Tree

Tree

Overview

A tree is a perennial
Perennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...

 woody plant
Woody plant
A woody plant is a plant that uses wood as its structural tissue. These are typically perennial plants whose stems and larger roots are reinforced with wood produced adjacent to the vascular tissues. The main stem, larger branches, and roots of these plants are usually covered by a layer of...

. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk
Trunk (botany)
In botany, trunk refers to the main wooden axis of a tree that supports the branches and is supported by and directly attached to the roots. The trunk is covered by the bark, which is an important diagnostic feature in tree identification, and which often differs markedly from the bottom of the...

 with clear apical dominance
Apical dominance
In plant physiology, apical dominance is the phenomenon whereby the main central stem of the plant is dominant over other side stems; on a branch the main stem of the branch is further dominant over its own side branchlets....

. A minimum height specification at maturity is cited by some authors, varying from 3 m to 6 m; some authors set a minimum of 10 cm trunk diameter (30 cm girth). Woody plants that do not meet these definitions by having multiple stems and/or small size are usually called shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...

s, although many trees such as mallee
Mallee
Mallee may refer to:* Mallee , the habit of woody plants that grow with multiple stems from underground lignotubers* Mallee , a biogeographic region in southern Western Australia...

 do not meet such definitions.
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Encyclopedia

A tree is a perennial
Perennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...

 woody plant
Woody plant
A woody plant is a plant that uses wood as its structural tissue. These are typically perennial plants whose stems and larger roots are reinforced with wood produced adjacent to the vascular tissues. The main stem, larger branches, and roots of these plants are usually covered by a layer of...

. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk
Trunk (botany)
In botany, trunk refers to the main wooden axis of a tree that supports the branches and is supported by and directly attached to the roots. The trunk is covered by the bark, which is an important diagnostic feature in tree identification, and which often differs markedly from the bottom of the...

 with clear apical dominance
Apical dominance
In plant physiology, apical dominance is the phenomenon whereby the main central stem of the plant is dominant over other side stems; on a branch the main stem of the branch is further dominant over its own side branchlets....

. A minimum height specification at maturity is cited by some authors, varying from 3 m to 6 m; some authors set a minimum of 10 cm trunk diameter (30 cm girth). Woody plants that do not meet these definitions by having multiple stems and/or small size are usually called shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...

s, although many trees such as mallee
Mallee
Mallee may refer to:* Mallee , the habit of woody plants that grow with multiple stems from underground lignotubers* Mallee , a biogeographic region in southern Western Australia...

 do not meet such definitions. Compared with most other plants, trees are long-lived, some reaching several thousand years old and growing to up to 115 m (379 ft) high.

Trees are an important component of the natural landscape
Natural landscape
A natural landscape is a landscape that is unaffected by human activity. A natural landscape is intact when all living and nonliving elements are free to move and change. The nonliving elements distinguish a natural landscape from a wilderness. A wilderness includes areas within which natural...

 because of their prevention of erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

 and the provision of a weather-sheltered ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....

 in and under their foliage
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....

. They also play an important role in producing oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 and reducing carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 in the atmosphere, as well as moderating ground temperatures. They are also elements in landscaping
Landscape architecture
Landscape architecture is the design of outdoor and public spaces to achieve environmental, socio-behavioral, or aesthetic outcomes. It involves the systematic investigation of existing social, ecological, and geological conditions and processes in the landscape, and the design of interventions...

 and agriculture
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...

, both for their aesthetic
Aesthetics
Aesthetics is a branch of philosophy dealing with the nature of beauty, art, and taste, and with the creation and appreciation of beauty. It is more scientifically defined as the study of sensory or sensori-emotional values, sometimes called judgments of sentiment and taste...

 appeal and their orchard
Orchard
An orchard is an intentional planting of trees or shrubs that is maintained for food production. Orchards comprise fruit or nut-producing trees which are grown for commercial production. Orchards are also sometimes a feature of large gardens, where they serve an aesthetic as well as a productive...

 crops (such as apple
Apple
The apple is the pomaceous fruit of the apple tree, species Malus domestica in the rose family . It is one of the most widely cultivated tree fruits, and the most widely known of the many members of genus Malus that are used by humans. Apple grow on small, deciduous trees that blossom in the spring...

s). Wood
Wood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...

 from trees is a building material
Building material
Building material is any material which is used for a construction purpose. Many naturally occurring substances, such as clay, sand, wood and rocks, even twigs and leaves have been used to construct buildings. Apart from naturally occurring materials, many man-made products are in use, some more...

, as well as a primary energy source in many developing countries. Trees also play a role in many of the world's mythologies
Mythology
The term mythology can refer either to the study of myths, or to a body or collection of myths. As examples, comparative mythology is the study of connections between myths from different cultures, whereas Greek mythology is the body of myths from ancient Greece...

 (see trees in mythology).

Classification


A tree is a plant form that occurs in many different orders
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 and families
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 of plants. Most species of trees today are flowering plants (Angiosperms) and conifers
Pinophyta
The conifers, division Pinophyta, also known as division Coniferophyta or Coniferae, are one of 13 or 14 division level taxa within the Kingdom Plantae. Pinophytes are gymnosperms. They are cone-bearing seed plants with vascular tissue; all extant conifers are woody plants, the great majority being...

. Trees show a variety of growth forms, leaf type and shape, bark characteristics and reproductive organs. For the listing of examples of well-known trees and how they are classified, see List of tree genera.

The tree form has evolved separately in unrelated classes of plants, in response to similar environmental challenges, making it a classic example of parallel evolution
Parallel evolution
Parallel evolution is the development of a similar trait in related, but distinct, species descending from the same ancestor, but from different clades.-Parallel vs...

