wood I-joists (far left), laminated strand lumber (left, right), laminated veneer lumber (center), and parallel strand lumber ( ...
[121]
Access to clean cooking – SDG7: Data and Projections - IEA
More than 2 billion people lack access to clean cooking facilities, relying on the traditional use of solid biomass, kerosene, or coal as their primary cooking ...
[122]
1. Descriptions of manufacturing processes
Sawmilling is a less sophisticated activity of the mechanical forest industries. It implies a certain number of operations from handling and transportation of ...
[123]
Forest Stewardship Council: Home
As the leader in sustainable forestry, FSC is trusted to protect forests for all, forever. ... Ensure the long-term health and viability of your forest with FSC ...What the FSC Labels Mean · Wood · FSC Public Certificate Search · FSC Standards
[124]
Apples - SNAP-Ed Connection - USDA
Washington Apple Commission. Nutrition Information. Serving Size: 1 medium apple ( 182g). Show Full Display. Nutrient, Amount. Total Calories, 95. Total Fat, 0 ...
[125]
Production - Apples - USDA Foreign Agricultural Service
10 Year Average MY 2015-2024. 79.15 Million Metric Tons ; 10-Year Compound Average Growth. 1% MY 2015-2024 ; 2023/2024. Production. 84.32 Million Metric Tons.
[126]
Calories in Nuts, almonds - 1 oz (23 whole kernels) from USDA
Feb 22, 2016 · One ounce (23 whole kernels) of almonds contains 164 calories, 14g total fat, 6.1g total carbohydrates, 3.5g fiber, 1.2g sugars, and 6g protein.
[127]
Almond Kernel production and top producing countries - Tridge
In 2023, United States was the largest producer of Almond Kernel, followed by Spain, Australia, Turkiye, Morocco, Syria, Iran, Italy, Tunisia, Algeria.
[128]
https://www.tridge.com/intelligences/almond-in-shell/production
[129]
Biomedical applications of natural rubber latex from the ... - PubMed
Apr 22, 2021 · A natural polymer that is biocompatible and has been proved as inducing tissue repair by enhancing the vasculogenesis process, guiding and recruiting cells ...
[130]
The aspirin story - from willow to wonder drug - PubMed
The story of the discovery of aspirin stretches back more than 3500 years to when bark from the willow tree was used as a pain reliever and antipyretic.
[131]
Evaluating Cinchona bark and quinine for treating and preventing ...
Numerous medical observations and case reports from all over the world soon indicated that quinine was specific for 'malarial' (intermittent) fevers. Treatment ...
[132]
understanding the clinically proven wound healing efficacy of birch ...
Jan 22, 2014 · Our results, together with the clinically proven efficacy, identify birch bark as the first medical plant with a high potential to improve wound healing.
[133]
Drivers of street tree species selection: The case of the London ...
The London planetree (or London plane in the UK: Platanus × hispanica) is one of the most common street trees in the world.
[134]
Platanus x acerifolia | Portland.gov
This tree is in a courtyard adjacent to the street. Platanus x acerifolia -- London Planetree View full size image of Platanus x acerifolia -- London Planetree.
[135]
Prunus serrulata - North Carolina Extension Gardener Plant Toolbox
The Japanese cherry tree flowers best in full sun and prefers moist, well-drained, loamy soils. Provide good air circulation to reduce the risk of disease. This ...
[136]
Ornamental Cherry, Plum, Apricot & Almond - Clemson HGIC
Jul 24, 2019 · Landscape Use: Flowering cherries are mainly used as lawn specimens, street trees and in groupings. Wide, spreading trees work well as shade ...
[137]
[PDF] Urban Forestry Outreach, Research & Extension Nursery and Lab ...
Jan 5, 2016 · throughout history and is documented to have been used in medieval times. Pleaching creates a natural arc out of trees or shrubs and in the ...
[138]
Espalier - Wisconsin Horticulture
This horticultural technique trains woody trees or shrubs through pruning and tying to create two-dimensional plants, often in specific patterns. Because a ...
[139]
Grafting & Espalier | NC Historic Sites
Two pieces of young wood of similar size produce the best graft. To be successful each growth must be cut cleanly and evenly, producing smooth, flat surfaces.
[140]
[PDF] Arborsculpture - Department of Human Ecology
Throughout history, no other figure went so far in demonstrating the tree's potential as Axel Erlandson and his ... Erlandson to begin shaping his own trees.
