雷州半岛尾叶桉和湿加松人工林的蒸腾耗水规律

为正确认识大径材桉树及湿加松耗水规律,为地区人工林树种选择、栽培及抚育提供指导,应用TDP热扩散探针技术,对10年生尾叶桉和湿加松树干液流进行连续监测,并同步测定各气象因子,分析了雷州半岛地区尾叶桉和湿加松蒸腾耗水的日变化特征和季节变化规律,并与气象因子建立了相关模型。结果表明:尾叶桉和湿加松边材液流均表现出典型的昼高夜低的单峰型日变化特征,各月平均液流速率不同,且旱雨季差异显著;其中峰值尾叶桉雨季(0.127 cm/min)和旱季(0.096 cm/min)分别是湿加松雨季和旱季的1.30倍和1.57倍;日平均液流速率尾叶桉雨季(0.045 cm/min)和旱季(0.033 cm/min)分别是湿加松雨季和旱季的1.27倍和1.54倍;启动时间和迅速下降时间雨季两树种间差异不大,但旱季尾叶桉要提前湿加松约1—1.5 h启动,并晚0.5—1 h迅速下降。影响两树种边材液流速率的主要气象因子相同。尾叶桉人工林年平均单株日耗水量为12.79 L/d,是湿加松的1.33倍,林分蒸腾耗水量尾叶桉(582.16 mm)和湿加松(483.24 mm),分别占同期年降雨量的34.2%和28.4%,且两树种旱雨季蒸腾耗水量均雨季显著大于旱季。

The transpiration water consumption of two common fast-growing forests in Leizhou Peninsula

To examine water consumption rules in Eucalyptus macrophylla and Pinus elliottii×P. caribaea and to provide guidance for tree species selection, cultivation and tending of regional plantation, sap flow of plantation grown, E. urophylla and Pinus elliottii×P. caribaea were continuously measured using the Thermal dissipation sap flow velocity probe technology and the meteorological factors were continuously monitored and measured simultaneously to establish a sap flow rate model with meteorological factors. The diurnal variation and seasonal variation of transpiration water consumption of E. urophylla and Pinus elliottii×P. caribaea in the Leizhou Peninsula were analyzed. Results showed that diurnal variations of sap flow of both E. urophylla and Pinus elliottii×P. caribaea displayed typical single-peaked curves. The average monthly flow rate was different and significant difference was found during the rainy season and drought. The peak sap flow of E. urophylla in the rainy season (0.127 cm/min) and dry season (0.096 cm/min) were 1.30 times and 1.57 times higher than that of Pinus elliottii×P. caribaea, respectively. The average daily flow rate of E. urophylla in the rainy season (0.045 cm/min) and dry season (0.033 cm/min) were 1.27 times and 1.54 times higher than that of Pinus elliottii×P. caribaea, respectively. There was no significant difference between the start-up time and the rapid decline time of the two species in the rainy season. But the E. urophylla in the dry season increased by about 1-1.5 hours in advance and started to decline rapidly 0.5-1 hour later than that of Pinus elliottii×P. caribaea. The main meteorological factors affecting the sapwood flow rate of the two species are the same. The average single plant daily water consumption of E. urophylla plantation was 12.79 L/d, which was 1.33 times higher than that of Pinus elliottii×P. caribaea. The stand transpiration water consumption of E. urophylla (582.16 mm) and Pinus elliottii×P. caribaea (483.24 mm) accounted for 34.2% and 28.4% of the annual rainfall, respectively, and the Stand transpiration water consumption of both tree species during the rainy season was significantly greater than that during the dry season.