EDITOR'S NOTE: In recent years, Haverhill has planted hundreds of new trees to improve the appearance of urban areas, but there is another benefit, according to the woman who wrote this column.
As climate change becomes an increasingly important issue, communities, individuals and governments are looking for solutions to minimize its effects.
One of the simplest and most holistic approaches to helping our cities prepare for a changing climate is not new technology but planting trees and developing the urban forest.
Cities are most vulnerable to the effects of climate change, especially historically underserved communities such as Lawrence.
Lawrence already benefits from tree planting initiatives, but the current tree density is not enough to sustain this city in the coming decades.
More planting is necessary to ensure a sustainable future.
Urban heat islands, caused by heat absorption and radiation from asphalt and concrete in neighborhoods, can cause these places to be 20 degrees warmer than suburban areas. This necessitates an increase in energy consumption, as more fans and air conditioners are used to fight the heat.
Trees lessen the effects of heat islands by providing needed shade and keeping surrounding areas cool.
In Lawrence alone, the cooling effect of trees prevents 523,000 pounds of carbon dioxide from being released due to energy consumption per year. That’s the equivalent of commuting in a car from Lawrence to Boston every day for 27 years.
Urban trees work double duty; they not only prevent energy consumption due to heat islands, they absorb carbon dioxide already in the atmosphere through photosynthesis. The trees in Lawrence absorb over 550,000 pounds of carbon dioxide annually.
This means urban trees are more effective at fighting climate change than their rural and suburban counterparts.
Flooding and stormwater runoff can be major issues in Lawrence, and they will worsen with the increasing intensity of storms due to climate change.
The impermeable surfaces throughout the city — roads, sidewalks and parking lots — cause flooding in our neighborhoods to be worse than in suburban areas.
The city’s trees reduce this hazard by intercepting over 3.3 million gallons of stormwater runoff each year, preventing it from flooding our streets, overwhelming our aging sewer system and causing combined sewage overflows.
In addition to these climate change fighting benefits, trees provide a number of public health and community benefits, such as decreases in asthma rates, decreases in crime rates and increases in property values.
While it is impressive to see how much our trees are already doing, it is important to realize that the need has never been greater for additional tree planting throughout the city.
Coming decades will see increased intensity of storms, more 90-plus degree days throughout the summer, and increased threats to public health as a result of climate change.
Our current tree cover is not adequate for what scientists predict the future holds, but we can prepare for this future now. The trees we plant today will benefit generations to come.
Groundwork Lawrence has long been on the front lines of fighting climate change, with an eye toward the immense benefits of trees.
In 2007 we launched our “Green Streets” program, making urban forestry a key part of our work. Since 2016, our work has been supported by the commonwealth’s Greening the Gateway Cities program, which aims to plant 2,400 trees in Lawrence and 2,400 trees in Haverhill.
If you live in Haverhill or Lawrence, you may be eligible for a free tree for your lawn. You can help fight climate change and improve your neighborhood today; visit groundworklawrence.org/greenstreets to see if you are eligible for a free tree.
When we begin planting trees again in the spring, we will quite literally be planting the seeds today to solve the problems of tomorrow.
Heather McMann is executive director of the Groundwork Lawrence organization.