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Kiwanis Park Buckthorn Management Project

Project type: 
Other
Year: 
2006
Season: 
Summer
Location: 
Southeast

Summer 2006

During the summer of 2006, ReForest London took on the challenging project of removing buckthorn from an area of Kiwanis Park. Common or European Buckthorn (Rhamnus cathartica) and Glossy Buckthorn (Rhamnus frangula), which are classified as highly invasive, are taking over many of the natural areas in London. In fact, there has been about a five-fold increase in the distribution of buckthorn species in London over the past quarter century. It was observed in only 5 of 34 sites (14.7%) visited for the London Ecological Site Survey in 1977, but data accumulated from the Sub-watershed Studies in 1994 and the Environmental Lands Review Study in 2004 show that it is present in almost three of every four (73.1%) vegetation patches surveyed.

Furthermore, buckthorn species represent 1.25% of the trees recorded in the 2002 London Street Trees Inventory. The value of 1.25% may seem small but it is 3 times the number of White Pine or 4 times the number of Serviceberry.

Buckthorns form dense thickets, crowding out native shrubs, wildflowers and herbs, often completely obliterating them. Their berries are not good food for birds, and in fact, the berries make the birds sick. Getting rid of buckthorn is no easy task. Cutting it down doesn't work -- the tree resprouts from the trunk, stronger than ever.

In the fall of 2005 and again the is spring of 2006, we planted trees and shrubs with community volunteers. In total, 240 native trees and shrubs have been planted in a new naturalization area in Kiwanis Park by more than 100 community volunteers.

In June, ReForest London assembled a crew to remove the buckthorn along the perimeter of the new naturalization area at Kiwanis Park. Buckthorn was removed in an area of approximately 3.8 hectares using either of two techniques: 1) complete removal by digging and extraction with the aid of the Weed Wrench (see www.weedwrench.com for more information about this tool); or 2), by girding by stripping a 3-inch band of bark around the tree or by attaching plastic tie wraps. In this way, we are eliminating the plant without usually chemicals. The City of London and the Upper Thames River Conservation Authority are trying other methods to manage buckthorn, and our project will help determine the most effective means.

As we have removed buckthorn in Kiwanis Park, we have mapped the locations of the genets or “mother trees” and the distribution of younger to older buckthorn plants at Kiwanis Park. The pattern of spread has helped us to learn more about this invasive alien species and to guide our management strategy of controlling the leading edge of distribution in areas of ecological significance and defining areas under control. Buckthorn coverage in the understory range from 0 to more than 90%. Within the areas where the buckthorn has been removed, we now show these area as having less than 5%. Follow-up monitoring in these areas in subsequent months and years will remove buckthorn recruits from the seed bank or by bird dispersal.

We have also formed partnerships with several of the neighbours of the park, who have indicated their support for our work. One neighbour has even allowed us to store our equipment in their locked shed, making the logistics of the project much easier. Others have agreed to watch over the newly planted trees and shrubs for vandalism and damage or disease.

Another important partnership formed during this quarter is one with Youth Opportunities Unlimited (YOU). YOU is an organization that helps youth find employment by offering job skills training and volunteer work experience. Our Buckthorn Removal Crew is made up of several paid members, and several YOU volunteers, three of whom we have hired after their volunteer work experience to continue to work on the project.

We completed the project by planting 120 native shrubs to replace the buckthorn we removed.

This project was generously funded by a grant from EcoAction.

A leaf of a Common Buckthorn plant. Leaves grow mostly opposite, 3–5 upcurved veins per side, dark green, minutely blunt-toothed, tips abruptly pointed, slightly folded and curled back.

A leaf of a Glossy Buckthorn plant. Leaves grow alternate, 5–10 parallel veins per side, glossy green, smooth edged, slightly wavy. underside of leaves hairy

Berries and branches of a Common Buckthorn. Branches generally are tipped with a thorn.

Berries and branches of a Glossy Buckthorn. Branches are brittle with brown-green bark, twigs hairy, and branches do not have thorns.

The Weed Wrench clamps around the base of the weed tree and pulls it out of the ground

The tool is easy to use -- and kind of fun too.

 

A Buckthorn shrub removed. Most shrubs we removed were larger than this one.

A Buckthorn plant removed by ReForest London. Note all the sucker this plant has put out in the past. Suckering is one of the many ways that Buckthorn survive, and why the plant must be completely removed, rather than cut down.