崇礼区典型林分空气负离子浓度及影响因素

目的]对崇礼区3种主要林分类型的空气负离子浓度变化规律以及影响因素进行研究,为该地生态效益评估以及生态旅游规划提供依据。方法]本研究通过对崇礼区典型林分类型空气负离子浓度进行连续观测,并以开阔无林地为参照对象,采用柱状图、散点图、回归分析等方法研究河北杨(Populus hopeiensis,PHF)、白桦(Betula platyphylla,BF)和油松(Pinus tabulaeformis,PF,)3种纯林以及无林地(NF)空气负离子浓度日变化特征,分析气象因素及植物光合特性对空气负离子的影响,并运用单极系数法以及空气质量系数法对不同林分空气质量进行评价。结果]表明:(1)空气负离子浓度变化趋势呈双峰型,最低值一般出现在中午,不同林分最高值出现时间不同。不同林分空气负离子浓度具有明显差别,空气负离子浓度从高到底依次为:河北杨(1 101 ion·cm-3)白桦(847 ion·cm-3)油松(755 ion·cm-3)无林地(344 ion·cm-3)。(2)不同林分空气负离子浓度与气温呈负相关,与相对湿度呈正相关;不同林分空气负离子浓度与植物光合特性总体呈正相关。(3)计算空气质量评价参数得出不同林分单极系数从小到大依次为河北杨(0.92)油松(1.01)白桦(1.25)无林地(1.37),各林分空气质量评价指数从大到小依次为河北杨(1.25)白桦(0.85)油松(0.80)无林地(0.27)。结论]不同林分空气负离子浓度存在差异且阔叶林高于针叶林,空气离子浓度的变化受外界气候因素及自身植物光合特性的影响明显,不同林分空气质量评价指数也存在差异,合理配置林分资源有利于空气质量提升。

Variations in Negative Air Ion Concentrations Associated with Different Vegetation Types and Influencing Factors in Chongli District

Objective] Studying the variation of negative air ion concentration in three main types of stand at Chongli district and the influencing factors in order to lay basis for ecological benefit evaluation and ecotourism planning. Method] Based on continuous observation of negative air ion concentration in typical stand at Chongli, the diurnal variation of negative air ion concentration in poplar (Populus hopeiensis Hu et Chow) forest (PHF), birch (Betula platyphylla Suk.) forest (BF), pine (Pinus tabulaeformis Carr.) forest (PF).and non-forest site (NF) was studied. The effects of meteorological factors and plant photosynthetic characteristics on negative air ion concentration were analyzed. The air quality of different stands was evaluated by unipolar coefficient method and air quality coefficient method.Result] The variation trend of negative air ion concentration had two peaks. The lowest value appeared at noon but the maximum value appeared in different time. The negative air ion concentration in different stands was obviously different. Broadleaved forest was superior to coniferous forest. The negative air ion concentrations of PHF, BF, PF and NF were 1 101, 847, 755 and 344 ion·cm^-3 respectively. The negative air ion concentration in different stands was negatively correlated with temperature, but positively correlated with humidity and the photosynthetic characteristics of plants. The single grade coefficients of PHF, BF, PF and non-forest land were 0.92, 1.01, 1.25 and 1.37. The air quality evaluation index of PHF, BF, PF and non-forest land were 1.25, 0.85, 0.80 and 0.27.Conclusion] The concentration of negative air ions in different stands is different and the broadleaved forest is superior to coniferous forest. The concentration of air ions is affected by external climatic factors and the photosynthetic characteristics of plants. There are also differences in the air quality evaluation index of different stands. Reasonable allocation of forest resources is beneficial to air quality improvement.