Forest management adaptations to biodiversity conservation in sawmill industry of South Patagonia

MARTÍNEZ PASTUR, G; M LENCINAS; P PERI; A MORETTO; J CELLINI; I MORMENEO; R VUKASOVIC

Chengdu (China)

Conferencia; Landscape Ecology Conference; 2008

IUFRO

Social demands related to native forest ecosystems around the world are based on an efficient silvicultural management, with a balance between biodiversity conservation and timber production. The profitability analysis always implicates to reach the maximum yield according to investment, but recently, ecological and social criteria have been prioritized over economic variables to achieve biodiversity conservation. Therefore, an opportunity appears to combine wildlife conservation and wood production through management strategies. For these, new silvicultural methods have proposed to conserve some of the original heterogeneity of the natural old-growth forest. This work describe the modification of a sawmill industry in south Patagonia Nothofagus pumilio forests by adapting the harvesting methodology through the innovation in the applied technology to the biodiversity conservation aspects, and by incorporating an environmental monitoring program. On the other hand, the feasibility of these new management proposals was analyzed comparing to traditional practices. Two permanent site study plots (50 ha and 70 ha) were established in 2001 and 2004 to study the proposals at landscape level. Biodiversity (birds, plants and insects), climate, nutrient cycles, overstory stability, whole regeneration cycle, as well as economic and yield variables in harvested stands and sawmill industry were conducted. The proposed new method for South Patagonia leaves 30% of the timber-quality forest as aggregated retention and 15 m².ha-1 basal area as dispersed retention, while the traditional practices proposed shelterwood cuts (a first cut leaving 30 m².ha-1 basal area and a final cut after 20 years). Yield quantity and quality of the felled forest structure changed according to the implemented regeneration systems, where new proposal harvested 50% stand basal area and maintained 30% of the original stand area. Timber yield was comparable to the first cuts of shelterwood cuts. Wind blow-downs of remaining trees were minimal, and established seedling bank quickly reacted after canopy open. Seedling mortality was related to microclimate changes, and recruitment to seeding patterns. Biodiversity (mainly insects) and nutrient cycles significantly changed in harvested sectors but the original values founded in old-growth forests were comparables to those measured into the aggregate retentions. This new alternative maintains compositional, structural, and functional diversity of primary forests, and produced a sustainable supply of timber, combining economic and conservation purposes. While many costs increased considerably, the incomes also may increase by applying new management strategies and technology innovation. These new systems are more biologically and socially acceptable, incorporating a complex set of possible management objectives.