Individual tree crown projection area models based on the data from the National forest inventory of the Czech Republic

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F62156489%3A43410%2F16%3A00091893" target="_blank" >RIV/62156489:43410/16:00091893 - isvavai.cz</a>

Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Individual tree crown projection area models based on the data from the National forest inventory of the Czech Republic

Original language description

Individual tree crown projection area is an important part of many forest models, e.g. estimation of tree biomass, species composition, canopy or natural regeneration (estimation of seed production). On the basis of Czech National Forest Inventory (CZNFI) data, two groups of models were fitted: (a) for trees with DBH above 7 cm, (b) for trees with DBH below 7 cm. Data were collected on 7772 inventory plots of CZNFI2 network (second period of inventory 2011 - 2015), totally 32 650 trees were measured (22 873 with DBH above 7 cm and 9 777 with DBH below 7 cm, respectively). Models with mixed effects proved the best results for all models. Models of the first group (DBH above 7 cm) were the 2nd order polynomials with centred DBH and IUFRO categories of heights (significant only for spruce, beech and pedunculate oak models) as fixed effects and segment of inventory plot as a random effect. Models of the second group (DBH below 7 cm) were nonlinear Michailoff functions (Michailoff 1943) with tree height, damage of the tree (significant only for spruce, beech, birch, pine and pedunculate oak models) and the type of regeneration (natural or artificial - significant only for larch model) as fixed effects and inventory plot as a random effect. Power weight function was part of all models because of coping with heteroscedasticity. According to AIC values, all models with mixed effects were significantly better compared with global models and heteroscedasticity of residuals was largely removed. Final models will be used for estimation of species composition in CZNFI on the levels of the whole state and selected subregions.

Czech name

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Czech description

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Type

O - Miscellaneous

CEP classification

GK - Forestry

OECD FORD branch

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Project

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Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2016

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů