Canadian Forest Service Publications
Forest growing stock volume of the northern hemisphere : Spatially explicit estimates for 2010 derived from Envisat ASAR. 2015. Santoro, M.; Beaudoin, A.; Beer, C.; Cartus, O.; Fransson, J.E.S.; Hall, R.J.; Pathe, C.; Schmullius, C.; Schepaschenko, D.; Shvidenko, A.; Thurner, M.; Wegmüller, U. Remote Sensing of Environ. 168:316-334.
Issued by: Laurentian Forestry Centre
Catalog ID: 37116
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This paper presents and assesses spatially explicit estimates of forest growing stock volume(GSV) of the northern hemisphere (north of 10°N) from hyper-temporal observations of Envisat Advanced Synthetic Aperture Radar (ASAR) backscattered intensity using the BIOMASAR algorithm. Approximately 70,000 ASAR images at a pixel size of 0.01° were used to estimate GSV representative for the year 2010. The spatial distribution of the GSV across four ecological zones (polar, boreal, temperate, subtropical)was well captured by the ASAR-based estimates. The uncertainty of the retrieved GSV was smallest in boreal and temperate forest (<30% for approximately 80% of the forest area) and largest in subtropical forest. ASAR-derived GSV averages at the level of administrative units were mostly in agreement with inventory-derived estimates. Underestimation occurred in regions of very high GSV (>300 m3/ha) and fragmented forest landscapes. For the major forested countries within the study region, the relative RMSE between ASAR-derived GSV averages at provincial level and corresponding values from National Forest Inventory was between 12% and 45% (average: 29%).
Plain Language Summary
This study assesses the precision of the 2010 timber volume estimates for the entire Northern Hemisphere. Timber estimates were made using the ASAR satellite radar (Envisat Advanced Synthetic Aperture Radar) and a proven methodology. For the four regions studied, timber volume estimates were found to be more exact in boreal and temperate forests than in subtropical and polar areas. On a large scale, the study shows that ASAR data provides relevant and unprecedented estimates of the timber volumes spanning three continents (North America, Africa and Eurasia) and four ecological areas, including Canada’s temperate and boreal forests. This study contributes significantly to the assessment of global carbon stocks.
Forest stock volumes (cubic metres/ha) are a key element in planning and managing forest resources, as well as in estimating carbon stocks.