鼎湖山森林群落的总生产力

本文根据鼎湖山季风常绿阔叶林和针阔叶混交林的垂直结构和成层现象,应用红外线CO_2气体分析等方法,分层测定了主要植物33种57株的光合速率,研究了两个群落的总初级生产力。结果表明:季风常绿阔叶林的总生产力(吨干物质·公顷~(-1),年~(-1))为146.695,针阔叶混交林为128.5597,前者比后者高,但后者叶面积指数适度,林内透光良好,树干生长粗壮,因而经济效益较高。

THE GROSS PRIMARY PRODUCTIVITY OF FOREST COMMUNITY IN DINGHUSHAN

The gross primary productivity of Dinghushan monsoon broad-leaved evergreen forest (Castanopsis chinensis+Schima superba+Crypiocarya chinensis community), needle and broadleaved mixed forest (Pinus massoniana+Schima superba+Castanopsis chinensis+Craibiodendron kwangtungense community) were studied. The pho-tosynthetic rate of 57 plants for 33 main species was measured by an infrared CO2 analyzer. The leaf area index of community was measured by using method of dripping tag and the vertical distribution of the photosynthetically available radiation flux intensity and relative rate in forests were measured by using method of the level moving quantum sensor.The results showed that the relative rate of the photosynthetically available radiation by the canopy reflection was of 3,16% and 3.79%, that by uptake was of 96.27% and 89.72%, and that by transmission was of 0.57% and 6.49% in monsoon broadleaved evergreen forest and needle and broad-leaved mixed forest, respectively. The leaf area index (m2.m-2) was of 17 and 12, the average net-photosynthesis rate (mg CO2.dm-2.h-1) was of 4.11 and 5.63, the gross primary productivity (t DM.ha-1.-1) was of 146.6950 and 128.5597 for the two types of above mentioned.The monsoon broad-leaved evergreen forest is the typical pattern of lower subtropical broad-leaved evergreen forest, since the gross primary productivity are less than that in tropical rain forest, but more than that in subtropical broad-leaved evergreen forest, so it is the representative in this location. The needle and broad-leaved mixed forest is a transitional type of lower subtropical secondary forest. The gross primary productivity of such mixed forest is close to that of the monsoon broad-leaved evergreen forest. This shows that the conservation of natural vegetation is successful.