PRODUCTIVITY OF NEEDLES AND ALLOCATION OF GROWTH IN YOUNG SCOTS PINE TREES OF DIFFERENT COMPETITIVE STATUS

It has been suggested that the allocation of carbon to stem wood growt h has low priority, and that productivity of needles (above-ground tre e biomass increment per unit leaf weight) decreases as competition bet ween trees increases. To test this, carbon allocation to different gro wth components and productivity of needles were compared between trees of different tree classes (dominant, codominant, intermediate and sup pressed). The study was carried out in two 16-year-old Scots pine (Pin us sylvestris L.) stands, planted at different initial densities: 40 0 00 and 10 000 seedlings ha-1. It was found that the allocation of carb on to stem wood production, and probably also fine root production, ha s high priority for trees under high competitive stress. It was also f ound that production per unit weight of needles increases with competi tion; at least for as long as the trees are experiencing approximately the same light regime.