The Lake Simcoe Region Conservation Authority

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Stories of Lake Simcoe - Science to Action

Stories of Lake Simcoe: Science to Action

Originally published as a storymap, this story series provides a behind-the-scenes look into our work monitoring and restoring the Lake Simcoe watershed. View the original storymap, including interactive maps and a data dashboard,

The Lake Simcoe Watershed

The Lake Simcoe watershed is a vibrant and diverse ecosystem and a precious source of water. It’s also a centre for tourism and recreation – generating over $450 million annually for the local economy – as well as industry and agriculture. Our lives and that of its plants and animals rely on its health.

What is a Watershed?

A watershed is an area of land drained by a river or stream. Similar to the branch of a tree, creeks flow into streams, which then flow into larger streams, eventually forming one main trunk, or river.

In our watershed, all of these rivers ultimately drain into Lake Simcoe. Within this system, everything is connected to everything else. In other words, actions which take place at the top of the system can and do affect those downstream.

Exploring the Watershed Stories

Because lake health is dependent on so many factors, monitoring programs on the lake take a holistic approach. This means we look at numerous parameters and how they interact and impact each other.

As you scroll through this storymap, you’ll see some highlights from our monitoring and restoration work. Some stories also include a link to “Explore the Watershed” where you’ll be able to view water quality indicators such as phosphorus, chloride and sediment concentrations, as well as brook trout biomass.

Our Stories​

A View of the Lake

Read about aquatic plant biomass and new invasive species, how quagga mussels are changing the lake, and how we work to restore the Lake Simcoe watershed.

From the Land to the Lake

Learn about three water quality indicators – phosphorus, salt and sediment – and how we’re working to restore the Holland Marsh.

The Stories Fish Tell

Learn about brook trout populations across the watershed and how streambank naturalization improves fish habitat. 

Forestry in a Climate of Change

Read about Newmarket’s urban forest and how we’re adapting our forestry program to prepare for the impacts of climate change.

Take ​​​​​Action

Ready to complete your own restoration project? Learn about our restoration funding program designed to help you complete your own environmental restoration project.

A View of the Lake

Lake Simcoe is a complex ecosystem with many factors impacting its health, including invasive species and climate change. Because lake health is dependent on so many factors, monitoring programs on the lake look at numerous indicators of health and how they interact and impact each other.

You Say Weeds, We Say Aquatic Plants

One of our indicators of health in Lake Simcoe is its aquatic plant community.

Aquatic plants are a natural, normal, and necessary part of a healthy lake ecosystem. Fish (and other animals) rely on them for shelter, shade and protection … and they also improve water quality and protect shorelines from erosion.

Although commonly referred to as “weeds”, we don’t like this term as it implies they are a problem. Aquatic plants are only a problem if their quantities are too high, making it difficult to swim or use your boat. And if their quantities are too high, it’s probably because of our actions on the land.

To better understand what types of aquatic plants live in Lake Simcoe, we monitor where plants are found (and in what amounts) and record the number of species.

Aquatic Plant Biomass

When we’re monitoring for aquatic plants, we conduct annual sampling at 50 sites across the lake each year, and do a more extensive study every 5 years, sampling 244 sites.

Since the 1980s, the amount of plants has increased because of increased phosphorus, increased water clarity, and invasive species.

Starry Stonewort … the Undercover Invader

Starry stonewort​ is one of the newest invaders, discovered in Lake Simcoe only 10 years ago. Though largely unreported, this macro-algae can double in size every 2 days during summer, forming dense, cloud shaped “pillows”. What’s worse – it’s difficult to remove once it takes hold because it doesn’t respond to any herbicides.

When marinas and canal estates used herbicides to remove starry stonewort, it killed off other aquatic plants, allowing starry stonewort to gain more ground.

A shallow water plant community, dominated by Eurasian watermilfoil (another invasive plant), still retains species diversity and a “forest-like” structure with habitat and shelter for smaller fish. When starry stonewort takes hold, it causes a loss of aquatic plant diversity, shallow water habitat and fish shelter. It forms a “wall”, pushing smaller fish offshore towards predators. Starry stonewort is particularly worrisome as it can completely change aquatic plant diversity and alter shallow water habitat. 

