- Deadwood Reduces the Variation in Soil Microbial Communities Caused by Experimental Forest Gaps , ECOSYSTEMS (2021)
- Effects of forest canopy gaps on the ground‐layer plant community depend on deer: Evidence from a controlled experiment , Journal of Vegetation Science (2021)
- Linking deadwood and soil GHG fluxes in a second growth north temperate deciduous forest (Upper Midwest USA) , BIOGEOCHEMISTRY (2021)
- Mortality patterns following a hickory decline event - Is density reduction key to maintaining bitternut hickory? , FOREST ECOLOGY AND MANAGEMENT (2021)
- Emergent properties of downed woody debris in canopy gaps: A response of the soil ecosystem to manipulation of forest structure , SOIL BIOLOGY & BIOCHEMISTRY (2020)
- Do biological legacies moderate the effects of forest harvesting on soil microbial community composition and soil respiration , FOREST ECOLOGY AND MANAGEMENT (2019)
- Long term effects of intensive biomass harvesting and compaction on the forest soil ecosystem , Soil Biology and Biochemistry (2019)
- Ungulate exclusion accentuates increases in woody species richness and abundance with canopy gap creation in a temperate hardwood forest , FOREST ECOLOGY AND MANAGEMENT (2019)
- Woody material structural degradation through decomposition on the forest floor , Canadian Journal of Forest Research (2018)
- Response of the soil microbial community and soil nutrient bioavailability to biomass harvesting and reserve tree retention in northern Minnesota aspen-dominated forests , Applied Soil Ecology (2016)
Oaks (Quercus spp.) are a dominant component of the overstory in nearly 50% of the forested land base (~79 million ha) in the eastern United States (Johnson et al., 2002; Smith et al., 2009), but widespread oak regeneration failure throughout their natural range threatens the persistence of oak cover (Dey 2014). As a result, contemporary deciduous oak-hickory (Quercus-Carya) forests are shifting towards domination by red maple (Acer rubrum), yellow-poplar (Liriodendron tulipifera), sugar maple (A. saccharum), or aspen (Populus spp.) (Abrams 1998, 2005, Nowacki and Abrams 2008, Dey 2014). These mesophytic species are more vulnerable to drought, fire, and insects with greater potential for reduced productivity and carbon storage capacity (Elliott et al. 2015, Roman et al. 2015, Klos et al. 2009). The increasing importance of more mesophytic and fire-sensitive species is linked to reduced water quantity and altered hydrology and nutrient availability through changes in stemflow, throughfall and litter quality (Alexander and Arthur 2010, Caldwell et al. 2016). This widespread conversion from dominance by oak to maple and other mesophytic species was caused by changes to the historical disturbance regime (Lorimer 1989, Runkle 1982, Rentch et al. 2003a, b). Prior to Euro- American settlement, mixed-oak forests were characterized by complex structure and diverse species composition, with high levels of heterogeneity at both the stand- and landscape-scales (Rentch et al. 2003a, b). Widespread resource extraction and other factors associated with Euro-American settlement (e.g., land clearing and subsequent land abandonment, wildfires, grazing, etc.), combined with pervasive clearcutting on public lands in the mid- to late 20th century, homogenized species composition (e.g., conversion of mixed-oak stands to pure yellow-poplar) and reduced structural complexity at all scales (Lorimer 1989, Runkle 1982, Rentch et al. 2003a, b). Mixed oak forests have high economic and ecological value. Declines in the amount of oak forests have significantly negative effects on water quantity and quality, nutrient cycling, and floral and faunal diversity. Sustainable management and restoration of oak ecosystems have become primary goals for many federal and state natural resource agencies and non-governmental conservation organizations (Dey 2014). Private landowners are also seeking novel approaches to manage for both high-quality timber and wildlife. Silvicultural recommendations for oak forests have advanced over the past decades. We propose to evaluate oak regeneration under traditional silvicultural systems and use these results to guide the design of an alternative expanding-gap approach; to initiate baseline sampling imperative in the long-term evaluation of the expanding-gap approach; and use stand- and landscape-scale simulations to test the degree to which a gap-based, silvicultural approach will increase: 1) oak regeneration, 2) structural complexity and species diversity; and 3) carbon sequestration and storage. This project will contribute to fundamental knowledge of the extensive, second-growth hardwood forests of the Southern Appalachians and will apply a new management practice to meet multiple goals of ecosystem function, biodiversity, and commodity production. Biodiversity conservation, carbon storage, and water yield need not be conflicting alternatives to timber production. Results from the proposed research will aid in developing management goals for greater structural, compositional and functional diversity in mature oak forests.
