Browsing by Subject "Duke Forest"

Now showing 1 - 7 of 7
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    Changing the Paradigm: Inventory Review and Scenario Modeling for the Duke Forest
    (2017-04-28) Burrows, John; Burton, Harley; Hipp, Timothy
    Since it was founded in 1931, the Duke Forest has shown a commitment to sustainable timber management practices and forestry education. However, in recent years, a misalignment between revenue expectations and the timber management paradigm have resulted in an uneven age class distribution favoring younger age classes of pine. The purpose of this project is help the Duke Forest address this management challenge by reassessing its inventory and yield projections from its 2010 inventory to understand how the Forest might be able to improve its estimation of sustainable harvest by more accurately accounting for volume growth. Additional analyses were also conducted to model different harvest rotation lengths using the US Forest Service’s Forest Vegetation Simulator (FVS) to understand how more intensive management practices, such as shortening the pine rotation length and planting genetically improved stock, could help balance the Forest’s age class distribution in other divisions while keeping the forest profitable.
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    Comparison of Methods for Surveying White-tailed Deer in the Duke Forest
    (2020-04-23) Saxton, Kaitlin
    White-tailed deer (Odocoileus virginianus) are one of the most recognizable and prevalent forest species in North America. Once near the brink of extirpation, their numbers have since rebounded into the millions due to their ability to adapt to fragmented and urbanized habitats coupled with the decline of their natural predators such as cougars and wolves. Acting as a keystone species in forest environments, their numbers can quickly exceed carrying capacity and lead to a cascade of ecological effects. Over-browsing, for example, results in the suppression or reduction of important plant species which can in turn negatively affect other organisms that depend on them to survive. In 2003, the Duke Forest began implementing a deer management program in response to a considerable browse-line throughout the forest. Each year, Duke Forest conducts a controlled hunt in three forest divisions followed by a spotlight survey to count deer and monitor the overall population trend and success of the program. Although past data have indicated a downward trend in deer numbers over the years, some skepticism remains as to whether the numbers estimated by spotlighting accurately reflect the density of deer in the forest. My project focused on designing and implementing several other common methods for surveying deer- camera traps, pellet counts, spotlighting, and distance sampling. More specifically, I sought to evaluate 1) the efficacy of camera trapping and pellet counts as alternative methods for monitoring, 2) whether distance sampling could improve the accuracy of the current spotlighting procedure, and 3) the relative effectiveness of all tested methods, including spotlighting, camera traps and pellet counts. This information was then used to inform the Duke Forest and recommend potential modifications to its deer management program. Of the three survey methods, camera traps were the most effective while pellet counts were the least effective. I failed to find enough pellet groups and spotlighting did not yield enough distance measurements to support distance sampling. This year’s spotlight deer count was the lowest in the program’s history. The camera traps captured thousands of observations of deer that were then used to calculate a density of 9.71 deer per square kilometer (25.15 deer per square mile) in the Korstian division which is considered medium density. Monitoring white-tailed deer is an important management tool in forested urban areas like the Duke Forest to prevent forest destruction and alteration and curb the risks of human-wildlife conflict that may arise from the overlap in deer and human habitats. The current spotlight method could be improved by adding more routes and survey nights to increase chances of finding deer, and, if enough observations are collected, distance sampling could be revisited. I recommend that the Duke Forest use distance sampling with camera traps to monitor their deer population and scale the methods used in this project up to include all divisions in the deer management program to get an overall density and examine environmental and seasonal factors that influence density and distribution.
