Tree allometry: Difference between revisions

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{{Short description|Quantitative relations between some key characteristic dimensions of trees}}

{{Wikify|date=April 2008}}

{{Expert|date=March 2008}}

{{Unreferenced|date=March 2008}}

'''Tree allometry''' is defined as the growth or size of some part of a tree in relation to the growth or size of different parts of a tree.

[[File:Profil du tronc.png|thumb|'''Stem profile measurement''' Electronic equipment (as [[:fr:Field-Map|Field-Map]] for example) is used for stem profile measurements and for measurements of profiles/projections of the crown. These key measurements are used for estimation of carbon sequestered in the plants.]]

The study of [[allometry]] is extremely important in dealing with measurements and data analysis in the practice of forestry. Allometry in general is defined as the growth of a part of an organism in relation to the growth of the whole organism or some part of it. Tree allometry narrows the definition to applications involving measurements of the growth or size of trees. Allometric relationships are often estimating difficult tree measurement, such as volume, from an easily-measured attribute such as [[diameter at breast height]] (DBH).

[[File:Structureforet.jpg|thumb|right|Forest structure measurement is needed for establishment of allometric equations.]]

'''Tree allometry''' establishes quantitative relations between some key characteristic dimensions of [[tree]]s ([[Forest inventory|usually fairly easy to measure]]) and other properties (often more difficult to assess). To the extent these statistical relations, established on the basis of detailed measurements on a small sample of typical trees, hold for other individuals, they permit extrapolations and estimations of a host of [[dendrometry|dendrometric]] quantities on the basis of a single (or at most a few) measurements.

The study of [[allometry]] is extremely important in dealing with measurements and data analysis in the practice of [[forestry]]. Allometry in general is defined asstudies the growthrelative of a partsize of an organism in relation to the growth of the whole organismorgans or some partparts of itorganisms. Tree allometry narrows the definition to applications involving measurements of the growth or size of trees. Allometric relationships often are oftenused to estimatingestimate difficult tree measurementmeasurements, such as volume, from an easily- measured attribute such as [[diameter at breast height]] (DBH).

The use of [[allometry]] is widespread in [[forestry]] and [[forest ecology]]. In order to develop an allometric relationship there must be a strong relationship and an ability to quantify this relationship between the parts of the subject measured and the other quantities of interest<ref>Smith, W.B., and G.J. Brand. 1983 Allometric biomass equations for 98 species of herbs, shrubs, and small trees. Research note NC-299. USDA Forest Service, North Central Forest Experiment Station, St. Paul, MN 8p.</ref>. Also when developing this equation one must play in factors which affect tree growth such as age, species, site ___location, etc.<ref>Avery and Burkhart. Forest Measurements. Copyright 2002 by McGraw-Hill Companies Inc. New York.</ref>. Once all these guidelines are met, one may attempt to develop an allometric equation.

The use of [[allometry]] is widespread in [[forestry]] and [[forest ecology]]. In order to develop an allometric relationship there must be a strong relationship and an ability to quantify this relationship between the parts of the subject measured and the other quantities of interest.<ref>Smith, W.B., and G.J. Brand. 1983 Allometric biomass equations for 98 species of herbs, shrubs, and small trees. Research note NC-299. USDA Forest Service, North Central Forest Experiment Station, St. Paul, MN 8p.</ref>. Also when developing this equation one must play in factors which affect tree growth such as age, species, site ___location, etc.<ref>Avery and Burkhart. Forest Measurements. Copyright 2002 by McGraw-Hill Companies Inc. New York.</ref>. Once all these guidelines are met, one may attempt to develop an allometric equation.

First thing to do is select a group of some subject (for forestry: trees). Then measure several easily measured attributes such as DBH, height, species, etc. Graph the results and perform a regression analysis and transform some of the variables until a correct [[regression]] is found.

