Bark thickness determines fire resistance of selected tree species from fire-prone tropical savanna in north Australia

Plant Ecology ◽  
2011 ◽  
Vol 212 (12) ◽  
pp. 2057-2069 ◽  
Author(s):  
Michael J. Lawes ◽  
Anna Richards ◽  
Josefine Dathe ◽  
Jeremy J. Midgley
2020 ◽  
Vol 3 (1) ◽  
pp. 66
Author(s):  
Ferréol Berendt ◽  
Erik Pegel ◽  
Lubomir Blasko ◽  
Tobias Cremer

The wood of Scots pine (Pinus sylvestris L.) shows good properties as building and construction timber but also as furniture or pulp and paper, and thus, is one of the most commercially important European tree species. Scots pine are mostly harvested and processed with a high degree of mechanization. In Northeast Germany (federal states of Brandenburg and Berlin), 36% of harvested Scots pine have a diameter at breast height (DBH) between 7 and 19.9 cm. As a typical industrial wood assortment, a large proportion of the resulting small-sized logs are used in the wood industry to produce boards. Although bark is considered a by-product or waste product of the industry, no actual study has quantified the bark thickness, bark volume, bark mass and bark damage of such Scots pine logs. Therefore, the bark characteristics from 50 logs from 10 different piles were analyzed. Bark volume was quantified using the water displacement method, bark mass by weighing, bark thickness with a precision caliper and bark damage by tape measurements. The diameters of the analyzed 150 log discs were normally distributed and the mean value was 12.9 cm. The results showed average bark damages from 12.0%, which were mostly caused during the felling and processing of logs with the harvester. No significant correlation was found between double bark thickness (mean: 3.0 mm) and the diameter; whereas fresh bark volume (mean: 5.6%) and dry bark mass (mean: 3.3%) were significantly affected by the diameter. As shown for spruce by other authors, bark characteristics may change over time and therefore, should be measured regularly. Moreover, it was shown that bark parameters are site dependent. Thus, quantifying bark characteristics for economically important tree species at both the local and national scale is of great relevance. More detailed analyzes are described by Berendt et al. (2021) [1].


2020 ◽  
Vol 71 (9) ◽  
pp. 2641-2649
Author(s):  
Romain Lehnebach ◽  
Tancrède Alméras ◽  
Bruno Clair

Abstract Recent works revealed that bark is able to produce mechanical stress to control the orientation of young tilted stems. Here we report how the potential performance of this function changes with stem size in six Amazonian species with contrasted bark anatomy. The potential performance of the mechanism depends both on the magnitude of bark stress and the relative thickness of the bark. We measured bark longitudinal residual strain and density, and the allometric relationship between bark thickness and stem radius over a gradient of tree sizes. Constant tensile stress was found in species that rely on bark for the control of stem orientation in young stages. Other species had increasing compressive stress, associated with increasing density attributed to the development of sclereids. Compressive stress was also associated with low relative bark thickness. The relative thickness of bark decreased with size in all species, suggesting that a reorientation mechanism based on bark progressively performs less well as the tree grows. However, greater relative thickness was observed in species with more tensile stress, thereby evidencing that this reduction in performance is mitigated in species that rely on bark for reorientation.


2020 ◽  
Vol 474 ◽  
pp. 118385
Author(s):  
Rachael H. Nolan ◽  
Simin Rahmani ◽  
Stephanie A. Samson ◽  
Harriet M. Simpson-Southward ◽  
Matthias M. Boer ◽  
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1981 ◽  
Vol 57 (4) ◽  
pp. 156-161 ◽  
Author(s):  
J. Harry G. Smith ◽  
A. Kozak

Diameters inside and outside bark from 13 sections were used to define variation in bark percentages for 33 844 trees representing 28 major groups of the commercial tree species of British Columbia. The range of age, height, dbh, and dbh/height associated with each group was determined. Statistical significance of effects of these factors and of up to 12 inventory zones was determined for double bark thickness as a percentage of dbh. Bole bark volumes were compared with wood volumes for trees exceeding two standard deviations of bark percentage at breast height. Thick barked trees were more common and a few have equal portions of wood and bark. Our description of the characteristics of the trees with least or most bark should help guide tree improvement programs. Identification of the extent to which stand factors can influence average bark characteristics may help timber managers grow trees of desired bark proportions.


Plant Ecology ◽  
2016 ◽  
Vol 217 (6) ◽  
pp. 683-696 ◽  
Author(s):  
A. T. Schubert ◽  
C. E. M. Nano ◽  
P. J. Clarke ◽  
M. J. Lawes

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