甘肃兴隆山天然林苔藓凋落物自然持水特性

Natural Water-Holding Characteristics of Moss and Litter under two Natural Forests in Xinglong Mountain of Gansu

2014—2015年,采用野外实地观测与人工降水试验法,对甘肃兴隆山天然青杄纯林和山杨—白桦—青杄混交林的苔藓和凋落物自然含水量动态、苔藓及凋落物持水性能与降水因子关系进行了研究。结果表明:(1)山杨—白桦—青杄混交林和青杄纯林苔藓生物量分别0.30t/hm^2和1.83t/hm^2;凋落物蓄积量分别为57.08t/hm^2和51.44t/hm^2;凋落物层在森林地被物中具有十分重要的位置,而苔藓层为次要位置;(2)青杄林苔藓、凋落物自然含水量月动态变化较大,但凋落物层变化明显滞后于苔藓层;苔藓、凋落物层自然含水量变化与当地降水量成正相关性,其含水量4—6月较小,7—8月较高;苔藓、凋落物层自然含水量最小值依次为10%和25%,最大依次为125%和115%;(3)在降水过程中,森林苔藓及凋落物吸持降水是一个十分缓慢的过程;只有在小强度、长历时降水条件下,才有可能使森林苔藓及凋落物层吸持水量达到饱和状态。

By the methods of field survey and artificial spraying test,the dynamic of natural water content and the relationship of water-holding capacity with precipitation factor of moss and litter were studied during 2014—2015,under two main natural forests（Picea wilsonii pure forest,and Populus davidiana-Betula platyphylla-P.wilosonii mixedforest）in Xinglong Mountain of Gansu.The results showed that：（1）The biomass of moss was 0.30t/hm^2 and 1.83t/hm^2 respectively for P.davidiana-B.platyphylla-P.wilosonii mixedforest and P.wilsonii pure forest,the total accumulation amount of litter was 57.08t/hm^2 and 51.44t/hm^2 for two forests respectively;Litter layer was very important position in forest cover,whereas moss layer was the secondary position;（2）The monthly dynamic change of natural water content of moss and litter layer was great for P.wilsonii pure forest,but the change of litter layer obviously lagged behind moss layer;The natural water content of moss and litter was positively related to local rainfall,and it was low during April to June,but high in July and August;The minimum of natural water content was 10% and 25%for the moss and litter layer,and the maximum was 125% and 115%respectively;（3）In the process of rainfall,the holding precipitation of moss and litter in forest was a very slow process;Only under the condition of small intensity and long duration of rainfall,the water-holding content of moss and litter of forest is likely to reach the saturated state.