Forest age is a major predictor of secondary forest functional properties and through the chronosequence approach continues to be a principal focus in local, landscape, and regional-scale studies of secondary succession. Recent work has shown that patterns of temporal change in functional properties differ markedly between wet and seasonally dry lowland forests, suggesting that decreasing light and increasing water availability, respectively, are the main drivers of successional change. Meanwhile, however, the potentially marked effects of anthropogenic factors (especially fire), soils, climate, and dispersal limitation on the variation of forest characteristics over landscapes remain poorly understood. We studied the functional properties of seasonally dry secondary forests 5–35 years after pasture abandonment on the Nicoya Peninsula, Costa Rica. We measured 11 functional traits for 63 dominant tree and palm species in 52 plots of 0.12 ha. We used linear regression and variation partitioning to determine the relative importance of soil, climate, site use, fire history, spatial factors, and forest age in the determination of community weighted mean (CWM) trait values. CWM leaf trait and stem trait spectra of the 52 plots were orthogonal in a PCA ordination. Our seasonal forest hypothesis, that forest functional properties become more acquisitive with age as suggested by other authors, was not supported, perhaps because our chronosequence was relatively short. Our fire tolerance hypothesis was that bark thickness, wood specific gravity and resprouting capacity would increase with time of exposure to fires. This hypothesis was not supported for bark thickness. Rather, our results suggest that wood specific gravity and resprouting capacity are better predictors of fire tolerance. Also, our results suggest that >10 years of exposure to fire generates changes in forest fire tolerance strategies from high CWM bark thickness to high wood specific gravity. Finally, we tested our dispersal limitation hypothesis, that spatial variables, expressed as principal coordinates of neighbor matrices (PCNM) eigenfunctions, predict variation in forest functional properties, using variation partitioning analysis with matrices of climate, soil, anthropogenic and spatial variables. The results (overall model R² = 0.46) indicated that spatial variables, followed by soil (acidity, depth, and extractable Mn), are the best overall predictors of forest functional traits values, supporting this hypothesis. Overall, fire, dispersal limitation and soil characteristics explain the functional properties of these secondary forests, with no effect of age in the 5–35 years range. This indicates a critical need for sampling designs and analytical approaches that take into account all these factors to advance understanding of tropical seasonal forest recovery at the landscape scale.

森林年龄是次生林功能特性的主要预测因子，通过时间序列方法继续成为次生演替的局部、景观和区域尺度研究的主要焦点。最近的工作表明，功能特性的时间变化模式在潮湿和季节性干燥的低地森林之间存在显着差异，这表明光照减少和可用水量增加分别是演替变化的主要驱动因素。然而，与此同时，人为因素（尤其是火灾）、土壤、气候和分布限制对森林特征在景观上的变化的潜在显着影响仍然知之甚少。我们研究了哥斯达黎加尼科亚半岛牧场废弃 5-35 年后季节性干燥次生林的功能特性。我们在 0.12 公顷的 52 个地块中测量了 63 种优势树种和棕榈树种的 11 个功能性状。我们使用线性回归和变异划分来确定土壤、气候、场地使用、火灾历史、空间因素和森林年龄在确定群落加权平均 (CWM) 特征值时的相对重要性。52 个地块的 CWM 叶性状和茎性状光谱在 PCA 排序中是正交的。我们的季节性森林假设，即森林功能特性随着年龄的增长而变得更加贪婪，正如其他作者所建议的那样，没有得到支持，这可能是因为我们的时间序列相对较短。我们的耐火性假设是树皮厚度、木材比重和重新发芽能力会随着暴露在火灾中的时间而增加。树皮厚度不支持该假设。相当，我们的结果表明，木材比重和再发芽能力是耐火性更好的预测指标。此外，我们的结果表明，超过 10 年的火灾暴露会导致森林防火策略发生变化，从高 CWM 树皮厚度到高木材比重。最后，我们测试了我们的扩散限制假设，即空间变量，表示为邻域矩阵的主坐标 (PCNM) 特征函数，使用气候、土壤、人为和空间变量矩阵的变异分区分析来预测森林功能特性的变化。结果（整体模型 R 10 年的火灾暴露导致森林防火策略发生变化，从高 CWM 树皮厚度到高木材比重。最后，我们测试了我们的扩散限制假设，即空间变量，表示为邻域矩阵的主坐标 (PCNM) 特征函数，使用气候、土壤、人为和空间变量矩阵的变异分区分析来预测森林功能特性的变化。结果（整体模型 R 10 年的火灾暴露导致森林防火策略发生变化，从高 CWM 树皮厚度到高木材比重。最后，我们测试了我们的扩散限制假设，即空间变量，表示为邻域矩阵 (PCNM) 特征函数的主坐标，使用气候、土壤、人为和空间变量矩阵的变异分区分析来预测森林功能特性的变化。结果（整体模型 R² = 0.46) 表明空间变量，其次是土壤（酸度、深度和可提取锰），是森林功能性状值的最佳整体预测因子，支持这一假设。总体而言，火、扩散限制和土壤特征解释了这些次生林的功能特性，在 5-35 年范围内不受年龄影响。这表明迫切需要考虑所有这些因素的抽样设计和分析方法，以促进对景观尺度热带季节性森林恢复的理解。