Litterfall in the Semideciduous Seasonal Forest in Southern Brazil

Abstract Litterfall and nutrient cycling are essential processes for the forest diversity and productivity maintenance. This study aims to characterize the litterfall and evaluate if it has correlations with climatic variables in the Semideciduous Seasonal Forest on advanced succession stage, in Southern Brazil. During the 2007-2010 period, the litterfall was collected every month, sorted into leaves, twigs, and miscellaneous fractions. The litterfall amount average was 7.75 Mg ha-1 year-1 and leaves constituted the highest litterfall percentage (75.0%), followed by twigs (14.7%), and miscellaneous (10.3%). Higher leaf amounts were recorded in August and September. The minimum air temperature was negatively correlated with the leaves and twigs production, that is, the litterfall amount increases when the air temperature decreases. The litterfall amount corresponds to values expected to advanced successional stage of the forest typology studied. In Semideciduous Seasonal Forest in Southern Brazil, the thermal stress exerts influence on the litterfall amount.

摘要：凋落物(litterfall)与养分循环(nutrient cycling)是维持森林多样性与生产力的核心过程。本研究旨在表征巴西南部演替后期阶段的半落叶季节性森林(Semideciduous Seasonal Forest)的凋落物特征，并评估其与气候变量(climatic variables)的相关性。2007-2010年期间，研究人员每月采集凋落物，并将其划分为叶片、细枝与杂项组分。该区域年均凋落物总量为7.75 Mg·ha⁻¹·年⁻¹，其中叶片占凋落物总量的比例最高（75.0%），其次为细枝（14.7%）与杂项组分（10.3%）。叶片凋落量在8月与9月达到较高水平。最低气温与叶片、细枝的凋落产量呈负相关关系，即气温下降时，凋落物总量随之升高。本次研究测得的凋落物总量与该森林类型演替后期阶段的预期值相符。在巴西南部的半落叶季节性森林中，热胁迫对凋落物总量存在影响。