Since it was originally found in 2009, it has spread to 35% of sampling sites in the lake. In 2018 it accounted for 54% of the total plant biomass (making it the most common “plant” in the lake) … in 2019 it accounted for 70%!

A lot can happen in 5 years!

With the threat of invasive species on the rise, monitoring of plant species in Lake Simcoe is more important than ever.

Thanks to funding from the Lake Simcoe Conservation Foundation, our Lake Doctor and his team have begun an annual plant survey to monitor aquatic plants and detect invasive species.

Be on the lookout

Help us prevent the spread of invasive species! Report sightings online using EDD Maps and let us know if you spot water chestnut, water soldier or asian carp in the watershed.

The Trouble with Mussels

Another species that has affected the Lake Simcoe ecosystem is one that may be more familiar – invasive mussels. The introduction of the zebra and quagga mussels have contributed to aquatic plant growth by increasing water clarity. This happens because invasive mussels are incredibly good at filtering water.

Although this might sound like a good thing, the increased clarity lets sunlight penetrate deeper into the water and all that sun encourages aquatic plant growth.

Mussel Loss, Mussel Gain

Zebra mussels were once the most recognizable invasive species found in Lake Simcoe. If you find a mussel in the lake today, you’re probably looking at a quagga mussel. That’s because we’ve seen a significant shift from a predominantly zebra mussel population to predominantly quagga mussels.

These invasive mussels are closely related with similar survival strategies; however, quagga mussels have several advantages that have allowed them to out-compete the zebra mussel.

Zebra Mussel Population Density

​In 2009, our lake monitoring program sampled 747 sites across Lake Simcoe to determine the distribution of mussels throughout the lake. The 2009 survey results showed that 84% of mussels in Lake Simcoe were zebra mussels. Within 5 years, this population shifted to 88% quagga mussels. 

Quagga Mussel Population Density

​Zebra mussels have a survival strategy based on high reproduction to occupy as much space as possible. They also require a large amount of algae for food. 

The consequence of this strategy is that, a few years after their invasion, they “eat themselves out of house and home” and the population crashes. Unlike zebra mussels, quagga mussels thrive in deep-water habitat as they are adapted to living on mud and silt. 

They need less food and can use other nutrient-rich particles, which comes in handy when they are cut off from algae and food particles for a large part of the year (they only have access to algae when the water column is fully mixed, in early spring, late fall, and part of the winter).

Changing the Lake

Like native mussels, zebra and quaggas eat algae and nutrient sediment. What’s different is their exceptionally high filtering rate, making them highly efficient at removing these important particles from the water.

Zebra and quagga mussels can filter a volume equivalent to that of Lake Simcoe every 5 days!

With high filtering rates, these invasive mussels have removed algae and other particles from the water, moving it to the sediment at the bottom of the lake (one reason Lake Simcoe has such clear water today). 

Water Clarity

Secchi disk depth is one of the easiest ways to measure water clarity. These disks are slowly lowered into the water until the disk is no longer visible. The depth to which the disk is visible indicates the clarity.

After the mussels invaded the lake in 1995, we saw a significant change in water clarity. The average disk depth increased from 4.5m to 7.3m between their invasion and when sampling began again in 2003. 

The impact caused by these invaders is so significant that they have been called “ecosystem engineers.”

Restoring the Lake

All of our actions in and around the waters feeding into Lake Simcoe impact the health of the Lake. But our actions on the land are just as impactful. That’s why protection and restoration of our forests, wetlands and other natural spaces, in addition to our watercourses, is of vital importance.

While part of our work involves scientific monitoring, we also work with the community to restore the watershed by undertaking improvements on the ground. 

“We support the efforts of people just like you – farmers, shoreline residents, and rural landowners – to protect and restore the Lake Simcoe Watershed.

The work that we do with private landowners is important because it allows us to restore and enhance areas that aren’t publicly owned. Homeowners that live next to a creek, stream or river, for example, want to help protect that habitat and make sure the water stays clean. We offer these homeowners funding grants to help them complete projects that protect nature in their own backyard, while also benefiting the air, water and land that sustains us all.