. With an estimate of 100,000 tree species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

, the number of tree species worldwide might total 25 percent of all living plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

 species. The majority of tree species grow in tropical regions of the world and many of these areas have not been surveyed yet by botanists, making species diversity and ranges poorly understood.
The earliest tree-like organisms were tree ferns, horsetail
Horsetail
Equisetum is the only living genus in the Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds.Equisetum is a "living fossil", as it is the only living genus of the entire class Equisetopsida, which for over one hundred million years was much more diverse and...

s and lycophytes, which grew in forest
Forest
A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...

s in the Carboniferous
Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...

 period, however these were plants were not trees, since they lacked woody tissue. Trees evolved in the Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...

 period, with conifers, ginkgo
Ginkgo
Ginkgo , also spelled gingko and known as the Maidenhair Tree, is a unique species of tree with no close living relatives...

s, cycad
Cycad
Cycads are seed plants typically characterized by a stout and woody trunk with a crown of large, hard and stiff, evergreen leaves. They usually have pinnate leaves. The individual plants are either all male or all female . Cycads vary in size from having a trunk that is only a few centimeters...

s and other gymnosperm
Gymnosperm
The gymnosperms are a group of seed-bearing plants that includes conifers, cycads, Ginkgo, and Gnetales. The term "gymnosperm" comes from the Greek word gymnospermos , meaning "naked seeds", after the unenclosed condition of their seeds...

s appeared producing woody tissue, and were subsequently followed by tree-form flowering plant
Flowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...

s in the Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...

 period.

A small group of trees growing together is called a grove
Grove (nature)
A grove is a small group of trees with minimal or no undergrowth, such as a sequoia grove, or a small orchard planted for the cultivation of fruits or nuts...

 or copse, and a landscape covered by a dense growth of trees is called a forest
Forest
A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...

. Several biotope
Biotope
Biotope is an area of uniform environmental conditions providing a living place for a specific assemblage of plants and animals. Biotope is almost synonymous with the term habitat, but while the subject of a habitat is a species or a population, the subject of a biotope is a biological community.It...

s are defined largely by the trees that inhabit them; examples are rainforest
Rainforest
Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...

 and taiga
Taiga
Taiga , also known as the boreal forest, is a biome characterized by coniferous forests.Taiga is the world's largest terrestrial biome. In North America it covers most of inland Canada and Alaska as well as parts of the extreme northern continental United States and is known as the Northwoods...

 (see ecozone
Ecozone
An ecozone is the broadest biogeographic division of the Earth's land surface, based on distributional patterns of terrestrial organisms.Ecozones delineate large areas of the Earth's surface within which organisms have been evolving in relative isolation over long periods of time, separated from...

s). A landscape of trees scattered or spaced across grassland (usually grazed or burned over periodically) is called a savanna
Savanna
A savanna, or savannah, is a grassland ecosystem characterized by the trees being sufficiently small or widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of C4 grasses.Some...

. A forest of great age is called old growth forest
Old growth forest
An old-growth forest is a forest that has attained great age , and thereby exhibits unique ecological features. An old growth forest has also usually reached a climax community...

or ancient woodland
Ancient woodland
Ancient woodland is a term used in the United Kingdom to refer specifically to woodland that has existed continuously since 1600 or before in England and Wales . Before those dates, planting of new woodland was uncommon, so a wood present in 1600 was likely to have developed naturally...

(in the UK). A young tree is called a sapling.

Morphology



The parts of a tree are the root
Root
In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...

s, trunk
Trunk (botany)
In botany, trunk refers to the main wooden axis of a tree that supports the branches and is supported by and directly attached to the roots. The trunk is covered by the bark, which is an important diagnostic feature in tree identification, and which often differs markedly from the bottom of the...

(s), branch
Branch
A branch or tree branch is a woody structural member connected to but not part of the central trunk of a tree...

es, twig
Twig
A twig is a small thin terminal branch of a woody plant. Twigs are critically important in identification of trees, shrubs and vines, especially in wintertime. The buds on the twig are an important diagnostic characteristic, as are the abscission scars where the leaves have fallen away...

s and leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....

. Tree stems consist mainly of support and transport tissues (xylem
Xylem
Xylem is one of the two types of transport tissue in vascular plants. . The word xylem is derived from the Classical Greek word ξυλον , meaning "wood"; the best-known xylem tissue is wood, though it is found throughout the plant...

 and phloem
Phloem
In vascular plants, phloem is the living tissue that carries organic nutrients , in particular, glucose, a sugar, to all parts of the plant where needed. In trees, the phloem is the innermost layer of the bark, hence the name, derived from the Greek word "bark"...

). Wood
Wood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...

 consists of xylem cells, and bark
Bark
Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines and shrubs. Bark refers to all the tissues outside of the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner...

 is made of phloem and other tissues external to the vascular cambium. Trees may be grouped into exogenous and endogenous trees according to the way in which their stem
Plant stem
A stem is one of two main structural axes of a vascular plant. The stem is normally divided into nodes and internodes, the nodes hold buds which grow into one or more leaves, inflorescence , conifer cones, roots, other stems etc. The internodes distance one node from another...

 diameter increases. Exogenous trees, which comprise the great majority of trees (all conifer
Pinophyta
The conifers, division Pinophyta, also known as division Coniferophyta or Coniferae, are one of 13 or 14 division level taxa within the Kingdom Plantae. Pinophytes are gymnosperms. They are cone-bearing seed plants with vascular tissue; all extant conifers are woody plants, the great majority being...

