Using leaf area index(LAI) to assess vegetation response to drought in Yunnan province of China

Climatic extremes such as drought have becoming a severe climate-related problem in many regions all over the world that can induce anomalies in vegetation condition. Growth and CO2 uptake by plants are constrained to a large extent by drought.Therefore, it is important to understand the spatial and temporal responses of vegetation to drought across the various land cover types and different regions. Leaf area index(LAI) derived from Global Land Surface Satellite(GLASS) data was used to evaluate the response of vegetation to drought occurrence across Yunnan Province, China(2001-2010). The meteorological drought was assessed based on Standardized Precipitation Index(SPI)values. Pearson's correlation coefficients between LAI and SPI were examined across several timescales within six sub-regions of the Yunnan. Further, the drought-prone area was identified based on LAI anomaly values. Lag and cumulative effects of lack of precipitation on vegetation were evident, with significant correlations found using 3-, 6-, 9-and 12-month timescale. We found 9-month timescale has higher correlations compared to another timescale.Approximately 29.4% of Yunnan's area was classified as drought-prone area, based on the LAI anomaly values. Most of this drought-prone area was distributed in the mountainous region of Yunnan.From the research, it is evident that GLASS LAI can be effectively used as an indicator for assessing drought conditions and it provide valuable information for drought risk defense and preparedness.

Global carbon sequestration potential of agroforestry and increased tree cover on agricultural land

Biomass is fundamental to circular agricultural systems.Estimates of above-and below-ground biomass on agricultural land based upon IPCC Tier 1 estimates are compared with an updated carbon density map based on remote sensing,with results indicating the methodology and initial estimations are robust.Two scenarios are evaluated to estimate carbon sequestration potential of increasing tree cover on agricultural land:1)incremental change and 2)a systemic change to agroforestry.Estimates of above-and below ground biomass carbon were combined with a tree cover analysis to estimate the increase in biomass.Global increases(4−6 PgC for incremental change;12−19 PgC for systemic change)highlight substantial mitigation potential.Increasing global tree cover on agricultural land by 10%would sequester more than 18 PgC.South America has the highest potential,followed by Southeast Asia,West and Central Africa,and North America.Brazil,Indonesia,Philippines,India,the United States and China are among the top countries with the highest carbon sequestration potential on agricultural land with increased tree cover.