Restoration Across the Watershed

Since 2004, we’ve worked with close to 2,000 landowners, with a focus on 3 main goals:

  1. Improving water quality through streambank erosion protection, limiting nutrient inputs and sediment loading, removal of fish barriers, and decreasing water temperatures. 
  2. Soil conservation by addressing water and wind erosion.
  3. Enhancing natural areas by increasing biodiversity and wildlife habitat, expanding buffers and encouraging other natural features such as grasslands.

Alongside these homeowners, we complete projects in municipal parks (and our own conservation areas) to help enhance and restore natural features like wetlands and forests.

Our actions upstream and downstream impact Lake Simcoe

All of the rivers and streams in this watershed drain into Lake Simcoe. It doesn’t matter if you live in Bradford or Beaverton, Schomberg or Stroud, Pefferlaw or Pottageville. If you live in this watershed, no matter where you are, your actions have an impact on the Lake.

From the Land to the Lake

Changes to the land and rivers surrounding Lake Simcoe have led to increasing levels of phosphorus, sediment and chloride. Understanding the cause of these increases and monitoring changes overtime help us identify restoration opportunities across the watershed.

Phosphorus Concentration

Phosphorus comes from many sources, but one of the most significant sources is stormwater. Stormwater picks up phosphorus as it travels across paved surfaces in urban areas. When it reaches rivers and streams, it degrades the quality of the water, making it difficult for sensitive species like brook trout to survive.

That’s because higher phosphorus concentrations lead to increased plant and algae growth. When the plant and algae die off, it reduces the amount of dissolved oxygen in the water (and brook trout need high levels of oxygen to survive!).

Across the Lake Simcoe watershed, we sample phosphorus concentrations at nearly 30 sites and take approximately 25 samples per year, on average. While we’ve made some progress with phosphorus in some areas, it still remains an issue throughout the watershed, with many of our monitoring stations showing average phosphorus concentrations above water quality guidelines.

But it’s not all bad news! Despite many stations showing concentrations above water quality guidelines, we are seeing decreasing trends in the East and West Holland subwatersheds

In the East Holland subwatershed, we collect approximately 75 samples per year across 3 different sites. Samples are collected from midstream and are sent to an accredited lab to analyze the amount of nutrients in the water. Over time we’ve been able to decrease phosphorus concentrations in the water, but that doesn’t mean our work is done. Samples in the East Holland subwatershed over the last 2 years show that levels are still too high.

​Reducing phosphorus is essential to a healthy lake 

Because rainwater can’t soak into the ground in urban areas, it travels across paved surfaces, carrying pollutants into rivers and streams. To see any changes in concentrations, we must get stormwater into the ground before it reaches our waterways.

In 2018, we created a first-of-its-kind policy in Canada to help control the amount of phosphorus leaving new and redeveloped properties. This means that new developments in the watershed are required to control of the phosphorus leaving their properties. If they can’t, they must pay for restoration projects to offset the phosphorus elsewhere.

These “offset” projects must include stormwater management retrofits, like those implemented as part of the Ray Twinney Recreation Complex Retrofit in Newmarket. This project combined low impact development features such as permeable pavers and rain gardens to help capture and treat stormwater, reducing the amount of phosphorus and sediment reaching the Western Creek tributary of the East Holland.


Phosphorus has been a problem in the Lake Simcoe watershed for decades and we’ve been successful in reducing concentrations from its height in the 80’s. But phosphorus isn’t the only stressor in the Lake. One of the newest challenges we’re facing is winter salt or more specifically, chloride.

The problem with chloride is that it’s highly water soluble. This means that once it dissolves into the water, there’s no effective way to get it out. And since we’re applying so much, chloride concentrations in Lake Simcoe are steadily increasing.

The biggest sources of chloride are commercial parking lots, roads, and sidewalks. We estimate that each year we put down the equivalent of at least 100,000 tonnes of salt in the Lake Simcoe watershed alone. In Canada, the number is close to 7 million tonnes​!

Because of this, we’re seeing the concentration increase 0.7 mg/L per year in the lake and consistently high concentrations in urban rivers and streams.

Across the watershed, we sample chloride levels at nearly 30 sites and take approximately 20 samples per site, per year. Site samples are compared to guidelines that outline exposure limits for the protection of aquatic life.

These guidelines are important because our plants and animals are accustomed to fresh water. The increasing salt concentrations affect their health and ultimately their ability to survive.

