六盘山主要植被类型的生物量及其分配

Biomass and Its Allocation of the Main Vegetation Types in Liupan Mountains

2009年,在宁夏六盘山南部林区香水河小流域,调查研究了主要森林类型的生物量及其层次和器官分配。结果表明:不同森林的活体植被总生物量(t.hm-2)差别较大,依次为华山松(102.70)>桦木林(84.42)>山杨林(79.97)>华北落叶松人工林(58.37)>疏林(44.91),按各类森林面积加权平均为78.37,远高于灌丛(20.77)、草地(1.07)和草甸(2.29)。各类森林的枯落物现存量(t.hm-2)为:华北落叶松人工林(18.21)>华山松林(11.99)>桦木林(10.90)>山杨林(7.67)>疏林(7.06),也都远高于灌木林(3.13)、草甸(0.82)和草地(0.49)。森林生物量集中在乔木层(占91.04%),灌木层仅占8.09%,草本层更低至0.87%。森林生物量的器官分配比例:乔木层为树干(54.06%)>枝(21.04%)>根(16.92%)>皮(5.34%)>叶(2.65%);灌木层为枝干(62.68%)>根(30.55%)>叶(6.77%);草本层为地上茎叶(58.82%)>根(41.18%)。乔木层地上与地下生物量比值的平均值为4.49,几种阔叶林都在4.0左右,但华北落叶松林为6.41,华山松林为5.80,都远大于灌木林的2.82、草地的1.89及草甸的1.20。不同林分的生物量均随林龄和林冠郁闭度的增大而几乎线性增加,并随林分密度的增加而增大,但在密度超过900株.hm-2后生物量增速减缓并渐趋其最大值。

In 2009,the biomass and its allocation among vegetation layers and organs were invested for the main forest types in the small watershed of Xiangshuihe,which locates at the southern part of Liupan Mountains.The results showed that there was an obvious difference in the total living biomass among different forest types,which followed the order of Pinus armandii forest（102.70 t·hm-2） Birch forest（84.42 t·hm-2）Populus davidiana forest（79.97 t·hm-2）Larix principis-rupprechtii plantation（58.37 t·hm-2）open forest（44.91 t·hm-2）.The area-weighted average of biomass of all forests investigated was 78.37 t·hm-2,which was much higher than that of shrubs（20.77 t·hm-2）,grassland（1.07 t·hm-2） and meadow（2.29 t·hm-2）.The order of litter biomass of each forest type was Larix principis-rupprechtii plantation（18.21 t·hm-2）Pinus armandii forest（11.99 t·hm-2）Birch forest（10.90 t·hm-2）Populus davidiana（7.67 t·hm-2）open forest（7.06 t·hm-2）,all of them was also much higher than that of shrubs（3.13 t·hm-2）,meadow（0.82 t·hm-2） and grassland（0.49 t·hm-2）.Most of the biomass in forest ecosystems concentrated in the tree layer with a ratio of 91.04%,while the ratio amounted to only 8.09% for the shrub layer and even 0.87% for the herb layer.The organ allocation of biomass in forest ecosystems was trunk（54.06%）branch（21.04%）root（16.92%）bark（5.34%）leaf（2.65%） for the tree layer,while it was stem and branch（62.68%）root（30.55%）leaf（6.77%） for the shrubs layer,and over-ground shoot（58.32%）root（41.18%） for the herb layer.The averaged ratio of above-to underground biomass for the tree layer of all forest types investigated was 4.49,while it was around 4.0 for the broadleaf forest types,6.41 for the Larix principis-rupprechtii plantation and 5.80 for the Pinus armandii forest;all of those were higher than that of shrubs（2.82）,grassland（1.89） and meadow（1.20）.The forest biomass increased nearly linearly with increasing forest age and canopy density within the range of the investigation.The forest biomass also increased rapidly with increasing stand density before the density reaches a threshold of 900 trees·hm-2;thereafter the biomass increased more slowly and towards its maximum.The forest biomass in Liupan Mountains is higher compared with that in the similar regions,showing a good result of the forest protection in last decades.