EFEITO DE VARIÁVEIS CLIMÁTICAS NO INCREMENTO EM DIÂMETRO DE Pinus taeda L.

Abstract

The objective of this work was to evaluate the influence of climatic variables on the increment of the basal area at 1.30m height in an experimental forest of Pinus taeda L. in the region of Guarapuava - PR and compare them with the occurrence of effects Climatic extremes ENSO). In this work we also evaluated the difference of increment between two slopes of south slope, being one with 2.5º and one with 7º of slope. The interactions between three diametric classes in the forest were also evaluated, with class 1 being equivalent to trees that had a circumference at the breast height (CAP) of less than one standard deviation (SD) of the mean CAP of the forest (CAP-1 SD), class 2 equivalent to trees that had an average CAP plus or minus a standard deviation (mean CAP +/- 1 SD.) and class 3 equivalent to trees that had more than one standard deviation of the mean forest CAP (CAP + 1 SD). The statistical analyzes used were longitudinal analysis (LA) to gauge whether the increments would differ both within and between the classes themselves during the growing years. Semiannual spring and autumn increments were measured with the help of LINTAB equipment, and data were saved in TSAP 3.0 software from the department of forestry at UNICENTRO campus Irati. The LA showed no significant difference in the increment of the trees located in the two incline ramps, but there was a significant difference in the increment for the three diameter classes within each year, between the years and also in the interaction between the classes and the years of growth. For the grouping of the climatic data, multivariate statistical analyzes were used to determine the climatic variables that were measured at the meteorological station of the State University of the Central West (UNICENTRO), “maximum, average and minimum temperature” (T C), “incident solar radiation” (mj / m² / s) (H / day), “evaporation” (mm / day), “relative humidity” (gH2O / m3 of air), “semiannual cumulative precipitation” (mm) and “wind at 10 meters high” (m / s). It was firstly used factorial analysis (FA) that suggested the elimination of the variable wind at 10 meters in height. After the main component analysis (PCA) was carried out, there was no formation of groups of months in which the climatic variables were similar throughout the growth period of the autumnal wood in any year of the study series. As for the period of formation of springwood, two years occurred in which the climatic variables were similar, but there was a difference between the two years, being the year 2010 and 2012. In these years there was a significant difference in the spring increment, being the year 2010 The period of greatest increment of trees. The results indicate that the El Niño climatic effect had a positive influence on the increment of the trees in the year 2010 and the climatic effect La Niña influenced negatively in the year 2012. In the Year of El Niño, climatic variables “Relative umidity” and “Precipitation” were significantly higher, while the variables “Incident solar radiation”, “Evaporation” and “Sunstroke” were significantly lower compared to the year of occurrence of La Niña.