==Assessment of forest biomass and carbon stocks==

In 2013, the [[Food and Agriculture Organization of the United Nations]] launched [http://www.fao.org/forestry/databases/allometric-equation/en/ GlobAllomeTree], a web-based platform designed to improve global access to tree allometric equations and support forest and climate-change project developers, researchers, scientists and foresters to assess forest volume and biomass, and carbon stocks. Jointly developed by [[FAO]], the French Research Centre [[CIRAD]] and [[Tuscia University]] of Italy, the GlobAllomeTree platform provides a consistent and harmonized database of tree and [[Stand level modelling|stand]] volume and biomass allometric equations; software to compare equations and assess variables of interests, such as volume, biomass and carbon stocks; access to scientific research information on allometric equations; and access to tutorials, manuals and documentation supporting the development and use of tree allometric equations.

In 2012, FAO and CIRAD published a manual for building tree volume and biomass allometric equations for students, technicians or researchers working to assess forest resources such as volume, biomass and carbon stocks for commercial, bioenergy or [[climate change mitigation]] purposes.<ref>[http://www.fao.org/docrep/018/i3058e/i3058e.pdf Picard N., Saint-André L., Henry M. 2012. Manual for building tree volume and biomass allometric equations: from field measurement to prediction. Food and Agricultural Organization of the United Nations, Rome, and Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Montpellier]</ref>

==Methodology==

First thing to do is select a group of some subject (for forestry: trees). Then measure several easily measured attributes such as DBH, height, species, etc. Graph the results and perform a regression analysis and transform some of the variables until a correct [[Regression analysis|regression]] is found.

<!-- Image with unknown copyright status removed: [[Image:Regressiongraph.jpg|thumb|right|300px|Allometric relationship of Volume Vs. Height*DBH² for an Appalachian oak stand]] -->

There are different tree species compositions in each region in the world and most of those regions have at least one equation that estimates tree volume from DBH. Research and the application of forest allometry have meshed over time to develop these quick equations to accurately estimate how much volume a particular forest stand holds.

The general allometric equation for mathematics and science is

'': <math> Y = a\beta X<sup>b^\alpha </supmath>''

where ''Y'' is a biological variable (such as tree height or DBH), ''β'' is a proportionality coefficient, ''α'' is the scaling exponent (which is equal to the slope of the line when plotted on logarithmic coordinates), and ''X'' is some physical measure such as body volume or body mass(M). While α is often quite similar between very diverse organisms, ''β'' differs from species to species. Because the proportionality constants ''β'' and the scaling exponents ''α'' are often denoted using Greek letters, it is desirable to use ''β'' as the proportionality coefficient versus ''α'', since α could be misread as the symbol for "proportional".

where ''b'' = allometric coefficient; ''a'' = slope; ''Y'' = measure/process; ''X'' = size.<ref>[http://weber.ucsd.edu/~jmoore/courses/allometry/allometry.html Allometry<!-- Bot generated title -->]</ref> However in [[forestry]] the equation takes on many forms in order to represent relationships between the many various attributes of tree size and growth. Below is an example...

A well-known allometric equation relates metabolic rate to body mass: ''Y'' =&nbsp;''βM''&nbsp;3/4.

''Y = b₀ + b₁ X''

where ''b'' = allometric coefficient; ''a'' = slope; ''Y'' = measure/process; ''X'' = size.<ref>[http://weber.ucsd.edu/~jmoore/courses/allometry/allometry.html Allometry<!-- Bot generated title -->]</ref> However inIn [[forestry]] the equation takes on many forms in order to represent relationships between the many various attributes of tree size and growth. Below is an example...:

: <math> Y = b_0 + b_1 X </math>

==See also==

* [[Biomass allocation]]

* [[da Vinci branching rule]]

==References==

{{reflist}}

#[http://www.cazv.cz/attachments/2-Cienciala.pdf Biomass functions applicable to European beech]{{Dead link|date=July 2018 |bot=InternetArchiveBot |fix-attempted=no }} E. CIENCIALA, M. ČERNÝ, J. APLTAUER, Z. EXNEROVÁ, JOURNAL OF FOREST SCIENCE, 51, 2005 (4): p.&nbsp;147–154;

{{Forestry}}

[[Category:Forest modelling]]