More of my neighbors are inveighing against home builders who demolish utilitarian old houses to make room for, well, mansions of questionable size and taste.

They have a fresh green argument.

“Nearly every day, another tear-down in our neighborhood leaves a lot stripped of every tree, bush, plant and blade of grass,” wrote Patricia Norland and Angela Dickey, who live off of Williamsburg Blvd. “Tree canopy, not to mention bird and wildlife, is diminishing in front of our eyes. Every night we hear the unearthly cry of a fox dispossessed of his home….”

These words appeared last week in the women’s fan letter to the Fairfax County Urban Forestry Commission. “When we walk in nearby Fairfax neighborhoods,” they continued, “we can’t help but note large homes that have big, shady trees left on their lots.”

The Fairfax Board of Supervisors has adopted a 30-year conservation goal based on environmental recommendations from a “Tree Action Plan” to increase tree coverage by 45 percent.

Among the many listed groups that could pitch in are land developers. The desire of many builders to meet a perceived demand for profitable luxury homes has prompted middle-income folks to decry tear-downs as economically elitist and contributors to soil erosion.

A March blog from the National Association of Home Builders shows the industry acknowledging the trend, if not the complaints of would-be homeowners and Realtors, whom many builders offer to bypass.

Nationwide, about 7.7 percent of single-family home starts in 2015 were attributable to tear-down-related construction, the association wrote. The survey showed that half of builders never do teardowns, while 3 percent do nothing but.

“Anecdotal evidence suggests tear-down construction has become a significant modus operandi in some parts of the country,” the blogpost said. “Due either to local topographic or political constraints, developable land in some places has become scarce.…Replacing older structures with new ones can potentially be an important option for builders.”

Arlington officials are concerned both about the tear-down problem and the threat to trees. But there are limits to what can be done in by-right development situations, I’m told by Urban Forest Manager Brian Keightley. “The county’s authority over trees is limited to ensuring that the owner/developer meets the requirements of Arlington’s Chesapeake Bay Preservation Ordinance. This ordinance requires a permit for any land-disturbing activities greater than 2,500 square feet. Developers of properties in single-family residential areas must submit plans demonstrating that 20 percent tree canopy coverage will be achieved within 20 years.”

The county can’t protect specific trees, though in 2014, the ordinance manual added an incentive to developers by awarding a double canopy coverage bonus for preserving existing trees on site. “We hope this will encourage more developers to preserve existing trees,” Keightley said.

The threat to the Arlington’s trees may not be dire. The canopy was 43 percent according to a 2008 assessment, but shrunk to 40 percent in 2011. Our own Urban Forestry Commission can point to voluntary efforts, such as public-private Tree Canopy Fund, tree recognition programs, and the policy of planting an average of 1,068 trees per year on county land. We hope that the next canopy assessment will show a leveling of canopy loss,” Keightley said.

Meanwhile, Arlington “has not seen a significant increase/decrease in development plans in the last few years,” he cautioned. “It hovers around 200 per year.”

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It was jarring to hear my own Metro stop at East Falls Church mentioned on radio news Friday as the epicenter of the subway’s latest snafu—a derailment.

Even so, on the whole I’d say Metro crews executing the long-term investment of SafeTrack are doing yeoman work. That’s under pressure both from angry commuters and the shimmering heat wave.

As a daily user, I felt grateful eyeing the repair crews stacking decayed wooden rail ties on an open-air stretch for Orange and Silver lines. Ditto for the hustling uniformed employees with bullhorns outside the Ballston and East Falls Church stops guiding bewildered riders toward express shuttle buses. I commuted with minimal delays.