ABSTRACT
In this study, the FireBGCv2 model was used to simulate the dynamics of forest carbon pools of Huzhong Nature Reserve within the next 100 years under various forest fire severity scena-rios. The aim of this study was to explore the responses of different forest carbon pools to fire disturbance, and to provide scientific basis for forest fuel management. The results showed that forest fire significantly reduced forest carbon storage, with the greatest reduction under the scenario of high-severity forest fire. Fire disturbance affected carbon storage in different pools, and relocated carbon among those pools. Forest fire disturbance reduced carbon storage of living trees and duff, increased that of coarse woody debris in the early and middle stages of simulation, and decreased that in late stage. The carbon storage of shrub and herb strata increased significantly in the late simulation period. The higher the fire severity, the lower the carbon storage of living tree and shrub-herb carbon pools, with snag and coarse woody debris showing the opposite trend. The impact of forest fire disturbance on the total carbon pool distribution was as follows: forest fire increased the proportion of shrub and herb strata, snag, coarse woody debris and soil carbon pool, and reduced the proportion of living tree and duff. The higher severity forest fire was, the lower the proportion of carbon pool of shrub-herb, and the higher the proportion of carbon pool of coarse wood debris. The severity of forest fire had less impact on the proportion of other carbon pools. In addition, our results demonstrated periodic change of litter carbon that reached a high value within 20 years and then dropped to a low value within 10 years. Our results could provide sound basis for determining the forest fuel treatment interval. We suggested performing prescribed burning every 20 years in the Great Xing'an Mountains area to protect forest resources.
Subject(s)
Carbon , Fires , Carbon/analysis , China , Forests , TreesABSTRACT
The land cover of Bohai Rim region has changed greatly due to urbanization and economic development. Monitoring the land cover with high accuracy and real time is the most important basis for relevant researches. Traditional single-machine processing mode is difficult to realize rapid monitoring for large-scale and long-time series. The emergence of remote sensing big data makes it possible to combine computing platform and massive data. The land cover maps of study area were interpreted based on Google Earth Engine (GEE) platform with decision tree (CART) method from 2000 to 2019. The land cover change was analyzed, and the interpretation results using different data sources were compared. The results showed that the GEE platform could realize the rapid land cover interpretation in a large area, which interpreted coastal wetlands and other cover types with high accuracy over 80% comparing the surveyed points. Compared with Landsat images, the Sentinel-2A images interpretation results had a great improvement in accuracy, which increased from 85% to 95%, and thus more detailed surface information could be reflected. In 2000, the area of wetland, build-up area, farmland, forest, and water in the study area were 1612.5, 5734.9, 32074.8, 11853 and 3504.3 km2, accounting for 2.9%, 10.5%, 58.6%, 21.6% and 6.4% respectively. By 2019, wetlands had been reduced by 775.1 km2, with a decline of 40.1%; built-up area increased by 5310.5 km2 with an increasing rate of 92.6%. The area of farmland, forestland and water area decreased 1841.6, 1823.5 and 870.3 km2, with a decreasing rate of 5.7%, 24.8% and 48.1%, respectively. The coastal urbanization process caused the occupation of built-up area to other land use types, which was the main driving force of land cover change in the study area.
Subject(s)
Conservation of Natural Resources , Wetlands , Environmental Monitoring , Forests , UrbanizationABSTRACT
Precise estimation of gross primary productivity (GPP), the key parameter in carbon cycle analysis, plays an important role in the research of carbon cycle and global climate change. Vegetation GPP was simulated by VPM model based on MOD09A1 and climate data in Changbai Mountain Natural Reserve from 2000 to 2015. The results showed that mean GPP was 1203 g C·m-2·a-1. The annual vegetation GPP significantly increased from 2000 to 2015. There was no significant difference in the temporal trends of forest GPP at different vertical vegetation zones. However, GPP of the alpine tundra decreased remarkably. The correlation between GPP and precipitation was not significant. The positive correlation of GPP and temperature was mainly distributed in broad-leaved Korean pine forests and alpine tundra. Spring temperature had the strongest influence on GPP, with 80% pixels had a positive correlation with temperature. The GPP had a stronger correlation with temperature compared with precipitation.
