Tree allometry: Difference between revisions

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

{{Expert-subject-multiple|Forestry|Ecology|date=March 2008}}

{{Wikify | date = October 2010}}

[[File:Profil_du_troncProfil 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.]]

[[File:Structureforet.jpg|thumb|right|Forest structure measurement is needed for establismentestablishment 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. [[Allometryforestry]]. Allometry studies the relative size of organs or parts of organisms. Tree allometry narrows the definition to applications involving measurements of the growth or size of trees. Allometric relationships often are oftenused estimatingto estimate 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.

==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.

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The general allometric equation for mathematics and science is

'': <math> Y = β\beta X<sup>α^\alpha </supmath>''

where "''Y"'' is ana 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 quietquite similar between very diverse organisms, ''β'' differs from species to species. Because the proportionality constant(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".

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

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:

'': <math> Y = b₀b_0 + b<sub>1b_1 X </submath> X''

==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;

[[Category:{{Forestry]]}}

[[Category:Forest modelling]]

[[fr:Allométrie des arbres]]