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粗木质残体是森林生态系统非常重要的结构性和功能性单元,对生态系统的水源涵养功能具有重要作用。为了解西藏色季拉山急尖长苞冷杉(Abies geoegeti var.smithii)林粗木质残体的持水特性,用典型样地法对生态系统内的粗木质残体进行调查并取样,用浸泡模拟法测定其吸水率、吸水速率及持水潜力。结果表明:(1)粗木质残体的吸水率、吸水速率及其持水能力在其吸水过程中基本表现为高腐烂等级高于低腐烂等级,其吸水率与浸水时间的关系可用对数函数y=alnx+b拟合,吸水速率与浸水时间的关系可用幂函数y=ax~(-b)拟合,二者均达到极显著水平(p<0.01);(2)粗木质残体的密度随腐烂等级的增高而减小,饱和吸水率则随腐烂等级的增高而升高,饱和吸水率随密度的减小而升高,3种关系分别服从二项式y=-0.004 7x~2-0.034 3x+0.443 6、二项式y=0.393 2x~2-1.569 3x+2.070 5以及幂函数y=0.153x~(-1.661)分布,前两者显著性水平p>0.05,后者达到显著性水平(p<0.05);(3)粗木质残体储量为60.363 t/hm~2,最大储水量为98.420 t/hm~2,有效储水量为83.657 t/hm~2,相当于8.366 mm的降雨。该成果为进一步开展色季拉山急尖长苞冷杉林粗木质残体的水文生态功能奠定了基础。
Coarse woody debris is a very important structural and functional unit of forest ecosystems and plays an important role in the water conservation of ecosystems. In order to understand the water-holding characteristics of coarse woody debris in Abies geoegeti var.smithii forest in the Sejila Mountain in Tibet, the coarse woody debris in the ecosystem was sampled and sampled by the typical sampling method. Water absorption, water absorption rate and water holding potential were determined by simulation method. The results showed that: (1) The water absorption rate, water absorption rate and water holding capacity of coarse woody residues were basically high rotten grade and low rotten grade during their water absorption. The relationship between water absorption and immersion time was logarithmic y = alnx + b fitting, the relationship between water absorption rate and immersion time can be fitted with power function y = ax ~ (-b), both of which reach the extremely significant level (p <0.01); (2) The density decreases with the increase of decay level, the saturated water absorption increases with the decay level, and the saturated water absorption increases with the decrease of density. The three relationships obey binomial y = -0.004 7x ~ 2 -0.034 3x + 0.443 6, the binomial y = 0.393 2x ~ 2-1.569 3x + 2.070 5 and the power function y = 0.153x ~ (-1.661), the former two significant p> 0.05, the latter reached significant (P <0.05); (3) The reserves of crude wood residues were 60.363 t / hm ~ 2, the maximum water storage capacity was 98.420 t / hm ~ 2 and the effective water storage capacity was 83.657 t / hm ~ 2, Of the rain. The results laid the foundation for further carrying out the hydrological and ecological functions of the coarse woody debris of the Abies georgei forest.