7/27/2011

Philadelphia's Garden City Progress

Long ago William Penn set out to plan his "Green Country Town", Philadelphia, which has quickly over the past decades faded from green to grey and black, with growing development depleting urban forest, paving of natural surfaces in residential areas, and lack of tree planting compared with growth of development.  Philadelphia has large swaths of land where asphalt and concrete predominate and tree and lawn cover is hard to find.  This is why the program to reforest the city is so important and revolutionary.




Philadelphia's ambitious tree planting initiative is to plan 300,000 trees over the next five years and to double the city's tree canopy by 2026.  Unfortunately the plan may be too ambitious due to City Council opposition last year of $2.5 million for tree planting allocated for the Department of Recreation's budget.  But, according to Patrick Morgan of the Recreation Department, there is still $2.5 million set aside in the city's budget for tree planting, plus $1.6 million in federal stimulus funds to pay for a year-long project to use laser technology to map with precision the city's tree canopy from the air.



Trees are ecological machines working as part of a global engine that powers our planet.  They remove pollutants from the air, absorb the runoff of storm water, thereby reducing the likelihood of floods or the necessity of building storm water holding tanks to manage sudden accumulation of water ( ever hear of a forest flooding?).  Trees also reduce the "heat island" effect, which occurs in dense urban environments where concrete and asphalt surfaces trap radiant heat, heating the air from the ground surface raising temperatures higher than necessary.  Remember last friday July 22, temperatures were well over 100, and even with total overcast of cloud cover you could still feel the heat rising from the sidewalk beneath you, not something you want to go through every day.  This is the reason the temperature is always several degrees higher in Philadelphia than in northern and western suburbs.

Overall, Philadelphia's tree canopy is much lower than its urban counterparts.  Tree cover in Philadelphia amounts to 15.7 percent of the city.  New York and Baltimore average 21 percent; Boston 22 percent; Washington D.C. 28 percent; and Atlanta 37 percent, according to the National Forest Service.



The ideal is a 30% tree canopy, according to Alan Jaffe of the Horticultural Society, and the goal of the tree initiative is to take it to that level over time.  This would mean doubling the existing inventory, estimated to be 1.5 million trees in parks and natural locations and about 130,000 trees now planted on city streets.  The problem is that Philadelphia's tree canopy is poorly distributed.  zit is dense in some areas, mainly close to parks and almost non-existent in others.  Philadelphia's most tree populous neighborhoods are Chestnut Hill and Germantown.  The most sparse sections are Central North Philadelphia and South Philadelphia.


South Philadelphia

Chestnut Hill/ Germantown

Street trees are expensive and require a lot of maintenance during the first year of planting.  A tree can cost up to $500 to plant, depending on whether sidewalks need to be cut and how many are planted at one time< trees cost less when purchases at nurseries in bulk.  During the first year of a tree's planted life, deep-soil watering with 15 to 20 gallons per tree on a weekly basis is crucial.

Significant Benefits of Trees

Aside from their tremendous boost to aesthetics and peace of mind in beautifying streets and neighborhoods, increasing tree cover in urban areas has many serious advantages.  Added benefits of a healthy substantial tree population include; significantly improving air quality (the US Forest Service estimates that 100 trees remove 1.2 tons of CO2 per year and 130 pounds of other pollutants); reducing home air-conditioning costs by as much as 30%; adding an additional 10% to property value per large tree on your lawn; improving physical health and preventing flooding by capturing rain water and filtering out impurities.