Smart Urban Planning and Wildlands–an interconnection

Posted on September 27, 2014 by Leslie

As a horticulturist and wildlands advocate, I heard a story on yesterdays Science Friday that got me pondering.

The essential jest of the story is that trees, like all plants, emit different chemicals, many of them considered toxic. Plants do this for a variety of reasons. Some might attract pollinators, others to ward off predators. Of course we’ve all known this for years. That is why some plants have medicinal uses, while other plants might give you a terrible reaction. But we have never considered that trees might be doing the same thing and those chemicals could be reacting in negative ways with pollutants in our cities air.

In this short segment Biologist Todd Rosenstiel explains some of the studies being done at Portland State University–that we only know a few of the emitted chemicals–like turpenes–and there are many more we are still investigating. He explains how these chemicals can react with ozone in polluted atmospheres to create more pollutants. Some trees make more of these toxic chemicals than others; and also chemicals might begin as toxins yet then combine with ozone in such a way as to actually scrub pollutants out of the atmosphere.

As a horticulturist, I’ve planted thousands of trees in suburbs and cities. I’ve thought of problems like soil, sun, wind, climate, insect resistant, etc. But this is an entirely new area of study. For instance, Rosenstiel points out that Oaks are big emitters of these toxins, while Maple not so much. But we can’t just plant Maples; we also need a diversity of trees in cities.

That got me thinking again about livable cities and how proper city/suburb planning is an important tool for saving our wildlands and wildlife. Proper planning so cities become more self-contained–growing their own foods [using rooftop year round gardens], solar power that is concentrated within the immediate area [rather than generated from massive wind/solar farms in fragile desert habitat or energy trucked from far away], green spaces for recreation, smart transportation, clustered housing, and other techniques will make the need to ‘escape’ less, and preserve lands for wildlife.

Rooftop garden

Cities/suburbs in general should be planned with wildlife in mind. Although cities won’t be having elk or wolves running around, there are ways to plan for wildlife corridors. Los Angeles as well as Santa Cruz’s Highway 17 are good examples of needed cougar corridors. While there is good habitat around the edges, freeways block corridors cougars use. And living with wildlife that has learned to exploit urban centers, such as mesopredators and their prey, –coyotes, foxes, raccoons, deer, possums, fishers–will enhance city living.

Urban coyote rests mid-day in local cemetary

Smart city planning for liveable cities, which seems to now include taking into the account the chemical biology of trees–is a necessity if we want to inhibit the sprawl that now threatens some of last remaining wildest lands in the United States.