秦岭太白山北坡五种林分凋落叶分解状况初步研究

对秦岭太白山北坡锐齿栎、牛皮桦、太白红杉、大叶杜鹃和巴山冷杉5种林分凋落叶的分解状况进行了研究。结果表明,受生物学特性、温度、湿度等因素的影响,不同林分凋落叶叶失重率不同,上述林分分别为38.20%,32.12%,16.23%,20.76%和17.87%～18.29%;其分解速率大小次序为锐齿栎>牛皮桦>大叶杜鹃>巴山冷杉>太白红杉。所测定的3种主要化学成分中,单宁分解最快,分布于海拔3000m的巴山冷杉和1430m的锐齿栎凋落叶中,单宁残留量只有34.39%和32.05%;粗脂肪分解速率次之,阔叶树种较针叶树种分解快,在凋落叶中的残留量为91.86%～99.14%;粗纤维分解最慢,与粗脂肪表现出相似的规律。林分凋落叶分解过程中能态的变化与分解速率高低基本保持一致,总体趋势为阔叶树种减低幅度较大,5种凋落叶能量降低率为12.54%～19.84%。

A preliminary study on the leaf decomposition of five stands on North-facing slope of the Taibai Mountains

This paper studies the decomposition situation of litters of five stands on the North-facing slope,namely Quorcus aliena BI var.acutesorrata,Betula utilis,Larix chinensis,Rhododendron purdomii,(Abies fargesii).The results show that the decomposition rate of litter leaves varies with biological characteristics,temperature,humidity and so on;the weight losing rate of Q.aliena,B.utilis,L.chinensis,R.purdomii,A.fargesii are respectively 38.20%,32.12%,16.23%,20.76%,and 17.87%-18.29%.Among the tested three main chemical compositions,tannin decomposes fastest,of which A.fargesii and Q.aliena are (34.39%) and 32.05% respectively at the height of 3 000 m and 1 430 m;the next is raw fat,the decrease of broadleaf is faster than that of conifer,the remaining content of raw fat in the litters is between 91.86% and 99.14%;the last is raw fiber,which has the similar tendency with raw fat.During the decomposition of litters,the change of energy is consistent with the decomposition rate,the general trend is that the diminution extent of broadleaf is larger than that of others,and the energy diminution rate of five litters are between 12.54% and 19.84%.