ECOLOGIA E MODELAGEM BIOMÉTRICA DE SAMAMBAIAS ARBORESCENTES EM FRAGMENTO DE FLORESTA OMBRÓFILA MISTA

Abstract

The objective of this study was to understand the ecology and biometric modeling of the tree ferns of the species Alsophila setosa, Cyathea corcovadensis, Cyathea phalerata and Dicksonia sellowiana. The interaction of soil attributes with the presence of arborescent ferns, their phenology, phytosociology, ecological indexes, spatial distribution and dynamics, adjustment of hypsometry equations, volumetry and tapering functions and the quantification of the biomass stock were evaluated in the Irati National Forest (PR), in two areas: Area 1 (native forest) and Area 2 (Araucária plantation). A matrix of soil attributes with a vegetational matrix was used for the analysis of canonical correspondence. In phenology (vegetative and reproductive), 10 individuals from A. setosa, C. phalerata, D. sellowiana, and nine individuals from C. corcovadensis were selected, with monthly monitoring in the period 2016-2019. The increase in total height was measured annually. Synchrony rates and correlations between phenological variables and environmental variables were evaluated. In phytosociology, DBH and height were measured in tree ferns, as well as other qualitative variables to calculate density, dominance, frequency and importance value, in addition to the ecological indexes (Shannon-Wiener, Pielou, Jaccard and Sorensen). To analyze the spatial distribution, the Morisita, Payandeh and Hazen indices were used. In the 2014-2017 dynamics studies, growth, ingrowth and mortality were assessed at the species level for diameter, crosssectional area and total height. In biometric modeling (hypsometry, volumetry and tapering functions), rigorous cubing data from 35 individuals from A. setosa and 35 from D. sellowiana were used, followed by extrapolation to the population. In biomass, 30 individuals of A. setosa, 30 of D. sellowiana and 30 individuals for the genus Cyathea were selected. The tree ferns were separated into two components, these being the caudex and frond (pinna and rachis), which after obtaining the green weight in the field, were taken to the greenhouse with forced ventilation at 70 ° C until they reached constant weight. The soil attributes showed greater discriminating power for the number of individuals of C. corcovadensis (higher percentages of saturation by aluminum and cation exchange capacity) and basal area of D. sellowiana (lower percentages of silt, magnesium, aluminum, potassium and phosphor). Regarding phenology, for A. setosa the croziers were produced between October and November and for their reproductive phase there was little synchrony for the immature sporangia and there was no synchrony for the closed sporangia and releasing spores. C. corcovadensis produced croziers between October and November, for its reproductive phase there was little synchrony. C. phalerata produced croziers from September to November, its reproductive phase was highly synchronized. For D. sellowiana, the croziers were produced from September to December, and in the reproductive phase there was no synchrony. About phytosociology, in Area 1 A. setosa presented 1539 ind.ha-1 , basal area of 14.3 m².ha- ¹ and the largest IVI, D. sellowiana had 82 ind.ha- ¹ and 5.41 m².ha - ¹ basal area, C. corcovadensis had 1 ind.ha- ¹ and basal area of 0.04 m².ha- ¹, C. phalerata had 19 ind.ha- ¹ and 0.35 m².ha- ¹. In Area 2 A. setosa had 601 ind.ha- ¹, with basal area of 5.23 m².ha- ¹ and second largest IVI, D. sellowiana had 14 ind.ha- ¹ and 0.39 m².ha- ¹, C. corcovadensis had 4 ind.ha- ¹ and 0.08 m².ha- ¹, C. phalerata had 2 ind.ha- ¹ and 0.02 m².ha- ¹ of basal area. Regarding ecological indexes, Area 1 has greater diversity. The spatial distribution of the species was aggregated. Regarding the dynamics, the percentage of ingrowth and mortality that was most expressive was Cyathea spp, with the highest ingrowth. In biometric modeling, for A. setosa the volume estimated by the Schumacher-Hall model was 60.015 m³.ha-1 for Area 1, and 38.510 m³.ha-1 for Area 2. For D. sellowiana, the model of Henricksen was the most adequate to estimate the total height, and the straight line model to estimate the commercial height, with the total volume estimated by the Stoate model, being 17.971 m³.ha-1 for Area 1 and 1.306 m³.ha-1 , and the commercial volume also estimated by the Stoate model, at 14.498 m³.ha-1 for Area 1 and 1.039 m³.ha-1 for Area 2. For the tapering functions of D. sellowiana, a 5th degree polynomial demonstrated better performance. In biomass A. setosa had a total biomass of 8,113 t.ha-1 for Area 1, in Area 2 it presented 2,684 t.ha-1 . Cyathea spp showed a total biomass of 0.177 t.ha-1 for Area 1, in Area 2 it had 0.0305 t.ha-1 . Dicksonia sellowiana had a total biomass of 1,495 t.ha-1 for Area 1 and in Area 2 it had 0.149 t.ha-1.