三峡库区几种林下枯落物的水文作用

Hydrological process of litter on forest stands in the Three Gorges area

该文通过对三峡库区 3种森林类型 (松栎混交林、栓皮栎纯林、马尾松纯林 )林下枯落物储量调查分析及其持水特性试验 ,得到不同森林类型林下枯落物储量、最大持水量、吸水速率等水文特征参数 .结果表明 ,栓皮栎纯林林下枯落物储量最大 (10 7t hm2 ) ,其后依次为松栎混交林 (10 1t hm2 )、马尾松纯林 (5 8t hm2 ) .松栎混交林林下枯落物未分解层最大持水量为 3 0 9mm ,栓皮栎纯林为 2 95mm ,马尾松纯林为 1 4 6mm .松栎混交林林下枯落物半分解层最大持水量为 3 0 3mm ,栓皮栎纯林为 2 37mm ,马尾松纯林为 0 99mm .研究结果还表明 ,在同为中龄林条件下 ,三峡库区针阔混交林林下枯落物持水能力大于阔叶树纯林或针叶树纯林林下枯落物持水能力 .在只有林下枯落物覆盖情况下 ,不同森林类型林内不产生水分下渗和地表径流时的最大降雨量和最大雨强分别为 :松栎混交林林地 6 12mm ,7 0 0 0mm h ;马尾松纯林林地 2 4 5mm ,1 76 0mm h ;栓皮栎纯林林地 5 32mm ,6 2 0 0mm h .

Through the survey of forest litter amount and the experiment of water holding characteristics in three kinds of forest stands (the mixed forest of Quercus variables B1. and Pinus massoniana Lamb., the pure Quercus variabils B1. forest and the pure Pinus massoniana Lamb. forest) in the Three Gorges area in Hubei Province of China, the litter amount and the characteristics parameters, such as the maximum water capacity and water absorption speed, was studied. The results showed that the litter amount in the pure forest stand of Quercus variabils B1. was the maximum (10.7 t/hm2), the second was the mixed forest stand (10.1 t/hm2) and the third was the pure forest stand of Pinus massoniana Lamb. (5.8 t/hm2). The maximum water capacity of the undecomposed litter in the mixed forest stand was 3.09 mm, that of the litter in the pure forest stand of Quercus variabils B1. was 2.95 mm and that of the litter in the forest stand of pure Pinus massoniana Lamb. was 1.46 mm. The maximum water capacity of the half-decomposed litter in the mixed forest stand was 3.03 mm, that of the litter in the pure forest stand of Quercus variabils B1. was 2.37 mm and that of the litter in the pure forest stand of Pinus massoniana Lamb. was 0.99 mm. The results also showed that when they were in mid-age, the water holding ability of the litter in the mixed forest stand of broadleaf and conifer was higher than that of the litter in the pure broadleaf or in the pure conifer forest stand. When there was only litter in the forest stands, when there was not water infiltration and surface runoff, the maximum rainfall amount and the maximum rainfall intensity in different forest stands, were 6.12 mm and 7.000 mm/h (the mixed forest stand), 2.45 mm, and 1.760 mm/h (the pure Pinus massoniana Lamb. forest stand), 5.32 mm and 6.200 mm/h (the pure Quercus variables B1. forest stand) respectively.