Abstract: This paper introduces two different methods for analyzing radiative energy distribution within agroforestry ecosystem. One is called geometrical or triangular method which can be used to calculate the position and time of crown shading in the fie'd. It is useful for determining intercropping species and afforestation density. The second is a numerical model which is able to simulate the radiative penetrating procedure in agroforest canopy. It can be used to calculate the radiation intensity in various depthes of the canopy, and is also valuable for further researches related to the photosynthetic rate of canopy, stomatal conductance and system productivity, etc.

Key words: Pinus sylvestris var. mongolica, tree ring width chronology, climate warming, radial growth