Core Ideas Long‐term (38 yr) soil changes after woody residue management were evaluated. There were no differences in soil physical and chemical properties. Differences in extractable cation pools may be due to different vegetation litter inputs. Soil changes associated with forest harvesting, differing utilization levels, and post‐harvest prescribed burning were determined using an empirical study to investigate the long‐term impacts on soil physical and chemical properties at Coram Experimental Forest in northwestern Montana. In 1974, two replications of three regeneration cuttings (shelterwood, group selection, and clearcut) were installed. In addition, four residue management regimes (high utilization with no burning, medium with no burning, medium with broadcast burning, and low with broadcast burning) were implemented (∼74, 63, 65, and 54% wood removal, respectively). Thirty‐eight years after harvesting, changes were evaluated in mineral soil and forest floor physical and chemical properties (organic matter [OM], C, N, Ca, K, and Mg pools, soil bulk density, and pH) and in coarse woody debris levels. There were no differences in soil pH and bulk density across all regeneration cuttings and residue treatments, probably due to the minimal soil effects associated with the forest harvesting operations that were used (hand felling and cable yarding). Comparisons between harvest and burning and the control indicate no statistical differences in OM, C, and N contents. Minor differences in extractable cation pools were noted in several comparisons among the treatments; these may be attributed to litter inputs from the differing vegetation compositions of overstory and shrub layers rather than nutrient changes within the mineral soil itself. At this moist‐cool forest, intensive biomass utilization, with or without broadcast burning, had few long‐term impacts on soil properties of soil C, OM, and nutrients.

Stand structure and spatial distribution of Picea jezoensis (Siebold et Zucc.) Carrière on Mt. Gyebang, Korea was investigated to provide information on the structural characteristics and the maintenance of P. jezoensis population in northern temperate mixed coniferous forests. Height and diameter at breast height (DBH) distribution, age, growth, and spatial distribution patterns of P. jezoensis were examined in thirty nine 100-400 m 2 quadrats or circular plots. The overall stand structure attributes in the study sites are stem density of 709 trees ha −1 , a mean DBH of 12.8 cm, and a mean height of 5.6 m, with reverse J shapes of DBH and height distributions. The stem density of P. jezoensis population was 81 trees ha −1 , a mean DBH of 20.7 cm, and a mean height of 9.1 m, showing bimodal-like shapes in age and DBH distributions. Several growth release periods implied that P. jezoensis stands experienced small disturbances. The radius of patches of similar-sized P. jezoensis in the variogram was equivalent with the height of the tallest trees, indicating that patches were established following the fall of trees in the upper canopy layer. Small windthrows in this region contributed to the maintenance of the P. jezoensis stand by releasing sapling growth and providing nursing logs and space for seedlings.

No abstract

Biomass harvesting extracts an increased amount of organic matter from forest ecosystems over conventional harvesting. Since organic matter plays a critical role in forest productivity, concerns of potential negative long-term impacts of biomass harvesting on forest productivity (i.e., changing nutrient/water cycling, aggravating soil properties, and compaction) have emerged. There is abundant prediction of long-term impacts of intensive biomass removal on forest productivity. However, the empirical knowledge and comprehensive understanding, especially on western forests, are limited thus far. Therefore, we utilize the available findings to evaluate potential impacts of increased biomass extraction on western forests. We compare biomass harvesting with natural disturbance regimes or conventional harvesting systems in terms of organic matter redistribution in order to evaluate the possible consequences of biomass harvesting on forest productivity. We review the role of organic matter on forest productivity and compare the organic matter redistribution or removal through biomass harvesting and natural disturbances or conventional harvesting to assess potential impacts. The summarized findings are: (1) the long-term impacts of intensive biomass harvesting will be mitigated by protection of the belowground organic matter; (2) biomass harvesting could result in the accelerated leaching of nutrients; and (3) immediate understory vegetation recovery can minimize potential negative impacts. Finally, sites sensitive to harvesting impacts (e.g., fine-textured soil and steep slopes) should be approached with caution and prior planning to minimize undesirable responses.

Forests provide bird communities with various resources, including food and habitats. Thus, forest attributes, such as size, structure, and species composition, influence the distribution and dynamics of bird species. This study was conducted to examine the association between forest condition, bird species abundance, and diversity within Chungcheongnam Province, South Korea. Zero-inflated binomial regression models were used to analyze a total of 1646 sampling points of abundance and diversity. Forest area, distance to forest edge, and tree size class were selected as covariates. Negative associations between forest area and overall bird abundance and species richness were indicated, whereas distance to forest edge was not a significant factor. This insignificance may be attributed to the relatively small, fragmented, and homogenous forest areas across the studied region. Results for individual bird species indicated that six out of the 35 major bird species had significant associations to the forest edge and three species showed a preference for the interior of the forest. The results of this study imply that other factors, such as food availability and biotic interaction, are more important when determining habitat preference in a relatively homogenous area with a long history of human disturbance.