Study On The Release Of VOCs From Typical Evergreen Broad-leaved Species And Their Mixed Forests In Hangzhou Banshan National Forest Park

As an important ecological health tourism resource,plant volatile organic compounds(VOCs)have various functions such as aromatizing environment,sterilization and disinfection,medical care,and repelling mosquitoes.Both Castanopsis sclerophylla and Lithocarpus glaber are typical evergreen broad-leaved species in Hangzhou Banshan National Forest Park.They are also excellent timber species and have great development value.In this study,bitter Castanopsis sclerophylla and Lithocarpus glaber and their mixed forests in the area were studied.The volatile organic compounds released from the air(environment)of the mixed forest and from the leaves of Castanopsis sclerophylla and Lithocarpus glaber in summer and winter were studied.The content and content were monitored to quantitatively characterize the differences and daily dynamics of the components and contents of volatile organic compounds in summer and winter.At the same time,the effects of Castanopsis sclerophylla and Lithocarpus glaber on the composition and content of volatile organic compounds in the air were analyzed.People provide scientific guidance in forest health activities in Banshan Park.This research adopts the QC-1 B type gas sampling instrument by dynamic headspace bagging method and sampling of niche,open stone oak leaves and its mixed release of volatile organic compounds in extraction,hexane by elution,concentrated into the gas chromatography-mass spectrometry detector(GC/MS)detection,through the peak area of calculating the relative content.The composition,composition,relative concentration,law of change and change between seasons were analyzed,and the following conclusions were drawn:In summer,the branches and leaves of Castanopsis sclerophylla have released 65 kinds of volatile organic compounds with 10 components.The branches and leaves of Lithocarpus glaber release 10 chemical components and 68 kinds of volatile organic compounds,and the proportion of alkane and olefin accounts for more than 80%.For terpenoids,the main branches and leaves of Castanopsis sclerophylla had ?-pinene,?-ocimene(E)and cinnamene,accounting for 20.20% and 12.29% of the volatiles,respectively;For Lithocarpus glaber,the percentages and relative concentrations of ?-pinene,?-pinene and terpene in volatile matter were 20.53% and 11.65%,respectively.12 chemical components and 79 kinds of volatile organic compounds in the mixed forest at 9:00 were detected in summer,17 chemical components and 91 kinds of volatile organic compounds at 13:00,and 13 chemical components and 90 kinds of volatile organic compounds at 17:00.Among them,the relative concentration of aromatics harmful to the human body at 13:00 is the highest,and visitors are not advised to conduct forest recreational activities in the afternoon;the relative concentration of terpenoids at 17:00 is the highest,which is 11.79%.People perform recreational activities in the evening for physical and mental health.Better results.In winter,there were 6 components and 23 volatile organic compounds released from the leaves of Castanopsis sclerophylla,6 components and 25 volatile organic compounds released from the leaves of Lithocarpus glaber,and more than 90% of alkanes and olefins.The percentage and relative concentration of terpenes released by Castanopsis sclerophylla leaves were 30.34% and 3.39% respectively,while the Lithocarpus glaber leaves were 28.20% and 3.13% respectively.In the volatile organic compounds in the three periods of winter,6 components and 28 volatile organic compounds were detected at 9:00,7 components and 35 volatile organic compounds were detected at 13:00,and 6 components and 31 volatile organic compounds were detected at 17:00.Among them,the relative concentration of terpenes at 13:00 is the highest,which is 3.07%.Therefore,it is better for people to carry out forest health activities in the afternoon.Volatile organic compounds and the relative concentrations of terpene compounds and were very significant positive correlation,air temperature and relative humidity had no obvious correlation,were very significant negative correlation relationship with CO2 concentration.In terms of comfort,people tend to feel more comfortable during the summer morning and afternoon in the forest.The relative concentrations of volatile organic compounds and terpenes in summer were higher than winter and the difference was extremely significant.This study can carry on the forest recreation activities for people the best time to provide some scientific theoretical guidance,at the same time,provide theoretical reference for forest vegetation construction and management,then for forest health tourism provides the theory basis for development and promotion.