Growing stock-based forest biomass estimate for India

Abstract

The total standing biomass (including above ground and below ground) in Indian forests for the year 1992–93 was estimated using information on state and union-territory field inventory based growing stock volume and the corresponding area under three different crown density classes (very dense forests with crown cover 70 percent and above, dense forest with crown cover 40 percent but <70 percent and open forests with crown cover between 10 and 40 percent) grouped under four major forest categories (hardwood, spruce-fir, pine and bamboo) by Forest Survey of India. The growing stock volume was converted to total biomass using biomass expansion factors as function of growing stock volume density. The average growing stock volume density in Indian forests for the study year 1992–93 was 74.42 m 3 ha −1 but it varied amongst states, with a range of 7.1 m 3 ha −1 in Punjab to 224.5 m 3 ha −1 in Jammu and Kashmir. The total standing biomass (above ground and below ground) was estimated as 8683.7 Mt ( Mt=10 12 g) . The aboveground and belowground biomass was estimated as 6865.1 and 1818.7 Mt , contributing 79 and 21 percent to the total biomass, respectively. The mean biomass density in Indian forests was estimated as 135.6 t ha −1 and amongst the states it varied from 27.4 t ha −1 in Punjab to 251.8 t ha −1 in Jammu and Kashmir, respectively. The estimates have been compared with previous studies, which had estimated biomass in the range of 4400– 8700 Mt for the corresponding period. Our results are an improvement over previous estimates as these incorporate biomass expansion factors which relate wood volume to biomass as a function of growing stock volume density, four forest types and three crown density classes of Indian forests. These improved biomass estimates are crucial to assess the total C pool of forests and further for use as inputs to models to estimate net C flux to atmosphere from Indian forests due to deforestation and landuse changes.