The method is of special interest for large taiga areas where forest inventory data is not available. Since carbon is a major component of biomass, there is great scientific interest in estimating it.
The researchers used high resolution satellite imagery (HRSI) as an alternative to the aerial photos traditionally used for forest inventory work. The shadows cast by the trees were proportional to several structural variables, such as diameter at breast height, tree height or crown diameter. On a given area of the image, they calculated the total proportion of the area covered by tree shadows and then used it in a mathematical equation to calculate the total biomass per surface unit.
To validate these calculations in the field, three complementary trial sites were chosen: the first was situated near Radisson, the second near Chibougamau and the third near Wabush in Labrador. The method allows us to estimate biomass with satisfactory precision for black spruce stands that are around 20 m in height and 70% density in a biomass range between 0 and 150 tonnes per hectare. The method is being fine-tuned with CFS colleagues across the country in order to apply it to other boreal species.