A study on reserves and water holding function of litter in four types of evergreen broadleaved forest in subtropical zone of China

In order to explore the litter hydrological functions in four types of forest stands in the process ofPhyllostachys edulisexpansion to evergreen broadleaved forest in subtropical zone of China, this paper studied the reserves and hydro-logical parameters of litter in semi-decomposed layer and undecomposed layer such as the maximum water holding capac-ity and rate, the water absorption rate and the effective interception amount under four kinds of forest stand: evergreenbroad-leaved forest, bamboo(20%)- broadleaf(80%) mixed forest, bamboo(80%)-broadleaf(20%) mixed forest andMao bamboo pure forest in Dagangshan mountain forest ecological station, Jiangxi Province. The results were shown asfollows: 1 the total litter reserves in four kinds of forest stand could be arranged from high to low as: Mao bamboo pureforest bamboo(80%)-broadleaf(20%) mixed forest bamboo(20%)- broadleaf(80%) mixed forest evergreenbroadleaved forest. And litter reserves of semi-decomposed layer was higher than that of undecomposed layer. Effectiveinterception rate of bamboo(20%)- broadleaf(80%) mixed forest was the highest, which was 0.78, slightly higher thanthat of the Mao bamboo forest(0.77). The lowest interception rate was found in broad-leaved forest(0.42). 2 The wa-terholding capacity of litter in different stands with various decomposition rate was consistent. Due to limited reserves,the waterholding quantities in broad-leaved forest were the smallest in both undecomposed and semi-decomposed layers,which were respectively 0.33 mm and 0.44 mm. 3 The relationship between water holding capacity and immersion timein litter of four forest stands could be shown in the equation:S=aln(t)+b, water holding capacity of litter increased rap-idly within the first four hours, nthen rose slowly. While, the equation of the relationship between water absorption rateand immersion time was:V=at, and the litter water absorption rate decreased rapidly within the first two hours, thenthe rate was steady after two hours. By comprehensively analyzing litter reserves, water holding capacity and effective in-terception capacity, four kinds of stands hydrological effects of litter stand was difficult to clearly sort, its complex mech-anism needs further study. Bamboo forest in terms of reserves and water holding capacity were significantly better thanthe evergreen broad-leaved forest, water conservation capacity, along with the evergreen broad-leaved forest wasgradually being replaced by Mao bamboo pure forest, hydrological function of litter also increased.