湖南沅陵天然次生白栎+檫木+杉木群落生物量及其分布规律

Biomass and its distribution of natural secondary Quercus fabri + Sassafras tsumu+ Cunninghamia lanceolata community in Yuanling County,Hunan Province

采用样方法和回归方程法,研究了湖南沅陵天然次生白栎+檫木+杉木群落生物量及其分布规律。结果表明:(1)群落总生物量为176.669t/hm2,其中乔木层、灌木层、草本层和死地被物层生物量分别为144.886、17.060、0.340和14.383t/hm2。(2)群落乔木层生物量径级分布中,生物量主要集中于10～18cm径级,随径级的增大生物量呈现双峰分布特点,其中第1个高峰为10cm径级,第2个高峰为16cm径级。干、枝随径级增大而增大,皮、叶、根随径级增大而略有减小。(3)白栎、檫木和杉木为群落建群种,生物量分别为51.228、33.460和21.590t/hm2,重要值分别为32.492、15.428和22.801。(4)群落乔木层生物量垂直分布中,地上部分生物量主要集中于7.6m以下,且7.6m以下生物量分布较均匀,7.6m以上生物量随高度的增加而逐渐减小。干、皮生物量也主要集中于7.6m以下,生物量随着高度变化呈金字塔型。枝、叶生物量分布相对集中,主要分布于5.6～7.6m。地下根系生物量垂直分布较为均匀;粗根和细根生物量垂直分布规律与总根系生物量分布规律相似;中根生物量分布与总根系分布有所差异,中根主要集中于45cm以上土层,生物量随土层加深呈正态分布。

Based on the history data of forest management and field survey in Yuanling of Hunan,Biomasses and their distribution of Quercus fabri Hance＋ Sassafras tsumu＋ Cunninghamia lanceolata community in four sample plots with similar site conditions and stand factors were measured and analyzed.The results show that：（1）The whole community biomass was 176.669 t/hm2,including the tree layer 144.886 t/hm2,the shrub layer 17.060 t/hm2,the herb layer 0.340 t/hm2,the death layer 14.383 t/hm2.（2）For the tree layer biomass diamater distribution,the biomasses mainly concentrated on 10～18 cm diamater class.With diameter increasing,the biomass presented double peak distribution.The first biomass peaks was 10 cm diameter,the second was 16 cm.For each organ biomass diamater distribution,the stem and branch biomass increased,the bark,leaf and root biomass decreased with diameter increasing.（3） There were three kinds of chief species： Quercus fabri Hance,Sassafras tsumu and Cunninghamia lanceolata;their biomasses were 51.228,33.460 and 21.590 t/hm2,importance values were 32.492,15.428 and 22.801.（4）For the tree layer＇s biomass vertical distribution,aboveground biomasses concentrated on 0～7.6 m.and were homogeneous distribution.The biomasses 7.6 m decreased with height increasing.For the aboveground organ biomass vertical distribution,the stem and trunk biomass also focused on 0～7.6 m,and presented pyramid-type with height increasing.The branches and leaves biomass mainly distributed between 5.6 and 7.6 cm.The root biomass vertical distribution,was with soil depth.And the thick and fine root biomass distributed as the same as the total root system＇s.However,the mediumsized root biomass distribution differed from the total root system＇s.Mediumsized root biomass focused on 0～45 cm soil and presented normal distribution with soil depth.This research results would provide scientific basis for forest nutrient cycling,sustainable management,global carbon cycle and climatic change.