关键词: 福建柏, 杉木, 凋落物, 季节动态, 养分, 能量

Abstract:

Three-year study was carried out to determine amount, component, seasonal dynamics and chemistry of litterfall and its returns of nutrient and energy in plantations of Fokienia hodginsii and Cunninghamia lanceolata in Fujian Province.Mean annual litterfall were up to 731.83 g·m ^-2 in F. hodginsii stand, being 1.34 times higher than that in C. lanceolata stand, of which 65.29% was occupied by needle litter. Except for components of needle and flower, the proportions of other fractions to total litterfall of F. hodginsii were all lower than those of C. lanceolata. Monthly litterfall of both stands peaked in April (or May) and November (or December), with the highest in December for F. hodginsii stand. While for C. lanceolata stand, peak values were close and there occurred another peak of litterfall in August. Annual returns of nutrient and energy of litterfall in F. hodginsii stand was 13.961 g·m ^-2 and 14 636.58 kJ·m ^-2 respectively, being respective 1.16 and 1.19 times as much as those in the stand of C. lanceolata. Moreover, nutrient and energy returns through needle litter was the primary pathway, with greater values also found in the stand of F. hodginsii.Litter chemistry (e.g. content of lignin and nitrogen) can exert a profound influence on the decay rate. In this study, contents of N, P and readily decomposable materials (such as water-soluble compounds, hemicellulose and coarse protein) in needle litter of F. hodginsii were higher than those of C. lanceolata. While the reverse was true for contents of decay-resistant materials and ratios of C/N, C/P, lignin/N and lignin/P in needle litter. These indicated that quality of needle litter of F. hodginsii was better than that of C. lanceolata, thus faster rates of decomposition and nutrient release occurred in litter of F. hodginsii in contrast to those of C. lanceolata.

Key words: Fokienia hodginsii, Cunninghamia lanceolata, Litterfall, Seasonal dynamics, Nutrient, Energy