JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2023, Vol. 47 ›› Issue (4): 148-156.doi: 10.12302/j.issn.1000-2006.202111041

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Evapotranspiration characteristics of Larix principis-rupprechtii plantation and its impact factors in the Daqing Mountains of Inner Mongolia

WANG Yunni1,2(), CAO Gongxiang1, XU Lihong2,*(), CHEN Shengnan3   

  1. 1. Inner Mongolia Academy of Forestry, Hohhot 010010, China
    2. The Research Institute of Forest Ecology, Environment and Nature Protection, Chinese Academy of Forestry, Beijing 100091, China
    3. College of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
  • Received:2021-11-25 Revised:2022-04-08 Online:2023-07-30 Published:2023-07-20

Abstract:

【Objective】 Water is the main factor limiting the sustainable stability of forest vegetation in semi-arid regions. The purpose of this study was to characterize evapotranspiration and its components in a larch (Larix principis-rupprechtii) plantation on the north side of the Daqing Mountains in Inner Mongolia, thereby providing a theoretical basis for forest management based on forest-water relationships. 【Method】The sap flow, canopy interception, forest floor evapotranspiration, and soil water content in a larch plantation stand, along with meteorological factors were monitored simultaneously in the north side of the Daqing Mountains of Inner Mongolia, China. Then, the variations in total stand evapotranspiration and its components as well as the relationship between evapotranspiration and environmental factors were analyzed. 【Result】On the seasonal scale, the evapotranspiration values in 2016 and 2017 were 522.57 and 583.67 mm respectively, accounting for 120.13% and 167.34% of the precipitation in the same period. This interannual difference was influenced by both the air temperature and water content of the soil. The percentage of canopy transpiration to total stand evapotranspiration was 45.44%, that of forest floor evapotranspiration was 40.28% and that of canopy interception was 14.28%. On the monthly scale, canopy transpiration and interception accounted for 37.30%-52.43% and 8.61%-21.81% of total evapotranspiration, respectively, whereas 31.52%-48.15% of the total stand evapotranspiration was caused by forest floor evapotranspiration. Air temperature, wind speed, and water conditions were the main factors influencing total stand evapotranspiration and canopy transpiration. Interception of the stand was mainly determined via precipitation and air humidity. Variations in forest floor evapotranspiration were closely dependent on solar radiation, saturated vapor pressure deficit, and water content of the soil. Additionally, the total evapotranspiration was 28.06 mm lower than the precipitation in July 2016, and the ratio of precipitation to evapotranspiration in other months was 0.55-0.92 under the monthly scale. 【Conclusion】In the mountain plantation ecosystem of typical rain-fed forestry in a semi-arid region, the amount of precipitation cannot meet the water consumption demand of the plantation. Therefore, in future research, it is necessary to pay more attention to the effects of precipitation types and time patterns on evapotranspiration.

Key words: larch(Larix principis-rupprechtii), forest floor evapotranspiration, canopy transpiration, canopy interception, meteorological factors

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