Growth and Simulation of Quercus mongolica Forests Driven by Site Environment and Stand Structure
[Objective]This study aims to quantitatively study the growth response of tree height and diameter at breast height(DBH)of Quercus mongolica forests to multiple factors of climate,topography,soil,and forest stand structure in the Liupan Mountains area of Ningxia Hui Autonomous Region of China,and further to build a multi-factor coupling model for accurately simulating and predicting the effects of climate and other factors on forest growth.[Method]Based on the environmental gradient in the Liupan Mountains area,79 plots of natural secondary forests of Quercus mongolica were established for doing individual tree survey in 2021 and 2022.Using upper outer boundary line method to determine the response relationships and function types of stand mean height and mean DBH to site environment and stand structure factors.A multifactorial coupled model framework was constructed through multiplying the single factor response functions,and model parameters were fitted based on measured data,to simulate the climate change effect on the forest growth.[Result]The main factors simultaneously affecting the growth of stand mean tree height and mean DBH of Quercus mongolica forests in the Liupan Mountains area were stand age,stand density,mean annual precipitation,mean annual temperature,and soil thickness.The stand mean tree height and mean DBH exhibit a slow-fast-slow growth pattern with increasing stand age.With increasing stand density,they first remain stable and then decline rapidly.As soil thickness and mean annual precipitation increase,they initially increase rapidly and then stabilize.With rising mean annual temperature,they show a unimodal trend,first rising rapidly and then declining rapidly.The multifactorial coupled models for stand mean tree height and mean DBH were constructed based on the single-factor response functions,and these models showed higher prediction accuracy(R2＞0.70).The simulation results of scenarios of 1.5 ℃ increase in mean annual temperature showed that the stand mean tree height and mean DBH growth of Quercus mongolica forests throughout the Liupan Mountains area would be decreased,with region-specific decrease ratios of 10％and 7％in the cold-humid southern part,15％and 12％in the warm-humid central part,and 18％and 13％in the warm-dry northern part of the Liupan Mountains area,respectively.[Conclusion]The stand mean tree height and mean DBH growth of the secondary forests of Quercus mongolica in Liupan Mountains area are influenced simultaneously by multiple factors of climate,stand structure,and site conditions.Establishing coupled growth models which can reflect the effects of multiple main driving factors(mean annual precipitation,mean annual temperature,stand age,stand density,soil thickness)can accurately predict the effects of climate change and density regulation on the stand mean tree height and mean DBH growth.Future increases in air temperature will decrease the growth of stand mean tree height and mean DBH,but the decrease extent has spatial variation,i.e.,higher growth decrease in areas with higher air temperature.It is necessary to take region-specific measures in forest management to address future climate change.The results of this study can provide theoretical and technical support for predicting the impacts of climate change and determining forest management measures.
Quercus mongolicanatural foresttree heightdiameter at breast heightclimate changesite conditionsstand structurecoupled modeling
万方数据
维普
