Influence of climatic variations on production, biomass and density of wood in eucalyptus clones of different species

The wood production potential that a site presents is largely represented by its climatic condition and by the affinity of its genetic material. An issue which concerns all wood producers is climate change and how it will influence wood production and wood characteristics, as they can be decisive in industrial applications. Therefore, this study aimed to: (i) verify the wood volume (WV), stem biomass (SB) and the basic wood density (BWD) behavior against different climatic scenarios; and (ii) verify the potential of estimating the BWD through meteorological variables. The WV, BWD and SB of four different Eucalyptus spp. clones as to their climate of origin and species were analyzed. The cultivation was from 2012 to 2015 (four years) with planting in 11 locations in Brazil, representing a wide range of climatic characteristics with average precipitation from 649 mm y(-1) to 1618 mm y(-1). Precipitation, maximum vapor-pressure deficit, water deficit in the soil, temperature and precipitation seasonality were used to characterize the regions during the growth period. Hierarchical grouping was carried out for the sites, and the WV, BWD and SB behavior within the groups were analyzed. Thus, a linear regression equation between the most influential meteorological variables in the BWD were adjusted in order to identify the potential of the estimative BWD. Four groups were formed between the sites, and the variation in WV, BWD and SB for each clone between the wet and dry groups were respectively: C3: -68.3%, +8.7% and -65.0%; K2: -77.5%, +8.3% and -74.3%, A1: -40.3%, -9.21% and -39.9%; and Q8 - -31.6%, +8.4% and -34.1%. The drier locations generally showed lower WV and SB, and higher BWD associated to a decrease in the growth rate. This behavior is intrinsic to each clone and does not establish a defined proportion. Humid locations did not show clear patterns in changing density. The maximum vapor-pressure deficit and the water deficit in the soil were the most significant variables and had the best potential to estimate the basic wood density of the wood. Basic wood density is a resource which can be strongly influenced by genetics, and above all there is a significant influence of climate on the sites.