Microclimate Features of Larix gmelinii var.principis-rupprechtii Plantations in the Liupan Mountains of Northwestern China
[Objective]The microclimate features under forest canopy(UFC)and in forest gap(IFG)of Larix gmelinii var.principis-rupprechtii plantations were monitored to provide a scientific basis for understanding the microclimate regulation effect of forest and for guiding the forest management promoting the regeneration of understory trees and the optimal use of multiple forest ecosystem services.[Methods]Microclimate monitoring plots of UFC(with an age of 40 years and a canopy density of 0.52)and IFG(with an area 750 m2)were established in the southern sub-humid area of the Liupan Mountains,Ningxia,Northwestern China.Meteorological parameters and the soil temperature and moisture at 10 cm depth were monitored by automatic weather stations for one year from December 2022.Based on the relationship between standard meteorological station data and altitude,linear interpolation method was used to obtain meteorological data in open field(IOF)as a control.[Results]Compared with the habitat of IOF,the habitats of UFC and IFG showed obvious microclimate regulation effects,which were manifested in:1)the annual means of cumulative value of solar radiation(MJ/m2)was UFC(4.53)＜IFG(8.87)＜IOF(13.99),indicating that the values of UFC and IFG were decreased to 32.4% and 63.4% of that of IOF.The difference of monthly mean solar radiation accumulation value between the habitats of IOF and UFC or IFG was greater in growing season than in non-growing season.2)The annual mean air temperature(℃)was UFC(7.2)＜IOF(7.5)＜IFG(7.8).The diurnal air temperature range(℃)was UFC(6.1)＜IFG(6.3)＜IOF(8.0),indicating a more gentle variation of air temperature of UFC and IFG.The average difference in air temperature between the habitat of UFC,IFG and IOF was smaller in growing season than in non-growing season.3)The annual means of relative air humidity(%)was UFC(69.1)＞IFG(64.7)＞IOF(62.5),indicating an increase of 6.6% and 2.2% by the habitats of UFC and IFG compared with that of IOF.The ability of UFC and IFG to increase air humidity during the growing season is greater than during the non-growing season.4)The annual mean soil temperature(℃)at the depth of 10 cm was UFC(6.8)＜IFG(8.8)＜IOF(9.1),indicating a decrease of 2.3℃and 0.3℃at the habitats of UFC and IFG compared with that of IOF.The diurnal range of soil temperature(℃)was UFC(0.7)＜IFG(1.5)＜IOF(4.5);The soil temperature was decreased at the habitats of UFC and IFG in growing season but increased in winter compared with that of IOF.5)The annual mean soil moisture(%)at the depth of 10 cm was UFC(24.4)＜IFG(29.8)＜IOF(33.8),indicating an decrease of 9.4% and 4.0% at the habitats of UFC and IFG compared with that of IOF.The difference in soil moisture between UFC and IOF is smaller during the growing season compared to the non-growing season,whereas the difference in soil moisture between IFG and IOF is greater during the growing season than in the non-growing season.[Conclusion]The microclimate regulation effect of the L.gmelinii var.principis-rupprechtii plantations is obvious,and it is greater in growing season than in non-growing season.Compared with open field,the solar radiation,soil temperature and soil moisture were significantly decreased at the habitats of under forest canopy and in forest gap,but the air humidity was significantly increased,and the variation amplitude of each index was reduced and the peak time was adjusted,has a good regulating and buffering effect on air temperature.
forest microclimateunder forest canopyin forest gapsolar radiationair temperature and humiditysoil temperature and moisture
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