Estimating the foliage area of Maritime pine (Pinus pinaster Ait.) branches and crowns with application to modelling the foliage area distribution inthe crown

Destructive measurements of architecture and biomass were pel formed on 63 trees from three Pinus pinaster stands (5, 21 and 26 year-old) in order to determine the quantity and distribution of foliage area inside the crown. A llometric equations were developed per site and needle age, which allowed t o correctly calculate (R-2 = 0.71 to 0.79) the foliage area of a branch, kn owing its basal diameter and its relative insertion height in the crown. Us ing these equations, we estimated total crown foliage area. A non-linear fu nction of tree diameter and tree age was fitted to these data (R-2 = 0.82 a nd 0.88). On the 5 and 26 year-old stands, we combined the branch level mod els and the architectural measurements to develop probability functions des cribing the vertical and horizontal foliage area distributions inside the c rown. The parameters of the beta functions varied with needle and stand age , foliage bring located mostly in the upper and outer Dart of the crown for the adult tree, whereas it was more abundant in the inner and lower parts of the crown in the 5 year-old trees. A simple representation of crown shap e was added to the study, so that knowing tree age and diameter, it could b e possible to fully describe the quantity of foliage area and its localisat ion inside a maritime pine crown.