Forest biomass collection from systematic mulching on post-fire pine regeneration with biobaler wb55: Productivity, cost and comparison with a conventional treatment

Abstract

Post-wildfire regenerated Mediterranean pine stands have a high risk of wildfire recurrence. Preventive clearings are frequently applied in a mix of systematic and selective ways, being a potential biomass source using technologies such as the collector-bundler BioBaler WB55. Our research aimed to compare the BioBaler with a chain mulcher performing systematic mulching of 50% vs. 67% of stand surface over 11.4 ha dominated by Pinus pinaster Ait. regenerated after a severe wildfire. Time studies included the machinery GPS follow-up and the weighing of each produced bale. Environmental aspects were also assessed. A regression curve related BioBaler weight productivity (odt Workh-1) to pine biovolume (cover (%) average tree height, m). Surface productivity (stand ha Workh-1) was greater for both technologies when a lower percentage of the total surface was cleared, but less than theoretically predicted. The BioBaler’s economic balance, including the cost of further selective clearing and the income from biomass selling, was costlier than that of the mulcher-in the most representative strata, 475 EUR ha-1 vs. 350 EUR ha-1. Under the studied conditions, BioBaler was not economically competitive with the conventional treatment, its main constraint being low collection efficiency (31% of the standing biomass in the cleared surface, 5.33 out of 17.1 fresh tonnes ha-1).