川西亚高山针阔混交林与针叶纯林苔藓凋落物层持水性能研究

Water Holding Capacities of Bryophyte and Litter Layer Under Mixed Forest and Coniferous Forest in Subalpine Region of Western Sichuan

采用野外实地观测和室内浸水法对川西亚高山地区针阔混交林与针叶纯林林下苔藓凋落物的持水能力进行了对比研究。结果表明:(1)混交林林下苔藓凋落物层储量为10.02t/hm2,最大平均持水量为54.96t/hm2,最大平均持水率为839.70%;苔藓储量为2.43t/hm2,最大平均持水量为11.47t/hm2,最大平均持水率为472.23%,吸水速率经过24h从7683.2g/(kg.h)下降为256.5g/(kg.h);凋落物储量为7.59t/hm2,最大平均持水量为24.07t/hm2,最大平均持水率为317.22%,吸水速率经过24h从8530.1g/(kg.h)下降为321.4g/(kg.h)。(2)针叶纯林林下苔藓凋落物层储量为9.37t/hm2,最大平均持水量为45.70t/hm2,最大平均持水率为766.05%;苔藓储量为2.13t/hm2,最大平均持水量为9.68t/hm2,最大平均持水率为454.85%,吸水速率经过24h从6444.4g/(kg.h)下降为231.4g/(kg.h);凋落物储量为7.24t/hm2,最大平均持水量为21.20t/hm2,最大平均持水率为292.68%,吸水速率经过24h从7004.9g/(kg.h)下降为251.4g/(kg.h)。因此,无论是持水量、持水率,还是吸水速率,混交林都强于针叶纯林。两种林分下,苔藓、凋落物持水率随浸泡时间的增加而增加,持水率与浸泡时间呈对数关系;苔藓、凋落物的吸水速率随浸泡时间的增加而降低,吸水速率与浸泡时间呈幂函数关系。

By field survey and water immersion,water holding capacities of bryophyte and litter layer under mixed forest and coniferous forest in sub-alpine region of western Sichuan were studied. The results showed that： （1）In the mixed forest,the storage amount bryophyte and litter layer was 10.02 t/hm2,the maximal water holding capacity was 54.96 t/hm2,the average mean maximal water holding rate was 839.70%;Bryophyte storage amount was 2.43 t/hm2,the maximal water holding capacity was 11.47 t/hm2,the maximal water holding rate was 472.23%,and the water absorption rate decreased from 7 683.2 g/（kg·h） to 256.5 g/（kg·h） after 24 h;litter storage amount was 7.59 t/hm2,the maximal water holding capacity was24.07 t/hm2,the maximal water holding rate was 317.22%,the water absorption rate decreased from 8 530.1 g/（kg·h） to 321.4 g/（kg·h） after 24 h. （2）In the coniferous forest,bryophyte and litter layer storage amount was 9.37 t/hm2,the maximal water holding capacity was 45.07 t/hm2,the maximal water holding rate was 766.05%;Bryophyte storage amount was 2.13 t/hm2,the maximal water holding capacity was 9.68 t/hm2,the maximal water holding rate was 454.85%,and after 24h,the water absorption rate decreased from 6 444.4 g/（kg·h） to 231.4 g/（kg·h）;while,litter storage amount was 7.24 t/hm2,the maximal water holding capacity was 21.20 t/hm2,the maximal water holding rate was 292.68%,and after 24 h,the water absorption rate decreased from 7 004.9 g/（kg·h） to 251.4 g/（kg·h）.Therefore,on the aspects of water holding capacity,water holding rate,or water absorption rate,the mixed forest was always higher than coniferous forest. Water holding rate of bryophyte and litter in the two kinds of forest increased logarithmically with time immersed in water;while water absorption rate decreased with the increasing time,representing power function trend.