WOOD RESEARCH Volume 64, Number 6, 2019
Kyriaki Giagli, Hanuš Vavrčík, Marek Fajstavr, Kateřina Novosadová, Antonín Martiník, and JAKUB ČERNÝ

Stand factors affecting the wood density of naturally regenerated young silver birch growing at the lower altitude of the Czech Republic region

The objective of this study was to investigate the basic wood density (ρk) of the silver birch (Betula pendula Roth.) trees in relation to the stand structure. This research was conducted in three stands of different structure and ages, located in the region of the lower part of the Jeseníky Mountains in the Czech Republic. In total, 71 healthy dominant silver birch trees were randomly selected. Two samples (cores) were taken per tree for performing the tree-ring width analysis and ρk determination. We found that the average ρk of the three examined stands ranged from 471.8 to 494.6 kg. m-3. The older trees showed a high variation of the ρk. The age of the tree and stem diameter positively influenced the ρk. Nevertheless, it was noted that the slenderness ratio had a negative influence on the ρk. Overall, the prediction of wood density using stand and tree characteristics, even when the management history records are available, remains a complex hypothesis.

WOOD RESEARCH Volume 65, Number 6, 2020
Jana Hacurová, Jakub Hacura, Vladimír Gryc, Jakub Černý, and Hanuš Vavrčík

Xylogenesis and phloemogenesis of Norway spruce in different ages stands at middle altitudinal zone

This study aimed to determine the influence of the stand age and selected weather conditions on the cambial activity, xylem and phloem formation and their development. For the analysis, microcores were taken weekly from two corresponding stands of Norway spruce (Picea abies (L.) Karst.) with various ages (35- and 106-years-old) during the growing season 2012 in the Czech Republic. Young specimens were characterised by higher cambium activity; however, more considerable variation and imbalance were found there. In old trees, delayed processes during the development of the xylem and phloem at the cell level were proved. The cambium activity started in March till mid-April, and it lasted for 22 weeks in both cases. The commencement of xylogenesis was established in the first half of May. In both investigated stands, the fully lignified ring was observed at the end of October. For the creation of most xylem cells, it was required 124 and 121 days in the young and old stands, respectively. Daily increment of 0.57 (young) and 0.49 (old) cells on average was observed during the active xylem growth. The relationship between air temperature and wood cell formation for both age groups was recorded. The precipitation influenced wood development just in the case of the young trees. Phloem formation was resistant to external influence according to the Pearson correlation coefficient.