滇西北高山松林净第一性生产力的初步研究

A Preliminary Study on net Phmary Producttivity of Pivus densata forests in Nofthwest Yunnan Pfovincc, China

本文研究了滇西北高山松林的净第一性生产力。林龄大净第一性生产力小。林龄约４０年的林分，净第一性生产力１２．１９２ｔ／ｈｍ￣２·ａ，林龄约１００年者为１０．０１３ｔ／ｈｍ￣２·ａ；高山松净第一性生产力为９．８４９和５．６２１ｔ／ｈｍ￣２·ａ，占群落净第一性生产力的８０．８４９％和５６．１４％；随着林龄增加，高山松的净策一性生产力及其在群落中所占的比例也逐渐减少，而其它树种的有所增加；在各器官中，叶的净第一性生产力最高，占３４％～３７％，其次为树干木材，占２１．６２％～２７．４４％。

The net prim ary productivitv of Pinus densata forests which locatein Northwest Yunnan Province China with 28°05′N and 99°40′E,and anelevation 3340～3500 m is studied with the dimension analysis method.The total net pri-mary productivity of 40-aged stand is l2.192 t / hm￣2· a and that of 100-aged stand is10. 013 t / hm￣2·a,Of the total net primary productivity, the first tree layers which areonly composed of Pinus densata share 80.78% and 56.14%,the second tree lavers whichare mainly composed of Quercus ponnosa,Rhododendron,and Lvonioa share 18.96%and 43.53 %,and the shrub layers and herbaceous layers share respictivelv 0.15 % and0.21 %,0.11% and 0.12%。The tree layer net primary productivity allocates differentlv toorgans,i,e, 27. 44% and 21.62% to stem wood, 11.20% and 9.00% to stem bark, 14.26% and 15.05% to branches,34.84 % and 37. 76% to needles(leaves),4.22%and 3.22% to root necks,and 8.04% and l3.35 % to root system. The importance ofPinus densata to the total net primary productivity of stands reduces and that of Quercuspennosa raises as the age of stands increases.