|Tree growth and biomechanics|
The work is focused on the biomechanical theory of tree growth, which states that radial growth of tree stems is mainly a result of mechanical stress, caused by wind sway. The long trem goal is to incorporate the theosy in a new generation of growth models.
So far only preliminary work has been conducted, like analysis crown-stem relationships, neighborhood influence on crown development, and neighborhood influence on wind induced mechanical stress acting on tree stems.
In the growth chamber experiments, 5-year old Scots pine saplings (Pinus sylvestris) were bent manually to predefined angles, three times a week for three weeks. Treated saplings had an increased radial xylem and bark growth at the point of bending, compared to untreated saplings, caused by a more rapid cell division.
In the field trial, treated trees were loaded with sand-bags during one winter (dormant period) and (or) summer (growth period). The treatments did not affect the temporal radial growth pattern, as measured with dendrometers, but winter loaded trees had significantly higher radial growth the two summers following treatment. Results therefore suggest that Scots pine trees have the ability to "remember" changes in mechanical stress applied during winter for at least two years.