关键词: 野核桃, 种群统计, 静态生命表, 谱分析, 海拔梯度

Abstract: To reveal the water use ability of Phyllostachys edulis and further provide theoretical guide for its water management, eddy covariance observation technology was used to obtain water vapor flux data and rain gauges were applied to gaine precipitation data of P. edulis forest ecosystem in Anji County, Zhejiang Province from 2012 to 2014. The results showed that water vapor fluxes were positive during 2012-2014, indicating the ecosystem was a good water vapor source for the atmosphere. Water vapor fluxes were 695.96, 749.07 and 656.47 kg·m^-2 in 2012, 2013 and 2014, respectively. Meanwhile, the maximum value occurred in July, and the minimum in December. Water vapor flux presented a seasonal variation, being summer > spring > autumn > winter (except spring < autumn in 2014). Monthly precipitation showed a good positive correlation with monthly evapotranspiration in the three years (r=0.67, P<0.05). In addition, both precipitation and evapotranspiration maximally occurred during the period from June to August. The total precipitation amounts were 2018, 1509 and 1476 mm in 2012, 2013 and 2014, soil moistures at depth of 5 cm were 3.173, 3.045 and 3.013 m³·m^-3, and water use efficiencies (WUE) were 2.84, 2.10 and 3.37 g·kg^-1, respectively. Annual evapotranspiration accounted for 34.49%, 49.66% and 44.48% of annual total precipitation for the three years, respectively, suggesting that the runoff of P. edulis forest was greater, with a lower WUE. Moreover, vapor pressure deficit and air temperature had significant effects on the WUE of P. edulis forest, which indicated that the asynchronization of water and heat was the main limiting reason of high WUE. It is recommended that the regulation of temperature and humidity (high temperature and high humidity or the opposite) should be conducted when managing the forest, so as to improve the WUE and production of P. edulis and avoid the waste of water resource.

Key words: Juglans cathayensis, demography, static life table, spectrum analysis, altitude gradient.