Assessing soil properties and chemical quality indices under trees outside forests (TOFs) in temperate Himalayan region.

Trees outside forests (TOFs) have assumed importance in view of its potential to mitigate CO2 under different carbon pools with soil as the prominent pool. The ability of any TOF practice to fix soil organic carbon (SOC) efficiently depends on its SOC build up and soil quality that varies across different strata within TOFs. Soil physico-chemical properties under six TOF practices (boundary plantation, roadside plantation, riverside plantation, horticulture, scattered patches with clumpy plantation (SPCP), and woodlot) in central region of Kashmir valley were investigated to assess SOC content and soil quality. Additive soil quality index (ASQI) approach was used to assess soil quality using "lower or higher is better" criteria. Correlation analysis between soil variables was carried out to assess the relationships. The results showed that TOF soils in the region were sandy clay loam in texture with slightly acidic to alkaline pH and electrical conductivity within normal limits. Lowest bulk density (0.94 g cm-3) was found in SPCP and highest (1.38 g cm-3) in roadside plantation. Highest SOC %, available nitrogen (N), and available phosphorus (P) values were observed in SPCP and lowest in boundary plantation. Average available potassium (K) was observed highest in SPCP (333.04 kg ha-1) and lowest in riverside plantation (244.58 kg ha-1). Soil pH showed significant but negative correlations with SOC and other nutrients (N and P). A significant but perfect positive correlation was observed between SOC and available N. SOC content was found highest in SPCP (60.16 t ha-1) and lowest in boundary plantation (34.56 t ha-1). The hypothesis that all soils under different TOF strata have similar quality and same SOC build up rate was observed otherwise with SPCP exhibiting highest CSQI. SPCP was observed to be more qualitative and dynamic growing system among all strata with an enhanced capacity to fix and conserve SOC to help mitigate climate change. Present study demands plantation of more trees outside the forest areas especially in the pattern of SPCP for enrichment of soil and enhancement of carbon sequestration.

Relationship of forest biomass carbon with biophysical parameters in north Kashmir region of Himalayas.

Biophysical parameters affecting biomass carbon have been emphasized in the Paris Agreement for realizing climatic benefits from mitigation projects. The present study was conducted to assess the relation of biophysical parameters with forest biomass carbon in north Kashmir region of Himalayas. The relation of biomass carbon was assessed with (1) species type or strata including Cedrus deodara, mixed I (Cedrus deodara-Pinus wallichiana), mixed II (Abies pindrow-Picea smithiana) and Pinus wallichiana, (2) altitude (1292-2911 m amsl), (3) crown density, (4) aspect, (5) tree count or density and (6) location. Using a stratified sampling design, a total of 188 quadrats of 0.1 ha were laid across the entire region representing different biophysical parameters. Field observation including diameter at breast height and height were recorded and sample biomass (t ha-1) was estimated using volumetric equations. The observed relation of aboveground biomass carbon with species revealed a trend of mixed II ˃ Cedrus deodara ˃ mixed I ˃ Pinus wallichiana. A positive but weak correlation (R2 = 0.02) was found between aboveground biomass carbon and altitude. A reasonably good correlation (R2 = 0.40) was observed to exist between aboveground biomass carbon and crown density. The highest value of average biomass carbon (72.63 t ha-1) was recorded for the north-eastern aspect whereas the lowest value (44.60 t ha-1) was recorded for the eastern aspect. The aboveground biomass carbon and tree count was found positively correlated (+ 0.475, R2 = 0.48). Forest biomass carbon fluctuates within the same geographical region with a variety of biophysical factors. The growth rate of species, photosynthetic ability under different crown densities and climatic conditions could address the reasons for this variability. Biophysical relations of forest biomass carbon can be viewed as an important input for guidelines and policy matters on climate change.