Abstract: A monitoring system was used to measure and record the cambium temperature of north-unexposed(NU) and south-exposed(SE) bark of Korla fragrant pear tree and the main weather factors across different seasons in Korla,Xinjiang,China.The variations of the cambium temperature of NU and SE barks and the possibility of thawing-freezing and sunscald damage of the two sides were analyzed.The results showed that the cambium temperature variations of NU and SE bark were different in each season.Cambium temperature fluctuations of SE bark were much bigger than that of NU bark,especially in winter.Cambium temperature difference between the NU and the SE bark were smaller in summer than in other seasons.Cambium temperature of SE bark was clearly higher than that of NU bark during daytime,but was slightly lower at night.The highest cambium temperature fluctuations of SE bark was 33.14℃,which occurred in winter,it was 17.14℃ higher than that of the NU bark.The minimum cambium temperature of SE bark was lower than that of NU,but the maximum cambium temperature of SE bark was higher than that of NU.Hence,SE bark was more likely to be damaged by freezing injury and sunscald during winter.The maximum cambium temperature of SE bark was higher than NU bark in summer,and the duration of higher than temperature 40°C lasted more than 20 d.Hence,SE bark was more likely to be damaged by sunburn in summer.

Key words: Korla fragrant pear, Korla fragrant pear, North-unexposed and south-exposed bark, Cambium temperature