A Mechanistic Model for Calculating Windthrow and Stem Breakage of Scots Pines at Stand Edge

1993

zahlr. Lit. Ang.

Unselbständiges Werk

2767

200040910

A model for the mechanism of windthrow and stem breakage was constructed for single Scots pines (Pinus sylvestris L.) at the stand edge. The total turning moment arising from the wind drag and from the bending of stem and crown was calculated along with the breaking stress of the stem. Similarly, the support given by the root-soil plate anchorage was calculated. Windspeed variation within the crown and the vertical distribution of stem and crown weight were taken into account. Model computations showed that trees having a large height to diameter ratio were subject to a greater risk of falling down or breaking than trees with a small heigth to diameter ratio. The windspeed required to blow down a tree or break the stem of a tree decreased if the height to diameter ratio or the crown to stem weight ratio of trees increased.