Increment in eucalyptus diameter as affected by seasonality and production system

Abstract

The objective of this work was to assess the current monthly increment in diameter of eucalyptus (Eucalyptus grandis x Eucalyptus urophylla) trees in response to different production systems, climatic factors, and thinning. The trees were evaluated in four production systems: monoculture and crop-forestry, livestock-forestry, and crop-livestock-forestry integration. The increment in diameter of 80 trees was measured monthly from May 2015 to May 2019. The effect of the climatic variables was determined through correlation and multiple regression analyses. The increment in current monthly diameter is seasonal and highly dependent on accumulated rainfall. The adopted modeling allowed concluding that both water shortage and excess (30 and 475 mm per month, respectively) decreased tree growth in diameter. The trees in the integrated systems showed a higher growth in diameter than those under monoculture, and intercropping with crops resulted in a greater diameter growth than that with pasture. Thinning accelerates the growth of the remaining trees, with an effect of higher magnitude and longer duration in the integrated production systems.

Diameter growth of eucalyptus trees in agroforestry systems and its relation to air temperature and precipitation

“…Such situation had probably ensured to the eucalyptus trees a non-limiting water availability through the most part of the experimental period and this favorable water balance may had contributed to suppress the relevance of the intra-annual air temperature fluctuation. Therefore, this result was different from those found at the northern Mato Grosso by Tonini et al (2021), since there the authors observed a not so strong, but relevant negative correlation between mean daily air temperature and eucalyptus diameter growth. The results found by us can be endorsed by those found by Ryan et al (2020).…”

“…According to the same authors, the mean annual air temperature across the sites was only relevant in situations where water availability was not guaranteed (rainfed). The studied sites had mean annual temperatures varying from 19.4 to 25.7 °C and the authors concluded that, for water limiting conditions, the annual increment in biomass was reduced by the increase in temperature across the sites, like the negative correlation found by Tonini et al (2021).…”

“…At that moment the eucalyptus in forest presented lower DBH as compared to those in the agroforestry. Also at the northern Mato Grosso, Tonini et al (2021) evaluated the behavior of the eucalyptus increment in diameter in forest and agroforestry systems. They also observed that the diameter growth of eucalyptus is higher when cultivated in agroforestry systems.…”