The majority of the sites sampled show an increasing trend in chloride concentrations, with no sites showing a decreasing trend. Although concentrations are trending up, 16 stations are still below the exposure guidelines. Unfortunately, 10 stations have concentrations above the long-term exposure limits, and 2 of these (Kidd’s Creek and Western Creek) have average concentrations above the short-term guidelines.

Where we’re seeing the highest concentrations of chloride in the watershed is in our urban rivers and streams. In the Barrie Creeks subwatershed, for example, we collect samples at 3 sites and take approximately 75 samples per year. In the last decade, 90% of samples taken exceeded recommended chloride concentrations – the water is too salty, even in the summer months.​

​Salty Stormwater Ponds

We haven’t found any blue crabs in our creeks and streams, like they did in Mimico Creek, but we are seeing some interesting changes. In 2 of our stormwater management ponds, for example, we found purple sulfur bacteria.

This bacteria is an extremophile (which means it survives in the most extreme conditions, such as waters with high salt concentration and low oxygen) that’s similar to what is usually found in hot springs and stagnant waters. Even though it’s kind of cool, it does show that our aquatic habitats are changing … and it can even impact the effectiveness of our stormwater ponds. How does salt affect stormwater ponds?

Because salty water is denser than fresh water, when it enters a stormwater pond (as in the case of melting snow from a parking lot), the salty water does not mix completely with the fresh water, but sinks to the bottom of the pond. The result is that there are two “layers” of water in the stormwater pond: a top layer of fresh water and a bottom layer of salty water.

When fresh water enters the stormwater pond in the summer through fall, rather than slowing down and depositing sediment like it’s supposed to, the water flows over top of the salty bottom. The water then carries the sediment through the outflow.

Ultimately, stormwater ponds that have salty water on the bottom (which are most of them nowadays because of our reliance on winter salt) are not collecting the sediment and nutrients that they’re supposed to, but releasing them back into the environment.

Salt Solutions

Most municipalities, including the City of Barrie, are working hard to improve their winter salt practices. We participate with municipal partners on working groups to identify salt management solutions as well as share information on proper salt application and alternatives.

We also formed a Freshwater Roundtable that brings together major stakeholders, including representatives from commercially owned properties, the insurance industry, snow and ice contractors, environmental agencies, conservation authorities and government ministries. We’re working to identify barriers to adopting effective winter maintenance practices in the commercial sector and to advocate for policy and legislative changes that will support the use of these practices.

By working with these partners, we hope to slow the increasing trends of chloride concentrations in our rivers and in Lake Simcoe.


Like phosphorus, sediment makes its way into rivers and streams after storms. 

Sediment is made up of solid particles that can be suspended in the water. While a certain amount of sediment in the water is normal (and is actually a sign of a healthy river), too much can cause problems. Significant sources of sediment include erosion from farm fields, construction sites, and unvegetated streambanks, and from excess sand used during winter road maintenance.

Essentially, any time you disturb soil, whether it’s in farming or construction, you expose yourself to the possibility of erosion.

These soils can be carried by rain or wind into rivers and streams, making erosion and sediment control measures during construction, and methods like cover crops and erosion controls on farms, vital to the health of our watercourses. These muddy waters can increase water temperatures, decrease oxygen levels and smother fish spawning grounds! Too much sediment also transports other pollutants, like phosphorus, into the lake. 

Across the Lake Simcoe watershed, we sample sediment in the water at 26 sites and take approximately 25 samples per site each year, on average. 8 of the stations sampled show an increasing trend of sediment concentration, with 18 stations remaining steady. Only 8 sites have concentrations above water quality guidelines.

​Suspended sediment is one material we look for when sampling total suspended solids (TSS). TSS consists of basically any material floating in the water column and may include any of the following pictured below. TSS concentrations over 30 mg/L indicate poor water quality.

In the West Holland subwatershed, we collect approximately 115 samples per year across 4 different sites. Samples are collected from the water column and sent to a lab for analysis. In the last decade, 77% of samples met water quality guidelines, while 23% of samples were considered fair or poor.

By working with farmers in this subwatershed, we hope to tackle high sediment concentrations (and phosphorus too!) by keeping the soil, and its nutrients, in its place.

