Evaluating a growth model for forest management using continuous forest inventory data

Evaluating a growth model for forest management using continuous forest inventory data

Model evaluation should include qualitative as well as quantitative examinations of the
model. The qualitative parts should comprise a critical appraisal of model logic as well
as theoretical and biological realism of the model. The quantitative parts should
comprise statistical tests and comparisons of predictions with observations
independent of those used to fit the model. Comprehensive model evaluation requires
several alternative approaches and criteria. Model evaluation is not one simple
procedure, but consists of a number of interrelated steps that should not be separated
from each other or from model construction. It is stressed that models can only be
evaluated in relative terms, and their predictive value is always open to question. Thus,
model evaluation is an ongoing process.

A case study with the PBRAVO growth model for maritime pine (Pinus pinaster Ait.) in
the Leiria forest, Portugal, illustrates the utility of selected criteria and graphical
techniques. Based on theoretical examinations and tests with data from continuou
forest inventories, we conclude that the Leiria version of the PBRAVO model does not
adequately represent reality and that forecasts lack sufficient accuracy for forest
management purposes.

Authors: Soares, P.; Torne, M.; Skovsgaard, J.P.; Vanclay, J.K.

Topic: evaluation,growth models,forest management,forest inventories

Publication Year: 1995

ISSN: 0378-1127

Source: Forest Ecology and Management 71(3): 251-265


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