- Tree seedlings are planted within two years of harvest, competing with other plants to re-establish forest cover. All harvested sites are monitored to ensure successful reforestation
- Annually 98% of reforested sites will not have any chemical application, we have reduced herbicide use by 35% since 2008
Herbicide Use in Our Forest Management Operations
We regenerate the trees we harvest in Canada by re-establishing forests. To ensure a harvested area is successfully re-established as forest, we manage the competition of plants. Managing vegetation (also known as brush) allows the young trees to get established and reduces the potential of the area to be converted to another type of land cover, such as grasslands.
After we have harvested an area, the seedlings we establish there enter an intensely competitive struggle with other plants. They are all vying for the same resources: water, nutrients and light. The healthiest, most robust plants outgrow others. These early winners can start to block other plants from accessing these crucial resources, resulting in reduced growth or plant death. For example, fast-growing grasses might outcompete young tree seedlings and, as a result, grassland could dominate an area where a conifer forest once stood.
Competition is nature’s way of building vibrant, healthy and vigorous plant life. In the case of reforestation, we are working to a specific purpose: to mimic the natural forest and vegetation that was on the land before we harvest it. It’s vital for the survival of the seedlings we plant that we ensure the right conditions so that other, faster-growing species of plants do not outcompete the forest we are re-establishing.
The Battle: Competing Brush & Seedlings
Competing vegetation can grow back very quickly on a site affected by forest disturbances such as fire, insect, wind damage or harvesting. As a result, fast-growing brush can be a challenge for young seedlings, outcompeting the trees for nutrients, light, water and growing space. Brush can include plants such as deciduous trees, grasses, and herbaceous plants such as fireweed and hellebore. Reforestation aims to return an area to forest more quickly than would occur in natural conditions, which can sometimes take decades. Managing competing species so that our young trees can grow to a healthy, mature forest within certain timeframes is essential in meeting public expectations and rigorous government regulations that support sustainable forest management.
There are several ways we can manage competing vegetation. Our foresters will survey the land before harvesting to classify the vegetation site to identify what brush naturally grows in the area. We then know what to be prepared for when we reforest after logging activity, which is a vital part of our reforestation plan. Sites are also classified in the surveys so areas can be categorized and identified for potential vegetation management regimes.
On some sites, vegetation management is not necessary, so we will monitor seedlings until they reach free-growing standards. On sites that require vegetation management soon after harvesting, we balance the benefits of the different tools available before making a plan. One of the tools we can use is to expose certain areas of soil (i.e., using mechanical site preparation methods such as trenching or mounding) to create a brush-free space for tree planting and for seedlings to grow. This approach can reduce brush competition and allows trees to get established more easily.
We aim to re-establish young forest in our cutblocks within two years of harvesting. We make informed choices about the tree seedling types we will be planting. In areas where we anticipate vegetation to overgrow, we can select tree seedlings from tree nurseries that create growing conditions to prepare seedlings to best adapt to the site they are planted on, to be robust to compete most successfully for resources.
We monitor reforested sites for up to 20 years before they’re established well enough and are considered to be “free-growing”. Within that time, government forest regulations require the management of competing brush vegetation. There are several tools in our toolkit to apply, such as manual brushing, grazing and chemical – such as herbicide. These options are carefully chosen based on which brush species we are managing.
Manual brushing requires a worker to cut over-growing vegetation with a brush saw or hand tools. This technique can be effective, but it brings physical safety risks (from saws and equipment), requires specialized training and is physically very demanding work. Manual brushing is not the best choice for all vegetation. For example, manually cutting certain species can spur them to grow back faster and in aspen’s case, even multiply. Sheep grazing is another method we use. Unfortunately, sheep are not an option everywhere due to availability and because they require very specific conditions to get the right result.
Herbicide, most commonly known as glyphosate, remains an effective tool to deal with certain types of brush vegetation. It is particularly effective for grasses that can easily grow out of control. Grasses can stunt growth and, in some cases, kill the young trees. We prescribe and apply herbicide on a very specific and judicious basis.
Overall, we have reduced the herbicide we use on our reforestation sites by 35% in the last decade. Herbicide use is tightly regulated, each year less than 2% of reforestation sites might have some chemical application.
Before we apply herbicide, we must go through a rigorous public and government consultation process that outlines our plans for vegetation management. Once approved, we may administer herbicide by air or selectively apply to individual plants depending on the site conditions, species, height and density of the brush species we are treating.
We consider all the tools we have at our disposal before using herbicide. Sometimes, however, it’s the only option that will have the necessary outcome to meet government regulatory requirements. We continue to look for options to reduce our use and explore the effectiveness of all alternative tools for vegetation management. We also work with government as policies that affect vegetation management evolves. We want to ensure that we are making the best possible decisions to support the reforestation of sustainable forest ecosystems.
Herbicide Use in Canada
Health Canada reviews and regulates all pesticide use in Canada. Click here for Health Canada’s glyphosate fact sheet. To learn more about herbicide use in Canadian forestry practices, you can check out this Government of Canada FAQ.