We have analysed the sustainable potential for the harvesting of woody biomass from forests for energy purposes, taking into consideration the demand for wood for other uses.

3.3.3.1 ADDITIONAL FOREST GROWTH

Sustainable additional forest growth is defined here as growth that is cur­rently not harvested and that:

• is not needed for future growth in demand for industrial roundwood, (e. g. for construction or paper production)

• can be harvested in an ecologically sound way.

The potential for sustainable additional forest growth was primarily based on a study by Smeets [2]. According to the study, the world’s techni­cal potential for additional forest growth would be ~64 EJ of woody bio­mass in 2050. However, the ecologically constrained potential is found to be ~8 EJ. The difference lies in the exclusion of all protected, inaccessible and undisturbed areas from the ecological potential. This means that only areas of forest classified as ‘disturbed and currently available for wood supply’ are included. A further sustainability safeguard is the use of only commercial species in the gross annual increment, rather than all available species.

Because the calculations by Smeets are partially based on an older source from 1998 [28], an additional calculation was done for a selection of six countries (Brazil, Russia, Latvia, Poland, Argentina and Canada). This was considered necessary because in some of these countries, the area of ‘disturbed’ forest could have considerably changed in the time pe­riod from 1998 until today.

In the additional calculation, the amount of sustainable complementary fellings resulting from the additional disturbed forest area available for wood supply, compared to the original base data, was determined, based on more recent country reports for the Global Forest Assessment 2010 (with data ranging from 2004 to 2008) [29]. This resulted in additional potential, particularly for Russia and Canada. The main differences were caused by the updated statistics on disturbed forest available for wood supply. The additional potential for the six countries was added to the eco­logical potential from [2], resulting in a total global potential for sustain­able additional forest growth of ~27 EJ.