Western branches out for arboretum tree count

Exactly eight London plane trees line Elgin Drive. Two horse-chestnut trees stand behind the Social Sciences Building. Untold numbers of maples, lindens and magnolias canopy the campus. Those untold numbers have also, until now, been unknown numbers.

This summer, Western is conducting the first Geographic Information System (GIS) mapping inventory of trees on campus. No more ‘eyeballing’ the species or counting on fingers the number of trees. No more handwritten additions or deletions on a printed database.

“It was previously a paper version with some maps and binders and things like that,” said Mike Lunau, Manager of Landscape Services.

Lunau and Biology professor Greg Thorn, Director of the W. Sherwood Fox Arboretum, and two co-op students are updating the database to make it more precise and user-friendly for researchers and landscape planners alike. “It’s useful both on the academic side and the operational side,” Lunau said.

Thorn said the inventory can help raise the profile of the arboretum and its goal to be a model of sustainability and biodiversity throughout the community.

“In turn, this has multiple potential benefits, since a healthy and diverse arboretum can protect and promote native tree species – as opposed to Norway maples, currently London’s and Western’s most abundant trees – and, in turn, the many native organisms that depend on them,” Thorn said.

Southwestern Ontario is unusual in that it is part of a growing area known as the Carolinian Zone, with a broad and unusual selection of native tree species.

Western is also one of Canada’s leafiest campuses. All planted trees on campus are part of the Sherwood Fox Arboretum, established in 1981 by then-president George Connell and named after Fox, an avid botanist who served as Western President, 1927-47.

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Under arboretum Director Jane Bowles, Western became home to numerous species, carefully curated to specialize in trees native to Southwestern Ontario. At last count, Western was cultivating about 2,400 trees representing 350 species. But the meticulous inventory undertaken by Bowles has been overtaken by time since her passing in 2013.

A lot of hewing and planting has taken place since then. “Even in the last two years, we’ve had a couple of significant storms go through and we’ve lost a couple of large trees,” Lunau said.

Disease and building expansion have claimed some, while additions have included commemorative plantings donated in honour of milestones within the Western community.

“We try to keep trees as long as we can. We also try and plant as many as we can. We planted 150 maples last year for Canada’s birthday and we have Vimy oaks on UC Hill. We try to plant two trees for every one we have to take down,” Lunau said.

Co-op student Angela Denomme, entering her third year of Environmental Design and Planning at Fanshawe College, has been documenting and plotting the trees – about 150 per day, for a tally of least 4,500 so far.

On an iPad she identifies each one by its precise location by longitude and latitude, its Latin and common names, whether it already has a nameplate, its condition, its health and its diameter at chest-height.

“Every tree is different in (its) own way,” she said. Willows are her favourites, but she holds a bit of a grudge against a low-hanging locust branch that nicked her left eyelid and briefly gave her a shiner.

The GIS mapping identifies provides layered, satellite-based precision and enables viewers to see patterns or specific points of interest. Once the data has been compiled and verified, it will become part of a database publicly searchable by location, species and planting date.

When deciding which new tress to plant or replace, for example, it will be helpful to know the number and distribution of similar trees on campus, Lunau said.

“This is a way to keep up with losses and additions moving forward.”

Thorn said the inventory also helps Western strengthen and promote native biodiversity on campus (a goal of the Corporate Biodiversity Action Plan, which is still in its working stages) – and that also helps make it exemplary in the community.

The arboretum can be a resource for arborists and property-owners alike. “We get word out that everyone can support native biodiversity by planting native on their property,” Thorn said.