Demand an Urban Forest that Works for Us

There is a basic (mis)understanding in the construction industry that the nicer a building's landscape looks, the more expensive it will be to install and maintain. A property owner's willingness to pay a price for looking well-kept depends largely on the type of property being managed. A luxury apartment building, upscale shopping mall or gated community is more likely to happily invest in maintenance fees than "functional" establishments such as auto body shops, elementary schools or barracks building on a military installation. In locations where a fussy landscape is not critical to the function of the establishment, owners will frequently opt for simple planting palettes comprised mostly of lawn, which is (mis)understood to be low maintenance.

Trimming a screening hedge so it screens slightly less effectively but looks.... better? Debatable.

Attempts to avoid maintenance have gotten so bad that on one military installation in the northeast, the base demands that NO trees be planted on any new project because the maintenance department doesn't have the resources to deal with fallen leaves. Another project in the coastal south listed all trees and shrubs as an optional bid item- an option that was not accepted due to inflated costs for the building construction. Considering how beneficial trees can be to our health (and urban infrastructure), property managers and departments of public works should take a step back to rethink how it allocates maintenance budgets to maximize their return on investment.

What is missing from the cost/benefit analysis when paying for site improvements is the value of ecosystem services. Any construction or capital improvement project will have a budget for stormwater management infrastructure and maintenance, heating and cooling costs, air filtration, and so on. Yet the green (literal and figurative) components that could contribute positively towards environmental management are alternately valued or bemoaned for aesthetic qualities rather than potential contributions toward site function. 

The most tangible benefit to consider is that of stormwater management (SWM) and the balance of impervious and pervious surfaces on a site. Stormwater infrastructure is a costly utility and the problem is getting worse due to expanding development and unpredictable storm events. Ask any site designer or natural resources professional and they'll tell you that rainwater sheets faster and in greater quantities over concrete than it does lawn, meadow, or forest. Yet planting plans are rarely considered a tool for easing the burden of SWM; they are traditionally considered a superfluous expense. 

Infrographic from the Chesapeake Bay Foundation showing plant material's ability to support stormwater management quality and quantity goals.

Why do we expect so little from something with the potential to be so productive?

One major factor is a matter of engineering uncertainty.  Soil can erode, become compacted or saturated with salt; plants can die from inundation, drought, pollution, pests, vehicular collisions, nearby construction, et al. Calculating the performance of living, malleable components like plants and soil can be inexact, especially when accounting for seasonal fluctuations and installation or maintenance discrepancies. And with uncertainty comes risk. Nobody wants to be liable for a flooded basement because a silt-clogged bioretention drain failed. Civil engineers tend to favor systems that can be calculated. Not always by choice; municipal regulations often have strict requirements for SWM plans, sometimes requiring a system that can handle twice the calculated rainfall in order to avoid failure. Any attempt to add green infrastructure components is an extra cost; the capacity of the required gray system cannot be reduced in response.

Many trailblazing organizations like i-Tree and NYC Department of Environmental Protection have been working hard to provide metrics for ecosystem services; because if you can't measure it, you can't show value. One of the biggest bridges to skirt the issue of uncertainty is to design a bioswale or bioretention cell that meets minimum stormwater requirements from day one, as if the plants and soil are moot. Over time, the performance of the facility will grow with the plants. And in the meantime, humans will benefit from increased air quality, local biodiversity, cooling from shade and reduced heat island effect, and of course, beauty. But regulations and policies may need to be tweaked to balance green and gray infrastructure together in the same system. We need both, but not independent of each other.

Back to the assigned role of aesthetics on landscapes. It's arguable that a landscape planted for a specific function will bring more beauty to an area, especially when compared to a patchy lawn and some token shrubs. Perhaps the practice of green infrastructure is to plants what feminists have been to womanhood. Your appearance does not dictate or limit your value, tree. Stand strong!

A beautiful landscape in Portland that is intregal to the site's stormwater management plan. Photo source: Green Infrastructure Digest.

Green Infrastructure as a practice has largely had the kinks worked out by early innovators such as Portland, Seattle, Philadelphia and NYC. While green infrastructure methods cannot be standardized to suit every case, the principles driving each design can be. It's time for the next wave- the early adopters- to change the tide of the industry and demand a new normal in site design.

Clients, property owners, city managers- demand a high functioning landscape. The industry has gotten into a rut and only your conscious requirements of something better will get you something different than the norm. Don't let construction overruns cut into the landscape budget. Don't let shrubs get sprinkled onto a plan after all the engineering is done, or use annuals like fringe on a sidewalk and expect the effect to be worthwhile. Demand that your budget gets you clean air, clean water, healthy land, and happy users.