A monitoring program for Carolina hemlock ecosystems will be implemented across the species range. Vulnerability will be assessed using long-term growth, climate, and insect infestation patterns. Growth and mortality rates from the spatially extensive empirical data will be tested against Carolina hemlock status conditions from the Forest Inventory and Analysis program data.
Significant changes to the historical disturbance complex have altered ecological function in many Southern Appalachian forested ecosystems. To maintain oak and hickory and perpetuate the forest types that have been ecologically and economically important to the region, it is necessary to seek alternative management approaches that will restore species, structural, and functional complexity to the Appalachian region. We are proposing to evaluate oak regeneration under traditional silvicultural systems and use these results to guide the design of an alternative expanding-gap approach; to initiate baseline sampling imperative in the long-term evaluation of the expanding-gap approach; and use stand- and landscape-scale simulations to test the degree to which a gap-based, silvicultural approach will increase: 1) oak regeneration, 2) structural complexity and species diversity; and 3) carbon sequestration and storage. Specifically we will evaluate the capacity for alternative hardwood management practices to increase the regeneration of oak and hickory within the Southern Appalachian mixed oak forest. We will assess the interactions among forest structure, composition, regeneration and ecosystem processes and integrate our empirical research into a spatially-explicit landscape model to simulate multiple scenarios of management, disturbance, and climate interactions. With strong support from local and regional forestry professionals and non-government organizations, our team of University and Forest Service scientists will ensure that the results will reach managers and resource professionals. We specifically address AFRI Program Area D, Priority 1 with the goals of advancing our understanding of processes and interactions and assessing and developing new management practices to improve ecosystem services.
In this study we propose to evaluate forest establishment and maintenance practices implemented as part of the Longleaf Pine Initiative and Working Lands for Wildlife. Sites will be chosen to represent a range of longleaf pine forest ages and planting densities, including seedling planting rates recommended for the establishment of gopher tortoise habitat (450-600 per acre) and rates recommended for timber and/or pine straw production (600-900 per acre). We will measure forest condition and habitat quality to assess if a threshold exists for balancing habitat and timber quality. The results will be used to quantify the benefit of NRCS past conservation efforts and to estimate the potential impact of future work across the gopher tortoise range.
The response of forest ecosystem carbon dynamics to disturbance is difficult to predict because it requires long term experiments on complex interactions among changing production, decomposition,microclimate, and nutrient regimes. Accomplishing this is critically important to predict and manage forests under future uncertainty, maintaining carbon management and sustainably meeting societal needs. To achieve this we are proposing to continue and expand process-based measurements of our long-term experimental manipulation of canopy openings and woody debris to evaluate the effects of disturbance on forest carbon pool dynamics and net ecosystem productivity. We are uniquely poised to address this question using our replicated, large-scale, field experiment established a decade ago in a sugar maple dominated northern hardwood forest in northern Wisconsin. The long-term goal of the on-going project is to quantify the effects of forest structure on carbon cycling and biodiversity and apply these first principles to ecosystem restoration, carbon management and sustainable forest management of northern hardwoods in the Great Lakes region. We propose to: 1) re-measure vegetation and soil carbon pools at three different time periods in the next decade to quantify the continued effects of the experimental treatments; 2) refine measurements of soil respiration to better estimate heterotrophic sources; 3) quantify decomposition dynamics 15 and 20 years following treatment; and 4) use the data from this process-based study in a simulation model to examine the effects of forest structural heterogeneity on landscape carbon dynamics
I will describe the contemporary forest structure and composition of the Bald Head Woods Maritime Forest Preserve. This work will quantify the mortality caused by Hurricane Florence and help to predict the future canopy of the forest. It will build on historical vegetation measurements by adding measurement locations in open canopy conditions created by recent hurricane disturbance. Tree, sapling, shrub and groundlayer vegetation will be measured within permanent established plots. Tree stem locations will be mapped in each plot, which will allow follow up surveys to track the growth and mortality of each individual. Canopy openness, soil moisture, and soil chemistry will be measured. Earlier descriptive studies (Taggart and Long, 2015) indicate a very sparse groundlayer flora, limited by low light availability beneath the closed canopy. Establishing additional measurement locations in these newly opened areas will help to describe the regeneration dynamics of this rare forest community. We will compile a species list, design a sampling protocol and provide training for the BHIC staff (if requested). Data will be summarized and submitted to BHIC upon completion.