IMPLICATIONS OF VARYING PIPE MODEL RELATIONSHIPS ON SCOTS PINE GROWTHIN DIFFERENT CLIMATES

1. The process-based model SIMFORG, based on the pipe theory, was para meterized for Scots Pine at six locations along a north-south gradient in Europe. The ratio of foliage mass to stem cross-sectional area was changed as a function of potential evapotranspiration as proposed by Berninger et al. (1995). 2. Allocation to the stem differed between th e locations and affected consequently the stemwood production. Variati on in the net primary production and differences in the pipe model par ameters were responsible for these differences. There was good agreeme nt between measured and simulated data. 3. Increase in primary product ion, as predicted by climate-change senarios, increased allocation to the stem. However, the results were sensitive to changes in the foliag e mass to stem sapwood cross-sectional area ratio. The changes in allo cation were higher in the north than in the south.