Restoring the Holland Marsh

Farmlands are a vital part of our landscape and make up nearly 36% of the Lake Simcoe watershed. 

These prime agricultural lands contribute an estimated total economic impact of over $1 billion each year! In the Holland Marsh alone, the annual value of carrots is $130 million, the onions are worth $160 million, and the salad greens are worth $160 million. 

The Marsh grows enough carrots that each Canadian can eat four pounds of Marsh carrots every year. Not surprising since the Holland Marsh contains some of the most productive and rich agricultural soils in all of Ontario.

The highly fertile “muck” soils in the Marsh are a precious resource but they’re not immune to issues like erosion and nutrient runoff. That’s why we work with farmers to protect muck soils, keeping nutrients in their place and improving soil health. 

In the past 13 years, we’ve funded more than 85 projects in the Marsh. These projects range from funding de-dirting equipment and tile outlet control structures, to funding tree planting and cover crops. In the past five years alone, we’ve planted 2,400 ha of cover crops! 

By funding these projects, we’re preventing the loss of soil and nutrients, like phosphorus, from reaching rivers and streams.

Marsh farmers like Ted Mendrek are doing their part.

Mendrek farms is one of 125 farms in the Marsh. In the past 4 years, Ted has completed 10 projects on his 55 acre farm. 

“My family has been growing in the marsh for the past 60 years. It’s been a long time, and we’ve seen a lot of changes over the years … and with those changes, we’ve been adapting and changing the way we farm. We’ve been making the right investments for our farm, with the help of the Conservation Authority, and those changes have been paying off – our soil is healthy and our crops have high yields.

One of the changes I’ve seen over time is the loss of land from erosion. Within the past 40 years, we’ve lost at least 25 feet of land to the river, a number I’m sure will continue climbing. By planting a buffer along the canal, we hope to stop the loss of that precious land. Soil will also be held in place, preventing erosion along the banks.

Do you remember the blowing soil in March of 2017? I do. The Marsh was hit was an extreme windstorm and if you drove on the 400 through the farms, you would’ve seen blowing soil all over the place. This is because bare soil is susceptible to both wind and rain – to keep it on your farm, you need to plant a cover crop … the roots of these crops hold the soil in place and keep your nutrients where they need to be.

​Not planting cover crops is such a lost opportunity because the bang for your buck is huge. These interim, off-season plants keep soil in place and improve soil health by increasing water infiltration and improving nutrient composition. Having exposed soil is quickly becoming a thing of the past, cover crops are becoming the new normal.

As the foundation of Ontario’s “Salad Bowl” we can’t afford to have the unique and organic Muck soils erode and blow away.” 

No one can deny that farming is changing. 

From shifts in weather patterns, to the crop choices that are grown, and the technology used – adapting is no longer a choice, it’s a necessity. And we see our role as supportive, collaborative in an industry that already has a lot of experience with managing difficult decisions.

Fortunately, most of the recommended practices that help farmers also help protect land and water. This means we go above and beyond to tailor our services to this unique part of our watershed through cost-sharing restoration funding. We offer over a dozen project types to pick from, some covering up to $10,000 in costs.

The Stories Fish Tell

Rivers have often been referred to as a mirror that reflects the health of the surrounding area. Fish, their primary residents, tell us a lot about the neighbourhood.

Did you know? 56 fish species have been captured in the Lake Simcoe tributaries over the last 57 years!

  • 39 are native species – 1 is at risk (redside dace)
  • 17 are non-native – 3 are aggressive invaders (round goby, goldfish, common carp)


Virtually all of the 4,225 km of streams and rivers in the watershed are home to diverse fish populations. The presence or absence of particular fish species and the numbers we find tells us a great deal about the health of the river.

Look Out for the Trout!

Brook trout are one of the few fish in the Lake Simcoe watershed that migrate. They have a keen sense of where groundwater is entering streams and will move to the headwaters of streams to seek out the coldwater areas in the fall to spawn.​

Brook trout clear off the soft sediments, creating a nest for their eggs to hatch and grow into small fish. The juvenile fish stay in these small streams for up to a year before moving to larger waters downstream. In the winter months, brook trout move to deep pools where the water doesn’t freeze. They also use these deep pools to escape the summer heat.