[141]
▷ History of Bonsai Trees - VirginiaBonsai.org
By the fourteenth century bonsai was indeed viewed as a highly refined art ... Bonsai techniques such as raising trees from seed or cuttings and the ...Missing: 14th | Show results with:14th
[142]
What Is Bonsai? | Virtual Culture | Kids Web Japan
The word "bonsai" was first used in a mid-14th century poem, but earlier bonsai culture can be seen in picture scrolls dating as far back as 1309. It became ...Missing: history | Show results with:history
[143]
Sacred Groves, the secret wizards of conservation - Blog | IUCN
Aug 28, 2023 · These wilderness areas hold deep religious and spiritual meaning to Indian Hindu indigenous communities. In Hinduism, it is believed that nature ...
[144]
The Spiritual, Socio-Cultural and Ecological Status of Sacred Groves ...
Trees such as banyan, peepal, neem and tamarind are considered to be the abode of spirits and worshipped. In many sacred groves people make offerings to the ...
[145]
History of the Christmas Tree | Arbor Day Foundation
Dec 11, 2019 · The 16th-century Germans started the Christmas tree tradition. The Protestant reformer Martin Luther is credited with adding lighted candles, inspired by the ...
[146]
How did evergreen trees become a symbol for Christmas?
Dec 6, 2016 · The evergreen fir tree has traditionally been used to celebrate winter festivals (pagan and Christian) for thousands of years. · Pagans used ...
[147]
Global deforestation slows, but forests remain under pressure, FAO ...
Oct 21, 2025 · Deforestation and expansion: Deforestation slowed to 10.9 million hectares per year in 2015–2025, down from 17.6 million in 1990–2000. The rate ...
[148]
Dutch Elm Disease - Invasive Species Centre
Ophiostoma novo-ulmi, the more aggressive of the two species, is the most common cause of DED infections today. The fungi spread primarily through several ...
[149]
8 billion North American ash trees at risk from emerald ash borer
Aug 5, 2022 · The EAB (Agrilus planipennis), which attacks all 16 species of ash trees in North America, has killed hundreds of millions of ash trees so far.
[150]
Regional vegetation die-off in response to global-change-type drought
Here, we quantify regional-scale vegetation die-off across southwestern North American woodlands in 2002-2003 in response to drought and associated bark beetle ...
[151]
Climate‐driven tree mortality: insights from the piñon pine die‐off in ...
Sep 18, 2013 · This die-off occurred across 1.2 Mha of the southwestern United States (Breshears et al., 2005) and killed up to 350 million piñon pines ( ...
[152]
Effects of Acid Rain | US EPA
Mar 19, 2025 · At high elevations, acidic fog and clouds might strip nutrients from trees' foliage, leaving them with brown or dead leaves and needles. The ...Effects of Acid Rain on... · Effects of Acid Rain on Materials
[153]
Heavy Metal Polluted Soils: Effect on Plants and Bioremediation ...
Aug 12, 2014 · Plants growing on heavy metal polluted soils show a reduction in growth due to changes in their physiological and biochemical activities.
[154]
Forests - Yellowstone National Park
Apr 18, 2025 · Forests cover roughly 80% of the park. Lodgepole pine, Engelmann spruce, subalpine fir, whitebark pine, and limber pine are found at higher elevations.Lodgepole Pine · Whitebark Pine · Understory Vegetation
[155]
Yellowstone National Park - UNESCO World Heritage Centre
All flora in the park are allowed to progress through natural succession with no direct management being practiced. Forest fires, if started from lightning, are ...Documents · Maps · Gallery · Videos
[156]
China's Great Green Wall | RGS - Royal Geographical Society
The planting of these trees started in 1978 and is due to be completed in 2050. At that time it is estimated the programme's tree belt will stretch for 4500km, ...
[157]
1t.org | Home
A platform for the trillion trees community. Conserving, restoring and growing a trillion trees by 2030 for people, biodiversity and planet.
[158]
Dalbergia nigra - CITES
Dalbergia nigra. Bahia Rosewood, Brazilian rosewood, Jacaranda, Pianowood, Rio Rosewood, Rosewood. Kingdom. Flora. Order. Fabales. Family.
[159]
What is REDD+? - UNFCCC
REDD+ primarily aims at the implementation of activities by national governments to reduce human pressure on forests that result in greenhouse gas emissions.
[160]
Kew's Millennium Seed Bank celebrates 25 years and looks to ...
Oct 20, 2025 · How many seeds? There are nearly 2.5 billion seeds banked at the MSB. How many species? There are approximately 40,000 different species of wild ...
