The removal of wood fuel from forests can result in the reduction of soil quality and productivity. This is especially true for intensive forest harvesting sites where whole tree harvesting occurs.
The potential negative effects can include:
- Depletion of organic matter in the soil
- Depletion of nutrients in the soil (e.g. nitrogen, phosphorous, potassium, calcium, magnesium and boron)
- Soil compaction
- Soil erosion and displacement
However, sustainable management practices like the management of soil properties and tree nutrition can reduce these effects.
Managing soil properties involves preventing soil damage (compaction and loss) and restoring soil through soil cultivation. Soil management plans need to be site specific as treatments will vary based on the characteristics of each location. Traffic on the site may need to be managed to avoid soil compaction (e.g. minimise traffic allowed on site or restrict access to dry periods) and ‘ripping’ and ‘mounding’ techniques can be used to repair damaged soils.
Managing tree nutrition involves considering the amount and type of wood fuel removed from sites, matching nutrients to tree demand and avoiding wood fuel removal from low nutrient sites. For instance, nutrient levels can be maintained by leaving nutrient rich twigs, leaves and needles on-site or applying wood ash or inorganic fertiliser. Reduced nitrogen levels are of particular concern in wood fuel harvesting operations, but they can be addressed through conserving organic matter and managing nitrogen-fixing legumes such as clover and lupin.