速生杨树越冬伤害阈值和发生时期的研究

Study on threshold and occurrence period of overwintering injury of fast-growing poplar

为了阐明杨树越冬伤害发生原因,解决杨树越冬伤害风险评估的基础性问题,以凌海市速生杨树为研究对象,采用定位监测的方法开展了速生杨树越冬伤害阈值和发生时期的研究。结果表明:冬季负积温、平均气温、最低气温与杨树树干破腹率及越冬死亡率无相关关系。大幅度日较差与速生杨树越冬死亡有关,但不是所有的大幅度日较差都会造成速生杨树越冬死亡,越冬死亡与大幅度日较差出现的时间有关。有效冻融型越冬伤害一般发生在抗寒锻炼期和脱锻炼期,深度休眠期的温度变化对杨树越冬影响相对较小。速生杨树在野外发生极端低温型越冬伤害的气温阈值小于-29.2℃,发生有效冻融型越冬伤害的气温日较差阈值≥15.5℃。该研究为速生杨树越冬伤害模型构建奠定了基础,具有一定的科研和实际应用价值。

In order to clarify the reasons of poplar overwintering injury and to solve the basic problems about risk assessment of poplar overwintering injury, this paper studied the threshold and occurrence period of overwintering injury of fast-growing poplar in Linghai City by using the method of location monitoring. The results showed that the negative accumulated temperature, average temperature and minimum temperature in winter had no correlation with poplar trunk broken rates and overwintering mortality rates. Large daily temperature range was related to overwintering death of fastgrowing poplar, but not all large daily range would cause overwintering death of fast-growing poplar. Overwintering death was related to the time of occurrence of large daily range. Effective freeze-thaw overwintering injury usually occurred during cold hardening period and de-exercises period. Temperature change during deep dormancy period had relatively small impact on poplar overwintering. The temperature threshold of extreme low temperature overwintering injury of fast-growing poplar in the field was less than-29.2℃ and the threshold of daily temperature range for effective freeze-thaw overwintering injury was ≥15.5℃. This paper provided a foundation for the establishment of overwintering injury model of fast-growing poplar, and had certain scientific research and practical application value.