THE MECHANICAL EFFECT OF CLIMBING PLANTS UPON THE HOST TREE

It could be shown that the directions of wood fibres at the surface of a host tree (Acer platanoides) are changing under the influence of st rangle from a climbing plant (Lonicera benryi). The angle of the wood fibres accomodates to the angle between the climbing plant and the hos t tree. A FEM analysis shows that in this case the orientation of the wood fibres is not load dependent. Biological compulsions seems to be responsible for this form of growth. The formation of a notch is an ef fect of the strangle of the climbing plant. The more the climbing plan t is growing into the host the higher is the stress concentration at t he notch. First, when the climbing plant: is fully covered by the host and a new annual ring has grown over the wound, the stress concentrat ion decreases rapidly. During the time of growing in, the carrying cap acity of the host tree is reduced. Especially young trees with a small cross-section of the stem are threatened by the mechanism of strangli ng.