柏木低效林林窗改造初期边界木细根形态和生物量变异

Fine Root Morphology and Biomass Characteristics at Preliminary Stage of Gap Border Trees of Reformed Low Beneficial Cupressus funebris Forests

为深入探究川中丘陵区柏木低效林林窗改造初期边界木林细根的生态适应,利用土柱法对34年生柏木低效林在人造小面积开窗（50m2、100m2、150m2）处理1年后的林窗边界木1~5级细根直径、根长、比根长、根长密度和生物量变异进行研究。结果显示：（1）柏木1~5级细根平均直径、根长随着根序的上升而增加,比根长、根长密度随着根序的上升而减小。（2）与林内对照（无林窗）相比,人工开林窗处理后边界木细根在同一根序上的平均直径变化不显著,根长和比根长增加,根长密度和生物量则呈降低的趋势。（3）开窗150m2面积林窗抚育后的柏木边界木更大限度地提高了低级根序的物质分配,提高比根长并降低组织密度,更快速地利用地下林窗空间资源。研究表明,柏木低效林林窗式疏伐得到的土壤资源由于更新草本、灌木的生长,增加了林木根系竞争土壤空间的压力,使得根系进行扩展性生长,细根形态和生物量表现出异质性变化。

In order to adapt the ecological adaptation of fine root of gap border trees at preliminary stage,we studied the 34-year old Cupressus funebris plantation in central Sichuan hilly region,researched the first five orders of fine root dynamic rules of fine root morphology and biomass of different size of gaps（50m2,100m2 and 150m2）and C.funebris plantation（Ⅳ）at the first year.The main results were found as follows：（1）The fine root morphology and biomass of different root orders of C.funebris plantation have obvious change rule.The specific root length（SRL）and root length density（RLD）of the first order root were the largest,but the average diameter,average root length and biomass of the first order root were the smallest.The SRL and RLD of the fifth order root were the smallest,but the average diameter and biomass of the fifth order root were the largest.Fine root biomass and average diameter of C.funebris significantly increased with increase in order（P〈0.05）,while SRL and RLD decreased.（2）Compared with C.funebrisplantation（Ⅳ）,fine root of gap border trees（GBT）have insignificant average diameter,increase average root length and SRL,reduce RLD and biomass at the same root order.（3）GBT at the gap of 150m2 highly raised Matter Distribution of low root orders,with increasing SRL and decline RLD,to use underground forest gap in a more quality way.In conclusion,with the renew of herbs and shrubs the forest gaps have increased pressure of root to competition soil spaces,expansionary growth and heterogeneous exchange of fine root morphology and biomass.