Desenvolvimento silvicultural e avaliação microclimática de sistema silvipastoril para bovinos de leite em clima subtropical úmido

Abstract

This study aimed to characterize the dendrometric, qualitative, and microclimatic aspects of a silvopastoral system oriented toward milk production in a humid subtropical climate, composed of Eucalyptus urophylla S.T. Blake and hybrid clone I144, associated with Cynodon spp. cv. Tifton 85 pasture and managed with Jersey cattle. Dendrometric, qualitative, and microclimatic variables were evaluated using exploratory analyses, parametric and non-parametric tests, generalized linear models, linear mixed models, and principal component analysis. The results showed significant differences in dendrometric development among the rows of the silvopastoral system. Row 1 presented the highest mean values for DBH (27.5 cm), volume (0.597 m³), total height (24.3 m), and crown area (4.87 m²), statistically differing from most of the other rows. The qualitative assessment indicated a predominance of stems classified in classes 1 and 2, demonstrating good structural form and an association between stem quality and shading potential. In the microclimatic evaluation, air temperature was significantly lower in shaded areas compared to full-sun areas (p = 0.048), while ground (sward) temperature showed more pronounced differences between shade and sun conditions (p < 0.001). Air and sward temperatures were higher in the afternoon period (p < 0.001), whereas relative humidity exhibited an inverse pattern (p < 0.001). Principal component analysis showed that the first two components explained 80.6% of the total variability in the microclimatic data, highlighting the influence of the thermal gradient in differentiating environmental conditions. It is concluded that the silvopastoral system showed satisfactory performance in silvicultural and microclimatic aspects, contributing to forest production, animal thermal comfort, and the maintenance of productivity.