Date of Award

12-2015

Level of Access

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Forest Resources

Advisor

William H. Livingston

Second Committee Member

Michael Day

Third Committee Member

Nathan W. Siegert

Additional Committee Members

David B. Struble

Alan S. White

Abstract

Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) (emerald ash borer) is causing widespread mortality in North American Fraxinus spp. One vulnerable species, F. nigra Marsh (Lamiales: Oleaceae) (black ash), is important both socio-economically and ecologically. Native Americans weave F. nigra baskets, which feature prominently in their histories, cultures, and economies. F. nigra also fills a particular ecological niche: it colonizes wetland sites, yet is one of the most drought-tolerant ash species. To maintain the species in the face of A. planipennis and other threats, it is essential to identify and map high-quality sites.

This study investigated characteristics associated with high-quality sites, defined as sites where F. nigra (1) is capable of successful regeneration, and (2) exhibits consistent, large radial growth (>2.0 mm/yr for 10 consecutive years). This radial growth measure was used to classify sites as basket-quality or non-basket-quality. To predict the location of basket-quality F. nigra sites, a logistic regression model was developed using data from 24 calibration sites in Maine. The best-fit logistic model associated basket-quality sites with (1) increased site drainage (i.e., flow accumulation) and (2) decreased softwood cover. Both independent variables were also recommended by Native American basket-tree harvesters. The model accurately classifies 75% of the calibration sites.

To test the robustness of the model and its applicability, we evaluated an additional 14 sites in New York. The New York model only used softwood cover type to classify sites. The model correctly classifies 64% of New York sites.

To compare models with traditional ecological knowledge, the Maine model was applied to 28 additional sites in Maine, which were located and classified by Wabanaki basket-tree harvesters. Harvesters classified sites as basket-quality or non-basket-quality based on site and tree characteristics, and the percent of basket-quality trees per site was calculated. The Maine logistic model correctly classifies 79% of the harvester-classified sites, and 71% of sites based on percentage of basket-quality trees.

The successful development of this model demonstrates how incorporating multiple information sources, such as scientific and traditional ecological knowledge, can result in powerful research outcomes. With careful application to A. planipennis control strategies, this model can help slow the mortality of a culturally and ecologically significant species, while preserving the basket-making tradition in Maine and northern New York.

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