树形管道模型原理

The Pipe Model Theory of Tree Form (A Review)

本文简介了树形管道模型的基本理论,并对若干问题进行了讨论。作者认为比管道长L将随分层厚度△Z的增大而增大,Yukihiro等[6]所给出的关系式L_a/L_b=b/a(L_a和L_b分别是△z=a和△z=b时的L值)是有疑问的。

The authors here introduce the pipe model theory and discuss some questions related to this model. Defining the gradients(L) of equation F(z)=LC(z) when the thickness of stratum △Az=a and △z=b as L_a and L_b, respectively, C. Yukihiro et al (1988) gave the relationship between L and △z: La/Lb=b/a. The authors do not think that this relationship is correct. According to the definition by the references (1～4), the density of the non-photosynthetic tissue [C(z)]contained in a horizontal layer of the thickness △z above a ground area A, C(z)=W(z)/(A.△z)(W(z)is the quantity of the non-photosynthetic tissue in the same layer above a unit area. The authors consider that C(z) will decrease when △z increases, so the specific pipe length L will increase with △z increasing. The authors suggest a method to calculate C(z) as follows: Calculate T_b(z) , the total biomass of the non-photosynthetic tissue above the z-horizon, by accumulating the data measured in the layers above z-horizon, and find out the T_b(z)—z curve equation, and obtain the C(z)—z curve equation by derivation [C(z)=dT_b/dz]. Then, the C(z) at any depth z can be calculated. Because T_b(z), which just corresponds to z, is not related to △z, C(z), as well as L, will not vary with △z. But in this case, the F(z)—C(z) line may not always be a straight line.