Simultaneous use of Landsat-TM and IRS-1C WiFS data in estimating large area tree stem volume and aboveground biomass

A multisource and multiresolution method was developed for estimating large area tree stem volume of growing stock and aboveground biomass of trees. Combined Landsat-TM data and IRS-1C WiFS data, together with field data of National Forest Inventories (NFIs), were applied. Landsat-TM data were used as an intermediate step between the field data and WiFS pixels. A nonparametric k-nearest neighbour (k-nn) estimation method was applied with Landsat-TM data and field plot data from the Swedish National Forest Inventory (SNFI). A nonlinear regression analysis was used in deriving models for volume and biomass as a function of WiFS data. The estimates were evaluated by applying independent estimates from the Finnish Multi-source National Forest Inventory (MS-FNFI): The estimates are derived using field plots from the Finnish National Forest Inventory (FNFI) and Landsat-TM images. Mean volume as estimated from the Finnish multisource data for a study area of 447 000 ha was 84.2 m3 ha−1. This compared with 87.2 m3 ha−1 as derived from the developed method presented in this paper. The corresponding estimates for aboveground tree biomass were 59.5 and 58.3 tons ha−1, respectively.