When applying mechanised processing, residues (i. e., branches and tops) should be dropped in piles that can be collected easily and efficiently. Although over consid-

eration of this can decrease harvester productivity as trees have to be turned and positioned over the pile (Nurmi 2007). Fewer larger piles also reduces the degree of contamination. While piles can be left on site for a winter (i. e., summer rainfall zone) to promote nutrient recycling through foliage loss, it is more rational to extract the residues to roadside landing while the forwarder is on site. For guidelines on the potential impact on the nutrient status of sites through this practice and the potential nutrient content of the various portions of forest residues, refer to Chap. 5.

Efficient extraction is highly dependent on load density, which has led to the development of extendable load beds on forwarders. Even so, achievable loads are under 50 % of mass pay-load capacity of the forwarder and longer extraction distances make collection infeasible. Laitila et al. (2005) showed a cost reduction of 10 % using an innovative combination of simultaneous residue recovery and site preparation by utilizing a forwarder fitted with disk scarifiers.

The compression of harvesting residues into bundles (e. g., slash bundling) in the stand remains in use to a limited degree but hasn’t realized the expected economic benefits (Karha and Vartiamaki 2006). In-field bundling does require a specialized base machine (e. g., forwarder) on which the bundling unit (e. g., the John Deere B380) is mounted. In an Australian study, slash was windrowed with an excavator, which resulted in good bundler productivity (21 bundles of 570 kg per productive machine hour), but was expensive and resulted in a high level of soil contamination (8.9 %) (Ghaffariyan et al. 2011). In-field bundling also requires forwarding to roadside, implying that it needs to be carried out in conjunction with the extraction of roundwood, or a forwarder must return to the site. Bundling units can also be mounted on trucks, giving greater mobility but requiring residues to be brought to roadside. When FT harvesting is done using skidders or cable yarders, this material is simultaneously extracted to roadside. Mobile truck mounted bundlers show good potential in serving numerous production points (Spinelli and Magagnotti 2009). These units are however restricted to roadside operations.