| Natural forest is a powerful terrestrial ecosystem with a complex and stable community structure.Compared with planted forests,natural forests are more capable of conserving water sources,absorbing carbon and fixing carbon,and mitigating climate change.Regarding the current wind-sand and haze problems,it is an inevitable trend to promote the coordinated development of forestry in the Beijing-Tianjin-Hebei region.Therefore,whether it is from the necessity of natural forest conservation or the urgency of implementation,accelerating the assessment of natural forest resources and overall planning for conservation and management has become a necessary way to build an ecological civilization in the Beijing-Tianjin-Hebei region.This research is based on the national forest inventory,the second-class survey data and the natural forest survey data of the temporary sample plots set up by random sampling.By constructing the optimal model,the principal component analysis method(PCA),the analytic hierarchy process(AHP)and The biomass conversion factor continuous function method(VBEFF),the natural forest ecosystem service function,natural forest quality,natural forest biomass,carbon storage and carbon sink value were systematically evaluated,and the spatial distribution map was drawn for reference.Finally,these evaluation results were discussed,and the natural forest conservation and management in the Beijing-Tianjin-Hebei region were given a panoramic view,and the typical conservation management model was designed with rural and Chinese pine natural forest surveys as examples.The Ninth Plan’s second clearance,the research results show:(1)The number of natural forests in the Beijing-Tianjin-Hebei region continues to increase.Natural forests are mainly young and middle-aged forests,whose area and accumulation account for 85.08%and79.53%of arbor forests.Natural arbor forests are dominated by oaks with an area of 45.90×10~4 hm~2.(2)In the Beijing-Tianjin-Hebei region,various indicators of natural forest ecological services and value have increased significantly.The dynamic distribution of the functions of each indicator in the total is mainly based on water conservation,biological protection,and carbon fixation and oxygen release.Respectively accounted for 41.42%,6.05%,14.03%of the total value.The protection ability of natural forests to provide ecological services is fixed in the aspects of water conservation,biological maintenance,and carbon and oxygen release.(3)The quality of natural forests in the Beijing-Tianjin-Hebei region is ranked as follows:Grade III>Grade IV>Grade II>Grade V>Grade I,which reflects that the quality of natural forests in the study area is generally low and at a medium level.The overall level of natural forest quality has much room for improvement.(4)In the comprehensive evaluation system of natural forest quality in the Beijing-Tianjin-Hebei region,in terms of the overall goal,the criterion layer that has the greatest impact on it is forest productivity,which accounts for 0.41 of the overall goal.In the index layer,the top five indicators with weight values are age group(0.2001)>average diameter at breast height(0.1801)>number of plants per hectare(0.0925)>average tree height(0.0853)>altitude(0.0493).Therefore,we can consider improving forest productivity,adjusting and optimizing age group structure and forest density.Improve the quality of natural forests in the study area.(4)The total biomass of natural forests in the Beijing-Tianjin-Hebei region is 10468.83×10~4t,the total carbon storage is 5234.423×10~4t,the total value of carbon is 14.92×10~8 yuan,and the average biomass per unit area of natural arbor forest is 41.98 t/hm~2,which is far lower The national average forest biomass per unit area is 84.73 t/hm~2,which reflects the fact that the quality of natural forests in the Beijing-Tianjin-Hebei region is not high.(5)The management model of natural forest conservation in the Beijing-Tianjin-Hebei region is divided into six types:strict conservation,closure for afforestation,degradation and restoration,ecological development,forest regeneration,and forest tending.There are four operation methods suitable for natural forest tending in the Beijing-Tianjin-Hebei region,namely,protection management operation method,individual tree selective cutting operation method,group selective cutting operation method,and umbrella-shaped progressive cutting operation method.Different natural forest tending operation methods shall be given to natural forests of different natural forest types and conservation management models.This research mainly provided data support for the collaborative conservation of natural forests in the Beijing-Tianjin-Hebei region,and also provided ideas for the planning and design of ecological compensation systems,public welfare forest compensation policies,natural forest restoration programs,etc.Therefore,this research had high theoretical significance and Practice value. |
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