s, and almost all broadleaf
Dicotyledon
The dicotyledons, also known as dicots, are a group of flowering plants whose seed typically has two embryonic leaves or cotyledons. There are around 199,350 species within this group...

 trees), grow by the addition of new wood outwards, immediately under the bark. Endogenous trees, mainly in the monocotyledon
Monocotyledon
Monocotyledons, also known as monocots, are one of two major groups of flowering plants that are traditionally recognized, the other being dicotyledons, or dicots. Monocot seedlings typically have one cotyledon , in contrast to the two cotyledons typical of dicots...

s (e.g., aloes
Aloe
Aloe , also Aloë, is a genus containing about 500 species of flowering succulent plants. The most common and well known of these is Aloe vera, or "true aloe"....

 and dragon trees
Dracaena (plant)
Dracaena is a genus of about 40 species of trees and succulent shrubs. In the APG III classification system, it is placed in the family Asparagaceae, subfamily Nolinoideae . It has also formerly been separated into the family Dracaenaceae or placed in the Agavaceae...

), grow by addition of new material as discrete bundles within the existing trunk tissue.

Trees can be identified to genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 or species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 by a combination of the tree's shape, and the characteristics of its bark, leaves, flowers, and fruit. The leaves may be either deciduous
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...

 or evergreen
Evergreen
In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...

.

As an exogenous tree grows, it creates growth rings as new wood is laid down concentrically over the old wood. In species growing in areas with seasonal climate changes, wood growth produced at different times of the year may be visible as alternating light and dark, or soft and hard, rings of wood. In temperate climates, and tropical climates with a single wet-dry season alternation, the growth rings are annual, each pair of light and dark rings being one year of growth; these are known as annual rings. In areas with two wet and dry seasons each year, there may be two pairs of light and dark rings each year; and in some (mainly semi-desert regions with irregular rainfall), there may be a new growth ring with each rainfall. In tropical rainforest
Rainforest
Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...

 regions, with constant year-round climate, growth is continuous and the growth rings are not visible nor is there a change in the wood texture. In species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 with annual rings, these rings can be counted to determine the age of the tree, and used to date cores or even wood taken from trees in the past, a practice known as the science of dendrochronology
Dendrochronology
Dendrochronology or tree-ring dating is the scientific method of dating based on the analysis of patterns of tree-rings. Dendrochronology can date the time at which tree rings were formed, in many types of wood, to the exact calendar year...

. Very few tropical trees can be accurately dated in this manner. Age determination in this manner is also impossible in endogenous trees.

The root
Root
In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...

s of a tree are generally embedded in earth, providing anchorage for the above-ground biomass
Biomass (ecology)
Biomass, in ecology, is the mass of living biological organisms in a given area or ecosystem at a given time. Biomass can refer to species biomass, which is the mass of one or more species, or to community biomass, which is the mass of all species in the community. It can include microorganisms,...

 and absorbing water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 and nutrients from the soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...

. However, while ground nutrients are essential to a tree's growth the majority of its biomass – over 90 percent – comes from carbon dioxide absorbed from the atmosphere (see photosynthesis
Photosynthesis
Photosynthesis is a chemical process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of bacteria, but not in archaea. Photosynthetic organisms are called photoautotrophs, since they can...

). Above ground, the trunk gives height to the leaf-bearing branches, aiding in competition with other plant species for sunlight
Sunlight
Sunlight, in the broad sense, is the total frequency spectrum of electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the Earth's atmosphere, and solar radiation is obvious as daylight when the Sun is above the horizon.When the direct solar radiation is not blocked...

. In many trees, the arrangement of the branches optimizes exposure of the leaves to sunlight.

Not all trees have all the plant organs or parts mentioned above. For example, the saguaro cactus
Saguaro
The saguaro is a large, tree-sized cactus species in the monotypic genus Carnegiea. It is native to the Sonoran Desert in the U.S. state of Arizona, the Mexican state of Sonora, a small part of Baja California in the San Felipe Desert and an extremely small area of California, U.S...

 of North America has no functional leaves. A plant form that is similar to a tree, but generally having smaller, multiple trunks and/or branches that arise near the ground, is called a shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...

. However, no precise differentiation between shrubs and trees is possible. Given their small size, bonsai
Bonsai
is a Japanese art form using miniature trees grown in containers. Similar practices exist in other cultures, including the Chinese tradition of penjing from which the art originated, and the miniature living landscapes of Vietnamese hòn non bộ...

 plants would not technically be "trees", but one should not confuse reference to the form of a species with the size or shape of individual specimens. A spruce seedling does not fit the definition of a tree, but all spruces are trees.

Record breaking trees


The world's champion trees can be rated on height, trunk diameter or girth, total size, and age.

Tallest trees


The heights of the tallest trees in the world have been the subject of considerable dispute and much exaggeration. Modern verified measurements with laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...

 rangefinders, other measuring devices, or with tape drop measurements made by tree climbers (such as those carried out by canopy researchers or members of groups like the U.S. Eastern Native Tree Society), have shown that some older measuring methods and measurements are often unreliable, sometimes producing exaggerations of 5% to 15% or more above the real height. Historical claims of trees growing to 130 m (426.5 ft), and even 150 m (492.1 ft), are now largely disregarded as unreliable, and attributed to human error. Historical records of fallen trees measured prostrate on the ground are considered to be somewhat more reliable. The following are now accepted as the top nine tallest reliably measured species (taken only currently standing specimens):
  1. Coast Redwood (Sequoia sempervirens): 115.56 m (379.1 ft), Hyperion
    Hyperion (tree)
    Hyperion is the name of a Coast Redwood in Northern California that was measured at , which ranks it as the world's tallest known living tree. Despite its great height, Hyperion is not the largest known coast redwood; that distinction belongs to the Lost Monarch tree.Hyperion was discovered August...

