A Mighty Wind and Nature’s Chaotic Beauty

  • Jeremy Wilson of the Harris Center for Conservation Education stands beside a white pine toppled during the Aug. 22 wind event that struck parts of Nelson and Hancock. Eric Aldrich Photo

  • Downed pines near Hunts Pond in Hancock show the force of a downburst that struck a narrow swath of Nelson and Hancock on Aug. 22.  Eric Aldrich Photo 

Tuesday, October 24, 2017 9:14AM

Unless you lived in parts of Hancock or Nelson, you might have forgotten Aug. 22, 2017.

It was one of those classic hot and humid summer days.

At 3 p.m. at the Jaffrey Airport, the temperature reached 86 degrees and the heat index (what the temperature feels like) was a sticky 91.5 degrees. Clouds had gradually started rolling in as a storm system marched across New York state and Vermont, slowly bringing down the temperature and the barometric pressure.

By about 10:30 p.m., as most folks were winding down for the evening, the thunderstorm had reached the Monadnock Region, bringing the usual elements of pounding rain, thunder and lightning. But as the storm rushed into Nelson, the storm became far from the usual late-summer thunder-boomer. Way up in the sky, portions of the cloud became super-cooled and moisture globbed together into droplets. At some point, the super-cooled air and growing droplets succumbed to the weight and pressure, and it all dropped in a violent, sudden downburst.

Starting just south of Nubanusit Lake – or somewhat southeast of there – the reaction was fierce. In a narrow zone of less than 100 yards or so, the pulse of wind barreled northeast like a speeding freight train, rushing violently through the western edge of Hancock until fizzling out some 8 miles later, just past the Hancock-Antrim line.

A classic downburst

As I watched the lightning from the comfort of my home in the southwestern part of Hancock, I wasn’t surprised when my Hancock Fire Department pager went off, with the dispatcher describing a tree across Stoddard Road, Route 123. It didn’t take long until more calls came in for trees across roads and utility wires.

What we saw on some roads was a crazy mess of downed trees. And as we plotted the incidents on a map at the fire station, we could see a clear, narrow line of damage across the town. Some veterans on the department naturally suspected a tornado was to blame.

But in terms of weather phenomena, the Aug. 22 event was a classic downburst, according to Justin Arnott, a meteorologist with the National Weather Service in Gray, Maine. One clue that meteorologists observe after a tornado are trees downed in a slanted right-to-left pattern along the path of the event. That reflects the tornado's counterclockwise rotation and its destructive leading edge. Most trees felled in the Aug. 22 event follow the storm's northeast path, a sign that it was straight-line wind damage, according to the National Weather Service.

Such events can be contained to narrow strips across the land, even skipping areas, then dropping back down to cause more damage, usually in the form of downed trees, Arnott said.

Those downed trees tell a lot about the storm, often falling in the direction of the downburst itself. In this case, the trees were fell in a northeasterly direction, with most falling whole — roots and all — and others snapping partway up.

The wind event passed through many parcels large and small, including lands conserved by the Society for the Protection of New Hampshire Forests and the Harris Center for Conservation Education.

A harmonious mess

At the Forest Society’s McGreal Forest off King’s Highway in Hancock, evidence of the storm is easily seen from the road and the trail into the tract. Just a short walk into McGreal Forest, you see downed trees — mostly huge white pines — some laying across the trail, others within sight of the trail. The further you walk, the more it becomes clear that the wind event blew a narrow, northeast path of downed trees.

The Forest Society wisely manages this 26-acre jewel as a reserve, or a natural area, where nature is allowed to take its course. Where the storm brought trees across the trail, the Forest Society may cut through the trees to clear the path, or re-route the trail around downed trees. Other than that, the storm’s impact on the forest will remain for decades to impress visitors about the fury of wind and its impact on trees and forest ecosystems.

To some people, those downed trees might look unsightly — a disorderly disruption of a clean, harmonious forest in perfect balance with itself. But nature is seldom clean, orderly and it’s never in balance. To my mind, those downed trees are a beautiful chaotic, harmonious mess. They’re a reminder that the forest is ever-changing, always moving, always dynamic and full of riddles, surprises, opportunities and challenges. They also remind us that humans can’t control everything, nor should we try.

Such wind events disproportionately affect New Hampshire’s iconic white pines over other tree species, according to Dave Anderson the Forest Society’s director of education. White pines’ shallow root system leave them susceptible to wind events. But their demise brings opportunities for salamanders, insects, birds and other wildlife, Anderson said.

The Dynamic Forest

I walked parts of the McGreal Forest recently with Jeremy Wilson, executive director of the Harris Center, who did his graduate dissertation on wind damage to forests in the Pacific Northwest.

What Wilson saw as he maneuvered among the downed trees in McGreal Forest was the awesome power of wind that overwhelmed both strong white pines and those weakened for one reason or another.

“This is a windthrow,” Wilson said, standing beside the upturned roots of an enormous white pine on the ground. The whole tree was down, roots and all, exposing what Wilson called the “root plate.” Normally invisible in the underground, the root plate was now on full display, showing just how shallow a white pine’s roots typically are. Instead of burrowing deep underground, as many people expect, the roots of pines and other tree species actually need to be near the ground surface, where they can absorb oxygen.

When wind exerts pressure on trees — especially tall white pines — that surface-centric root plate can leave the trees vulnerable to wind events. Add shallow granite ledge and rot into the mix and a tree can become even more susceptible to high winds. Examples are all over McGreal Forest and the Forest Society’s nearby Welch Farm Forest.

And in the jumbled mix of fallen trees and tipped-up roots are a wealth of opportunities for wildlife. A partially fallen pine exposes a root tip-up that becomes a black bear’s winter den. A damaged pine will die, become infested with beetles, ultimately attracting woodpeckers, flying squirrels and other wildlife.

Nature persists. Resilience rules. It’s nature’s sloppy mess that makes the world work in small, miraculous ways.

The Harris Center for Conservation Education plans to show the storm’s impact on the land in an event next spring. So, stay tuned for that.

(Eric Aldrich writes from his home in Hancock and can be reached at ericadine@gmail.com)