Skip to main content

Weibull models for single-tree increment of Norway spruce, Scots pine, birch and other broadleaves in Norway

Buy Article:

$55.00 plus tax (Refund Policy)

Distance-independent, non-linear models of 5-year diameter increment for Norway spruce, Scots pine, birch and other broadleaved trees were developed, evaluated and compared on data from the Norwegian National Forest Inventory. The models were based on a Weibull curve dependent on diameter and a modifier function dependent on site parameters. A non-linear mixed model approach was used to fit the models. Model fit was assessed by the Pseudo-R2 on total level and on plot level reflecting a random plot effect. The [image omitted]  values were 0.31, 0.20, 0.13 and 0.10 for Norway spruce, Scots pine, birch and other broadleaves, respectively. The bias estimates from an independent validation were 0.1, 0.0, 0.1 and 0.3 mm for Norway spruce, Scots pine, birch and other broadleaves, respectively. The results from the independent validation were compared with results from identical tests of three other sets of models. The comparison indicated good model performance of the current models. The models were also compared by evaluating their behaviour when the tree size component was extrapolated beyond the range of the model development data. The results indicated that an additive model of diameter increment and the current non-linear Weibull and modifier model of diameter increment performed best.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Data/Media
No Metrics

Keywords: Mixed models; NFI data; Weibull; radial growth; single tree

Document Type: Research Article

Affiliations: Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway

Publication date: 2009-02-01

More about this publication?
  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more