    , Redwood National Park, California
    California
    California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

    , United States
    United States
    The United States of America is a federal constitutional republic comprising fifty states and a federal district...

  2. Australian Mountain-ash
    Eucalyptus regnans
    Eucalyptus regnans, known variously by the common names Mountain Ash, Victorian Ash, Swamp Gum, Tasmanian Oak or Stringy Gum, is a species of Eucalyptus native to southeastern Australia, in Tasmania and Victoria...

     (Eucalyptus regnans): 99.6 m (326.8 ft), south of Hobart
    Hobart
    Hobart is the state capital and most populous city of the Australian island state of Tasmania. Founded in 1804 as a penal colony,Hobart is Australia's second oldest capital city after Sydney. In 2009, the city had a greater area population of approximately 212,019. A resident of Hobart is known as...

    , Tasmania
    Tasmania
    Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...

    , Australia
    Australia
    Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

  3. Coast Douglas-fir
    Coast Douglas-fir
    Pseudotsuga menziesii, known as Douglas-fir, Oregon Pine, or Douglas spruce, is an evergreen conifer species native to western North America. Its variety Pseudotsuga menziesii var. menziesii, also known as coast Douglas-fir grows in the coastal regions, from west-central British Columbia, Canada...

     (Pseudotsuga menziesii): 99.4 m (326.1 ft), Brummit Creek, Coos County
    Coos County, Oregon
    -National protected areas:*Bandon Marsh National Wildlife Refuge*Oregon Islands National Wildlife Refuge *Siskiyou National Forest *Siuslaw National Forest - Incorporated cities:- Unincorporated communities and CDPs:-See also:...

    , Oregon
    Oregon
    Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...

    , United States
  4. Sitka Spruce
    Sitka Spruce
    Picea sitchensis, the Sitka Spruce, is a large coniferous evergreen tree growing to 50–70 m tall, exceptionally to 95 m tall, and with a trunk diameter of up to 5 m, exceptionally to 6–7 m diameter...

     (Picea sitchensis): 96.7 m (317.3 ft), Prairie Creek Redwoods State Park
    Prairie Creek Redwoods State Park
    Prairie Creek Redwoods State Park is a state park, located in Humboldt County, California, near the town of Orick and 50 miles north of Eureka...

    , California, United States
  5. Giant Sequoia
    Sequoiadendron
    Sequoiadendron giganteum is the sole living species in the genus Sequoiadendron, and one of three species of coniferous trees known as redwoods, classified in the family Cupressaceae in the subfamily Sequoioideae, together with Sequoia sempervirens and...

     (Sequoiadendron giganteum): 94.9 m (311.4 ft), Redwood Mountain Grove
    Redwood Mountain Grove
    Redwood Mountain Grove is the largest grove of giant sequoia on earth. It is located in Kings Canyon National Park and Giant Sequoia National Monument on the western slope of California's Sierra Nevada. The grove contains the world's tallest giant sequoia...

    , Kings Canyon National Park
    Kings Canyon National Park
    Kings Canyon National Park is a National Park in the southern Sierra Nevada, east of Fresno, California. The park was established in 1940 and covers...

    , California, United States
  6. Tasmanian Blue Gum
    Eucalyptus globulus
    The Tasmanian Blue Gum, Southern Blue Gum or Blue Gum, is an evergreen tree, one of the most widely cultivated trees native to Australia. They typically grow from 30 to 55 m tall. The tallest currently known specimen in Tasmania is 90.7 m tall...

     (Eucalyptus globulus): 90.7 m (297.6 ft), Tasmania, Australia
  7. Manna Gum (Eucalyptus viminalis): 89 m (292 ft), Evercreech Forest Reserve, Tasmania, Australia
  8. Shorea faguetiana
    Shorea faguetiana
    Shorea faguetiana is a species of plant in the Dipterocarpaceae family. It is found in Indonesia, Malaysia, and Thailand. The tallest documented tropical angiosperm is a 88.3 m tall Shorea faguetiana in the Tawau Hills National Park, in Sabah on the island of Borneo.-Source:* Ashton, P. 1998. . ...

    : 88.3 m (289.7 ft) Tawau Hills National Park
    Tawau Hills National Park
    Tawau Hills National Park, also Tawau Hills Park, was established in 1979, primarily as a protection for the water catchment area of Tawau town, in Sabah, east Malaysia on the island of Borneo. It is located 24 kilometers from Tawau, and comprises 279.72 km² of lowland dipterocarp rainforest,...

    , in Sabah
    Sabah
    Sabah is one of 13 member states of Malaysia. It is located on the northern portion of the island of Borneo. It is the second largest state in the country after Sarawak, which it borders on its southwest. It also shares a border with the province of East Kalimantan of Indonesia in the south...

     on the island of Borneo
    Borneo
    Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....

  9. Alpine Ash
    Eucalyptus delegatensis
    Eucalyptus delegatensis, commonly known as Alpine Ash or Gum-topped stringybark or White-top, is a sub-alpine or temperate tree of southeastern Australia. A straight, grey-trunked tree, it reaches heights of over 90 metres in suitable conditions. The tallest currently known specimen is located in...