For these fish to move throughout the year, they need streams that are free of barriers such as dams, weirs and perched culverts. When sensitive species such as brook trout are present in the water, it generally indicates that the stream is healthy, because they need cold, clean water to thrive. 

In the Lake Simcoe watershed, we continue to survey brook trout populations at 16 sites. We monitor long term trends in fish populations at 53 sites across the watershed. ​Despite a warming climate, we’re still seeing stable populations at the sites we survey. 

​Finding the Fish

To better understand the diversity and abundance of fish, we use a scientific survey method called electrofishing. Electrofishing is a harmless method of capturing fish using an electrical current that temporarily stuns the fish in the water, enabling them to be caught with nets, identified, measured and returned to the stream. 

In the Pefferlaw River subwatershed, we survey fish for long term trend analysis at 9 sites. The fish community in this part of the watershed ranges from coldwater species like brook trout and mottled sculpin in the smaller headwater streams to warm water fish like largemouth bass and brown bullhead in the wider sections of the river. A total of 45 different species of fish have been captured from the Pefferlaw River system since 1930.

In general, the Pefferlaw River subwatershed has a relatively stable fish population. The brook trout biomass (the mass of fish per square metre of stream) for the headwater areas of the Pefferlaw River has been relatively consistent over the monitoring period.

Did you know?

The outlet of the Pefferlaw River was the location of the first reported sighting of the invasive round goby in the Lake Simcoe watershed. They were first observed in 2004 and despite efforts to prevent them from spreading to the rest of the watershed, they became fully established in Lake Simcoe by 2010.

Partnering for Success

In addition to cold, clear, well-oxygenated water, brook trout also need a mix of quiet pools and fast water, clear sand or gravel for spawning, shade, and cover under banks. When ponds or dams are put in place, they increase the temperature of the water, impact water quality, and block fish from accessing upstream habitat.

This was the case in the Pefferlaw Brook. Prior to 2011, the river flowed through an online pond, known by locals as Siloam Pond. This pond provided water for irrigation at the Mill Run Golf Club.

The dam that was put in place to control water levels, acted as a significant barrier to fish migration. Scheduled maintenance to the pond in 2011 provided an opportunity to create a bypass. To restore the creek and remove the fish barrier, Mill Run Golf Club worked with us to complete a pond bypass.

This bypass eliminated the barrier, created 500 metres of new habitat, and connected brook trout to 17 kilometres of creek upstream while leaving the pond for irrigation. Bypassing the pond and planting more than 5,000 trees and shrubs along the streambank also helped cool the water, creating the ideal brook trout habitat. In 2012, the water temperature reached the optimal range for brook trout.

After the bypass was completed, we saw an immediate drop in fish biomass, followed by a recovery to the highest biomass we’ve recorded at the site within 4 years of the construction! This was expected as the newly constructed site needed time to stabilize, and the downstream population needed time to explore its new habitat. More importantly, brook trout are now connected with neighbouring communities (which creates a diverse population!) and have access to new habitat refuges.

Restoring Lovers Creek

The team at LSRCA was thrilled to find a “young of the year” brook trout upstream of Centennial Park in Innisfil. We only captured one baby brook trout upstream of the pond in 2019 but this means that some adult brook trout made their way upstream and spawned some little ones in the fall of 2018. 

At one time, brook trout weren’t able to swim upstream. A man-made pond, created in 1967 as a recreational swimming pond, prevented fish from reaching Lovers Creek. Over time, the pond began deteriorating. 

To help restore the fish passage through Lovers Creek, skilled staff from the Town of Innisfil and South Simcoe Streams Network joined together with LSRCA, Lake Simcoe Conservation Foundation, Ministry of Natural Resources & Forestry, Dufferin-Simcoe Land Stewardship Network and Ducks Unlimited Canada to naturalize the creek and remove the online pond. The project involved removing the online pond, creating a creek bypass, creating an open water wetland, and planting trees and shrubs along the newly created stream.

It’s clear that the removal of online ponds can improve cold water fish habitat and we’re excited to see brook trout swimming through this new stream to get to their native spawning grounds once again! 

Be a Fish Friend

Imagine seeing schools of cold water species such as brook trout right on your property. You can achieve this by taking your pond “offline” which might be as simple as redirecting the creek around your pond. And we’ll cover up to 50% of your project costs.

