Reducing Solar Heat Gain during Winter: The Role of White Bark in Northern Deciduous Trees
ABSTRACT. Deciduous tree species throughout the boreal forest of North America have lighter-coloured bark than do species restricted to more southern forests. We tested the hypothesis that light-coloured bark minimizes the thawing and freezing of cambium tissue during winter that could contribute to...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.116.7787 2023-05-15T14:20:17+02:00 Reducing Solar Heat Gain during Winter: The Role of White Bark in Northern Deciduous Trees Tim J. Karels Rudy Boonstra The Pennsylvania State University CiteSeerX Archives 2002 application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.116.7787 http://www.csun.edu/~karels/Pubs/karels & boonstra Arctic 2003.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.116.7787 http://www.csun.edu/~karels/Pubs/karels & boonstra Arctic 2003.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://www.csun.edu/~karels/Pubs/karels & boonstra Arctic 2003.pdf text 2002 ftciteseerx 2016-01-07T13:55:10Z ABSTRACT. Deciduous tree species throughout the boreal forest of North America have lighter-coloured bark than do species restricted to more southern forests. We tested the hypothesis that light-coloured bark minimizes the thawing and freezing of cambium tissue during winter that could contribute to sunscald injury. During mid-winter, maximum midday cambium temperatures of south-exposed bark of white birch (Betula papyrifera Marsh.) near Timmins, Ontario, were higher for brownpainted bark (+1.6 ˚C) than for natural bark (-9.4 ˚C) and white-painted bark (-12.1 ˚C). Rates of temperature decrease after trees were shaded at midday were more rapid for brown-painted bark (0.06 ˚C/min) than for natural bark (0.03 ˚C/min) and whitepainted bark (0.03 ˚C/min). When stems of white birch, trembling aspen (Populus tremuloides Michx.), yellow birch (B. alleghaniensis Britton), and largetooth aspen (P. grandidentata Michx.) were illuminated and subsequently shaded at-10 ˚C ambient air temperature, maximum cambium temperatures and rates of cambium cooling increased with decreasing measures of whiteness. For trembling aspen in the southwest Yukon, we found that after two years, brown-painted trees had a higher incidence (35%) of wounding that resembled sunscald injury than did white-painted trees (2.5%) and natural trees (4.5%). Therefore, we suggest that light-coloured bark reduces the risk of winter sunscald injury, probably by protecting the cambium from solar heat gain in subfreezing temperatures. This physical mechanism for reducing sunscald risk may explain why the deciduous trees at the northern limit of tree growth are those with highly reflective bark. Key words: bark colour, white birch, cambium temperatures, trembling aspen, sunscald, boreal forest, deciduous trees Text Arctic Yukon Unknown Yukon |
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English |
description |
ABSTRACT. Deciduous tree species throughout the boreal forest of North America have lighter-coloured bark than do species restricted to more southern forests. We tested the hypothesis that light-coloured bark minimizes the thawing and freezing of cambium tissue during winter that could contribute to sunscald injury. During mid-winter, maximum midday cambium temperatures of south-exposed bark of white birch (Betula papyrifera Marsh.) near Timmins, Ontario, were higher for brownpainted bark (+1.6 ˚C) than for natural bark (-9.4 ˚C) and white-painted bark (-12.1 ˚C). Rates of temperature decrease after trees were shaded at midday were more rapid for brown-painted bark (0.06 ˚C/min) than for natural bark (0.03 ˚C/min) and whitepainted bark (0.03 ˚C/min). When stems of white birch, trembling aspen (Populus tremuloides Michx.), yellow birch (B. alleghaniensis Britton), and largetooth aspen (P. grandidentata Michx.) were illuminated and subsequently shaded at-10 ˚C ambient air temperature, maximum cambium temperatures and rates of cambium cooling increased with decreasing measures of whiteness. For trembling aspen in the southwest Yukon, we found that after two years, brown-painted trees had a higher incidence (35%) of wounding that resembled sunscald injury than did white-painted trees (2.5%) and natural trees (4.5%). Therefore, we suggest that light-coloured bark reduces the risk of winter sunscald injury, probably by protecting the cambium from solar heat gain in subfreezing temperatures. This physical mechanism for reducing sunscald risk may explain why the deciduous trees at the northern limit of tree growth are those with highly reflective bark. Key words: bark colour, white birch, cambium temperatures, trembling aspen, sunscald, boreal forest, deciduous trees |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Tim J. Karels Rudy Boonstra |
spellingShingle |
Tim J. Karels Rudy Boonstra Reducing Solar Heat Gain during Winter: The Role of White Bark in Northern Deciduous Trees |
author_facet |
Tim J. Karels Rudy Boonstra |
author_sort |
Tim J. Karels |
title |
Reducing Solar Heat Gain during Winter: The Role of White Bark in Northern Deciduous Trees |
title_short |
Reducing Solar Heat Gain during Winter: The Role of White Bark in Northern Deciduous Trees |
title_full |
Reducing Solar Heat Gain during Winter: The Role of White Bark in Northern Deciduous Trees |
title_fullStr |
Reducing Solar Heat Gain during Winter: The Role of White Bark in Northern Deciduous Trees |
title_full_unstemmed |
Reducing Solar Heat Gain during Winter: The Role of White Bark in Northern Deciduous Trees |
title_sort |
reducing solar heat gain during winter: the role of white bark in northern deciduous trees |
publishDate |
2002 |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.116.7787 http://www.csun.edu/~karels/Pubs/karels & boonstra Arctic 2003.pdf |
geographic |
Yukon |
geographic_facet |
Yukon |
genre |
Arctic Yukon |
genre_facet |
Arctic Yukon |
op_source |
http://www.csun.edu/~karels/Pubs/karels & boonstra Arctic 2003.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.116.7787 http://www.csun.edu/~karels/Pubs/karels & boonstra Arctic 2003.pdf |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
_version_ |
1766292118212444160 |