Vascular epiphyte biomass in a South Brazilian fragment of Atlantic Forest

Abstract The present study aimed at sampling the biomass of vascular epiphytes within a protected area in South Brazilian Atlantic Forest. All tree specimens with diameter at breast height equal or greater than 4.8 cm were measured and divided into classes. In each class, 10% of tree specimens were randomly selected for epiphytic biomass measuring. Furthermore, we divided the phorophytes into five tree parts to analyze epiphytic biomass. We generated mathematical models to estimate epiphytic biomass in similar forest areas. We analyzed 55 phorophytes and found an estimated epiphytic biomass of 5.3 Mg/ha. Epiphytic biomass ranged from 0.02 to 135 kg and the lower values were found on small-sized phorophytes. Higher values of epiphytic biomass were found on phorophytes with diameter at breast height between 30 and 36.5 cm. The tree part with higher epiphytic biomass was the outer crown. The epiphytic biomass showed a high correlation with phorophyte diameter, according to the mathematical models. We selected two equations which presented the most similar values to the ones we measured. Our results corroborate that epiphytes play a very important role as to the biomass level within tropical forests.

摘要 本研究旨在对巴西南部大西洋森林某保护区内的维管附生植物（vascular epiphytes）生物量开展采样调查。所有胸径（diameter at breast height）不小于4.8 cm的树木样本均被测量并划分至相应径级。每个径级中随机选取10%的树木样本，用于附生植物生物量的测定。此外，我们将附生宿主树（phorophytes）划分为五个树体部位，以分析附生植物生物量的分布特征。本研究构建了数学模型，用于估算同类森林区域的附生植物生物量。本次研究共分析了55株附生宿主树，估算得到的附生植物生物量为5.3 Mg/ha。附生植物生物量范围为0.02至135 kg，低值多出现于小型附生宿主树中。胸径介于30至36.5 cm之间的附生宿主树，其附生植物生物量水平更高。附生植物生物量最高的树体部位为树冠外层。数学模型分析显示，附生植物生物量与附生宿主树胸径呈现高度相关性。我们筛选出两个与实测值最为接近的拟合方程。本研究结果证实，附生植物在热带森林的生物量构成中发挥着极为重要的作用。