Summary
This article presents a processing chain for forest volume mapping based on multi-source forest inventory methodology and the existing inventory data collected from the Kon Tum region, Vietnam. The modelling framework for imputing tally tree heights was built based on a mixed-effects height generalisation model. Mapping of the stem volume was based on nearest neighbour techniques (k-NN) and Landsat TM data after relative calibration with MODIS image material as underlying reference. The use of optical image materials, together with the demanding conditions set by a tropical forest structure, resulted in a moderate root mean square error value (76.6%) for the stem volume. The resulting volume maps, which were based on an objective estimation procedure, create the appropriate model dataset needed for testing the optimal large-scale inventory designs of forthcoming forest inventories that will be carried out in Vietnam.
Acknowledgements
This study was conducted at the Joensuu Research Unit of the Finnish Forest Research Institute (Metla) and at the Headquarters of the Forest Inventory and Planning Institute (FIPI) located in Hanoi, Vietnam. We are grateful to these institutions for their resources and facilities. This study was partly funded by the Ministry for Foreign Affairs of Finland through an inter-institutional development cooperation project entitled ‘Improving Research Capacity of Forest Resource Information Technology in Vietnam and Nepal’ (contract number: HELM431-14, intervention code: 79811501).