The Implications of the Emerald Ash Borer (Agrilus planipennis) on Riparian Canopy Cover in Three Halifax Regional Municipality Parks
Date
2020-04
Authors
Haughn, Jordan
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Abstract
Invasive species are posing an increasingly large threat to Canada’s urban forest. The Emerald
Ash Borer (EAB) is an invasive pest with the potential to eliminate entire ash stands. The EAB
was discovered in Nova Scotia in 2018. In this study I aimed to address the research question
“what are the implications of the EAB on short-term riparian zone canopy cover in three Halifax
Regional Municipality (HRM) parks?”. Both census and cruise-transect-sampling methods were
exercised to determine ash proportions and distribution in each park. For the census method, all
trees within the park were measured (diameter at breast height (DBH), crown condition, crown
position) and digitally geo-positioned to determine distribution. Using an equation derived from
existing ash data, ash crown projections were then calculated for each ash tree based on DBH.
The cruise method was conducted using plots dispersed along a transect line stretching the length
of the stream. It was found in the park undergoing census method (Fish Hatchery Park) that ash
accounted for approximately 30% of total canopy cover within the assessed park. Analysis of
plot data demonstrated ash presence in 41% of all plots sampled, only five of which were
projected to fall below Nova Scotia’s riparian-zone regulatory basal area as a result of ash
removal. In Moirs Mill Park, ash accounted for 20% of all trees measured, and were present in
eight of the 11 plots. In Sir Sandford Fleming Park, ash accounted for 5.5% of all trees measured
and were present in eight of the 20 plots. Overall, the arrival of EAB will have a modest impact
on riparian canopy cover in the HRM parks sampled. The visual distribution and locationspecific
data along the riparian zone will help forest managers and planners understand areas of
highest risk.
Description
ENVS 4902 Environmental Science Undergraduate Honours Thesis