Lebanon to combat heat with trees

By FRANCES MIZE

Valley News Staff Writer

Published: 09-23-2023 7:56 AM

LEBANON — A relatively new Lebanon committee has proven that money can, in fact, grow on trees. Last week, the Tree Advisory Board was awarded nearly a quarter of a million dollars from the federal government to plant trees across the city.

Temperatures soar in areas researchers have dubbed “heat islands,” where heat-absorbing asphalt dominates and trees are few. New Hampshire’s 2021 climate assessment predicts more days of extreme heat each year, and staving off higher temperatures in shade deserts by planting trees will be increasingly important.

“Frankly, this is really transformative for Lebanon,” said tree board member Andrew Garthwaite. “Some of these trees will be with us for more than 100 years.”

With $244,275 in funding from the Inflation Reduction Act, the board has the cash to plant 220 trees across the city over the next five years.

In March, the Tree Advisory Board reported to the City Council that additional findings from the study suggest lower-income residents are more likely to live or spend time in the city’s heat islands. Extreme heat can be particularly dangerous for those who live in older residential buildings in low tree-density, high population-density neighborhoods.

Rising temperatures pose a health risk: Prolonged exposure to extreme heat can lead to heat stroke, cramps and nausea.

“The trees that the City will plant will provide shade to reduce the impacts of heat that disproportionately impacts the elderly and those who can least afford air conditioning,” said City Manager Shaun Mulholland in a statement about the grant.

Advance Transit bus stops by City Hall and Kilton Library are the most popular stops on public property and have the least amount of shade, a heat island study conducted by the group last summer found.

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“Providing shelter and shade from trees in those places will really make a difference,” Garthwaite said.

Planting trees on private property, such as at the bus stop in the Walmart parking lot on Route 12A, is more difficult. “But the Walmart bus stop just sits on a stretch of pavement,” he said. “There’s no shade of any sort.”

Half of the trees planted with the grant money will be large and more mature and require professional planting.

“We need some trees to be large enough to survive snowplows and people,” said Tree Board member Susan Johnson. “Those require heavy equipment to plant.”

A future team of volunteers, which the tree board has named the “tree corps,” will plant the smaller trees.

Tree Board member Charlie Dupuy said there’s still work to be done in studying areas most impacted by, and insulated from, extreme heat. An investigation of wind directions across the city, which impacts cooling, could be fruitful, Dupuy said.

“This is a big grant, but it’s not going to allow us to flood the city with trees,” he said. “So we need to plant them judiciously.”

The grant will also help fund a part-time city tree warden, who will be employed through the Department of Public Works. “They’ll have expertise and be able to advocate for tree planting and preservation documentation,” Dupuy said. The position hasn’t existed in Lebanon before.

The trees planted over the next five years have to be done so with the next century in mind: Rising temperatures are shifting the ranges of many arboreal species, driving southern trees north.

A stretch of natural sycamores, unusual to the area, is growing near the sewage treatment plant by the Connecticut River, Johnson noted.

The city planted its own sycamore in April, to celebrate Arbor Day. Garthwaite suggested the species could planted as part of the Tree Board’s more weather-resistant tree repertoire.

“We can’t just plant some of our favorite trees, which really like the cold,” Garthwaite said.

Maples and white birches, weathering warmer winters and sweltering summers, are under stress, he said.

“So, unfortunately, we have to be mindful.”

Frances Mize is a Report for America corps member. She can be reached at fmize@vnews.com or 603-727-3242.