And what if you have a stream running through your property? We’ve been working with homeowners to plant trees and shrubs along streambanks for 15+ years. We’ve restored more 9,000 m of streambank across the watershed since 2015! Planting native trees and shrubs can protect the streambanks from eroding, provide wildlife habitat, and filter pollutants from stormwater runoff to improve the quality of the stream. 

It also helps shade the water, keeping it cool for species like brook trout to enjoy.

Forestry in a Climate of Change

Climate change affects the Lake Simcoe watershed’s forests, wildlife, water and aquatic life. To adapt to growing development and rising temperature trends, it’s more important than ever to protect and restore the watershed’s natural heritage, which is closely linked to water quality and quantity. That’s why the first step is to maintain, expand and improve tree canopy cover.

A changing climate brings with it extreme heat, drought, flooding, more intense weather and storms, and a host of other impacts that all contribute to the potential for environmental, social and economic upheaval. These changes threaten the very survival of our trees and forests because they aren’t equipped to adapt to the current pace of climate change.

We’re preparing for this uncertain future by studying the makeup of our forests and learning what species will adapt or decline.

Our Forests Today

One of the ways we measure the size of our forests is by estimating canopy cover. This is a measurement of the amount of land covered by tree and shrub canopies. This land could include the urban trees, like those in your backyard or lining your street, as well as woodlands, like those you would find at any of our conservation areas.

All of these trees contribute to the overall forest canopy.

Nearly 35% of the Lake Simcoe watershed is currently under canopy cover. As of 2018, some of the best overall forest conditions were found in the Hawkestone Creek subwatershed and on Georgina Island. ​The forests in these areas are high quality and largely untouched.

Over the past 10 years, we’ve planted more than 220 hectares (over 400,000 trees) across the watershed! 

Despite increasing pressures from development and invasive species like the emerald ash borer, forest cover in the watershed has remained relatively stable since 2009. But we can’t take that stability for granted. We will continue planting trees to maintain our current cover and reach our Natural Heritage System target of 40% forest cover across the watershed.

Newmarket’s Urban Forest

In 2016, we worked with our partners to create a baseline of information about the urban forest in the Town of Newmarket. This was the fifth study undertaken in York Region, but the first to be led by us. 

How did we do it? 

Overall canopy cover was calculated using an advanced analysis of high-resolution satellite imagery that identified canopy cover, soft and hard surfaces, and land use. Then we hit the ground to gather tree-specific data like species, size and health. Combined with the satellite imagery analysis, this data allowed us to calculate benefits of the urban forest like energy savings and carbon sequestration.

What did we find?

24% of Newmarket is currently under tree canopy. The most common species are cedar and pine, which make up about 20% of the species represented.

Like many of the Lake Simcoe watershed municipalities, Newmarket has plans to increase its overall canopy cover to mitigate the impacts of climate change. But the number of trees we’re planting isn’t our only consideration – we must also look at the species of trees we’re planting and where we’re planting them.​

Adapting to a Climate of Change

We know that climate change will impact the survival of our trees and forests. Some species will continue to thrive, while others will decline, and new species will become common. 

Identifying these trends was the motivation behind a climate change study we conducted on our forestry program. We confirmed what we already suspected … extreme weather, a longer growing season, variable precipitation patterns, invasive species – these are already having dramatic impacts on our forests, and we can expect more change and challenges in the future.

Something Old, Something New

We created a list of tree species that reflects what trees are suitable for our changing climate.

Don’t worry about losing our beautiful maples (sugar, red, silver) or our provincial tree, the white pine. These “enduring species” are common in our watershed and will continue to thrive.

As our climate changes, models predict that some of our common native trees, such as white spruce, balsam fir and eastern white cedar, will become “retreating species”. This means the future climate may be unsuitable for these species to thrive like they once did. Although this species will still grow and form an important part of our forests, they will be subject to increased stress, slower growth and shorter lifespans.

