DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 7-8/2020 str. 26 <-- 26 --> PDF |
environment (R Core Team, 2016) with a probability of type I error of α = 5%. Plots were produced using “ggplot2” package (Wickham, 2009). RESULTS REZULTATI Climate conditions – Klimatski uvjeti High mean temperatures and low precipitation were present especially in years 2000 and 2003, while high temperatures in 2007 were not coupled with low precipitation (Figure 2). Considering the ranges of SPI and scPDSI, water deficits on the research plot could have been expected especially in 2000 and 2003. The scPDSI index also shows the possibility of drought in 2007. Defoliation – Osutost There is an increasing statistically significant trend of defoliation throughout the observed period (Figure 3). Statistical differences in mean defoliation were established between survey years (Df = 11; MS = 480.3; F = 7.7; p < 0.001). Defoliation was higher in the years following a drought year than in drought years but these differences were not significant. However, defoliation in year 2004 was significantly higher than in the years prior to 2003 drought (Figure 3). Nutritional status – Stanje ishrane Based on the foliar concentrations, plot Sljeme provides satisfactory nutrition for beech trees. Some differences in element values depending on the sampling year are evident. These differences are especially interesting if the values fall below limit values (Figure 4). Ca and Mg deficiency was recorded in drought years (Figure 2). We found that the ratio of K and Ca in beech leaves was high in years 2000, 2003 and 2004 as shown in Table 1. Tree ring width – Širina goda Beech chronology spans the period from 1904 to 2007 (103 years, Table 2). Since the purpose of this study was not to reconstruct climatic patterns but to evaluate effects of climate |