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    Ecosystem Service Analysis of Duke Forest
    (2022-04-22) Hayashi, Shouta; Horrigan, Eamon
    Our team was tasked with evaluating the quantitative and monetary value of ecosystem services offered by the Duke Forest. Our client, the Duke Forest, manages and actively harvests 7,100 acres of timberlands used for research, education, and recreation by Duke University and the broader community. The overall purpose of assessing these services is to communicate the importance of the Duke Forest and offer implications for resource management. The term “ecosystem service” refers to benefits humans obtain from nature, and it is categorized into four different services; provisioning service; regulating service; supporting service; cultural service. Based on the client’s requests, we analyzed a subset of ecosystem services provided by the Duke Forest – carbon storage and sequestration, which have an important implication for climate change mitigation, and nutrient and sediment retention, which contribute to downstream water quality improvement. For spatial analysis of the focal ecosystem services, we used the InVEST suite of models, developed by the Natural Capital Project at Stanford University. We used the InVEST Carbon Storage & Sequestration model to spatially assess carbon storage and sequestration in the Duke Forest. For the land cover/ land use data input, we used spatial forest class and age data provided by the client. We referred to a USDA study to estimate carbon storage for the different forest types and age classes in the spatial data input and to populate the carbon pool table, another input of the InVEST carbon model. The monetary values of carbon storage and sequestration were estimated with the average carbon credit value for forestry projects from the World Bank, as well as with two domestic markets: the California Cap and Trade (CaT) and Regional Greenhouse Gas Initiative (RGGI), a regional northeastern US market. For assessment of water quality improvement, we ran the InVEST Nutrient Delivery Ratio (NDR) and Sediment Delivery Ratio (SDR) models to estimate phosphorus, nitrogen, and sediment export across four 10-digit HUC watersheds which Duke Forest occupies. Model calculations are determined by hydrological modelling, as well as biophysical statistics on a variety of land use/land cover classes. SDR results were used to produce a monetary estimation of Duke Forest’s contribution to sediment retention using estimates of Neuse River water treatment facility cost savings from reductions in turbidity. InVEST Carbon modelling estimated a total of 543,000 tons of carbon being stored across all Duke Forest divisions at an average of 80 tons per acre. The highest storage rates were observed in the Oosting Natural Area at 94 tons per acre and the lowest storage rates were seen in the Hillsboro division at 71 tons per acre. Using the value of carbon offset projects from terrestrial forests globally, this total storage is estimated to be worth over $15 million in value. In terms of domestic carbon offset markets across all projects, this value is estimated to be even greater: ranging from $17.3 to 35.8 million. Our future projections of carbon for the next 50 years revealed an estimate of 2,000 tons being stored yearly, equaling about $56,000 in monetary value using the global estimate for forestry offset projects. Results from NDR and SDR indicated Duke Forest’s contribution to downstream water quality protection and improvement. NDR estimated nutrient export rate in the Duke Forest is significantly lower than the watershed average. Average nitrogen export values in the Duke Forest in each of the four watersheds were lower than the average value in the watersheds by 25.7% - 44.7%. Mean phosphorus export values in the Duke Forest were lower than the watersheds by 67.3% - 83.1%. Similarly, SDR estimated sediment export rate in the Duke Forest significantly lower than the watersheds, by 78.8% ~ 98.4%. The monetary value of sediment retention based on turbidity reduction was estimated to be worth $43,000 and $113,000 annually in two different alternative land use scenarios. The greatest annual value was found in the B Everett Jordan Lake – New Hope River basin, where Duke Forest’s sediment buffering was valued at $26,000 and $50,000 in the two scenarios. For communication of significance and key results of this project to a broader audience, we developed a StoryMap on ArcGIS Oline. This StoryMap includes a brief description of the Duke Forest, an introductory explanation of ecosystem services, and key results from our analysis. It uses plain language and visual materials so audiences without a strong background can become interested in and grasp the benefits the Duke Forest provides the larger region. Future work on ecosystem service analysis in Duke Forest should focus on collecting accurate field data to refine the biophysical statistics which drive all the models we ran, rather than using values found in the literature. In addition, assessment of other ecosystem services offered by the Duke Forest would complement the results of this analysis. Final recommendations for the client include conservatively managing older stands with high carbon stocks, tracking opportunities to become involved in carbon offsets, and mitigating erosion during timber harvests.
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    Identifying Forest Management Scale Variables to Manage White-Tailed Deer (Odocoileus virginianus) in Duke Forest, North Carolina
    (2016-04-28) Payeur, Hunterr; Smerczynski, Patrick
    Higher densities of white-tailed deer (WTD) populations lead to alterations in forest structure, forest regeneration dynamics, and plant morphology from selective browse. Forests in urbanized landscapes, otherwise known as urban-wildland interfaces (UWI), are not only affected by WTD browse, but are connected with the human health risks that WTD present such as being a vector for disease or deer-car collisions. Limited resources of forest managers in UWIs cause the primary methods of WTD management to be increasing alternative forage and implementing deer culling programs. The Duke Forest currently implements a WTD culling program, but research has shown that this method, alone, will only suppress the population for a limited time. With limited resources, it is crucial to investigate relationships between WTD in various Duke Forest management areas to generate new ideas on effectively reducing the WTD populations.
