Slash bundling offers many benefits, but represents an additional process step in the forest biomass supply chain, which can only pay if the cost incurred by bundling is offset by the gains accrued on transportation, storage and comminution. This study develops a comprehensive system analysis aimed at determining this balance, under the specific conditions of mountain forestry. The work lasted three years, and covered all the main process steps. The study allowed attaching a cost to all the above-mentioned steps, and reached the conclusion that the truck-mounted bundler on test was too expensive for its limited productivity level. Under the specific conditions of mountain forestry, bundling does not pay, unless it allows for shifting to a more efficient transportation vehicle and if a roofed shed is not available for chip storage. Bundling could turn into a good overall competitor if the bundler was 30% more productive, or if its capital cost was one third less. Otherwise, less expensive alternatives can be deployed. The main limit of the study was the sampling of just one bundler, the only truck-mounted unit so far deployed in the Alps. Unfortunately, no other truck-mounted bundlers were available at the time of the study, in Europe or elsewhere. Using a forwarder-mounted unit would have proved less efficient, for the work had to be performed at the roadside and the machine needed to relocate very often. (C) 2011 Elsevier Ltd. All rights reserved.