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Credit Valley Conservation shares restoration and invasive species plans

March 25, 2021   ·   0 Comments

By Sam Odrowski

Invasive species and forest management was an area of focus during Orangeville Council’s meeting on Monday (March 22).

Staff from Credit Valley Conservation (CVC) delivered a presentation their restoration programs, Invasive Species Strategy and Sustainable Forest Management Plan (SFMP).

The CVC’s SFMP, which was recently approved by its Board, is responding to the stressors and challenges that forest face throughout the Credit Valley Watershed. 

“One of these is climate change, which is expected to bring droughts, intense storms and warmer winters that will damage trees and impact forest health,” said Aaron Day, CVC program manager of forestry.

“For example, these events can lead to more hazards along trails and the need to close parks more frequently for hazard removal and cleanup. These changing conditions in the watershed will also affect what species can survive and grow here and therefore, it will affect the biodiversity of our forest and their resilience to change.”

Watershed plantations are a priority for management under the SFMP and since the 1950s, 45 hectares of plantation were established in the Island Lake Conservation Area. In total, the CVC has planted over 7 million trees since 1955.

“The long-term intent is to establish and transition these plantations to natural forests to replace what was lost during settlement and agricultural expansion in the 19th and early 20th centuries,” explained Day.

“Plantations require regular periodic management to slowly convert them to natural, mixed forests and without proper management plantations often experience issues such as a lack of native trees, shrubs and herbs in the understory.”

Roughly 80 per cent of watershed plantations are not being properly managed and 24 per cent could fail in the next 20 years, according to the CVC.

“When we say they’re not being properly managed, it doesn’t necessarily mean that somebody is doing something negative or adverse to the forest, it’s just simply that it’s not receiving what would be considered its routine or proper management to ensure that it stays on that growth trajectory towards a healthy mixed forest, which is the end goal of these plantations,” noted Day.

Management involves thinning of trees so they have healthy space to grow, similar to how carrots are thinned when gardening. Once a plantation reaches 20 to 30 years of age, they’re typically ready to be managed

When management doesn’t occur, the plantations often have problems further into the future, after roughly 50 to 70 years, where you have long skinny weak trees that didn’t have enough space to grow. Thinning also reduces the risk of wildfires.

“The other result of managing forests is to help native trees and shrubs, deciduous primarily, to take root in the understory and grow as sort of that next generation, so that when these coniferous plantations do get removed or fail or fall or die, you have that next forest ready to take over in a in a sustainable fashion,” said Day.

He noted that the conservation authority will continue to work with private landowners to increase healthy forest cover in the region.

“Expanding and connecting forest cover, maintaining and improving biodiversity and restoring forests health and resilience are key objectives for us, since healthy forests will better withstand disturbance and stressors, including climate change,” explained Day.

When looking at the CVC’s Invasive Species Strategy (ISS), the focus on managing and mitigating the impacts of invasive species on the region’s forests, such as phragmites and dog strangling vine.

“Unfortunately, Ontario has the highest number of invasive species of any province or territory in Canada and being in southern Ontario, the Credit River is no exception,” said Frejya Whitten, CVC’s senior coordinator for invasive species.

“There are currently 214 documented invasive species in the watershed, and over 90 per cent of the surveyed vegetation communities across the watershed have been found to contain at least one invasive plant species that has the potential to dominate the native ecosystem.”

When invasive species dominates an ecosystem, there’s a number of negative ecological impacts to native species.

“Some forest pests, as seen with EAV or Emerald Ash Boer, can directly harm native species, while others could cause indirect harm by competing for resources in the space, as seen with phragmites and yellow floating heart,” said Whitten.

“By dominating an ecosystem, invasive species reduce the diversity of native species. Ecosystems with high biodiversity are typically more resilient to disturbance and environmental change.”

When looking at the socio-economic impacts of invasive species it goes beyond watershed health and into the pocketbooks of residents.

“There are some routine costs that can happen such as zebra mussels clogging water intake pipes, which is an issue down on Lake Ontario, or phragmites filling in ditches and blocking out sight lines as seen throughout much of Caledon and Peel as well as right at Dragonfly Park in Orangeville,” explained Whitten.

The estimated economic cost to Ontario’s municipalities and conservation authorities for invasive species management is $50.8 million annually, according to a 2017-2019 study conducted by the Invasive Species Centre.

The devastation caused by Emerald Ash Boer in Peel and Halton has cost over $3 million since 2014.

Looking ahead, the United Nations has declared 2021 to 2030 as the decade of ecosystem restoration and Whitten says the CVC is well positioned to respond to this global call to action to massively scale up restoration.

“We welcome the opportunity to respond to this call for action in partnership with the Town and we are more than happy to provide technical expertise on restoration management to you as a key partner when requested,” noted Whitten.

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