Measuring the social performance of forest management

Forests produce several types of benefits to both forest landowners and society. The social benefit of private forestry is equal to private benefit plus positive externalities minus negative externalities. This study developed alternative metrics for the evaluation of the social benefit of forest management. Forest management was assessed in terms of five criteria: economic, socio-cultural, environmental and ecological performance and the resilience of the forest ecosystem. Each criterion was described with three numerical indicators. Alternative performance indices were calculated from the indicator values using methods developed for multi-criteria decision making. It was concluded that indices based on the multiplicative Cobb–Douglas utility function might be the most recommendable when forestry should produce a balanced combination of different ecosystem services. When the indices were used to compare alternative silvicultural systems in terms of their social performance, continuous cover management was ranked better than even-aged management. The performance of even-aged management improved when it aimed at increasing the share of mixed stands and broadleaf species. Maximizing net present value (NPV) with a 1% discount rate led to better social performance than maximizing NPV with a 4% discount rate.

Short- and Long-Term Results of Alternative Silviculture in Peatland Black Spruce in Minnesota, USA

Across the boreal forest in North America, the black spruce (Picea mariana) cover type is ecologically and economically important, occupying roughly 10 percent of Minnesota’s, USA 17.4 million acres (7.0 million hectares) of forestland. Traditionally managed through clearcut regeneration harvests, alternative silvicultural systems are being increasingly used in Canada. Here, we examine the 10- and 57-year effects of six silvicultural treatments (clearcut strips, clearcut patches, thinning, group selection, single-tree selection, shelterwood) on stand structure and dynamics in lowland black spruce. Treatments were installed in 1948 in northern Minnesota, and remeasured and re-treated 10 years later. A subset of the clearcut strips, clearcut patches, and shelterwood treatments were remeasured in 2017. After 10 years, diameter growth of residual stems varied by treatment, with the shelterwood experiencing the greatest growth, and basal area increased in all but the shelterwood treatment. Over the long term, the shelterwood exhibited larger diameters and heights and greater crown ratios, basal area, structural complexity, and compositional diversity than the clearcuts. Our results suggest that managers may consider using a shelterwood instead of traditional large clearcuts to achieve increased structural and compositional diversity, particularly when eastern spruce dwarf mistletoe (Arceuthobium pusillum) does not necessitate a traditional clearcut.

Post-harvest nitrogen cycling in clearcut and alternative silvicultural systems in a montane forest in coastal British Columbia

The MASS (Montane Alternative Silvicultural Systems) trial was established in the coastal mountains of British Columbia to compare clearcut, patch cut, green tree and shelterwood systems. A number of studies were carried out at the MASS trial to determine the extent to which these variable levels of stand retention retained old-growth attributes of N cycling and associated ecological processes. Harvesting led to increases in N mineralization in the forest floor (2×) and mineral soil (10×), and fluxes of N through the upper 25 cm of mineral soil (2× to 3×). However, fluxes of N were not large (< 0.35 kg ha-1 per growing season). Nitrogen mineralized was predominantly ammonium and not nitrate in the forest floor (> 95% in all but clearcut, > 75% in clearcut) and upper mineral soil horizon (42–86%). The nitrate component came from heterotrophic decomposition of organic matter, not conversion of ammonium to nitrate by autotrophs, and nitrate increases resulted from decreased gross nitrate consumption with harvesting, rather than increased nitrate production. The increases in soil N availability resulting from harvesting were reflected in only slight increases in seedling foliar N concentrations for two to four years after logging (peak of ~ 2% for western hemlock and ~ 1.6% for amabilis fir) before decreasing to below deficiency thresholds for both species. Overall, estimated losses of N from the rooting zone after harvesting (1 kg ha-1 yr-1) were minimal in comparison to estimated N inputs (4 kg ha-1 yr-1), N exports in logs at harvesting (250 kg ha-1) and soil reserves (11 400 kg ha-1). Although unlikely to affect future site productivity, losses of N could be reduced somewhat through the use of shelterwood harvesting. Key words: alternative silvicultural systems, variable retention harvesting, nitrogen cycling, litterfall, decomposition, nitrification, N mineralization, microbial ecology, leaching, foliar N, Abies amabilis, Tsuga heterophylla, Thuja plicata