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.

O estudo das epífitas vasculares foi realizado em floresta ombrófila mista aluvial do rio Barigüi, município de Araucária (25º34' S e 49º20' W); o levantamento qualitativo foi realizado em uma área aproximada de 8,6 ha. Para o estudo quantitativo foram sorteados 110 forófitos, divididos em três estratos (fuste baixo, fuste alto e copa). Em cada estrato foram atribuídas notas de abundância para as espécies epifíticas ocorrentes. No levantamento florístico foram encontradas 49 espécies (16 de Pteridophyta, 23 de Liliopsida e 10 de Magnoliopsida), das quais 34 foram observadas na amostragem quantitativa. As famílias e gêneros mais ricos foram: Orchidaceae, Polypodiaceae e Bromeliaceae, e Pleurothallis, Tillandsia e Oncidium. As áreas de maior similaridade florística com este estudo localizam-se no município de Curitiba (PR). As espécies mais importantes quantitativamente foram Microgramma squamulosa (Kaulf.) de la Sota, Pleopeltis angusta Humb. & Bonpl. ex Kunth, Peperomia catharinae Miq. e Polypodium hirsutissimum Raddi. Em um mesmo forófito, o número de espécies ocorrentes variou de zero a 13, enquanto a soma das notas de abundância para as epífitas variou de zero a 24. A copa apresentou a maior abundância de epífitos, seguido do fuste alto e do fuste baixo.

Structure and floristic composition of the vascular epiphyte component of a subtropical ombrophilous alluvial forest located along the Barigüi river, Southern Brazil (25º34' S and 49º20' W) is described. The qualitative survey was carried out in an8.6 ha area while the quantitative survey was done on 110 assorted trees. The surveyed trees were divided into tree strata (low trunk, high trunk and canopy). In each stratum, scores were given (one to three) for all of the occurring epiphytic species according to its abundance. We listed 49 vascular epiphytic species (16 Pteridophyta, 23 Liliopsida and 10 Magnoliopsida) from 28 genera spread into 12 families, however only 34 species were found for the quantitative survey. The richest families were Orchidaceae, Polypodiaceae and Bromeliaceae, while Pleurothallis, Tillandsia and Oncidium made up the richest genera. Areas presenting the closest floristic similarity with this survey are located in the Curitiba County, state of Paraná, Brasil. For the quantitative survey, Microgramma squamulosa (Kaulf.) de la Sota, Pleopeltis angusta Humb. & Bonpl. ex Kunth, Peperomia catharinae Miq.and Polypodium hirsutissimum Raddi were the most important species. The number of species found for single host-trees ranged from zero to 13 while scores for abundance (VA) ranged from zero to 24. The canopy presented the highest abundance with a VA equal to 622 (high trunk = 308 and low trunk = 110).