ISSN:
1399-3054
Quelle:
Blackwell Publishing Journal Backfiles 1879-2005
Thema:
Biologie
Notizen:
To investigate the mechanism of frost damage in trees, the temperature fluctualions in the stems and leaves of some wintering trees were recorded with copperconstantan thermocouples.In Sapporo, even the trunk of large elm trees with diameter of 86 cm are frozen during the winter. In a Kalopanax trunk with a diameter of 13.5 cm, the bark temperature on the south side which is exposed to direct sunshine reaches nearly 20°C about midday in midwinter; while, on the north side, the temperature remains nearly the same as the environmental temperature (0 to -5°C). The rise in the bark temperature in trees is considerably affected by factors such as the intensity of sunshine, the environmental temperature, the diameter of the trunk, the side of the trunk which the bark is on, the height above the ground, and the colour of the bark surface, etc. This rise is far less in small twigs, slender stems, and small leaves than in large ones. The south side of the bark 10 to 15 cm above the snow surface or above the ground in a slender stem is exposed to a remarkable fluctuation in temperature, especially when the ground is covered with snow.Even in northern trees, the cortical cells on the south side of trunks and twigs are less resistant to freezing than those on the north.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1111/j.1399-3054.1966.tb09080.x
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