© 2000 Heron Publishing—Victoria, Canada
Needle and stem wood production in Scots pine (Pinus sylvestris) trees of different age, size and competitive status
Petteri Vanninen (1, 2) and Annikki Mäkelä (1)
1. Department of Forest Ecology, University of Helsinki, Helsinki, Finland / 2. SAIMA—Centre for Environmental Sciences, Linnankatu 11, 57130 Savonlinna, Finland (Petteri.Vanninen@Helsinki.fi) / Received June 2, 1999
Summary
We studied effects of tree age, size and competitive status on foliage and stem production of 43 Scots pine (Pinus sylvestris L.) trees in southern Finland. The tree attributes related to competition included foliage density, crown ratio and height/diameter
ratio. Needle mass was considered to be the primary cause of growth through photosynthesis. Both stem growth and foliage growth
were strongly correlated with foliage mass. Consequently, differences in growth allocation between needles and stem wood in
trees of different age, size, or position were small. However, increasing relative height increased the sum of stem growth
and foliage growth per unit foliage mass, indicating an effect of available light. Suppressed trees seemed to allocate more
growth to stem wood than dominant trees, and their stem growth per unit foliage mass was larger. Similarly, trees in dense
stands allocated more growth to stem wood than trees in sparse stands. The results conformed to the pipe model theory but
seemed to contradict the priority principle of allocation.
Keywords:
allocation, growth efficiency, pipe model, priority principle.