     (Eucalyptus delegatensis): 87.9 m (288.4 ft), Tasmania, Australia



Stoutest trees


The girth
Circumference
The circumference is the distance around a closed curve. Circumference is a special perimeter.-Circumference of a circle:The circumference of a circle is the length around it....

 of a tree is usually much easier to measure than the height, as it is a simple matter of stretching a tape round the trunk, and pulling it taut to find the circumference. Despite this, UK tree author Alan Mitchell
Alan Mitchell
Alan F. Mitchell was a British forester, dendrologist and botanist, and author of several books on trees.He almost single-handedly measured every notable tree in the British Isles, founding the Tree Register of the British Isles , which held records of over 100,000 individual notable trees at the...

 made the following comment about measurements of yew
Taxus baccata
Taxus baccata is a conifer native to western, central and southern Europe, northwest Africa, northern Iran and southwest Asia. It is the tree originally known as yew, though with other related trees becoming known, it may be now known as the English yew, or European yew.-Description:It is a small-...

 trees:
As a general standard, tree girth is taken at "breast height". This is cited as dbh (diameter at breast height
Diameter at breast height
Diameter at breast height, or DBH, is a standard method of expressing the diameter of the trunk or bole of a standing tree. DBH is one of the most common dendrometric measurements....

) in tree and forestry literature. Breast height is defined differently in different situations, with most forestry
Forestry
Forestry is the interdisciplinary profession embracing the science, art, and craft of creating, managing, using, and conserving forests and associated resources in a sustainable manner to meet desired goals, needs, and values for human benefit. Forestry is practiced in plantations and natural stands...

 measurements taking girth at 1.3 m above ground, while those who measure ornamental trees
Ornamental plant
Ornamental plants are plants that are grown for decorative purposes in gardens and landscape design projects, as house plants, for cut flowers and specimen display...

 usually measure at 1.5 m above ground; in most cases this makes little difference to the measured girth. On sloping ground, the "above ground" reference point is usually taken as the highest point on the ground touching the trunk, but some use the average between the highest and lowest points of ground. Some of the inflated old measurements may have been taken at ground level. Some past exaggerated measurements also result from measuring the complete next-to-bark measurement, pushing the tape in and out over every crevice and buttress.

Modern trends are to cite the tree's diameter
Diameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...

 rather than the circumference. Diameter of the tree is calculated by finding the medium diameter of the trunk, in most cases obtained by dividing the measured circumference by π
Pi
' is a mathematical constant that is the ratio of any circle's circumference to its diameter. is approximately equal to 3.14. Many formulae in mathematics, science, and engineering involve , which makes it one of the most important mathematical constants...

; this assumes the trunk is mostly circular in cross-section (an oval or irregular cross-section would result in a mean diameter slightly greater than the assumed circle). Accurately measuring circumference or diameter is difficult in species with the large buttresses that are especially characteristic in many species of rainforest trees. Simple measurement of circumference of such trees can be misleading when the circumference includes much empty space between buttresses.

One further problem with measuring baobab
Baobab
Adansonia is a genus of eight species of tree, six native to Madagascar, one native to mainland Africa and the Arabian Peninsula and one to Australia. The mainland African species also occurs on Madagascar, but it is not a native of that island....

s Adansonia is that these trees store large amounts of water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 in the very soft wood in their trunks. This leads to marked variation in their girth over the year (though not more than about 2.5%), swelling to a maximum at the end of the rainy season, minimum at the end of the dry season.

The stoutest living single-trunk species in diameter are:
  1. Montezuma Cypress
    Taxodium mucronatum
    Taxodium mucronatum, also known as Montezuma Cypress, Sabino, or Ahuehuete is a species of Taxodium native to much of Mexico , and also the Rio Grande Valley in southernmost Texas, USA as well as Huehuetenango Department in Guatemala...

     Taxodium mucronatum: 11.62 m (38.1 ft), Árbol del Tule
    Árbol del Tule
    El Árbol del Tule is a tree located in the church grounds in the town center of Santa María del Tule in the Mexican state of Oaxaca, approximately 9 km east of the city of Oaxaca on the road to Mitla. It is a Montezuma Cypress , or Ahuehuete...

    , Santa Maria del Tule, Oaxaca, Mexico. Note though that this diameter includes buttressing; the actual idealised diameter of the area of its wood is 9.38 m (30.8 ft).
  2. Giant Sequoia
    Sequoiadendron
    Sequoiadendron giganteum is the sole living species in the genus Sequoiadendron, and one of three species of coniferous trees known as redwoods, classified in the family Cupressaceae in the subfamily Sequoioideae, together with Sequoia sempervirens and...

     Sequoiadendron giganteum: 8.85 m (29 ft), General Grant tree
    General Grant tree
    The General Grant tree is the largest giant sequoia in the General Grant Grove section of Kings Canyon National Park in California and the second largest tree in the world.-History:...

    , General Grant Grove, California, United States
  3. Coast Redwood Sequoia sempervirens: 7.9 m (25.9 ft), Lost Monarch
    Lost Monarch
    Lost Monarch is the name of a Coast Redwood tree in Northern California that is in diameter at breast height , and in height...

     Jedediah Smith Redwoods State Park, California, United States.
  4. Australian Oak
    Eucalyptus obliqua
    Eucalyptus obliqua, commonly known as Australian Oak, Brown Top, Brown Top Stringbark, Messmate, Messmate Stringybark, Stringybark and Tasmanian Oak, is a hardwood tree native to south-eastern Australia....

     Eucalyptus obliqua: 6.72 m (22 ft)
  5. Australian Mountain-ash
    Eucalyptus regnans
    Eucalyptus regnans, known variously by the common names Mountain Ash, Victorian Ash, Swamp Gum, Tasmanian Oak or Stringy Gum, is a species of Eucalyptus native to southeastern Australia, in Tasmania and Victoria...

