Eva-Lotta Lindholm
The Forestry Research Institute of Sweden
Staffan Berg
The Forestry Research Institute of Sweden
Abstract
A comparison is made of energy usage and the contribution made to the global warming potential (GWP) by present (1997) and past (1972) forestry operations (including secondary haulage) in Sweden. The results are expressed in units of one cubic metre (solid u.b.) of harvested timber.
The results indicate that, since 1972, improvements in fully mechanized forestry operations, particularly logging, have led to a reduction in total energy use from 1972 (236 MJ). In fact, the energy used by today's (1997) mechanized logging systems (147-200 MJ) is roughly the same as that used by motormanual systems back in 1972 (156-177 MJ). The same is true as regards the contribution made to global warming potential: more fossil carbon was released in mechanized forestry (22 GWP) in 1972 than in 1997 (13-17 GWP). What's more, the contribution to GWP in 1997 is on the same level as that made by motormanual systems in 1972 (15-16 GWP).
It is accepted that forest management in Sweden mitigates the global warming potential. This is because the resulting sequestration effect in forest biomass is greater than the level of emissions from forestry operations.
