Wood decomposition in tropical forests is strongly linked to the terrestrial carbon cycle. Our understanding of the successional changes in wood decomposition in diverse tropical forests is still limited. In this study, we tested the hypothesis that fine wood decomposition rates decline with the increasing age of successional forests due to the interspecific variation in wood density and changes in species composition. We studied fine wood decomposition in a chronosequence of tropical forests representing four successional phases in southern Mexico. Wood segments (1–7.5 cm diameter) from 30 dominant species (wood density range 0.34–0.83 g cm⁻³) were left on the ground for decomposition, and samples were recollected at different time intervals for three years. We used a modified negative exponential model by introducing the power parameter (p) that allowed for a time-dependent decomposition rate (k). Average k within a successional phase ranged from 0.22 to 0.39 yr⁻¹ and declined gradually with the increase in forest age. We found a significant negative correlation between wood density and decomposition rate constants. The k_species ranged from 0.07 to 1.11 yr⁻¹, whereas p-parameters varied between 0.65 and 1.42. Trees such as Bursera simaruba, and Cascabela gaumeri decomposed faster, while Eugenia ibarrae, and Pouteria reticulata decomposed slower. Average fine woody debris inputs ranged from 1.2 to 3.7 Mg ha⁻¹ yr⁻¹ which increased with forest age. Increasing production and declining decomposition rates during succession contribute to the higher accumulation of deadwood in primary forests. The results on generalized, age- and species-specific wood decay parameters have important implications in simulating carbon dynamics of the changing tropical forests.

热带森林中的木材分解与陆地碳循环密切相关。我们对不同热带森林中木材分解的演替变化的了解仍然有限。在这项研究中，我们检验了以下假设：由于木材密度的种间变化和物种组成的变化，细木分解率随着演替森林年龄的增加而下降。我们在代表墨西哥南部四个演替阶段的热带森林的时间序列中研究了细木分解。来自 30 种优势树种的木段（直径 1-7.5 cm）（木材密度范围 0.34-0.83 g cm ^-3) 留在地上进行分解，并在三年的不同时间间隔重新收集样品。我们通过引入允许时间相关分解率 ( k )的功率参数 ( p ) 来使用修改后的负指数模型。演替阶段的平均k范围为 0.22 至 0.39 yr ^-1并随着林龄的增加而逐渐下降。我们发现木材密度和分解速率常数之间存在显着的负相关。所述ķ_物种范围从0.07至1.11年^-1，而对参数0.65和1.42之间变化。树，如Bursera simaruba和Cascabela gaumeri分解快，而尤金尼亚ibarrae，和桃榄属网状分解要慢。平均细木屑输入范围为 1.2 到 3.7 Mg ha ^-1 yr ^-1，随着森林年龄的增加而增加。演替过程中产量的增加和分解率的下降导致原始森林中枯木的积累增加。广义的、特定于年龄和物种的木材腐烂参数的结果对模拟不断变化的热带森林的碳动态具有重要意义。