珠江流域中游主要森林类型凋落物持水特性

Water-holding Characteristics of Litter Under Main Forest Types in the Middle Reaches of Pearl River Basin

采用野外实地调查与室内分析相结合的方法,对珠江流域中游苍梧县的5种森林类型的凋落物累积量和持水量、持水率、吸水速率等持水特性进行了研究。结果表明:不同森林类型凋落物总储量为湿地松(Pinus elliottii)+荷木(Schima superba)混交林(40.18t/hm^2)>桉树(Eucalyptus)林(11.77t/hm^2)>马尾松(Pinus massoniana)林(10.97t/hm^2)>红锥(Castanopsis hystrix)林(8.75t/hm^2)>大叶栎(Quercus griffithii)林(7.71t/hm^2),且半分解层累积量所占比例均大于未分解层,马尾松林则相反;5种森林类型不同分解程度的凋落物持水量和持水率与浸泡时间均呈对数关系,吸水速率与浸泡时间呈幂函数关系;凋落物最大持水量为13.12~77.09t/hm^2,湿地松+荷木混交林最大,红锥林最小;最大持水率为150.8~187.9%,大叶栎林最大,红锥林最小;有效拦蓄量为8.26~49.31t/hm^2,大小顺序为湿地松+荷木混交林>大叶栎林>红锥林>桉树林>马尾松林。综合考虑,研究区5种森林类型中湿地松+荷木针阔混交林持水能力最强,且优势明显,因此,水源涵养林宜优先选择针阔混交林模式。

Litter layer plays a significant hydro-ecological role in forest ecosystem. By the field investigation and laboratory analysis, a study was conducted on the accumulation amount, water-holding capacity, water- holding rate and water-absorption rate of the litter under five main forests （Pinus massoniana forest, Eucalyptus forest, Castanopsis h ystrix forest, Quercus griffithii forest, Pinus elliottii ＋ Schima su perba forest） in the middle reaches of Pearl River. The litter accumulation under the forest decreased in the order of P. elliottii ＋ S. superba forest （40. 18 t/hm^2） 〉Eucalyptus forest （11. 77 t/hm^2） 〉P. rnassoniana forest （10.97 t/hm^2）〉C . hystrix forest （8.75 t/hm^2）〉Q. griffithii forest （7.71 t/hm^2）, and the percentage of semi-decomposed litter storage was higher than that of un-decomposed litter, whereas for P. massoniana forest, it was in adverse. The water-holding capacity and water-holding rate of litter at different decomposition degrees changed logarithmically, while the water-absorption rate assumed a power function of soaking time. The maximum water-holding capacity of the litter varied from 13.12 t/hm^2 to 77.09 t/hm^2 , being the highest for P. elliottii ＋ Schima superba forest and the lowest for C. hystrix forest. The maximum water-holding rate of the litter was 150. 8- 187. 9%, being the highest for Q. griffithii forest and the lowest for C. hystrix forest. The effective retaining capacity of the litter ranged from 8. 26 t/hm^2 to 49. 31 t/hm^2, and decreased in the order of P. elliottii forest〉P, massoniana forest. among these forests. So, this needle modes and broadleaved Water ＋ S. superba f conservation ca study can deciduous provide the m Improving orest〉Q, gri f fithii forest〉C, hystrix fores t〉Eucalyptus pacity of P. elliottii ＋ S. superba forest was the strongest important basic theory that can select conifer-broadleaf forest hydro-ecological effects of water conservation forests.