[161]
The Origin and Meaning of the Name Yggdrasill - jstor
Even the world is in the form of the cross. So also the Norse ash-tree Yggdrasill is a symbol of the world. The myth is a fine example of that poetic ...
[162]
Yggdrasil: The Sacred Ash Tree of Norse Mythology
Nov 26, 2019 · A giant ash tree described in both the Poetic Edda and Snorri Sturluson's 13th-century Prose Edda, Yggdrasil stands at the absolute center of the Norse cosmos.
[163]
Bodh Gaya: the site of the Buddha's enlightenment - Smarthistory
Bodh Gaya is understood to be the site of the enlightenment, or “great awakening” (Sanskrit, mahabodhi), of Siddhartha Gautama, the Buddha.Missing: source | Show results with:source
[164]
Buddhist Studies: Primary Level Unit 3. Under the Bodhi Tree
When the Buddha stood up at last, he gazed at the tree in gratitude, to thank it for having given him shelter. From then on, the tree was known as the Bodhi ...
[165]
(PDF) Oak tree symbolism - ResearchGate
Sep 20, 2018 · Oak trees are thought to represent everything that is true. The oldest oracle of Ancient Greece lived. in ; the new faith, and was at the ...
[166]
Oak mythology and folklore | Trees for Life
The word Druid may derive from a Celtic word meaning “knower of the oak tree”. ... They wore crowns of oak leaves, as a symbol of the god they represented as ...
[167]
The Olive Tree and the Rise of Athens - Olive Oil Times
Jan 16, 2024 · Its fruit and oil form the foundation of the Mediterranean diet, and its branches represent peace in Judaism, Christianity and Islam; its iconic ...
[168]
Olive Tree - Centro Laudato Si
The olive tree is a symbol of peace, both religious and pagan. In pagan mythology, it is a tree sacred to Minerva, and a symbol of Athena and the city of Athens ...
[169]
Folklore and Tradition | SpringerLink
The baobabs are an object of folklore and fetish throughout Africa, Madagascar and Australia. Africa is the best documented, although there is a noticeable ...
[170]
Historic baobab trees of Senegal | Eric Ross, academic
Jan 25, 2012 · Some ancient baobabs are true historical landmarks in that they predate human settlement as recorded in oral histories.
[171]
Indigenous Sacred Plants: Red Cedar
As with sweetgrass, cedar is burned during prayers so the smoke will carry the prayers to the Creator. In some First Nations, cedar boughs and sage are mixed ...
[172]
UVM Tree Profiles : Eastern Red Cedar : Native Cultural Significance
The Eastern red cedar has a variety of ethnobotanic uses and is regarded with special spiritual significance in many Native American tribes.
[173]
What is the Tree of Life (Etz Chaim)? - My Jewish Learning
The tree of life as a metaphor for the Torah comes from the Book of Proverbs, which uses the term three times, the most famous of which is the saying in ...
[174]
The tree of life has been a powerful image in Jewish tradition for ...
Jun 20, 2023 · In Jewish Scripture and Jewish thought, the tree of life speaks to fundamental aspects of what it means to be human in the world. In my research ...
[175]
The Lone Cypress Stands Alone - Pebble Beach Resorts
Apr 4, 2017 · Land, tree and ocean were the basis of this development, and therefore The Lone Cypress became the perfect symbol.”Missing: environmental | Show results with:environmental
[176]
California's most photographed tree should be allowed to die
Feb 2, 2025 · SFGATE editor-at-large Andrew Chamings on the Lone Cypress, a symbol of American resilience held up by wires.
[177]
Tallest tree living | Guinness World Records
Tallest tree living ; Who: Hyperion, Coast redwood, Sequoia sempervirens ; What: 116.07 metre(s) ; Where: United States ; When: 2019.
[178]
Methuselah, a Bristlecone Pine is Thought to be the Oldest Living ...
Apr 21, 2011 · Over 4,789 years old, the age of Methuselah was determined by the measurement of core samples taken in 1957. The storied bristlecone pines ...Missing: White Mountains
[179]
The Largest Trees in the World - Sequoia & Kings Canyon National ...
Nov 1, 2024 · The General Sherman Tree is the largest in the world at 52,508 cubic feet (1,487 cubic meters). The General Grant Tree is the second largest at ...
[180]
Baobab | San Diego Zoo Animals & Plants
It was said to be 72 feet (22 meters) tall and 155 feet (47 meters) in girth. The Sunland Baobab died in 2017. AKA. Baobab trees are known by many common names, ...Missing: size guinnessworldrecords.
[181]
https://www.nps.gov/seki/learn/nature/largest-trees-in-world.htm