秦岭南坡锐齿栎林的生态环境及其营养积累

秦岭锐齿栎林 (含 0～ 6 0cm土层 )营养元素总储量达 182 .6 4 5～ 394 .70 1t·hm-2 ,植被占 0 .5 9%～2 .13% ;林分生物量为 131.713～ 5 0 3.82 2t·hm-2 ,乔木层占 92 .1%～ 99.2 % ;凋落物层现存量和营养元素积累量分别为 2 .897～ 33.999t·hm-2 和 10 4 .339～ 1136 .5 36kg·hm-2 .在一定范围内 ,林分生物量和营养元素积累量随密度的增加而增大 ;立地、林分条件相似的林分 ,生物量和营养元素积累量与林龄呈正相关 .林分针叶树占的比例越大 ,营养元素积累量越小 ,而且对生物量的影响远小于对营养元素积累量的影响 .在同一地区 ,立地、林分状况相似 ,林型不同 ,生物量及营养元素积累量差别不大 ,树种组成和林型不同林分的生物量和营养元素积累量均不同 .不同地区 ,生态和林分条件相似的林分的生物量和营养元素积累量也有差异 ;林型、结构相似林分生物量和营养元素积累量南坡 >北坡 ,中段 东段≈西段 .林分对营养元素利用率与海拔呈负相关 ,且南坡 >北坡 ,中段 >东西段 ,中段 >西段 >东段 .

Eco-environment and nutrient accumulation of sharptooth oak stands in southern slope of Mt.Qinling

Based on the date from chemical analysis of 10,785 botanical and 1489 edaphic samples, the amount of nutrients accumulated in soil layer (0-60 cm) of sharptooth oak stands, the total biomass of the stands and their contents of accumulated nutrients, and the amount of litter and its contents of accumulated nutrients in southern slope of Mt. Qinling were calculated. To a certain extent, the biomass and the nutrient accumulation of the stands were increased with stand densities and stand ages from thin to high or from young to old, similar to the utilization efficiency of the stands to soil nutrient elements and the trunk canopy ratio. The tree composition of the stands much more influenced nutrient accumulation contents than the biomass. The more broad-leaved tree of species composition, the higher nutrient accumulation contents of stands. In the same region biomass and its nutrient contents of the stands with similar site factors and stand factors had not remarkably difference among different forest-types, but had a difference among various forest types and species composition. In different region, biomass and its nutrient contents of the stands with similar site factors and stand factors had a difference with the sequence of south slope > north slope, middle section > east section or west section. The utilization efficiency of soil nutrient elements by the stands was decreased from lower to higher elevation, from the south to north slope, from middle to east and west section.