Although we won’t be planting as many of our retreating species, we recommend planting more “enduring species,” as well as “advancing species” like hickories and oaks (more common in forests to the south). These species will be suitable to plant as our climate continues to warm. View the full list of trees

It's never too late to (re)connect with nature

Healthy forests sustain an abundance of life. This life is interconnected, thriving despite disturbances and providing us with a place to enjoy all nature has to offer. David Barton knows this all too well … last year he planted thousands of trees to connect and enhance his forests and provide a place for wildlife to thrive.

Growing a nature lover 

Meet David Barton … Former motorcycle rider. Husband and father to a horse-loving family. Former researcher of atmospheric science and instructor at York University. City slicker turned nature lover.

David wasn’t always a nature lover. In fact, he used to love the hustle and bustle of the city, only turning to nature when the stress of the job and the drive to the office became too much. When he needed a break, he escaped to the forest, feeling the stress melt away after only a few minutes breathing in the fresh air.

Today, David rarely leaves his 100-acre property in King. Watching nature brings him joy and delight … the slow steps of a deer crossing his field. The flocks of wild turkeys foraging for food. The little critters exploring the forest. His love of wildlife is one of the reasons why he wanted to connect the smaller forests on his land.

“I’ve noticed that when I see wild turkey out in the field, and they see me coming, they start to huddle together with the larger group, squabbling and feeling skittish. I’d like to provide them with some cover to feel safe,” David explains.

Noting many animals are drawn to the stream, he came to us to start connecting his smaller forest patches, enhancing his existing ones and planting more cover along his stream. With our help, more than 3,000 trees and shrubs found a new home.

“The trees planted included mostly native species. I wanted to make sure we planted what was already here 1,000 years ago because the animals will understand these species and know how to use them for their needs.” 

To add resiliency to this forest, we planted trees from 3 different seed zones (the area where the seed originated). 

  • 80% of the trees were locally sourced
  • 10% were from the zone south of here  (Kitchener-Waterloo)
  • 10% were from even further south (Simcoe-Long Point Area)

But it wasn’t just about using native species. David wanted to make sure there was variety, a combination of species when we planted our rows. If you were to visit his property in the fall, you’d see the red of the sumac, the yellow of the tamarack, the bright green of the white pine amongst the vibrant colours of the surrounding forests … but these babies are only a few years old and have only been living on their new land for a year.

The surrounding forests also welcomed some new trees. The ash, ironwood and basswood will stand watch over time as the new sugar maples and oaks grow to match their size and strength. 

“Hiking on my property is my own kind of therapy. Spending just 5 minutes here melts the stress away. 

The colours, the sound of the wind in the leaves, the slow swaying movement of branches, the smell of the forest, the birds and chipmunks, it all comes together to instill peace and tranquility. I’m not a spiritual or religious person, but I feel some deep connection out in the forest.

Planting 3,000 trees is just the beginning. 

David plans to expand his forest, growing his own piece of paradise and providing a safe haven for the wildlife visitors he’s keen to welcome.

You have the land, we have the trees. 

Planting trees is one of the ways you can fight climate change. And we can help! We can cover up to 90% of your planting costs. Find out more at

Take Action

Help us protect and restore the Lake Simcoe watershed by completing your own restoration project (with our help!)

This past year the world seemed to take notice of many environmental issues such as plastic pollution, carbon emissions, the loss of forests and how the impacts of climate change will cause big shifts in how we live.

So, if you’ve been thinking about undertaking an environmental project, now is the perfect time to start!

Funding Your Restoration Project

​We’re in the business of helping restore our collective watershed – with people like you, one project at a time. If you have some ideas or if you need some inspiration, we are here for you. Whether it’s on your farm, your acreage, in your neighbourhood, at your school or at your workplace, we have funding available to enhance and protect your land.

Community Action Grants

We don’t just fund projects for rural landowners and farmers! We work with community partners and environmental organizations to complete on the ground improvements across the watershed.

What do we fund? Tree plantings, pollinator gardens, environmental workshops, citizen science initiatives, invasive species removal and more. 

We’re here to discuss our funding or other project opportunities. Reach out anytime at

Lake Simcoe Conservation Foundation

Our work wouldn’t be possible without the generous support of the Lake Simcoe Conservation Foundation (LSCF). Each year, LSCF supports environmental programs and projects that help support our vision of a cleaner and healthier Lake Simcoe watershed.

Donate to a cleaner and healthier Lake Simcoe watershed today!​​​

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