Preferred Name

Christopher Coggin

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Date of Graduation

Summer 2019

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Department of Biology

Advisor(s)

Dr. Heather Griscom

Dr. Bruce Wiggins

Dr. Scott Eaton

Abstract

Understanding patterns of forest succession can help advise management plans within New England nature preserves. This study took place on Block Island, 13 miles off the coast of Rhode Island. The island has greater than 200+ years of farming practices. After 1960, conservation groups began reforesting the island using different strategies, such as actively planting with native and exotic tree species, mowing, and preventing further development. In 2018, woody vegetation was inventoried along transects within four reforested sites. Sites were characterized as the following: actively planted with exotic and native tree species and mowed (AP-M), actively planted with exotic and native species with no mowing (AP-NM), passively managed (no planting or mowing) (NP-NM), and never deforested (F). Trees (>5 cm DBH) were measured and identified within 10m of four 20m transects at each site. Saplings or shrubs (< 5cm DBH, > 1 m in height) were counted and identified within 5m of each transect. Tree seedlings (10 cm to 1 m in height) were counted and identified within 1m of each transect. Soil samples were taken every 20m along each transect and analyzed in a soil particle analyzer to determine soil texture. Reforestation strategy had a significant effect on adult tree basal area and diversity (p-value < 0.001). AP-NM had a significantly greater basal area (38.06 m2/ha) compared to “NP-NM” (13.14 m2/ha). The greatest richness of tree species was also found at “NP-NM” (5 species) while the lowest diversity was at “AP-M”, which was represented by one species (Prunus serotina). Overall, seedlings were rarely encountered, but the greatest number of seedlings (660 individuals per ha) was found at “NP-NM”, most of which were shadbush (Amelanchier canadensis). Soil texture was found to have no significant effect upon canopy but showed trends toward increased basal area and stem density with increased sand content. In conclusion, “AP-NM” significantly increased the diversity and basal area but had no effect on seedling recruitment in the understory. This is most likely due to the overpopulation of deer on the island.

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