11. Tree rings, wood density and climate–growth relationships of four Douglas-fir provenances in sub-Mediterranean SloveniaLuka Krajnc, Jožica Gričar, Jernej Jevšenak, Polona Hafner, Robert Brus, 2022, original scientific article Abstract: Tree rings, wood density and the climate–growth relationship of four Douglas-fir provenances were analysed separately for the juvenile and adult phases. Four provenances were selected from an existing IUFRO provenance trial planted in 1971 based on their diameter at breast height and vitality. Increment cores were extracted from individual trees, on which we measured tree-ring widths (RW), earlywood widths (EWW) and latewood widths (LWW). Wood density was assessed in standing trees using resistance drilling. The climate–growth correlations were calculated between provenance chronologies of RW, EWW, LWW and latewood share, and the day-wise aggregated Standardised Precipitation-Evapotranspiration Index (SPEI). The analysis was done separately for the juvenile and mature phases of growth. Provenances 1064 (Jefferson) and 1080 (Yelm) exhibited larger annual radial increments than provenances 1028 (Merrit) and 1089 (Cathlamet). The two provenances with the highest annual radial increment in the juvenile phase did not exhibit the same trend in the adult phase. In all provenances, RW, and consequently EWW and LWW, were wider in the juvenile than in adult phase. The share of latewood was in all cases higher in juvenile wood than in mature wood. All four provenances had similar wood densities in both analyzed growth phases. Our analysis showed that when selecting the most promising provenance for planting, possible changes in relative growth rate from the juvenile to adult phase need to be considered.
Keywords: Pseudotsuga menziesii, SPEI, juvenile phase, adult phase, latewood share, resistance drilling
Published in DiRROS: 21.11.2022; Views: 461; Downloads: 150
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13. Obstoj, branost in kakovost revije Gozdarski vestnik so odvisni od nas vsehMitja Skudnik, Polona Hafner, 2022, preface, editorial, afterword Keywords: obstoj revije, branost revije, kvaliteta revije, Gozdarski vestnik, strokovne revije, gozdarstvo
Published in DiRROS: 08.03.2022; Views: 838; Downloads: 264
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15. Stabilni izotopi v gozdnem ekosistemu - analizne metode in uporabaSaša Zavadlav, Grega E. Voglar, Polona Hafner, Mitja Ferlan, Tom Levanič, 2016, published scientific conference contribution abstract Keywords: stabilni izotopi, masna spektrometrija, laserska absorpcijska spektroskopija, EA-IRMS, OA-ICOS
Published in DiRROS: 03.11.2021; Views: 749; Downloads: 266
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18. Climatic regulation of leaf and cambial phenology in Quercus pubescens : their interlinkage and impact on xylem and phloem conduitsJožica Gričar, Jernej Jevšenak, Polona Hafner, Peter Prislan, Mitja Ferlan, Martina Lavrič, Dominik Vodnik, Klemen Eler, 2022, original scientific article Abstract: Increased frequency and severity of stressful events affects the growth patterns and functioning of trees which adjust their phenology to given conditions. Here, we analysed environmental effects (temperature, precipitation, VPD and SWC) on the timing of leaf phenology, seasonal stem radial growth patterns, and xylem and phloem anatomy of Quercus pubescens in the sub-Mediterranean in the period 2014%2019, when various adverse weather events occurred, i.e. spring drought in 2015, summer fire in 2016 and summer drought in 2017. Results showed that the timings of leaf and cambium phenology do not occur simultaneously in Q. pubescens, reflecting different environmental and internal constraints. Although year-to-year variability in the timings of leaf and cambial phenology exists, their chronological sequence is fairly fixed. Different effects of weather conditions on different stages of leaf development in spring were observed. Common climatic drivers (i.e., negative effect of hot and dry summers and a positive effect of increasing moisture availability in winter and summer) were found to affect the widths of xylem and phloem increments with more pronounced effect on late formed parts. A legacy effect of the timing of leaf and cambial phenology of the previous growing season on the timing of phenology of the following spring was confirmed. Rarely available phloem data permitted a comprehensive insight into the interlinkage of the timing of cambium and leaf phenology and adjustment strategies of vascular tissues in Mediterranean pubescent oak to various environmental constraints, including frequent extreme events (drought, fire). Our results suggest that predicted changes in autumn/winter and spring climatic conditions for this area could affect the timings of leaf and stem cambial phenology of Q. pubescens in the coming years, which would affect stem xylem and phloem structure and hydraulic properties, and ultimately its performance.
Keywords: pubescent oak, leaf development, radial growth, initial earlywood vessel, sieve tube, anatomy, cambial cell production, extreme weather events
Published in DiRROS: 06.09.2021; Views: 972; Downloads: 288
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