Using Ground-Penetrating Radar to Map Buried Trunks of Prostrate-Growing Eastern Red Cedar Trees on Coskata/Coatue Wildlife Refuge
Submitted in fulfillment of a 2014 Nantucket Biodiversity Initiative grant. We used Ground Penetrating Radar (GPR) transects, which is not disruptive to trees and substrate, to test whether it could be used to provide evidence of underground stems and roots of low-growing Eastern Red Cedars on the Coatue/Coskata Wildlife Refuge, Nantucket. This coastal Maritime Juniper Woodland/Shrubland, is classified as a critically imperiled natural community. These trees described as dwarf cedars, are
... f cedars, are better described as large, prostrate-growing trees buried by sand with exposed, upright-growing branches in this dynamic, coastal habitat. GPR signals using 200 MHz antennas were collected to create profile images showing diffractions in the sand substrate. Interpretations of several profile images showed diffractions that are likely from trunks, branches or roots. Above ground tree dimensions were measured with one tree 16 m long x 6 m wide and only 1.75 m tall. Exposed roots were observed growing north-northwest, toward shore, and above ground portions growing south-southeast, away from prevailing winds. Core samples of some branches were taken to determine ages of branches, and whether it was stem or root material, which differs orphologically. Ring counts from core samples taken on exposed trunks of the larger trees indicate ages of 55+ years, with severe stress signals in the rings.