FLIGHT 93 NATIONAL MEMORIAL REFORESTATION PROJECT: SURVIVAL AND GROWTH OF NATIVE WOODY PLANTS ESTABLISHED ON RECLAIMED MINELAND

Abstract

Abstract. The Flight 93 National Memorial is located in Somerset Co., near Shanksville, PA. The site was surfaced mined and much of the 890 ha of reclaimed land was re-contoured and seeded in the mid 1990’s. Starting in the spring 2012, the National Park Service, Office of Surface Mining Reclamation and Enforcement, and others have worked to reforest sections of the total area using native woody trees and shrubs. Each spring for the past six years (2012-17) over 500 volunteers planted a new section, which we have defined as a “Phase,” of the National Memorial. The Flight 93 National Memorial Reforestation Project was established to evaluate reforestation success and provide data to drive future management decisions. Specifically, this work aims to: O1) Determine abundance and percent stocking for each of the 34 native, woody species planted across the six Phases; O2) evaluate growth of woody plants; and O3) describe level of competing vegetation across each phase. Two hundred and sixteen permanent, fixed radius plots were established randomly throughout the six planting phases with the goal to maintain a minimum target sampling intensity of 10%. Percent stocking, growth, and deer browse data were collected for all planted trees and shrubs within the sampling plots. Competition data was collected using 1 m rectangular sub-plots nested within whole-plot. Of the 102,393 trees and shrubs (1,792 trees ha) planted at The Flight 93 National Memorial we sampled a total of 8,673 individual trees and shrubs. Total percent stocking across all six planting Phases was 74.5% ranging from 40-121% within individual Phases, with natural regeneration driving stocking levels above 100% in one of the planting phases. Greatest plant growth was observed in the conifer species with white pine and pitch pine driving this pattern. Among the deciduous trees we observed the greatest growth among the early successional species such as quaking aspen and black locust. Overall, 88% of all plants showed no sign of deer browse, however, this rate is expected to increase as the plants emerge above the competing vegetation. Competing vegetation across all six planting phases was dominated by grasses, sedges, and herbaceous dicots and constitutes the largest limitation to woody plant establishment.