Caracterização de variáveis dendrométricas e hidrometeorológicas em povoamento de eucalipto

Abstract

We conducted this study in a eucalypt population located in an experimental area of the Federal University of Lavras - UFLA campus. The database used for this study was comprised of dendrometry data derived from forest inventory, climatic data from meteorological stations located in and outside the plantation, and collections of pluvial rainfall inside the plantation. The primary objective was to evaluate the influence of the hydrometeorological conditions on the growth of eucalypt. To do this, we assessed the population density conditions based on the stand density index (SDI), adjusted to the Reineke model. We installed 27 plots into the plantation, distributed in the three spacings that comprised the population (3x2m), (3x3.5m), and (3x5m). To understand the climatic dynamics, we evaluated the variables of temperature, relative humidity of the air, and precipitation, both inside and outside the population and its relations with the historical averages. We quantified the repartition of the pluvial rainfall into internal rainfall (IR), trunk flow (TF), and the percentage intercepted by the tree canopies. We collected the rain from November of 2013 to October of 2017, completing four hydrological years. To do this, we installed 37 pluviometers and 30 trunk flow collectors to monitor the IR and TF. Furthermore, we evaluated the spatial distribution of the dendrometry and hydrological variables to verify the degree of spatial dependence and the correlation of these variables with the plantation growth. According to the SDI value, 83% of the 3x2 spacing plots are in the phase of high competition or storage. The meteorological variable of temperature and relative humidity presented a different behavior when compared to the normal climatological values, with an average temperature of 0.4ºC superior to the historical averaged and a decrease of 3% of humidity. The total internal rainfall was of 3269.3 mm, which represents 70.3% of the external rainfall. The total value of water that flowed by the trunks was of 114.3 mm, representing 2.5% of the external rainfall. Finally, the tree canopies intercepted 1268 mm of water, representing 27% of the total rainfall that occurred over the four hydrological years. The dendrometry and hydrological variables presented a moderate to strong spatial dependence. The spacing effect influenced the dendrometry variables. According to the kriging maps, the internal rainfall increased from the denser to the less dense regions of the plantation and can be correlated to the development of the population in some situations due to the hydrological effects.