Studies On Net Carbon Reserves In Beijing Urban Landscape Green Based On Biomass Measurement

At present,with the international community highly concerned about climate change,carbon dioxide emission reduction has become an important topic of climate negotiations,countries are actively implementing carbon emission reduction measures to reduce carbon emissions.At home and abroad about the scope of a global or regional carbon storage,the volume of carbon sinks,carbon emission reduction,carbon sinks,such as research by the ascendant,the forests,soils,agriculture, grassland,such as carbon sinks research and carry out than earlier estimates,the results are also relatively rich.But research on the measurement method of city gardens green vegetation and soil carbon storage from a regional perspective,the micro-view also were very rare.Urban landscape green stores a certain amount of carbon each year through the absorption of carbon dioxide,and plays an important role on purification of urban air,reduce carbon dioxide, maintaining a good city living environment,carbon and oxygen balance in the town,the maintenance of ecological balance in the city.Therefore urban landscape green ecological functions has become the important content and topics on new era city garden and city forestry.Research on net carbon storage and carbon balance in Beijing urban landscape green land,for the city's ecological environment construction management,urban regional carbon measurement methods and the global carbon plan,is an important theoretical and practical significance.In this paper,a systematic analysis of the city's ecological environment,the ecological environment features of landscape plants,differences and similarities between gardens and forest and are achieving the same,characteristics of urban forestry,measuring the evaluation questions of carbon sinks on urban landscape green land,etc,were investigated.On this basis,a series of research on plant diameter/heigh distribution,plant biomass,net carbon reserves,carbon balance,the potential of increasing carbon sink and policy recommendations were carried out in Beijing urban landscape green.The main research method is:(1) 138 simple points and 2789 sample trees were investigated by sampling,statistical analysis,simulation methods.This article explored the main types of landscape plants and their average size and distribution to resolve the lack of plant size in landscape survey;(2) By the method of all types average standard wood of 22 plants different parts actual determination value,plant parts biomass distribution law was firstly explored and the biomass of landscape plants in Beijing was calculated;(3) According to 10 plants mean standard tree diameter growing,the growth of Beijing garden arbor diameter and annual plant biomass increment were investigated;(4) Beijing urban main garden plant and each part of plant carbon content rate change and distribution law were discussed firstly by all types average standard wood data of 22 plants carbon content rate.Garden plant net carbon reserves and net carbon density were calculated by biomass method;(5) According to 40 garden green space soil profiles layered sample determination data,distribution law of soil layer carbon reserves were measured.Soil total carbon reserves and carbon density in Beijing urban were calculated; Present total net carbon reserves,carbon density and annual net increasing carbon sequestration of Beijing garden green space were calculated;From two sides of Beijing city carbon emission and biological carbon fixation adsorption,Beijing city carbon balance and increasing carbon sequestration potential was discussed.Associated policies and technological suggestions on Beijing urban biological environment construction and carbon emission reduction were put forward.The results showed that:(1) For arbor,the diameter ratio of large(＞30cm),middle(10-30cm) and small(＜10cm)are 25.9%,49.7%and 24.4%in Beijing city(including 8 districts),estimated tree numbers are 2.94×10~6,5.64×10~6 and 2.77×10~6;(2) The average diameter,average tree height and average crown diameter of the existing landscape plants are not large,these of the deciduous arbor is the largest.the average diameter,average height and average crown diameter of the evergreen are respectively 13.5cm,5.8m,3.1m;and these of the deciduous are respectively 24.2cm,10.5m,6.0m;(3) A net biomass of the existing landscape plants are 1.82×10~6 t in Beijing(including the outer suburbs), in which,Beijing City(including 8 districts) occupied 1.29×10~6t with an average of 40.95 t/hm~2;(4) The mean carbon content rate of Beijing landscape plants was 0.486,with a ranging from 0.4 to 0.6. The evergreen are higher than the deciduous and the arbor are higher than the shrub The order according to part size is:leave(trunk),trunk(leave),branch,root and cortex;(5) The total carbon reserves of the existing green space are 3.71×10~6 t with an average of 92.46 t/hm~2,these reserves are mainly plant and soil carbon(77.9%).Existing carbon reserves in Beijing city green space are 8.88×10~5 t,with an average of 22.1 t/hm~2 Existing landscape soil carbon reserves are 2.82×10~6 t,which is 3.18 times more than that of landscape plants with an average of 70.33t / hm~2;(6)The annual growth of existing arbor's breast diameter was 0.8 cm,6.6×10~4 t for the annual biomass.The net increase of carbon reserves was about 4.5×10~4 t in Beijing.The per hectare growth of biomass and carbon reserves were 2.09 t and 1.12 t respectively;(7) Annual carbon emission of Beijing was 1.4×10~8 t and per capital was 7.2 t.Beijing city forest and garden plant could absorb 7.13×10~7 t CO~2,which occupied 53.2%of emission.The effect of emission reduction was obvious with great potential.The study also suggested that,(1) Urban ecological environment construction is should attach great importance to the problem for modern Beijing,and is the inevitable requirement of livable cities and ecological civilization.Recommendations that the concept of the scientific planning,strengthen the natural pattern,diverse ecosystems,restoration of natural river channels and wetlands,suburban integration,opening green and so on,be should changed,it will be useful of sustainable development, promoting urban ecological harmony.(2) Actively adopt a scientific and rational and orderly response measures to reduce carbon emissions and increase carbon storage.The Government should take effective measures to reduce CO~2 emissions due to accumulation of a series of ecological urban environmental problems,and implement a proactive policy of greenhouse gas emissions for urban development and make due contributions to human society,From outreach carbon sinks of knowledge, scientific research and popularization of scientific and technological achievements,carbon trading, developing low-carbon and renewable energy sources,control population growth,promoting green consumption,carbon tax,development of bio-carbon sequestration,etc.(3) City landscape survey method is not scientific,the use of census data value is not high.The study proposed the survey of landscape greens and forestry resources carried out simultaneously,re-formulated the landscape green Census indicators,projects and investigate technology options to determine the diameter at breast height,tree height,biomass and other indicators,to strengthen the city's ecological assessment of environmental benefits,to exert on the town's main role in the ecological environment.