Decomposition of coarse woody debris in a long-term litter manipulation experiment: a focus on nutrient availability

1.The majority of aboveground carbon in tropical forests is stored in wood, which is returned to the atmosphere during decomposition of coarse woody debris. However, the factors controlling wood decomposition have not been experimentally manipulated over time scales comparable to the length of this process.

2.We hypothesized that wood decomposition is limited by nutrient availability and tested this hypothesis in a long-term litter addition and removal experiment in a lowland tropical forest in Panama. Specifically, we quantified decomposition using a 15 year chronosequence of decaying boles, and measured respiration rates and nutrient limitation of wood decomposer communities.

3.The long-term probability that a dead tree completely decomposed was decreased in plots where litter was removed, but did not differ between litter addition and control treatments. Similarly, respiration rates of wood decomposer communities were greater in control treatments relative to litter removal plo...

1. 热带森林的地上碳库大多储存在木材中，而粗木质残体（coarse woody debris）分解过程中，这些碳会重新释放回大气。然而，目前尚无在与木材分解过程时长相当的时间尺度上，对调控木材分解的因子开展实验操控的相关研究。
2. 我们提出假设：木材分解过程受养分有效性限制，并在巴拿马低地热带雨林开展了长期凋落物添加与移除实验以验证该假说。具体而言，我们利用15年的枯立木腐烂年代序列（chronosequence）量化分解程度，并测定了木材分解群落的呼吸速率与养分限制情况。
3. 移除凋落物的样地中，枯木完全分解的长期概率有所降低，但凋落物添加组与对照组之间并无显著差异。与之类似，木材分解群落的呼吸速率在对照组中高于凋落物移除样地。