Temporal And Spatial Variation Of Forest In Typical Boreal Forest In Siberia Under The Background Of Climate Change

In the context of global warming,the long-term spatial change characteristics of boreal forest coverage and species in Siberia are not only of great significance to global climate change research and sustainable development,but also provide support for further exploring the response of boreal forest change to climate change.The data sources are Landsat TM/OLI images with 4 temporal series in summer season from 1985 to 2015,respectively.The Krasnoyarsk region in Russia was selected as the typical study area of boreal forest in Siberian.The forested and non-forested lands were discriminated by decision tree method,and further the forested land was classified to broad-leaved and coniferous forests by random forest algorithm,and verification with random sample points of GF-2 satellite images,and the overall accuracy was 90.37%.The information of the dynamic temporal and spatial distribution of forest coverage and species change is quantified through latitude zones with 2° interval in the range of 51°N-69°N and the spatial overlay analysis for the dynamic forest coverage and species change maps of the four periods.The correlation between forest change and climate variables of temperature and precipitation was analyzed by partial least squares regression.The main conclusions are as follows:(1)The boreal forest coverage increased 5.11%from 75.42%in 1985 to 80.53%in 2015 over the past 3 decades in general.Simultaneously,the spatial divergences of the changes of the boreal forest coverage in different latitude zones are significant:the increased area was mainly distributed in the latitude zone of 53°N-55°N,55°N-57°N,63°N-65°N,and 65°N-67°N;the area of decreased was mainly distributed in the latitude zone of 55°N-57°N and 57°N-59°N.(2)The area of coniferous forest and broad-leaved forest showed an increasing trend in general,but the area of coniferous forest decreased in 61°N-63°N and 57°N-59°N latitudes.After over 3 decades of evolution,the increased area of coniferous forest by 25269.72 km2,the proportion increased by 3.54%,and the increased area of broad-leaved forest by 11210.00 km2,the proportion increased by 1.57%.Among them,the area of coniferous forest increased fastest from 1995 to 2005,and the increased latitudes were 53°N-55°N,63°N-65°N,and 65°N-67°N.The area of broad-leaved forest increased fastest from 2005 to 2015,and the increased latitudes were 51°N-53°N,57°N-59°N,63°N-65°N,and 65°N-67°N.(3)The climate variables of temperature and precipitation from 1981 to 2010 had the highest correlation with the forest change from 1985 to 2015,and can be better interpretability.The correlation analysis showed that the response mechanism of forest change in high latitude region(HB)and low latitude region(LB)is different:The increased of average temperature has positive effect on forest change in both HB and LB,and forest change in HB was more sensitive to the increased of average temperature.The increased of precipitation promoted the forest change in Hb,but did not promote the forest change in LB.Figure[40]table[9]reference[110]...