     Eucalyptus regnans: 6.52 m (21.4 ft), Big Foot
  6. Western Redcedar
    Thuja plicata
    Thuja plicata, commonly called Western or pacific red cedar, giant or western arborvitae, giant cedar, or shinglewood, is a species of Thuja, an evergreen coniferous tree in the cypress family Cupressaceae native to western North America...

     Thuja plicata: 5.99 m (19.7 ft), Kalaloch Cedar, Olympic National Park
  7. Sitka Spruce
    Sitka Spruce
    Picea sitchensis, the Sitka Spruce, is a large coniferous evergreen tree growing to 50–70 m tall, exceptionally to 95 m tall, and with a trunk diameter of up to 5 m, exceptionally to 6–7 m diameter...

     Picea sitchensis: 5.39 m (17.7 ft), Quinalt Lake Spruce, Olympic National Park
    Olympic National Park
    Olympic National Park is located in the U.S. state of Washington, in the Olympic Peninsula. The park can be divided into four basic regions: the Pacific coastline, alpine areas, the west side temperate rainforest and the forests of the drier east side. U.S...

  8. Kauri
    Agathis australis
    Agathis australis, commonly known as the kauri, is a coniferous tree found north of 38°S in the northern districts of New Zealand's North Island. It is the largest but not tallest species of tree in New Zealand, standing up to 50 m tall in the emergent layer above the forest's main canopy. The...

     Agathis australis (Te Matua Ngahere
    Te Matua Ngahere
    Te Matua Ngahere is a giant kauri coniferous tree in the Waipoua Forest of Northland Region, New Zealand. The tree's Maori name means "Father of the Forest". Although not as massive or tall as its neighbour Tāne Mahuta, Te Matua Ngahere is stouter, with a girth just over...

    ): 5.33 m (17.5 ft).
  9. Alerce
    Fitzroya
    Fitzroya is a monotypic genus in the cypress family.-Species:The single living species, Fitzroya cupressoides, is a tall, long-lived conifer native to the Andes mountains of southern Chile and Argentina, where it is an important member of the Valdivian temperate rain forests...

     Fitzroya cupressoides: 5 m (16.4 ft)

An additional problem lies in instances where multiple trunks (whether from an individual tree or multiple trees) grow together. The Sacred Fig
Sacred Fig
The Sacred Fig, Ficus religiosa, or Bo-Tree , Peepal is a species of banyan fig native to India, Bangladesh, Nepal, Pakistan, Sri Lanka, southwest China and Indochina...

 is a notable example of this, forming additional "trunks" by growing adventitious roots down from the branches, which then thicken up when the root reaches the ground to form new trunks; a single Sacred Fig tree can have hundreds of such trunks.
The multi-stemmed Hundred Horse Chestnut was known to have a circumference of 57.9 m (190 ft) when it was measured in 1780.

Largest trees



The largest trees in total volume
Volume
Volume is the quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance or shape occupies or contains....

 are both tall and large in diameter and, in particular, hold a large diameter high up the trunk. Measurement is very complex, particularly if branch volume is to be included as well as the trunk volume, so measurements have only been made for a small number of trees, and generally only for the trunk. No attempt has ever been made to include root
Root
In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...

 volume. Measuring standards vary.

The top ten species measured so far are*:
  1. Giant Sequoia
    Sequoiadendron
    Sequoiadendron giganteum is the sole living species in the genus Sequoiadendron, and one of three species of coniferous trees known as redwoods, classified in the family Cupressaceae in the subfamily Sequoioideae, together with Sequoia sempervirens and...

     Sequoiadendron giganteum: 1,487 m³ (52,508 cu ft), General Sherman
    General Sherman (tree)
    The General Sherman is a giant sequoia tree located in the Giant Forest of Sequoia National Park in Tulare County, California. By volume, it is the largest known living single stem tree on Earth...

  2. Coast Redwood Sequoia sempervirens: 1,203 m³ (42,500 cu ft), Lost Monarch
    Lost Monarch
    Lost Monarch is the name of a Coast Redwood tree in Northern California that is in diameter at breast height , and in height...

  3. Montezuma Cypress
    Taxodium mucronatum
    Taxodium mucronatum, also known as Montezuma Cypress, Sabino, or Ahuehuete is a species of Taxodium native to much of Mexico , and also the Rio Grande Valley in southernmost Texas, USA as well as Huehuetenango Department in Guatemala...

     Taxodium mucronatum: 750 m³ (25,000 cu ft), Árbol del Tule
    Árbol del Tule
    El Árbol del Tule is a tree located in the church grounds in the town center of Santa María del Tule in the Mexican state of Oaxaca, approximately 9 km east of the city of Oaxaca on the road to Mitla. It is a Montezuma Cypress , or Ahuehuete...

  4. Kauri
    Agathis australis
    Agathis australis, commonly known as the kauri, is a coniferous tree found north of 38°S in the northern districts of New Zealand's North Island. It is the largest but not tallest species of tree in New Zealand, standing up to 50 m tall in the emergent layer above the forest's main canopy. The...

     Agathis australis (Tāne Mahuta
    Tane Mahuta
    Tāne Mahuta is a giant kauri tree in the Waipoua Forest of Northland Region, New Zealand. Its age is unknown but is estimated to be between 1,250 and 2,500 years old. It is the largest kauri known to stand today...

    ): 516 m³
  5. Western Redcedar
    Thuja plicata
    Thuja plicata, commonly called Western or pacific red cedar, giant or western arborvitae, giant cedar, or shinglewood, is a species of Thuja, an evergreen coniferous tree in the cypress family Cupressaceae native to western North America...

