Environment Committee

The Bruce Trail Conservancy Restores Biodiversity to Conifer Plantations

The diverse array of ecosystems that have been conserved along the Bruce Trail include Carolinian forest, mixed forests, wetlands, cascading waterfalls, clear streams, pebbled beaches, and most notable, the formidable cliffs along the Niagara Escarpment itself. Along with the natural ecosystems found along the Bruce Trail, cultural ecosystems include old fields, grasslands, farmland, and conifer plantations. As the Bruce Trail Conservancy acquires more property in its goal to “establish a conservation corridor containing a public footpath along the Niagara escarpment” these properties are being maintained and managed to ensure enjoyment of the Trail by its members and the public. In addition to conserving these areas one of the core values of the BTC includes “restoration and stewardship of the lands” which the BTC manages. Recently the BTC has undertaken the task of restoring conifer plantations to include more native species of trees and herbaceous plants in an effort to increase the native forest cover along the Bruce Trail. In an effort to be proactive and increase native biodiversity in these conifer plantations the BTC Environment Committee has developed a plan to restore these plantations to a more natural hardwood forest.

The history of conifer plantations in Ontario began in the late 1800s when scientists and environmentalists noticed the degradation of land and loss of soil on abandoned farm lands. These lands were abandoned as they were found to be underlain by glacial till and have a shallow soil which makes them unfavourable for growing crops. Since conifer trees, especially red pine, were able to grow quickly on sandy dry soils, the Ontario government subsidized the planting of thousands of hectares of monoculture conifer plantations throughout the twentieth century in an effort to prevent soil erosion, provide an alternative source of income to land owners and restore these lands in order to increase forest cover in Ontario.  Conifer plantations in Ontario have been successful in achieving these goals.

In recent decades scientists have realized the role biodiversity plays in enhancing ecosystem functioning, resilience, and integrity. Conifer plantations do provide some habitat for animals and will increase in native biodiversity over time, however, they tend to inhibit native plant establishment due to a lack of light and a thick bed of conifer needles. The natural succession of conifer plantations may take hundreds of years before they resemble the native forests that once dominated the landscape. In southern Ontario, where forests are fragmented by farm land and development and often times plantation forests are not connected to native hardwood forest communities, this succession would take longer due to a lack of native seed source.

As a first step in restoration of these lands conifer plantations have conserved soil and improved microclimate conditions necessary for the under plantings of native trees and herbaceous plants. Studies examining how to actively restore these plantations into a more native hardwood forest have found the major inhabiting factor of hardwood tree establishment has been the lack of light in these plantations. The next step in the successful restoration of these plantations can be achieved through the row thinning of the closely planted conifer trees and establishing gaps within the plantation. The hardwood trees found to have the best growth rate are those planted in gap cuts due to the increased light penetration and more favorable temperature and moisture conditions. Keeping to this approach the conifer plantations on BTC managed land will be thinned and gap cuts created to improve conditions for native plants.

Following the thinning of the conifer trees volunteers will plant hundreds of native hardwood trees and herbaceous plants which will speed the restoration of the plantations and increase biodiversity. This opportunity allows the BTC to increase native forest cover in Ontario, increase habitat for native plants and animals, and improve the ecosystem functioning of these forests.

Sal Spitale

BTC Environment Committee

This article appeared in the Bruce Trail Magazine – Spring 2009

Red Pine Plantation

Sal Spitale

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