Browsing by Subject "Inventory"
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Item Open Access ACE Basin National Wildlife Refuge Forest Inventory and Carbon Stock Analysis(2021-12-08) Murphy, Mary CarltonThe ACE Basin National Wildlife Refuge (NWR) is 11,815 acres of critical wildlife habitat in South Carolina’s Lowcountry region. The Refuge contains a mosaic of forest types, including upland pine and hardwood, bottomland hardwood, and cypress-tupelo swamps. Periodic forest inventories serve to update Refuge managers on current forest conditions and identify areas outside of desired forest conditions. Desired Forest Conditions (DFC) are defined forest composition and structure metrics representing critical wildlife habitat. Active forest management, including thinning and prescribed fire, is often used on NWRs to meet DFC metrics, and thereby promote and enhance wildlife habitat. This project consisted of a 10-week forest inventory field assessment of ACE Basin NWR to evaluate current forest conditions in relation to DFC metrics. A subsequent analysis quantified how potential forest management activities to achieve DFC metrics would affect carbon stocks. Project findings suggest that most Refuge forests are outside of desired conditions and require a suite of management activities to achieve optimal wildlife habitat. These activities, however, will reduce forest carbon stocks and this project suggests forest management practices that may address these tradeoffs.Item Open Access Changing the Paradigm: Inventory Review and Scenario Modeling for the Duke Forest(2017-04-28) Burrows, John; Burton, Harley; Hipp, TimothySince 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.Item Open Access Essays in Macroeconomics(2018) Chen, LinxiThis dissertation consists of my essays in macroeconomics. In the first essay, I develop a new general equilibrium model to explain several facts about aggregate inventory that are challenging to existing inventory models. This work highlights the importance of taking into account consumers' search behavior in understanding aggregate inventory dynamics. In the second essay, I adapt a Markov-switching vector autoregression (MS-VAR) to uncover detailed asymmetries embedded in inventory dynamics. This work further demonstrates the shortcomings of existing inventory models and points to new directions in improving inventory models.
Item Open Access Impact of Prices on Inventory Systems: Theory and Emerging Issues(2013) Li, YangFirms' inventory or production decisions are influenced by a variety of factors, including both the selling price of the end products and the purchasing cost of raw materials. In most cases, there is a strong connection between purchasing costs and selling prices. In my dissertation, I study the impact of prices on a firm's inventory
decisions, particularly in systems with delivery lead time and environmental concerns. The findings are reported in three studies. The first study analyzes the joint inventory and pricing problem with lead time, which is known to be difficult to solve due to its computational complexity. We develop a simple heuristic to resolve
the computational issue and reveal the impact of lead time on the joint decisions. In the second study, we extend the heuristic approach in the previous study to systems with both positive lead time and fixed ordering costs. The effectiveness of the heuristic in both studies are verified through both theoretical bounds and numerical experiments. In the third study, we examine the effect of the procurement cost and its volatility on a firm's profit. This allows us to study under what conditions a firm can profitably operate an eco-friendly supply chain. Our study also helps the firms to understand what type of products would better absorb the higher costs associated with an eco-friendly production system.