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Turf That Grass?
The other day I was reading about UofT plans to convert their large playing field to synthetic grass. The decision to support this idea or not has been posed by the media as a comparison between the cost of injuries and reduced playing time on the field due to poor site conditions verses the ecological benefits of natural grass. In these situations social concerns usually take precedence.
I would venture to guess that if it were not for the fact that synthetic turf is significantly more expensive we would be seeing a lot more synthetic turf than we do now regardless of environmental concerns. What I find interesting about this story is the argument for and against synthetic turf in this situation are not clear cut between good and bad when you explore the issues a little deeper. Consider regular turf for instance, clearly this choice has been put forward in the narrative of the story as the “natural” choice. However, it is well known that the sod industry has an environmental impact in their production process. Furthermore natural grass does not do well beyond its capacity to accommodate traffic and compaction (several of our more popular parks such as Dufferin Grove come to mind). Compaction and high traffic in parks were a hot topic last year when the city decided not to issue permits for the popular festival Afrofest traditionally held at Queens Park. I read the document released by the city and concerns regarding compaction and damage to grass and trees were paramount in that decision. I approach this issue first by looking at carrying capacity. If we accept the premise that the field is a mud pit with risk of injury for players, and a shorter season, the university has two options: Estimate the amount of use that the field can handle and set limits to its use, or look at alternatives. We can safely assume that due to the current lack of open space for outdoor activities the university would be unlikely to consider the first option. Considering synthetic turf probably seemed like the obvious next step. The high cost of synthetic turf could have ruled out this option but due to the imminent arrival of the Pan Am games economic considerations appear to have been overcome. Other financial considerations would need to factor in maintenance. Maintaining grass does take significant labour, resources and energy. Synthetic grass on the other hand is often described as maintenance free. In my opinion leaves falling from adjacent trees would still need to be removed. Also synthetic grass needs to be cleaned periodically with water, garbage removed and repairs made. Moving on from financial matters one should take into account social considerations. The university is arguing that synthetic grass makes sense due to the anticipated reduction of injuries and increased playing time for participants. I think these are strong arguments assuming that usage rates will always remain above the capacity of natural grass. Other social issues to consider would be non sports usage. It is my experience that synthetic lawns are not as comfortable to sit and hang out on as the real thing. One reason for this is they tend to heat up in warm weather. Finally we can consider the environmental benefits and costs of each option. Unfortunately this part of the equation is the least likely to sway the decision making process. It is important to highlight that grass does provide ecological services such as temperature regulation, habitat and water cycling. Furthermore synthetic grass is often installed on an aggregate base requiring removal of valuable top soil. Comparing the ecological impact of sod production and synthetic grass manufacturing would be an exercise in comparing apples and oranges and is beyond the scope of this post.
Another interesting dimension of this debate is politics and public opinion. Recently Margaret Atwood entered the fray threatening to withdraw support for her former alma mater if they do not change course. In addition our own horticultural trade association Landscape Ontario has sent the petition that been making the rounds out to its membership for their consideration. I find the kneejerk reaction of most horticulture types I have spoken with are against synthetic grass in general and do not support its use at UofT. It is my opinion that these same people are also the ones promoting alternatives to lawn, this indicates to me that this issue has galvanized support amongst some unlikely bedfellows. Leaving public opinion and politics aside for the moment, lets consider what we know.
Synthetic grass will likely expand the usable season, increase capacity for activities, likely reduce injuries and provide a consistent surface to play on. Sod provides ecological services such as cooling. Natural grass does have some limitations with capacity and is prone to compaction. The initial cost of installation for synthetic grass is likely much higher than resodding but maintenance would likely cost less over time. Finally public opinion and politics have pitted sod growers and gardeners against UofT and synthetic grass in general. After reviewing the issues and discussing it amongst my colleages I am convinced a hybrid solution would provide the most benefit. Why not use synthetic grass for the playing area itself and resod the rest? The university will have solved the injury/short season problem without eliminating all of the benefits of natural grass. Another approach would be to quantify the cooling benefit lost from the removal of grass and plant an appropriate number of trees around the perimeter. This would have the added benefit of shading spectators, non athletes and the general public who are coming to enjoy a little greenspace. I am curious to know what you all think.