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The purpose of this study was to identify the management strategies that lead to maximum financial returns from a black walnut plantation. To evaluate a selection of plantation establishment scenarios, thinning treatments, and product objectives, an Excel-based black walnut financial model was updated and revised. Key updates to the model included incorporating three cash flows for 1) the collection and wholesale of black walnut sap, 2) producing black walnut syrup, and 3) leasing black walnut trees for tapping. Additionally, outputs from the Forest Vegetation Simulator were integrated into the model’s growth and yield projections as a means of more accurately projecting sawtimber, nut, and sap yields over a 70-year period. Financial criteria including Net Present Value (NPV), Equivalent Annual Income (EAI), Benefit/Cost Ratio (BCR), and Internal Rate of Return (IRR) were calculated for a range of scenarios; NPV and IRR were used to rank each scenario. A discounted cash flow analysis was then performed, as well as sensitivity analyses to determine the impact of receiving cost-share funds, increasing plantation acreage and stumpage value, and adjusting the discount rate. Of the scenarios examined, NPV ranking indicated that the highest net returns are achieved by planting on 8 x 8 foot spacing without thinning, and gaining revenue through timber sales, nut harvesting, and leasing taps. The greatest losses were seen when planting on 8 x 8 foot spacing without thinning, but pursuing revenue through nut harvesting and wholesaling collected sap.

Replacing native forests by plantations of exotic tree species causes a reduction in the local biodiversity because plantations are commonly simplified systems. This practice would have greater impacts on islands, where the biota is especially vulnerable to environmental changes. I studied leaflitter arthropod diversity associated with native forests and abandoned (45 years) exotic wood plantations of mahogany, Casuarina and Caribbean pine in tropical islands. My general hypotheses were: (1) native forests harbor higher species richness than abandoned exotic wood plantations; (2) leaflitter structural complexity influences positively the arthropod species richness, and (3) endemic and native arthropods will be more diverse in native forests than in the plantations. I found a general tendency of higher species richness in the native forests than in the plantations. Nevertheless, the arthropod species richness was higher in one of the mahogany plantation study sites. Consequently, I seek to identify a mechanism behind these patterns. Since the complexity of the leaflitter habitat is related to the diversity of the surrounding forest, one would expect that a natural, diverse forest would exhibit more complexity in the leaflitter habitat than a timber plantation. I tested this hypothesis using leaflitter interstitial space as a surrogate for leaflitter complexity. Although the native forest exhibited higher leaflitter habitat complexity, it was not correlated with higher arthropod species richness. Then, I conducted a translocation experiment using native forest, mahogany and Casuarina leaflitter, and found that the arthropod species composition was influenced by the leaflitter type more than by the surrounding forest. For my third hypothesis, I used leaflitter ants as the target group. I found that endemic, native and exotic ants were diverse in native forest and exotic plantations, and concluded that this change did not have a differential impact on endemic, native, or exotic ant species. In general, this study found native forests had higher species richness of leaflitter arthropods than Casuarina and pine plantations, even after the plantations were abandon for 45 years. It also indicates that for wood plantations, certain tree species harbor higher biological diversity than others. Hence, forest management decisions need to incorporate ecological knowledge of the systems to conserve their biodiversity.