250-plus Trees To Go From Airport Wetlands Areas

CHATHAM – As part of a plan to improve safety for aircraft, consultants have proposed removing 250 or more trees from the protected areas around wetlands near the Chatham Airport.

Discussed by the conservation commission last week, the plan calls for the removal of around 200 trees of three-inch diameter or larger from the area close to the cranberry bogs at the northeast end of the runway, with the remainder coming from the buffer zones around a vernal pool and three nearby ponds. The consultants representing the airport commission proposed a number of efforts to offset the loss of trees, including replanting, invasive species control and contributions to a new tree replacement fund.

Because the conservation commission’s jurisdiction is limited to areas around wetlands, the plan does not address potential tree removal in upland areas farther away from the airport, like the wooded area behind Ocean State Job Lot, where the tree removal is expected to be significant.

The notice of intent filed by airport officials indicates that tree removal will take place in a maximum area of 2.6 acres immediately around the airport, including buffer zones around the vernal pool near the southwest end of the runway, near Bearse’s Pond, Black Pond and Emery Pond, and by the cranberry bogs. In those areas, trees will be removed or trimmed to provide safer approach clearances for the runways.

Adrienne Dunk of the consulting firm GZA GeoEnvironmental, Inc., representing the airport, presented a mitigation plan designed to offset the environmental loss of the trees. A key component of that plan involves the long-term control of invasive plants like multiflora rose, phragmites, bittersweet and honeysuckle that would be expected to spring up in areas where the tree canopy is removed, she said. Native plant and shrub seeds would be spread “if there are bare areas above a certain size,” Dunk said.

“How long does that take to actually establish?” commissioner Elise Gordon asked. Some seeds will sprout very quickly, while others will require over wintering to germinate, Dunk said.

The invasive plant removal contractor will use a “cut-and-dab” technique, “using herbicides that are identified by [the Massachusetts Division of Agricultural Resources] as more sensitive,” she said. The controversial herbicide glyphosate would not be used.

Another key mitigation strategy is tree replacement. Because tall trees can’t be planted near the runway approaches, low-growing species may be planted in some areas, with the airport making a contribution to buy trees to be planted elsewhere in town. A recently passed tree protection bylaw provides for creation of a fund for tree replacement, and Dunk said the airport has proposed contributing $7,500 per acre of buffer zone clearing. In the first year of work, which would involve 1.4 acres, the airport would pay $11,000 into the fund, with around $10,000 to be contributed in later years for additional work.

“So the payment is not going to be tagged to the number of trees that are removed?” conservation commission Chair Janet Williams asked.

Gordon noted that the plan calls for around 207 trees to be removed from the area around the bog, 69 to be kept, “and an additional 115 would be determined in the field.” It could be that the more than 300 trees are actually removed.

“I wonder if there should be something indicating that final determination of the contribution would be based on actual removal,” she said.

Dunk said the town is applying for state and federal grants to cover the work — including the tree fund payment — and the exact number of trees to be removed won’t be known until work begins. It would be difficult for the town to go back to those funding sources to ask for more money later.

“That’s why the airport prefers an area-based contribution, so they can get the money once with the least administrative effort and cost to the town,” she said.

Dunk said the project team can purchase four- to six-foot native trees at a cost of around $16 each. Commissioner Eric Hilbert warned that trees of that size would likely have a very small trunk diameter, or caliper. It typically costs several hundred dollars to buy an oak tree with a two- to four-inch caliper, he noted. “The money’s in the caliper,” Hilbert said. Most of the trees being removed have trunks between three and 15 inches in size.

While towns like to buy larger shade trees when planting in parks or along roadways, that’s not necessary in restoration planting, Dunk said.

“Small trees do establish better,” she said.

The conservation commission continued its hearing until June 12, and expected to issue a decision on the notice of intent by June 26.