     Thuja plicata: 500 m³ (17,650 cu ft ), Quinault Lake Redcedar
  6. Tasmanian Blue Gum
    Eucalyptus globulus
    The Tasmanian Blue Gum, Southern Blue Gum or Blue Gum, is an evergreen tree, one of the most widely cultivated trees native to Australia. They typically grow from 30 to 55 m tall. The tallest currently known specimen in Tasmania is 90.7 m tall...

     Eucalyptus globulus: 368 m³ (13,000 cu ft), Rullah Longatyle (Strong Girl, also Grieving Giant)
  7. Australian Mountain-ash
    Eucalyptus regnans
    Eucalyptus regnans, known variously by the common names Mountain Ash, Victorian Ash, Swamp Gum, Tasmanian Oak or Stringy Gum, is a species of Eucalyptus native to southeastern Australia, in Tasmania and Victoria...

     Eucalyptus regnans: 360 m³ (12,714 cu ft), Arve Big Tree
  8. Coast Douglas-fir
    Coast Douglas-fir
    Pseudotsuga menziesii, known as Douglas-fir, Oregon Pine, or Douglas spruce, is an evergreen conifer species native to western North America. Its variety Pseudotsuga menziesii var. menziesii, also known as coast Douglas-fir grows in the coastal regions, from west-central British Columbia, Canada...

     Pseudotsuga menziesii 349 m³ (12,320 cu ft) Red Creek Tree
  9. Sitka Spruce
    Sitka Spruce
    Picea sitchensis, the Sitka Spruce, is a large coniferous evergreen tree growing to 50–70 m tall, exceptionally to 95 m tall, and with a trunk diameter of up to 5 m, exceptionally to 6–7 m diameter...

     Picea sitchensis 337 m³ (11,920 cu ft) Queets Spruce
  10. Australian Oak
    Eucalyptus obliqua
    Eucalyptus obliqua, commonly known as Australian Oak, Brown Top, Brown Top Stringbark, Messmate, Messmate Stringybark, Stringybark and Tasmanian Oak, is a hardwood tree native to south-eastern Australia....

     Eucalyptus obliqua: 337 m³ (11,920 cu ft) Gothmog
  11. Alpine Ash
    Eucalyptus delegatensis
    Eucalyptus delegatensis, commonly known as Alpine Ash or Gum-topped stringybark or White-top, is a sub-alpine or temperate tree of southeastern Australia. A straight, grey-trunked tree, it reaches heights of over 90 metres in suitable conditions. The tallest currently known specimen is located in...

     Eucalyptus delegatensis: 286 m³ (10,100 cu ft), located in Styx River Valley


(*)This list does not take into account now dead specimens.

Oldest trees


The oldest trees are determined by growth rings
Dendrochronology
Dendrochronology or tree-ring dating is the scientific method of dating based on the analysis of patterns of tree-rings. Dendrochronology can date the time at which tree rings were formed, in many types of wood, to the exact calendar year...

, which can be seen if the tree is cut down, or in cores taken from the bark to the center of the tree. Accurate determination is only possible for trees that produce growth rings, generally those in seasonal climates. Trees in uniform non-seasonal tropical climates grow continuously and do not have distinct growth rings. It is also only possible for trees that are solid to the center. Many very old trees become hollow as the dead heartwood decays. For some of these species, age estimates have been made on the basis of extrapolating current growth rates, but the results are usually largely speculation. White (1998) proposes a method of estimating the age of large and veteran trees in the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 through the correlation between a tree's stem diameter, growth character and age.

The verified oldest measured ages are:
  1. Great Basin Bristlecone Pine
    Great Basin Bristlecone Pine
    Pinus longaeva, the Great Basin Bristlecone Pine, is a long-living species of tree found in the higher mountains of the southwest United States. The species is one of three closely related trees known as bristlecone pines and is sometimes known as the Intermountain or Western bristlecone pine...

     (Methuselah
    Methuselah (tree)
    Methuselah is a Great Basin Bristlecone Pine tree growing high in the White Mountains of Inyo County in eastern California. Its measured age of 4,842 years makes it the world's oldest known living non-clonal organism...

    ) Pinus longaeva: 4,844 years
  2. Alerce
    Fitzroya
    Fitzroya is a monotypic genus in the cypress family.-Species:The single living species, Fitzroya cupressoides, is a tall, long-lived conifer native to the Andes mountains of southern Chile and Argentina, where it is an important member of the Valdivian temperate rain forests...

     Fitzroya cupressoides: 3,622 years
  3. Giant Sequoia
    Sequoiadendron
    Sequoiadendron giganteum is the sole living species in the genus Sequoiadendron, and one of three species of coniferous trees known as redwoods, classified in the family Cupressaceae in the subfamily Sequoioideae, together with Sequoia sempervirens and...

     Sequoiadendron giganteum: 3,266 years
  4. Sugi
    Cryptomeria
    Cryptomeria is a monotypic genus of conifer in the cypress family Cupressaceae formerly belonging to the family Taxodiaceae; it includes only one species, Cryptomeria japonica . It is endemic to Japan, where it is known as Sugi...

     Cryptomeria japonica: 3,000 years
  5. Huon-pine Lagarostrobos franklinii: 2,500 years


Other species suspected of reaching exceptional age include European Yew
Taxus baccata
Taxus baccata is a conifer native to western, central and southern Europe, northwest Africa, northern Iran and southwest Asia. It is the tree originally known as yew, though with other related trees becoming known, it may be now known as the English yew, or European yew.-Description:It is a small-...

 Taxus baccata (probably over 2,000 years) and Western Redcedar
Thuja plicata
Thuja plicata, commonly called Western or pacific red cedar, giant or western arborvitae, giant cedar, or shinglewood, is a species of Thuja, an evergreen coniferous tree in the cypress family Cupressaceae native to western North America...

