DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 5-6/2023 str. 11 <-- 11 --> PDF |
measured in the last ten years to provide increment for the last five (MAI-5) and ten years (MAI-10) (Reid and Robb, 1999). Mean annual increment in the past five years divided by the mean annual increment of the preceding five years to determine periodic growth ratio (PGR) (Mahoney, 1978; Reid and Robb, 1999; Wainhouse, 2005). The number of xylem cells (tracheids) in a radial file formed in the last year until the sampling date were studied on cross sections. Phloem thickness was measured on core samples. Leica M60 stereomicroscope was used to make measurements and Olympus BX53 light microscope to take photographs. Values of the measured characteristics are presented in Table 1-2. Analysis – Analiza Data were analyzed using IBM SPSS statistics version 19.0. Measured variables were compared between naturally infested and uninfested trees by t test. Standard error of mean (SEM) and minimum and maximum values were given with means. RESULTS REZULTATI Phloem thickness, MAI-5, MAI-10, mean annual increment in the last year until the sampling date and number of xylem cells were higher in infested trees (Table 3). Phloem thickness was 4.19 mm ± 0.31 (1.63 – 8.80 mm) and 3.01 mm ± 0.23 (1.43 – 7.07 mm) in infested (Figure 1d) and uninfested trees, respectively. The difference between infested and uninfested trees was significant (t test, t = 3.071, df = 58, p < 0.05). MAI-5 and MAI-10 was 1.47 mm ± 0.15 (0.20 – 3.36 mm) and 1.47 mm ± 0.14 (0.32 – 3.54 mm) in infested, and 1.08 |