基于固定样地和小班数据的天台县林分乔木层年净生产力结构化计算

Annual Net Productivity of Arbor Layer of Forest in Tiantai Based on Data of Permanent Sample Plots and Subcompartments

利用浙江省天台县2009-2014年、2014-2016年、2016-2017年固定样地的单木生物量数据,考虑森林类别、龄组和林型计算出保留木生物量年均生长率、生物量的年均保留率、进界木生物量年均生长率和年均进界木株数;根据天台县2017年调查的小班数据计算小班各树种组的生物量,作为计算2018年净生产力的基数,结合对应参数,计算出小班内各树种2018年的保留木生产力、采伐木和枯损木的未测生产力、进界木的生产力,统计全县林分乔木层年净生产力。结果表明,2018年天台县林分乔木层净生产力58.95万t,其中保留木54.04万t,采伐木、枯损木未测生产力1.25万t,进界木3.66万t,单位面积净生产力7.00 t·hm^-2·a^-1。公益林净生产力35.23万t,商品林23.72万t,单位面积净生产力商品林大于公益林。针阔混交林年净生产力最多,为18.49万t,硬阔林单位面积净生产力最大,为8.33 t·hm^-2·a^-1。中龄林年净生产力最多,为27.82万t,幼龄林单位面积净生产力最大,为8.33 t·hm^-2·a^-1。

Based on individual tree biomass of permanent sample plots from 2009 to 2014,2014 to 2016 and 2016 to 2017 in Tiantai county,Zhejiang province,parameters such as average annual growth rate of biomass of reserved trees,average annual reserved rate of biomass,average annual number of ingrowth and their growth rate of biomass were calculated combining with ecological forest and commercial one,forest types and age groups.The biomass of each tree species group at subcompartment in 2017 was calculated for cardinal number of annual net productivity calculation in 2018.The productivity of reserved tree,potential one of felled or mortality and ingrowth of different species at subcompartments was calculated combined with responding parameters,and then the annual net productivity of arbor layer of forest in the county could be calculated.The results showed that in 2018,the net productivity of arbor layer of forest in Tiantai was 5.895×10^5 t of which 5.404×10^5 t of reserved tree,0.125×10^5 t of potential,0.366×10^5 tons of ingrowth,and annual net productivity per unit area was 7.00 t/ha.The net productivity of ecological forest was 3.523×10^5 t,and that of commercial one was 2.372×10^5 t.The annual net productivity of coniferous-broad-leaved mixed forest was the highest,1.849×10^5 t,and that per unit area of hard broad-leaved forest was the largest,0.833×10^5 t.The annual net productivity of middle-aged forest was the highest,2.782×10^5 t,and that per unit area of young forest was the largest,0.833×10^5 t.