福建九龙江口不同林龄拉关木人工林 凋落物组成及季节动态

The litter of three different forest ages (4, 6, and 8 years old) of Laguncularia racemosa in the artificial mangrove forest at the estuary of the Jiulong River in Fujian was collected throughout the year, and its quantity, composition, and seasonal dynamics were measured. The results showed that the annual litterfall amounts of the 4-, 6-, and 8-year-old Laguncularia racemosa forests were 10,930.1, 12,085.3, and 13,723.4 kg/hm² respectively. The litter composition of the Laguncularia racemosa forests of each forest age was mainly composed of fallen leaves. The amounts of fallen leaves of the 4-, 6-, and 8-year-old Laguncularia racemosa forests accounted for 86.16%, 77.47%, and 81.30% of the total annual litterfall respectively, and the proportions of fallen branches, fallen flowers, and fallen fruits in the annual litter were relatively small. The annual litterfall amounts of the Laguncularia racemosa forests of each forest age all showed obvious seasonal dynamics, and their seasonal variation curves were all bimodal. The peaks of the 4-year-old and 6-year-old Laguncularia racemosa forests appeared in May and September, while those of the 8-year-old Laguncularia racemosa forest appeared in April and September. The change patterns of fallen leaves and total litterfall of the Laguncularia racemosa forests of each age group were the same, while the change patterns of fallen branches, fallen flowers, and fallen fruits were not exactly the same. The research results can provide a reference for the management of the artificial Laguncularia racemosa forest in the estuarine wetland ecosystem.

收集福建九龙江口人工红树林拉关木( Laguncularia racemosa) 中的4、6、8 年生3 种不同林龄植被全年的凋落物，测定其数量、组成及季节动态． 结果表明，4、6、8 年生拉关木林年凋落量分别为10 930． 1、12 085． 3、13 723． 4 kg /hm2 ． 各林龄拉关木林的凋落物组成均以落叶为主，4、6、8 年生拉.关木林的凋落叶量分别占年总凋落量的86． 16%、77． 47%、81． 30%，落枝、落花、落果在年凋落物中所占的比例较小． 各林龄拉关木林年凋落物量均显示出明显的季节动态，其季节变化曲线均呈双峰型，4 年生和6 年生的拉关木林均在5 月和9 月出现峰值，而8 年生的拉关木林则在4 月和9 月.出现峰值; 各年龄段的拉关木林的落叶和总凋落量变化模式相同，而落枝、落花、落果的变化模式不尽相同． 研究结果可为河口湿地生态系统拉关木人工林的经营管理提供参考．