Vegetation-Climate Relationship and Its Application in the Division of Vegetation Zone in China

Distribution of vegetation is closely coupled with climate; the climate controls distribution of vegetation and the vegetation type reflects regional climates. To reveal vegetation_climate relationships is the foundation for understanding the vegetation distribution and theoretically serving vegetation regionalization. Vegetation regionalization is a theoretical integration of vegetation studies and provides a base for physiogeographical regionalization as well as agriculture and forestry regionalization. Based on a brief historical overview on studies of vegetation_climate relationships and vegetation regionalization conducted in China, we review the principles, bases and major schemes of previous vegetation regionalization and discuss on several contentious boundaries of vegetation zones in the present paper. We proposed that, under the circumstances that the primary vegetation has been destroyed in most parts of China, the division of vegetation zones/regions should be based on the distribution of primary and its secondary vegetation types and climatic indices that delimit distribution of the vegetation types. This not only reveals the closed relationship between vegetation and climate, but also is feasible practically. Although there still are divergence of views on the name and their boundaries of the several vegetation zones, it is commonly accepted that there are eight major vegetation regions in China, i.e. cold temperate needleleaf forest region, temperate needleleaf and broadleaf mixed forest region, warm temperate deciduous broadleaf forest region, subtropical evergreen broadleaf forest region, tropical monsoon forest and rain forest region, temperate steppe region, temperate desert region, and Qinghai_Xizang (Tibetan) Plateau high_cold vegetation region. Analyzing characteristics of vegetation and climate of major vegetation boundaries, we suggested that: 1) Qinling Mountain_Huaihe River line is an important arid/humid climatic, but not a thermal climatic boundary, and thus can not also be regarded as the northern limit of the subtropical vegetation zone; 2) the northern limit of subtropical vegetation zone in China is along the northern coast of the Yangtze River, from Hangzhou Bay, via Taihu Lake, Xuancheng and Tongling in Anhui Province, through by southern slope of the Dabie Mountains, to Wuhan and its west, coinciding with a warmth index ( WI ) value of 130-140 ℃·month; 3) the tropical region is limited in a very small area in southeastern Hainan Island and southern edge of Taiwan Island; and 4) considering a significant difference in climates between the southern and northern parts of the warm temperate zone, we suggested that the warm temperate zone in China is divided into two vegetation regions, deciduous broadleaf woodland region and deciduous and evergreen broadleaf mixed forest region, the Qinling Mountain_Huaihe River line being as their boundary. We also claimed that the zonal vegetation in North China is deciduous broadleaf woodland. Finally, we emphasized the importance of dynamic vegetation regionalization linked to climate changes.

Exploring building's envelope thermal behavior of the neo-vernacular residential architecture in a hot and dry climate region of Algeria

It is well known that the passive strategies applying in traditional buildings respond satisfactory to climatic requirements and succeed to provide maximum indoor comfort with minimum energy consumption.From this point of view,it is interesting to quantitatively assess the effectiveness of the vernacular strategies to improve the environmental performance of the building's envelope under desert climate conditions.The research tries to address this issue and was undertaken in southern Algeria where a very hot and arid climate prevails.The effect of some selected passive cooling strategies on enhancing the building's envelope climate performance was examined.These strategies are inspired from the local vernacular architecture,and they are expected to provide satisfactory indoor thermal comfort for users and to reduce the energy cooling demand from residential buildings.Applying field and computational investigations,two existing residential buildings were tested:a typical residential unit and a contemporary vernacular(neo-vernacular)building.In the latter,climate responsive strategies inspired from vernacular architecture were applied.A comparison based on site measurements was carried out on the two selected buildings which differ from their envelope design properties and components.

Changes in thermal comfortable condition in the Qinghai‒Tibet Plateau from 1979 to 2020

Qinghai‒Tibet Plateau(QTP)is one of the most sensitive regions to climate change in the world.As a result,people in the QTP are more likely to be sensitively affected by climate change than those in other regions,particularly in the poverty area.Using the Universal Thermal Climate Index(UTCI)derived from ERA5 and population data,changes in annual thermal comfort condition and population under such condition in the QTP are systematically analyzed.The results reveal that there is considerable regional heterogeneity in the distribution of UTCI and the number of comfortable days(CDs),mainly due to the complex geographic features.In most areas of the QTP,the increase in UTCI leads to an increased number of comfortable days.Spatial distribution and temporal change in the number of comfortable days are found to be principally related to altitude.In areas within altitudes of 3000–4500 m,the number of comfortable days increases by up to 6 d per decade,which is faster than that in higher elevation areas above 4500 m.Results also indicate that thermal comfortable condition has improved in areas of 2500–5000 m(medium to high altitude),particularly in spring and autumn.Further research indicates that population distribution also shows a regional clustering feature,with the majority of residents residing in cities and their vicinities,where a higher number of comfortable days were observed.Most areas with a greater number of comfortable days have experienced a more significant increase in population under thermal comfortable conditions.It implies that climate change more likely has a large influence on population in the QTP.These findings are expected to enhance tourism development and the assessment of the impact on the living environment.The findings can be helpful for optimizing of tourism development and better understanding how climate change affects population distribution.