Abba Chhabra , V. K. Dadhwal

Abstract

The Indian forest soil organic C densities for two-depth classes (top 50 cm and 1 m) were estimated using a database of published measurements with depth of soil organic carbon (SOC) containing information on location, soil type, texture, measured/estimated bulk density and forest type. The mean soil organic C density estimates for top 50 cm based on 175 observations ranged from 37.5 t/ha in tropical dry deciduous forest to 92 tha^-1 in littoral and swamp forest. The mean soil organic C density estimates for top 1 m depth based on 136 observations ranged from 70 tha^-1 in tropical dry deciduous forest to 162 tha^-1 in montanc temperate forest. The estimated soil organic C densities were combined with remote sensing (RS)-based forcst area inventory to arrive at cstimates of soil organic C pool of major forest types of India. The total soil organic C pools in Indian forests were estimated as 4.1 and 6.8 PgC (PgC = 10¹⁵ gC) in top 50 cm and top 1 m-soil depths, respectively. The estimate is comparable to carlier Indian forest soil organic C pool estimates, which are in the range of 5.4-6.7 PgC (top 1m depth). A few Indian studics were also reviewed to dctermine the impact of various anthropogenic changes such as conversion of natural forests to plantations, deforestation, and shifting cultivation on forest soil organic C pools.

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V. K. Dadhwal , N. Shukla , A. B. Vora

Abstract

Using 44 published studies describing 64 and 75 measurements on total and leaf litterfall in Indian forest, respectively, average litterfall for major forest types was computed. This ranged from 8.5 to 4.3 t/ha/yr for total litterfall and 6.9 to 3.4 t/ha/yr for leaf litterfall. The mean litterfall was used along with remote sensing based forest type inventory by Forest Survey of India (1987 assessment, based on 1980-82 satellite data) to estimate aboveground total and leaf litterfall carbon flux of 188 ± 24 and 152 ± 13 Mt C/yr in forest in India.

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A. Velmurugan ¹, Suresh Kumar ¹, V. K. Dadhwal ¹, M. K. Gupta ¹

Affiliations
1 Indian Institute of Remote Sensing, Dehradun, IN

Abstract

Soil organic carbon (SOC) is a major component of global carbon sinks and forests being one of the most important ecosystems for storing SOC. A database of SOC estimates along with other attribute information for different forest types of India were compiled from various literature sources and normalized for 1990 using modeling approach. Different thematic maps in digital format were prepared and harmonized using standard geospatial reference. The database was linked to thematic maps and used to estimate SOC densities and stock for three depth classes (0-25, 0-50 and 0-100 cm) in geographical information system. The mean soil organic carbon density estimates for top 30 cm ranged from 22.42 t/ha in sub-tropical dry evergreen forest to 100.33 t/ha in Himalayan moist temperate forest and similar trend was observed for top 0-50 and 0-100 cm as well. Soil organic carbon stock estimates for top 30 cm ranged from 1.89 Tg C in Himalayan dry temperate to 1406.68 Tg C in tropical moist deciduous forest and comparable trend was observed for top 0-50 and 0-100 cm. The total soil organic C pools in Indian forests have been estimated as 3.72, 5.25 and 7.66 Pg C in top 0-25, 0-50 and 0-100 cm soil depth respectively (1 Pg = 1000 Tg). The present database may form inputs in models to study carbon flux and help in prioritizing areas for carbon sequestration in Indian forests.

Keywords

Soil Organic Carbon (soc), Indian Forests, Carbon Flux, Carbon Sequestration

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