北京市3种典型森林类型林内植物源挥发性有机物变化特征

Variation characteristics of biogenic volatile organic compounds in three typical kinds of forests in Beijing

【目的】揭示北京市九龙山国家森林康养基地典型森林类型BVOCs时空变化特征及其影响因素,以期为森林康养基地建设提供数据和理论支撑。【方法】以北京九龙山森林康养基地核心区的油松纯林、侧柏纯林、山楂-日本落叶松混交林为研究对象,采用主动采样法测定不同森林类型内BVOCs的组成,分析主要BVOCs的时空变化规律及气象要素、空气负离子对其的影响。【结果】秋季北京九龙山森林康养基地核心区3种典型森林类型林内BVOCs成分组成大致相同,且均以芳香烃、酯类、烷烃、醛类物质为主,而烯烃类物质较少;不同林分类型BVOCs组分日平均相对含量仅烯烃存在显著差异,且针叶纯林显著高于针阔混交林,其他BVOCs组分相对含量无显著差异;3种林分空气中萜类化合物的相对含量总体较低,且除叶绿醇为针阔混交林相对含量较高外,其他均为针叶纯林高于针阔混交林;针阔混交林一天内不同时间段林内BVOCs相对含量无显著差异,而针叶纯林林内仅萜类、烯烃、醇类物质存在明显的“单峰型”日变化规律,即12:00最高,而9:00、15:00较低;一天内相同的时间,针叶纯林林内萜类、烯烃类、醇类物质显著高于针阔混交林,其他物质无显著差异;5种环境因子与不同林分林内BVOCs相对含量以显著正相关为主,且气温的影响最大,其次是风速,而光合有效辐射和空气负离子的影响最小。【结论】植物组成、温度、风速是影响北京九龙山森林康养基地林内BVOCs的关键因素,且在温度较高、风速较小的午后,常绿针叶纯林林内对人体健康有益的BVOCs含量相对较高,更适合开展森林康养活动。

【Objective】This work aimed to reveal the temporal and spatial variation laws of main BVOCs and the influence of meteorological elements and negative air ions on them in Beijing Jiulong Moutain Forest Health Base,in order to provide data and theoretical support for the construction of the forest health base.【Method】This study took the Pinus tabuliformis pure forest,Platycladus orientalis pure forest,and Crataegus pinnatifida×Larix kaempferi mixed forest in the core area of Beijing Jiulong Moutain Forest Health Base as the research objects,and used the active sampling method to determine the composition of BVOCs in forests of different types.【Result】The composition of BVOCs in three typical kinds of forests in autumn was roughly the same,and they were all dominated by aromatic hydrocarbons,esters,alkanes,and aldehydes,while olefins were few.There were significant differences in the average daily relative content of olefins in different stand types,meanwhile,other BVOCs components showed no significant difference.Moreover,the average daily relative content of pure coniferous forest was significantly higher than that in the coniferous broad-leaved mixed forest.The relative content of terpenoids in the air of the three stands was generally low,and the relative content of terpenoids in the pure coniferous forest was higher than that in the mixed coniferous broad-leaved forest,except phytol which was higher in the mixed forest.There was no significant difference in the relative content of BVOCs in the mixed coniferous broad-leaved forest during different time periods,while only terpenes,olefins and alcohols existed in the pure coniferous forest had a noticeable“single peak”diurnal variation pattern,which was the highest at 12:00,and showed lower values at 9:00 and 15:00.At the same time in one day,the relative contents of terpenes,olefins,and alcohols in the pure coniferous forest were significantly higher than those in the coniferous broad-leaved mixed forest.Meanwhile,other compounds had no significant difference.The five environmental factors were mainly positively correlated with the relative content of BVOCs in different stands,specifically,the influence of temperature was the most significant,followed by wind speed,while the influence of photosynthetically active radiation and negative air ions was the least.【Conclusion】Plant composition,temperature and wind speed are the key influencing factors for the temporal and spatial variation of BVOCs in Beijing Jiulong Mountain Forest Health Care Base.In the afternoon with high temperature and breeze,the content of BVOCs which is beneficial to human health is relatively high in the pure evergreen coniferous forest,which is more suitable for forest health care activities.