Abstract:

In order to get more accurate forest winter facies porosity and permeability conversion formula, the physical mechanism of the resistance formation was used to deduce an approximate conversion formula of cylindrical fence porosity and permeability with different rows of trees, for revealing the consistency and the numerical variation rule of windbreak effect and the physical mechanism with different row numbers. The results showed that with the shelterbelt with the same porosity, the less the row number, the smaller the permeability, and the better the windbreak effect. With geometry similarity approaching as the principle, approximate conversion relationships between the forest winter phase permeability α, and porosity β were developed: single belt α=β^0.7, two belt α=β^0.6, for multiple belts α=β^0.55, which was more actual than the belt simulation formula α=β^0.4 which ignores rows and seasonal aspect effects, and assumes the ratio of length and height close to 1. The new relationships conduced to accurately understanding and applying windbreak effect principle and structure design of forest shelter belts.

Key words: winter facies, porosity, permeability