Monday, January 29, 2007

Forest Improvement Project

The city has embarked on a small but important project in Taylor Park, between Dawes Road and Victoria Park Avenue. This area is known as the Goulding Estate and used to be owned by the Massey family who made their money in farm equipment (the Massey in Massey-Ferguson).

Location of project (click to expand)

One of the big problems with urban ravine forests is the prevalence of Norway Maples (Acer platanoides). This is a common street tree and is planted for its dense shade and tolerance of urban conditions. Unfortunately it is highly invasive and has been making its way into our native forests for several decades. Its dense shade allows little understory to grow and its prolific seed production outpaces native trees such as Sugar Maple (Acer Saccharum).

Starting in December, the city in partnership with Urban Forest Associates and Friends of the Don East started to cut down the Norway Maples in a section of the forest (see map). With the removal of the trees, this will open up the forest canopy and allow for native trees that will be planted in the spring to have a chance to grow. The logs will be left in place. This will provide a shelter for wildlife. Over time, as they decompose they will add their biomass to the forest floor to benefit future plants.

FODE hopes to involve the community in the initial spring plantings and ongoing stewardship of the forest to ensure that there are no new invasions that might threaten the nascent forest.

Norway Maples cut on forest slope

Logs are left in place to provide habitat for small woodland creatures

Thursday, January 18, 2007

Your Chance to Design Paradise

Well maybe not paradise but at least the Lower Don Lands. As reported on Spacing Wire, the Toronto Waterfront Development Corporation is soliciting designs from the public.

Not sure why the TWRC is doing this since they already have any number of high powered design firms to tap into but it is interesting idea nonetheless. Read the Spacing Wire post, they have all the links.

Tuesday, January 16, 2007

Don River Rates a Doctoral Thesis

I found this article in one of my regular web searches. Jennifer Bonnell is doing her PhD on "Imagining the Don: A Social and Environmental History of an Urban River". Her reasoning is that the Don has shaped Toronto's history in a variety of ways, many of which are forgotten or taken for granted.

This looks like a new column for the Toronto Star, highlighting interesting research that is happening in Toronto. Who knows, when (if) I get to that point in my scholastic studies I may get a mention too :-)

In the same vein, I just found another scholar doing research on the Don. Jackson Parrell created a website to solicit opinions on the subject "Importance of Urban Green Spaces: The Don Valley". His essay discusses that remote natural areas aren't as important as urban green spaces. An interesting idea although I found his writing style a little scattered. He also wants visitors to fill out a survey, presumably to add to his research. Best of luck to both of these students.

Friday, January 12, 2007

Crothers' Woods: the Other Side of the Tracks

Crothers' Woods: the other side of the tracks (click to expand)

Crothers' Woods is a fairly well known location in the Don Valley. It is the area bounded roughly by Pottery Rd and the Leaside Bridge on the north and west side of the river. It is a popular area for hiking, dog walking and mountain biking. The main trail hugs the western slope and can be followed all the way east to E.T. Seton Park.

One of the defining features in this part of the valley is the CNR tracks. They travel through the bottom of the valley going back and forth across the river depending on how the river meanders. Just south of the North Toronto Sewage Treatment Plant, the railroad crosses the river and creates a sliver of land that is very hard to access. Technically, it is illegal (and dangerous) to cross the tracks. Yet there is a section of this bridge that crosses over a low part of the riverbank where, if you duck down, you can get under the bridge to access this section of the valley. Because this section is relatively inaccessible, it has been informally adopted by the mountain bikers.

There is a trail known as "The Flats" that runs beside the river all the way to E.T. Seton Park. Coupled with the ridge trail this forms a loop which many of the bikers enjoy as a single circuit. Their use of this section of the valley hasn't stopped here. A subgroup of mountain bikers likes to do "stunting", basically pedalling their bikes over a series of jumps or narrow bridges placed in a certin sequence to create a challenge course. In the Don this has been done at two places. One place is known as "DJs", (short for Dirt Jumps, see map). This area has been highly modified with packed earth jumps and ramps. They are set in sequence so that the bikers can practice their skills over a set course.

