Celentano Danielle, Zahawi Rakan A, Finegan Bryan, Casanoves Fernando, Ostertag Rebecca, Cole Rebecca J, Holl Karen D
Centro Agronómico Tropical de Investigación y Enseñanza (CATIE), Apartado Postal 7170, Turrialba, Cartago, Costa Rica.
Rev Biol Trop. 2011 Sep;59(3):1323-36.
Tropical forest restoration strategies have the potential to accelerate the recovery of the nutrient cycles in degraded lands. Litter production and its decomposition represent the main transfer of organic material and nutrients into the soil substrate. We evaluated litter production, accumulation on the forest floor, and its decomposition under three restoration strategies: plantation (entire area planted with trees), island (trees planted in patches of three different sizes) and control (natural regeneration) plots. We also compared restoration strategies to young secondary forest (7-9 yr). Restoration treatments were established in 50 x 50m plots in June 2004 at six sites in Southern Costa Rica. Planted tree species included two native timber species (Terminalia amazonia and Vochysia guatemalensis) interplanted with two N fixers (Erythrina poeppigiana and Inga edulis). Litter was collected every 15 days between September 2008 and August 2009 in 12 0.25m2 litter traps distributed within each plot; litter that accumulated on the soil surface was collected at four locations (0.25m2 quadrats) within each plot in February and May 2009. Total litter production in plantation (6.3Mg/ha) and secondary forest (7.3Mg/ha) did not differ, but were greater than in islands (3.5Mg/ha) and control (1.4 Mg/ha). Plantation had greatest accumulation of litter on the soil surface (10.6 Mg/ha) as compared to the other treatments (SF = 7.2; I = 6.7; C = 4.9). Secondary forest was the only treatment with a greater annual production of litter than litter accumulation on the soil surface. Carbon storage in litter was similar between plantation and secondary forest, and significantly greater than the other treatments. No differences were found for carbon concentration and storage in the soil among treatments. There was also high variability in the production and accumulation of litter and carbon among sites. Active restoration treatments accelerated the production of litter and carbon storage in comparison to areas under natural recovery. However, the nutrient cycle has not necessarily been restored under these conditions, as high litter accumulation on the soil surface indicates a low decomposition rate, which slows nutrient return to the soil.
热带森林恢复策略有潜力加速退化土地养分循环的恢复。凋落物的产生及其分解是有机物质和养分向土壤基质转移的主要途径。我们评估了三种恢复策略下的凋落物产生量、在森林地面的积累情况及其分解情况：人工林（整个区域种植树木）、岛屿式（树木种植在三种不同大小的斑块中）和对照（自然更新）样地。我们还将恢复策略与年轻的次生林（7 - 9年）进行了比较。2004年6月，在哥斯达黎加南部的六个地点，在50×50米的样地中建立了恢复处理。种植的树种包括两种本地木材树种（亚马孙榄仁树和危地马拉沃奇西亚木）与两种固氮树种（波氏刺桐和可食印加树）间种。2008年9月至2009年8月期间，每隔15天在每个样地内分布的12个0.25平方米的凋落物收集器中收集凋落物；2009年2月和5月，在每个样地内的四个位置（0.25平方米的样方）收集积累在土壤表面的凋落物。人工林（6.3吨/公顷）和次生林（7.3吨/公顷）的总凋落物产量没有差异，但高于岛屿式（3.5吨/公顷）和对照（1.4吨/公顷）。与其他处理相比，人工林在土壤表面的凋落物积累量最大（10.6吨/公顷）（次生林 = 7.2；岛屿式 = 6.7；对照 = 4.9）。次生林是唯一年凋落物产量高于土壤表面凋落物积累量的处理。人工林和次生林凋落物中的碳储量相似，且显著高于其他处理。各处理间土壤中的碳浓度和储量没有差异。不同地点间凋落物和碳的产量及积累量也存在很大差异。与自然恢复区域相比，积极的恢复处理加速了凋落物的产生和碳储存。然而，在这些条件下养分循环不一定得到了恢复，因为土壤表面高凋落物积累表明分解速率低，这减缓了养分返回土壤的速度。
