Gap-based silvicultural systems were developed under the assumption that richness, and diversity of tree species and other biota positively respond to variation in size of harvest-created canopy gaps. However, varying gap size alone often does not meet diversity objectives and broader goals to address contemporary forest conditions. Recent research highlights the need to consider site factors and history, natural disturbance models, within-gap structure and recruitment requirements in addition to light resources for desired tree diversity. This synthesis brings together silvicultural developments and ecological literature on gap-based management, highlighting interactions with other factors such as microsite conditions, non-tree vegetation and more. We pose a revised concept for managers and researchers to use in prescriptions and studies focused on integrated overstory and understory manipulations that increase structural complexity within and around canopy openings.

The Gap Partitioning Hypothesis (GPH) posits that gaps create heterogeneity in resources crucial for tree regeneration in closed-canopy forests, allowing trees with contrasting strategies to coexist along resource gradients. Few studies have examined gap partitioning of temperate, ground-layer vascular plants. We used a ground-layer plant community of a temperate deciduous forest in northern Wisconsin, USA, as a model system to test whether the GPH extends to the relatively species-rich ground layer. We used a well-replicated experimental approach that included a gap opening gradient (five gap sizes, 6, 10, 20, 30 and 46 m diameter, and undisturbed reference areas), a within-gap location gradient (gap edge to center), and a temporal gradient (0, 2, 6 and 13 years after gap creation). The data were observations of ground-layer plant abundance, published plant traits, and a modeled index of understory light environments. We ordinated the plant abundance data and evaluated the relationships of composition, traits and light environment by gap size, location along the forest-gap transect and time, with several approaches such as correlations, descriptivestatistics, non-parametric tests of group differences and indicator species importance values. Ground-layer plant composition and traits differed across gap sizes, within-gap locations and over time. Gaps of all sizes differed in composition from undisturbed areas, and all pair-wise combinations of gap size also differed in composition, except the 6 m from the 10-m gaps. Large gaps (46 m) also displayed within-gap compositional gradients from gap edge to center locations. Compositional differences in gap size were evident 2 years after gap creation and, contrary to our hypotheses, remained different over the 13-year period, even in gaps with crown closure. In contrast to the neutral theory, species functional traits and microenvironmental conditions were related to variation in ground-layer composition. Species with smaller seeds, lower shade tolerance, later bloom times, shorter stature and longer leaves were associated with higher light, more central gap locations, larger gap sizes and greater time since gap creation. The correlation between gap size and ground-layer plant composition and traits provides evidence for gap partitioning by the diverse ground-layer community in this temperate deciduous forest community.

A closely spaced (1 x 1 m) cottonwood (Populus deltoides Bartr.) plantation was established to evaluate the effects of nutrient availability on fine root dynamics. Slow-release fertilizer (17:6:12 N,P,K plus micronutrients) was applied to 225-m² plots at 0, 50, 100 and 200 kg N ha⁻¹, and plots were monitored for two growing seasons. Fine root production, mortality, live root standing crop and life span were analyzed based on monthly minirhizotron observations. Fine root biomass was measured in soil cores. Fine root dynamics were controlled more by temporal, depth and root diameter factors than by fertilization. Cumulative fine root production and mortality showed strong seasonal patterns; production was greatest in the middle of the growing season and mortality was greatest after the growing season. Small diameter roots at shallow soil depths cycled more rapidly than larger or deeper roots. The strongest treatment effects were found in the most rapidly cycling roots. The standing crop of live roots increased with fertilizer treatment according to both minirhizotron and soil coring methods. However, production and mortality had unique treatment response patterns. Although cumulative mortality decreased in response to increased fertilization, cumulative production was intermediate at 0 kg N ha⁻¹, lowest with 50 kg N ha ⁻¹, and highest with 200 kg N ha⁻¹. Aboveground growth responded positively to fertilization up to an application rate of 50 kg N ha⁻¹, but no further increases in growth were observed despite a threefold increase in application rate. Median fine root life span varied from 307 to over 700 days and increased with depth, diameter and nutrient availability.

Biodiversity conservation within managed forests depends, in part, on management practices that restore or maintain plant community diversity and function. Beca

Past research has established that diverse scientific communities foster innovation and problem solving more effectively than communities with a narrow range of knowledge, skills, and experience. However, gender diversity among scientists is limited, particularly in natural-resource fields. We compared data on scientist gender and rank from the US Department of Agriculture Forest Service Research and Development (FSR&D, a hierarchical organization) with data on faculty gender and tenure status from universities (loosely coupled systems) with comparable areas of study. We found that the representation of women was greater among FSR&D scientists than among university faculty but declined with seniority in both institutions. Within FSR&D, data showed demographic inertia, suggesting that the representation of women in senior scientist positions will increase. Although many mechanisms affect gender representation, our findings suggest that organizational structure affects the diversity of the scientific workforce.