多年冻土区白桦次生林蒸腾特征及其对影响因子的响应  

Transpiration Characteristics and Its Response to Influence Factors of Betula platyphylla Secondary Forest in Permafrost Area

作　　者：尚友贤 满秀玲[1] 徐志鹏 SHANG Youxian;MAN Xiuling;XU Zhipeng(School of Forestry,Northeast Forestry University,Harbin 150040)

机构地区：[1]东北林业大学林学院,哈尔滨150040

出　　处：《水土保持学报》2023年第2期310-319,共10页Journal of Soil and Water Conservation

基　　金：国家重点研发项目(2021YFD2200405)。

摘　　要：探究多年冻土区白桦次生林蒸腾特征对影响因子的响应,为准确评估该地区森林生态系统水文效应提供科学参考。运用热扩散式探针法,从2021年5—9月对多年冻土区的白桦树干液流进行监测,并同步观测影响因子变化情况。结果表明:整个观测期,白桦次生林蒸腾表现出明显的小时、日、月变化。(1)白桦次生林小时蒸腾特征表现为优势木>中等木>被压木,蒸腾动态在晴天呈单峰曲线,在雨天呈双峰曲线。日尺度上,白桦次生林蒸腾平均值为1.47 mm/d,且最大值出现在7月。在整个观测期,林分蒸腾表现出明显的月变化,即7月>6月>8月>9月>5月,分别为65.08,62.43,54.27,22.92,19.84 mm;(2)林分累计蒸腾量共计224.54 mm,占同期降雨量的32.41%,其中优势木为林分蒸腾的主要贡献者,占林分总蒸腾量的62.64%;(3)在小时尺度上,林分蒸腾量主要受大气温度和饱和水汽压差所影响;日尺度上,林分蒸腾与潜在蒸散、空气温度、太阳辐射、饱和水汽压差、叶面积指数以及土壤温度极显著正相关(p<0.01);与空气相对湿度极显著负相关(p<0.01);与土壤含水量关系不显著(p>0.05),潜在蒸散、叶面积指数、饱和水汽压差以及空气温度是驱动林分日蒸腾的主要影响因子;月尺度上,空气温度对林分蒸腾的影响最大,其对林分蒸腾的解释度高达93.90%。To investigate the response of transpiration characteristics of Betula platyphylla secondary forest to influencing factors in permafrost area,and to provide scientific reference for accurate assessment of the hydrological effects of forest ecosystems in this region.The sap flow of Betula platyphylla was measured using thermal dissipation probes from May to September 2021 in permafrost area,and the influence factors were observed simultaneously.The results showed that the stand transpiration of Betula platyphylla secondary forest showed obvious hourly,daily and monthly changes during the study period.(1)The hourly transpiration characteristics of Betula platyphylla secondary forest was exhibited that dominant trees>intermediate trees>suppressed trees.Furthermore,diurnal variations of daily transpiration performed a single peak curve pattern in sunny days,while the bimodal curve was observed in rainy days.Meanwhile,the daily mean stand transpiration of Betula platyphylla secondary forest was 1.47 mm/d,with the maximum value appeared in July.A significant monthly variation of transpiration was found during the whole observation period and ranked as follows:July>June>August>September>May,which was 65.08,62.43,54.27,22.92 and 19.84 mm,respectively.(2)The cumulative transpiration of the stand was 224.54 mm,accounting for 32.41%of the total precipitation over the same period,and the transpiration of the dominant trees was the main contributors to the stand transpiration,accounting for 62.64%of the stand transpiration.(3)At the hourly scale,transpiration was mainly affected by air temperature and vapor pressure deficit.At the daily scale,transpiration was positively correlation with potential evapotranspiration,air temperature,solar radiation,vapor pressure deficit,leaf area index and soil temperature(p<0.01),which was significant negative correlation with air relative humidity(p<0.01)and no significant correlation with soil water content(p>0.05),and potential evapotranspiration,leaf area index,vapor pressure deficit and

关 键 词：多年冻土区 林分蒸腾 大气因子 叶面积指数 土壤含水量 

分 类 号：S718.55[农业科学—林学]