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Assessment of bias due to random measurement errors in stem volume growth estimation by the Swedish National Forest Inventory

Suty, Nicole and Nyström, Kenneth and Ståhl, Göran (2013). Assessment of bias due to random measurement errors in stem volume growth estimation by the Swedish National Forest Inventory. Scandinavian journal of forest research. 28:2, 174-183
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Official URL: http://dx.doi.org/10.1080/02827581.2012.734329

Abstract

We evaluated the performance of two methods for estimating stem volume increment at individual tree level with respect to bias due to random measurement errors. Here, growth is either predicted as the difference between two consecutive volume estimates where single-tree volume functions are applied to data from repeated measurements or by a regression model that is applied to data from a single survey and includes radial increment. In national forest inventories (NFIs), the first method is typically used for permanent plots, the second for temporary plots. The Swedish NFI combines estimates from both plot types to assess growth at national and regional scales and it is, therefore, important that the two methods provide similar results. The accuracy of these estimates is affected by random measurement errors in the independent variables, which may lead to systematic errors in predicted variables due to model non-linearity. Using Taylor series expansion and empirical data from the Swedish NFI we compared the expected bias in stem volume growth estimates for different diameter classes of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.). Our results indicate that both methods are fairly insensitive to random measurement errors of the size that occur in the Swedish NFI. The empirical comparison between the two methods showed greater differences for large diameter trees of both pine and spruce. A likely explanation is that the regressions are uncertain because few large trees were available for developing the models.

Authors/Creators:Suty, Nicole and Nyström, Kenneth and Ståhl, Göran
Title:Assessment of bias due to random measurement errors in stem volume growth estimation by the Swedish National Forest Inventory
Series/Journal:Scandinavian journal of forest research (0282-7581)
Year of publishing :2013
Volume:28
Number:2
Page range:174-183
Publisher:Taylor & Francis
ISSN:0282-7581
Language:English
Publication Type:Journal article
Refereed:Yes
Article category:Scientific peer reviewed
Version:Accepted version
Full Text Status:Public
Agris subject categories.:K Forestry > K10 Forestry production
U Auxiliary disciplines > U10 Mathematical and statistical methods
U Auxiliary disciplines > U40 Surveying methods
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Forest Science
Keywords:National forest inventory, Picea abies, Pinus sylvestris, random measurement errors, stem volume increment, Taylor series expansion
URN:NBN:urn:nbn:se:slu:epsilon-e-803
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-803
Additional ID:
Type of IDID
DOI10.1080/02827581.2012.734329
ID Code:9357
Department:(S) > Dept. of Forest Resource Management
(NL, NJ) > Dept. of Forest Resource Management
External funders:FORMAS
Deposited By: Skogsbiblioteket Umeå
Deposited On:19 Dec 2012 08:48
Metadata Last Modified:02 Dec 2014 10:54

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