Cross-correlations among Single Tree Growth Models : Spatial Accuracy Assessment in Natural Resources and Environmental Sciences/ Second International Symposium : Spatial Accuracy Assesment in Natural Resources and Environmental Sciences/Second International Symposium

1996

20 Lit. Ang.

Unselbständiges Werk

12314

200047489

Single tree growth and yield models basically consist of a number of equations to update tree parameters over time. Although it seems reasonable to assert that these equations are interrelated from a biological standpoint, it is customary to consider them independently and apply linear or nonlinear regression techniques separately rather than jointly. Using more than 7,500 Norway spruce (Picea abies) trees, we compare an individual tree basal area increment model, a height increment model, and a crown model using least square methods separately and jointly by applying three stage least square (3SLS) regression techniques. Results indicate a strong cross- equation correlation between the basal area and the height increment modell and the heigth increment and the crown model. This suggests that the use of joint regression techniques would be superior.