Series of packer dirt jumps at DJs.

Bikers have a nice little camp setup nearby.

More jumps setup in a grove of Cottonwoods and Manitoba Maples.

The pond next to DJ's. A popular spot for Black Crowned Night Herons to fish.

Another area known as "The Camp" (see map) has been used to build some wooden bridges, ramps and teeter totters which is another type of stunt used by the bikers.

Bridge and turnpike for mountain bikes

Ramp at the camp

If you make it to the top, you then have to jump down to the bottom since it ends abruptly!

This area has existed for at least two years and has been recently expanded. Due to the inaccessibility of the area and also due to the degraded nature of the natural environment, the city has allowed it to remain. There is currently a city wide issue with these types stunt areas and they can be found in several places throughout the watershed. This is partly due to the fact that there is no official place available where bikers can go to practice and perform.

A management plan is currently being created to take care of Crothers' Woods and the use of this area will certainly be mentioned. As part of the study process, public consultations were held and the mountain biking community was consulted about their needs.

While it is too early to predict what the plan will say, the prevailing wisdom is that this type of activity doesn't conform to the use of a natural area. However, places like DJs can't be successfully closed down until the city develops facilities in regular parks for this type of activity. Until then I think we are stuck with it.

Friday, January 05, 2007

Moving a River No Easy Task

If you’ve traveled through E.T. Seton Park recently, you may have noticed a massive construction project. Basically they are moving the course of the Don River a little bit to the left over the course of about 300 metres. This project is being performed by the Toronto Region Conservation Authority. It is not something they are doing on a whim. In fact they have been talking about this project for several years. It is only now that they are getting around to working on it.

E.T. Seton Park: moving the Don River

Over time, a mature river in a wide valley such as the Don will create meanders. These are long gradual bends caused by variations in flow. As the river goes around a curve, erosion will slowly eat away at the outside bank, moving the river in one direction until it reaches the side of the valley or cuts a new channel. If it reaches the side of the valley it will slowly eat away at the side causing it to erode and collapse. This is one method that the river uses to alter the landscape. This process is studied as geomorphology, the science of landforms.

The land adjacent to the Don Valley is heavily urbanized. Before such rules as the ravine bylaw were introduced, property owners were allowed to build right up to the edge of the ravine. It so happens that on the south side of the valley just west of the Ontario Science Centre is a property owned by Tremco, a chemical company that makes sealants and paints. They have a plant very close to the valley edge, indeed their rear parking lot extends right to the edge. By the vagaries in the river’s course it turns out that one of the meanders is cutting into the bank just below the Tremco plant. The bank is beginning to undercut the parking lot. Rather than let the river take its natural course our response is to change the course of the river to conform to our human needs.

I visited the site a couple of months ago and had a chance to talk to the site manager, Afzal Memon, who works for the TRCA. He told me that the project is scheduled to last almost a year. During that time the project will go through three phases. The first phase, underway right now, is to dig a new river channel and create temporary paths for park users to get by the construction zone. Once this is accomplished, the next phase will be to move the construction equipment to the other side of the river and let the water flow through the new channel. They will then fill in the old channel at the bottom of the eroded slope. Once this is done they will truck in loads of fill and dump it on the slope. This will stabilize the slope and improve the grade.

The final phase will be to build a bridge over the new channel, reconnect the original path, and re-landscape the entire area. They will also create a small pond from part of the remnant channel that will improve the natural habitat of the riverine environment. It’s expected that all this will be complete by the end of the summer 2007.

Facing north from existing path: digging the new river channel

Facing south: more excavation.

Eroded slope. At the top you can see piles of material at the very edge of the ravine.

A view of the construction zone from the top of slope (click to enlarge).