• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.4
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• pp.206-212
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• 2009

We investigated the patterns of freeze injury in dormant 'Changhowon Hwangdo' peach fruit by observing the extent of browning and germination of the branches that were treated with freezing temperature sets simulating the process of natural freezing incidences in orchards. Under the treatment of freezing temperature of $-15^{\circ}C$, the browning ratios were 15% for flower bud and less than 3% for both leaf bud and cambium. Under the $-20^{\circ}C$ treatment, the browning ratios were 40% for both flower and leaf buds and 1% for cambium. The browning ratios were 86%, 68% and 40% respectively for flower bud, leaf bud, and cambium under the $-25^{\circ}C$ treatment. All the samples showed 100% browning ratio under the $-30^{\circ}C$ treatment. The budburst ratios of leaf buds were 85%, 66%, 32%, and 0% under the -15, -20, -25 and $-30^{\circ}C$ treatments, respectively. The branches of peach fruit treated with the same freezing temperature showed different responses depending on the sampling date. In January the browning ratio was low and the budburst ratio was high whereas in February the opposite was the case, showing vulnerability of peach trees to low temperature after endo-dormancy release.

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.6
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• pp.118-125
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• 2011

This study was conducted to check danger of the cold injury by reviewing the lowest temperature by regions and the cold tolerance of Lagerstroemia indica and Pyracantha angustifolia. The cold tolerance of the samples treated at low temperature was evaluated by measuring electrical conductivity and observing browning of the cambium. It was proved that the lethal temperature of L. indica is below $-17.1^{\circ}C$, and that of P. angustifolia is below $-18.9^{\circ}C$. The frequency of the lowest temperature went down below $-17.1^{\circ}C$, was 7 times in Daejeon, 55 times in Cheongju and 72 times in Suwon for the last 45 years. In Daejeon, it has happened only once since 1975. The temperature dropped below $-18.9^{\circ}C$ 45 times in Cheongju and 32 times in Suwon during the same period, but it has not happened at all since 1991. It appears that the rising coefficient of the lowest temperature increases, as the latitude gets higher. As a result, L. indica and P. angustifolia which were planted in the central region of Korea, are considered in danger from freezing injury because the temperature can get very low intermittently in winter. But, the risk of freezing has reduced gradually as the lowest temperature raises each year.