Changes

Trees may be broadly grouped into ''exogenous'' and ''endogenous'' trees according to the way in which their stem diameter increases. Exogenous trees, which comprise the great majority of modern trees (all [[Pinophyta|conifer]]s, and all [[dicotyledon|broadleaf]] trees), grow by the addition of new wood outwards, immediately under the bark. Endogenous trees, mainly in the [[monocotyledon]]s (e.g. [[palm tree|palms]]), grow by addition of new material inwards.

Trees may be broadly grouped into ''exogenous'' and ''endogenous'' trees according to the way in which their stem diameter increases. Exogenous trees, which comprise the great majority of modern trees (all [[Pinophyta|conifer]]s, and all [[dicotyledon|broadleaf]] trees), grow by the addition of new wood outwards, immediately under the bark. Endogenous trees, mainly in the [[monocotyledon]]s (e.g. [[palm tree|palms]]), grow by addition of new material inwards.

As an exogenous tree

As an exogenous tree grows, it creates [[growth ring]]s. In temperate climates, these are commonly visible due to changes in the rate of growth with temperature variation over an annual cycle. 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; this practice is known as the science of [[dendrochronology]]. In some tropical regions with constant year-round climate, growth is continuous and distinct rings are not formed, so age determination is impossible. Age determination is also impossible in endogenous trees.

grows, it creates [[growth ring]]s. In temperate climates, these are commonly visible due to changes in the rate of growth with temperature variation over an annual cycle. 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; this practice is known as the science of [[dendrochronology]]. In some tropical regions with constant year-round climate, growth is continuous and distinct rings are not formed, so age determination is impossible. Age determination is also impossible in endogenous trees.

The roots of a tree are generally embedded in earth, providing anchorage for the above-ground [[biomass]] and absorbing [[water]] and [[nutrients]] from the [[soil]]. It should be noted, however, that while ground nutrients are essential to a tree's growth the majority of its biomass comes from carbon dioxide absorbed from the atmosphere (see [[photosynthesis]]). Above ground, the trunk gives height to the leaf-bearing branches, aiding in competition with other plant species for [[sunlight]]. In many trees, the arrangement of the branches optimizes exposure of the leaves to sunlight.

The roots of a tree are generally embedded in earth, providing anchorage for the above-ground [[biomass]] and absorbing [[water]] and [[nutrients]] from the [[soil]]. It should be noted, however, that while ground nutrients are essential to a tree's growth the majority of its biomass comes from carbon dioxide absorbed from the atmosphere (see [[photosynthesis]]). Above ground, the trunk gives height to the leaf-bearing branches, aiding in competition with other plant species for [[sunlight]]. In many trees, the arrangement of the branches optimizes exposure of the leaves to sunlight.

===Tallest trees===  

===Tallest trees===  

The heights of the tallest trees in the world have been the subject of considerable dispute and much (often wild) exaggeration. Modern verified measurement with [[laser]] rangefinders combined with tape drop measurements made by tree climbers, carried out by the [http://www.nativetreesociety.org/ U.S. Eastern Native Tree Society] has shown that most older measuring methods and measurements are unreliable, often producing exaggerations of 5% to 15% above the real height. Historical

The heights of the tallest trees in the world have been the subject of considerable dispute and much (often wild) exaggeration. Modern verified measurement with [[laser]] rangefinders combined with tape drop measurements made by tree climbers, carried out by the [http://www.nativetreesociety.org/ U.S. Eastern Native Tree Society] has shown that most older measuring methods and measurements are unreliable, often producing exaggerations of 5% to 15% above the real height. Historical claims of trees of 117 m, 130 m, and even 150 m, are now largely disregarded as unreliable, fantasy or outright fraud. The following are now accepted as the top five tallest reliably measured species:

claims of trees of 117 m, 130 m, and even 150 m, are now largely disregarded as unreliable, fantasy or outright fraud. The following are now accepted as the top five tallest reliably measured species:

# [[Sequoia|Coast Redwood]] ''Sequoia sempervirens'': '''115.55 m''' '''(379.1 ft.)''', [[Redwood National Park]], [[California]] ([http://www.conifers.org/cu/se/index.htm Gymnosperm Database])

# [[Sequoia|Coast Redwood]] ''Sequoia sempervirens'': '''115.55 m''' '''(379.1 ft.)''', [[Redwood National Park]], [[California]] ([http://www.conifers.org/cu/se/index.htm Gymnosperm Database])

