Assessing the Vulnerability of the HRM Urban and Rural Canopy to the Potential Arrival of the Emerald Ash Borer
Invasive species are an ever-increasing problem in urban and rural forests, and have the potential to severely decimate tree populations. The Emerald Ash Borer (EAB) is one such invasive species, which targets ash trees. Ash trees are ecologically, socially, and economically valuable trees. The EAB is predicted to move into the Halifax Regional Municipality (HRM), and this of concern to many forest managers. In this study, I assessed the vulnerability of ash trees in the urban and rural HRM to the potential arrival of the EAB. This assessment was conducted using spatial data compiled from different studies and sources. The locations of ash trees were extracted from these datasets to get a spatial distribution of the ash trees in the HRM. An assessment of the distribution was then conducted using the tree metrics provided in the data (e.g. diameter at breast height (DBH), stem count/plot), the spatial distribution of ash trees, and the existing literature on EAB dispersal. The objective of the study was to show how the urban and rural forest will be affected by the EAB. It was found that 2.54% of the trees found in the urban forest were ash trees, and that in the rural forest, 0.02% of the trees in the FRI data, as well 0.14% of trees found in the UFORE and PSP data, were ash. The urban forest may be more susceptible to the EAB given the shorter distances between ash trees, compared to the longer distances between ash trees and groves in the rural forest. However, given the overall low density of ash trees found in the datasets, the movement of EAB into the HRM may not affect the overall canopy cover to a high degree. The spatial distribution will provide forest managers with a clear depiction of which areas may be affected the most. It will also aid in deciding which mitigation practices can be put in place to contain the spread of EAB should it arrive into the HRM.