Modelling the profile and internal structure of tree stem. Application to Cedrus atlantica (Manetti)

Abstract

A set of compatible models are established to simulate the profile and internal structure of stems: ring distribution, bark and sapwood profiles. First, models are built tree by tree; they are then generalized by establishing relationships between the estimates of treewise model parameters and the individual tree characteristics. The residuals are examined against the relative height or distance from the apex. Using an independent sample of 4 trees, the observed stem and annual increment profiles are compared to the modelled profi- les, firstly using a stem profile model and secondly using a ring profile established previously (10). Generally, each model proves to be more accurate when used directly to predict the type of profile - stem or increment - for which it has been calibrated. In the lower part of the tree, the ring profile model gives less biased and more accurate estimates of ring width and tree diameter than the stem profile models.