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Why Forests


Baltimore Green Space became aware of the need for more forest protection in 2012 when several neighbors reached out to us about protection of their forest patches. When we gathered with these neighbors and partner agencies, we hosted our first meeting of the Forest Stewardship Network that now governs all of the work we do with community leaders in neighborhood forest patches.

Ms. Mabel Smith, Ms. Henashena Hayes, and Mr. Charles Brown of Historic Wilson Park especially reached out to us in hopes that we could stop several lots of Wilson Woods from being cleared. We all believed something was in place in City government to protect their beloved forest. After researching regulations, we learned there was nothing to prevent the loss of the forest lots.

The total square footage of the lost Wilson Woods lots was under the 20,000 sqft trigger for the forest conservation regulations. As you can tell in photographs those lots were cleared. What you cannot see from photos is that the lots cleared are at least 10 degrees hotter every day of the year than those that remain forested.

Because of this loss, we conducted original research with the Baltimore Office of Sustainability and UMBC’s Dr. Matthew Baker, to learn that over 20% of Baltimore’s tree canopy is in forest patches outside of parks. We also produced our white paper on forest patches.

Why Forests?

More than twenty percent of Baltimore’s tree canopy is in forested patches of at least 15,000 square feet outside parks. Since 2013, through research by Baltimore Green Space with the U.S. Forest Service and the Baltimore Ecosystem Study, and through research with other area nonprofits and by other scientists, the environmental and social importance of these forested areas has been established. We have surveyed 110 forest patches; 88 through a “walkabout” field survey and 45 with a scientific protocol.

We know that:

Forest is the land use that best filters stormwater. Best Management Practices seek to mimic the action of a forest. Our research in 45 patches shows that the soil’s bulk density and organic matter are comparable to those of rural forests, suggesting that urban forest patches are extremely valuable for handling stormwater.

Forest patches make important contributions to cooling communities. Forest patches are better at cooling than street trees. Smaller, scattered patches more effectively cool the city than do fewer, larger patches.

Forest patches are key resources for biodiversity. We have documented over 91 species of birds, including federally protected species and forest specialists that require a forest interior to survive. Recently we documented sawtoothed goldenrod in a forest which is an endangered species with few sightings in Maryland.

More than 80% of the canopy trees are native in nearly all the patches surveyed, and we have documented more than 50 species of native trees.

Forest patches promote respiratory health. With their high area of leaf surface per square foot, forest patches can filter more pollutants from the air. The Baltimore zip codes with the least tree canopy have the highest rates of hospital visits for asthma.

Forest patches promote cardiovascular health. Blood pressure slows more for people who take a walk in a forested area than for people who take the same length walk in a developed setting.

Forest patches provide places for neighbors to exercise, enjoy nature, and work together. In 2016 Baltimore Green Space held 15 forest events reaching 256 people.

Increased tree canopy reduces crime. A 2012 study showed that “a 10% increase in tree canopy was associated with a roughly 12% decrease in crime.”

Forest patches increase property values. A 2007 study showed that prices increased by 4.9% for multifamily homes with a forested view.

Forest patches along roadways may calm traffic. A 2005 study notes that “There is a growing body of evidence suggesting that the inclusion of trees and other streetscape features in the roadside environment may actually reduce crashes and injuries on urban roadways.”

More Forest Facts

Several forest patches have an unusual diversity of tree species. For example, Fairwood Forest in Hamilton has 23 species of trees, and a forest patch in south Baltimore includes every oak species that we have found elsewhere in Baltimore City.

Forest patches often have very large trees nestled within them. The largest tree we have documented is 56 inches diameter at breast height (four people would be needed to circle this tree).

Through historical research done by the U.S. Forest Service we have learned that the 2.5-acre forest Springfield Woods (between Wilson Park and Pen-Lucy) is almost 100 years old.

Forest patches are valued by neighbors. In our survey of 88 patches, 52% showed signs of human use and 36% showed evidence of stewardship.

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