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    Managing for Wildlife Habitat and Connectivity in the Duke Forest: Case Studies of Bobcats and Three Salamander Species
    (2021-04-29) Sultzer, Kendra
    With the expansion of human development, wildlife habitat is becoming more isolated on the landscape. To maintain healthy wildlife populations, land must be protected for connectivity among habitat patches. This study focused on meeting both wildlife habitat and connectivity needs within Duke Forest, a large 7,000 acre forest in an otherwise mostly urban matrix. Four indicator species (marbled salamanders, spotted salamanders, four-toed salamanders, and bobcats), representing three major habitats within Duke Forest, were selected from a recent regional connectivity plan. A maximum entropy (Maxent) modeling approach was used to predict bobcat habitat in Durham, Orange, and Chatham counties. Overlaying this bobcat prediction and three salamander species Maxent-predicted habitat layers onto the connectivity data determined priority management areas. Recommendations were compiled from the literature to provide Duke Forest guidance on where and how to manage for the habitats of salamander species, which would be most sensitive to management activities. Suggestions included management specifications pertaining to timber harvest, prescribed fire, streamside management zones, and vernal pools or constructed wetlands. This work highlighted how a regional connectivity plan can be implemented at a local level and used for future management strategies.
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    PRODUCING GROWTH ESTIMATES OF DUKE FOREST PINE STANDS USING USDA’S FOREST VEGETATION SIMULATOR
    (2021-04-28) Bowman, Hunter
    Duke Forest manages its loblolly pine stands for timber revenues. Duke Forest seeks construct a management plan informed by an optimized harvest schedule. This project aims to produce a reliable growth and yield model in order to produce the volume yield estimates necessary to compute the optimized harvest schedule. This was accomplished by testing and calibrating USDA’s Forest Vegetation Simulator (FVS) using Duke Forest Continuous Forest Inventory data. FVS was tested by using different site index inputs, and the diameter growth modifiers of FVS were then applied to reproduce current loblolly pine stand characteristics. It was found that the observed site index of a Duke Forest loblolly pine stand produces a better estimate of Duke Forest basal areas than do the Natural Resource Conservation Service’s Web Soil Survey site indices. Despite the use of the more accurate site index numbers, FVS needed further calibration in order to produce statistically significant estimates of Duke Forest basal areas. Diameter growth modifiers of 1.25, 2.6, and 2.6 were applied to stands with low, average, and high site indices respectively, which calibrated the model. FVS, when calibrated, can provide Duke Forest with a workable growth and yield model. In the future, even more precise calibrations will be possible as the continuous Forest Inventory process continues, and plots sampled for this project are re-sampled. This will inform the diameter and height growth increments FVS uses to grow the inputted trees into the future.
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    Quantifying Emerald Ash Borer Induced Ash Mortality & Assessing Ash Reintroduction Strategies in the Duke Forest
    (2023-12-15) Kolarova, Andrea
    The Emerald Ash Borer (Agrilus planipennis), or EAB, is a non-native invasive pest responsible for the widespread loss of millions of ash trees (genus Fraxinus) in the United States. Initially detected near Detroit, Michigan, in 2002, this wood-boring beetle has since expanded its range to thirty-six states, including North Carolina. Observational evidence suggests A. planipennis began impacting ash trees in the Duke Forest as early as 2017. This project serves as the first organized survey of ash decline and mortality in the Duke Forest, quantifying the current extent of EAB damage. Additionally, plot samples from select hardwood covertypes were used to model ash regeneration strategies and inform reintroduction recommendations. Although damage from A. planipennis is ongoing and a strategy for landscape-level protection of mature ash has not been developed, the results from this project assist the Duke Forest in understanding current conditions and will inform future reintroduction efforts.