Subject(s)
Conservation of Natural Resources , Ecosystem , Environmental Monitoring/methods , Forests , China , Climate Change , SeasonsABSTRACT
Objective:To investigate the effects of Shanxian granule on proliferation of Lewis lung cancer cells and anti-tumor immunity and immune microenvironment of Lewis lung cancer-bearing mice in order to explore the molecular mechanism of anti-tumor of Shanxian Granule and improve the anti-tumor immunity of the body, and provide further theoretical basis for its clinical application. Methods:Lewis lung cancer cells was transplanted to axillary skin to establish mouse tumor model. The mice divided into blank group,model group,chemotherapy group and Shanxian granule group. The tumor tissue of Lewis lung cancer tumor bearing mice was weighed and the tumor inhibition rate was calculated. Immunohistochemical method was used to detect the expression of CD and CD8 in spleen tissue. The effect of lymphocytes on the proliferation of Lewis lung cancer cells was detected by CCK-8 method. The level of IFN-γ,TNF-βand IL-10 in peripheral blood were detected by ELISA. Results:①The tumor inhibition rate of Lewis lung cancer was 45. 99% in Shanxian Granule group,which was significantly higher than that of chemotherapy group (P<0. 05).②The lymphocytes of mouse can inhibit the proliferation of Lewis lung cancer cells and have a positive correlation with lymphocyte concentration and duration of action. Moreover,CD4+ T cells,CD4+/CD8+ratio and lymphocyte inhibition rate of Lewis lung cancer cells in model group and chem-otherapy group were significantly lower than those in blank group (P<0. 05). Shanxian granule group was significantly higher than the model group and chemotherapy group ( P<0. 05 ) . However, there was no significant difference between Shanxian granule group and blank group(P>0. 05).③The levels of IFN-γand TNF-βin peripheral blood of model group and chemotherapy group were significantly lower than those in blank group,while IL-10 was significantly higher than that in blank group (P<0. 05). The levels of IFN-γand TNF-βin peripheral blood of mice in Shanxian granule group were significantly higher than those in model group and chemotherapy group, while IL-10 was significantly lower than that in model group and chemotherapy group (P<0. 05). There was no significant difference in IFN-γ,TNF-β and IL-10 in peripheral blood of mice between Shanxian granule group and blank group. Conclusion:Shanxian granule can significantly inhibit the growth of tumor tissue of Lewis lung cancer tumor bearing mice,increase the spleen index of mice,enhance the activity of T lymphocytes,upregulate IFN-γ and TNF-β in peripheral blood and decrease IL-I. These suggested that the anti-tumor effect of Shanxian granule may be achieved by regulating the content of CD4+ T lymphocyte,the ration of CD4+/CD8+ and Th1/Th2 ratio,in order to restore the immune steady function of tumor patients,improve the immune system and enhance the immune surveillance function.
ABSTRACT
Objective:To investigate the effects of Shanxian granule on proliferation of Lewis lung cancer cells and anti-tumor immunity and immune microenvironment of Lewis lung cancer-bearing mice in order to explore the molecular mechanism of anti-tumor of Shanxian Granule and improve the anti-tumor immunity of the body, and provide further theoretical basis for its clinical application. Methods:Lewis lung cancer cells was transplanted to axillary skin to establish mouse tumor model. The mice divided into blank group,model group,chemotherapy group and Shanxian granule group. The tumor tissue of Lewis lung cancer tumor bearing mice was weighed and the tumor inhibition rate was calculated. Immunohistochemical method was used to detect the expression of CD and CD8 in spleen tissue. The effect of lymphocytes on the proliferation of Lewis lung cancer cells was detected by CCK-8 method. The level of IFN-γ,TNF-βand IL-10 in peripheral blood were detected by ELISA. Results:①The tumor inhibition rate of Lewis lung cancer was 45. 99% in Shanxian Granule group,which was significantly higher than that of chemotherapy group (P<0. 05).②The lymphocytes of mouse can inhibit the proliferation of Lewis lung cancer cells and have a positive correlation with lymphocyte concentration and duration of action. Moreover,CD4+ T cells,CD4+/CD8+ratio and lymphocyte inhibition rate of Lewis lung cancer cells in model group and chem-otherapy group were significantly lower than those in blank group (P<0. 05). Shanxian granule group was significantly higher than the model group and chemotherapy group ( P<0. 05 ) . However, there was no significant difference between Shanxian granule group and blank group(P>0. 05).③The levels of IFN-γand TNF-βin peripheral blood of model group and chemotherapy group were significantly lower than those in blank group,while IL-10 was significantly higher than that in blank group (P<0. 05). The levels of IFN-γand TNF-βin peripheral blood of mice in Shanxian granule group were significantly higher than those in model group and chemotherapy group, while IL-10 was significantly lower than that in model group and chemotherapy group (P<0. 05). There was no significant difference in IFN-γ,TNF-β and IL-10 in peripheral blood of mice between Shanxian granule group and blank group. Conclusion:Shanxian granule can significantly inhibit the growth of tumor tissue of Lewis lung cancer tumor bearing mice,increase the spleen index of mice,enhance the activity of T lymphocytes,upregulate IFN-γ and TNF-β in peripheral blood and decrease IL-I. These suggested that the anti-tumor effect of Shanxian granule may be achieved by regulating the content of CD4+ T lymphocyte,the ration of CD4+/CD8+ and Th1/Th2 ratio,in order to restore the immune steady function of tumor patients,improve the immune system and enhance the immune surveillance function.