 Thuja plicata. The oldest known European Yew is the Llangernyw Yew
Llangernyw Yew
The Llangernyw Yew is an ancient yew in the churchyard of the village of Llangernyw in Conwy County Borough, North Wales. The tree is fragmented and its core part has been lost, leaving several enormous offshoots. The girth of the tree at the ground level is 10.75 m.-History:This male yew tree...

 in the Churchyard of Llangernyw
Llangernyw
Llangernyw is a rural, mostly Welsh-speaking, village in Conwy County Borough, north Wales. The population was 960 in 2001, 67% Welsh-speaking...

 village in North Wales
North Wales
North Wales is the northernmost unofficial region of Wales. It is bordered to the south by the counties of Ceredigion and Powys in Mid Wales and to the east by the counties of Shropshire in the West Midlands and Cheshire in North West England...

, which is estimated to be between 4,000 and 5,000 years old.

Damage


The two sources of tree damage are either biotic (from living sources) or abiotic (from non-living sources). Biotic sources include insects that bore into the tree, deer that rub bark off, and fungi.

Abiotic sources include lightning, vehicles impacts, and construction activities. Construction activities can involve a number of damage sources, including grade changes that prevent aeration to roots, spills involving toxic chemicals such as cement or petroleum products, or severing of branches or roots.

Both damage sources can result in trees becoming dangerous, and the term "hazard trees" is commonly used by arborists, and industry groups such as power line operators. Hazard trees are trees that, due to disease or other factors, are more susceptible to falling in windstorms, or having parts of the tree fall.

Evaluating the danger a tree presents is based on a process called the Quantified Tree Risk Assessment.

Assessment as to labeling a tree a hazard tree can be based on a field examination. Assessment as a result of construction activities that will damage a tree is based on three factors: severity, extent and duration. Severity relates usually to the degree of intrusion into the TPZ and resultant root loss. Extent is frequently a percentage of a factor such as canopy, roots or bark, and duration is normally based on time. Root severing is considered permanent in time.

Trees are similar to people. Both can withstand massive amounts of some types of damage and survive, but even small amounts of certain types of trauma can result in death. Arborists are very aware that established trees will not tolerate any appreciable disturbance of the root system. However, lay people and construction professionals seldom recognise how easily a tree can be killed.

One reason for confusion about tree damage from construction involves the dormancy of trees during winter. Another factor is that trees may not show symptoms of damage until two years or longer after damage has occurred. For that reason, persons uneducated in arboricultural
Arboriculture
Arboriculture is the cultivation, management, and study of individual trees, shrubs, vines, and other perennial woody plants. It is both a practice and a science....

 science may not correlate the actual cause and resultant effect.

Various organisations, such as the International Society of Arboriculture, the British Standards Institute and the Tree Industry Association (formerly the National Arborist Association), have long recognised the importance of construction activities that impact tree health. The impacts are important because they can result in monetary losses due to tree damage and resultant remediation or replacement costs, as well as violation of government ordinances or community or subdivision restrictions.

As a result, protocols for tree management prior to, during and after construction activities are well established, tested and refined. These basic steps are involved:
  • Review of the construction plans
  • Development of the related tree inventory
  • Application of standard construction tree management protocols
  • Assessment of potential for expected tree damages
  • Development of a tree protection plan (providing for pre-, concurrent, and post construction damage prevention and remediation steps)
  • Development of a tree protection plan
  • Development of a remediation plan
  • Implementation of tree protection zones (TPZ)
  • Assessment of construction tree damage, post-construction
  • Implementation of the remediation plan

Trees in culture



The tree has always been a cultural symbol. Common icons are the World tree
World tree
The world tree is a motif present in several religions and mythologies, particularly Indo-European religions, Siberian religions, and Native American religions. The world tree is represented as a colossal tree which supports the heavens, thereby connecting the heavens, the earth, and, through its...

, for instance Yggdrasil
Yggdrasil
In Norse mythology, Yggdrasil is an immense tree that is central in Norse cosmology. It was said to be the world tree around which the nine worlds existed...

, and the tree of life
Tree of life
The concept of a tree of life, a many-branched tree illustrating the idea that all life on earth is related, has been used in science , religion, philosophy, mythology, and other areas...

. The tree is often used to represent nature or the environment itself.

Tree value approximation (USA)


Studies have shown that trees contribute as much as 27% of the appraised land value in certain markets and cite the following which can be extrapolated with care.
Basic tree values (varies by region)
diameter
(inches)
value
(1985 US$)
10 $1,729
14 $3,388
18 $5,588
26 $11,682
30 $15,554


These most likely use diameter measured at breast height, 4.5 feet (137.2 cm) above ground, not the larger base diameter. A general model for any year and diameter is Value = 17.27939*(diameter^2)*1.022^(year-1985) assuming 2.2% inflation per year. The right side of this equation is written to paste into Excel
Microsoft Excel
Microsoft Excel is a proprietary commercial spreadsheet application written and distributed by Microsoft for Microsoft Windows and Mac OS X. It features calculation, graphing tools, pivot tables, and a macro programming language called Visual Basic for Applications...

 or Google
Google
Google Inc. is an American multinational public corporation invested in Internet search, cloud computing, and advertising technologies. Google hosts and develops a number of Internet-based services and products, and generates profit primarily from advertising through its AdWords program...

 to perform the calculation. Extrapolations from any model can vary widely, so value estimates for diameters larger than 30 inches (762 mm) may have to be capped so trees do not exceed 27% of total appraised land value.

See also



External links