# [[Coast Douglas-fir]] ''Pseudotsuga menziesii'': '''100.3 m''' '''(329.1 ft.)''', Brummit Creek, [[Coos County, Oregon|Coos County]], [[Oregon]] ([http://www.conifers.org/pi/ps/menziesii2.htm Gymnosperm Database])

# [[Coast Douglas-fir]] ''Pseudotsuga menziesii'': '''100.3 m''' '''(329.1 ft.)''', Brummit Creek, [[Coos County, Oregon|Coos County]], [[Oregon]] ([http://www.conifers.org/pi/ps/menziesii2.htm Gymnosperm Database])

The stoutest species in diameter, excluding baobabs, are:

The stoutest species in diameter, excluding baobabs, are:

# [[Taxodium mucronatum|Montezuma Cypress]] ''Taxodium mucronatum'': '''11.42 m''', [[Árbol del Tule]], Santa Maria del Tule, [[Oaxaca]], [[Mexico]] (A. F. Mitchell, ''International Dendrology Society Year Book 1983'': 93, 1984).

# [[Taxodium mucronatum|Montezuma Cypress]] ''Taxodium mucronatum'': '''11.42 m''', [[Árbol del Tule]], Santa Maria del Tule, [[Oaxaca]], [[Mexico]] (A. F. Mitchell, ''International Dendrology Society Year Book 1983'': 93, 1984).

# [[Se

# [[Sequoiadendron|Giant Sequoia]] ''Sequoiadendron giganteum'': '''8.85 m''', [[General Grant tree]], [[Grant Grove]], California ([http://www.conifers.org/cu/se2/index.htm Gymnosperm Database])

quoiadendron|Giant Sequoia]] ''Sequoiadendron giganteum'': '''8.85 m''', [[General Grant tree]], [[Grant Grove]], California ([http://www.conifers.org/cu/se2/index.htm Gymnosperm Database])

# [[Sequoia|Coast Redwood]] ''Sequoia sempervirens'': '''7.44 m''', Prairie Creek Redwoods State Park, California ([http://www.conifers.org/cu/se/index.htm Gymnosperm Database])

# [[Sequoia|Coast Redwood]] ''Sequoia sempervirens'': '''7.44 m''', Prairie Creek Redwoods State Park, California ([http://www.conifers.org/cu/se/index.htm Gymnosperm Database])

The top four species measured so far are ([http://www.conifers.org/topics/biggest.htm Gymnosperm Database]):

The top four species measured so far are ([http://www.conifers.org/topics/biggest.htm Gymnosperm Database]):

# [[Sequoiadendron|Giant Sequoia]] ''Sequoiadendron giganteum'': '''1489 m³''', [[General Sherman (tree)|General Sherman]]  

# [[Sequoiadendron|Giant Sequoia]] ''Sequoiadendron giganteum'': '''1489 m³''', [[General Sherman(tree)|General Sherman]]  

# [[Sequoia|Coast Redwood]] ''Sequoia sempervirens'': '''1045 m³''', Del Norte Titan tree

# [[Sequoia|Coast Redwood]] ''Sequoia sempervirens'': '''1045 m³''', Del Norte Titan tree

# [[Thuja plicata|Western Redcedar]] ''Thuja plicata'': '''500 m³''', [[:Image:QuinaultLakeCedar 7274c.jpg|Quinault Lake Redcedar]]

# [[Thuja plicata|Western Redcedar]] ''Thuja plicata'': '''500 m³''', [[:Image:QuinaultLakeCedar 7274c.jpg|Quinault Lake Redcedar]]

** [[Bead tree]], ''Melia azedarach''

** [[Bead tree]], ''Melia azedarach''

** [[Mahogany]], ''Swietenia mahagoni''

** [[Mahogany]], ''Swietenia mahagoni''

* [[Moraceae]] ([[Mulberry]] family) [[Image:Applebox.JPG|thumb|r

* [[Moraceae]] ([[Mulberry]] family) [[Image:Applebox.JPG|thumb|right|''[[Eucalyptus|Eucalyptus bridgesiana]]'' on [[Red Hill, Australian Capital Territory]].]]

ight|''[[Eucalyptus|Eucalyptus bridgesiana]]'' on [[Red Hill, Australian Capital Territory]].]]

** [[Ficus|Fig]], ''Ficus'' species

** [[Ficus|Fig]], ''Ficus'' species

** [[Mulberry]], ''Morus'' species

** [[Mulberry]], ''Morus'' species