Recounting sports comeback stories is great, but even better is hearing a tale of
resurrection from the biological world. Right here in New England, the red spruce,
Picea rubens, a species thought by some to be headed toward inevitable demise, seems
to be rebounding. Recently, researchers from the University of Vermont and the U.S.
Forest Service measured the growth rates of 379 red spruce trees from Vermont, New
Hampshire, and Massachusetts and found a surprising trend: not only were the trees not
declining in growth as they’d expected, but they’re growing faster than they ever have in
A species in trouble
This red spruce story goes back to the 1960s. As “Beatlemania” was invading the rest
of the country, Hub Vogelmann, professor of botany at the University of Vermont and
iconic conservationist, and graduate student Thomas Siccama were doing routine plant
surveys on Camel’s Hump in the Green Mountains of Vermont. The work was to be part
of Siccama’s doctoral research documenting plant communities and forest succession at
differing elevations. After recording large numbers of high-elevation red spruce trees that
were stressed and dying, they returned 15 years later and were shocked to discover that
over half the trees had been lost.
At first, the cause of death was a mystery. The researchers could tell that natural
stresses, particularly winter injury, had played a role, but it wasn’t clear why the trees died.
Eventually, it became apparent that acid rain (discovered in the 1960s) was a contributing factor. Deposits of sulfur and nitrogen dioxide were causing calcium to be leached
from the forest soils and the trees’ needles, compromising their tolerance to cold winters.
In 1982, Vogelmann published an influential article in Natural History magazine called
“Catastrophe on Camel’s Hump,” linking the spruce decline to air pollution.
Vogelmann and Siccama’s findings caused other scientists to take a closer look at the
effects of acid rain and calcium deficiency on the forest ecosystem. In the years that followed, researchers considered other variables that were at play in the spruce decline, such
as wind exposure, root damage, natural succession, and climate change, but acid rain
remained the focal point. In 1990, federal lawmakers approved changes that bolstered the
Clean Air Act as a direct result of the work done on Camel’s Hump and elsewhere in the
As acid rain in the region gradually abated, newspaper headlines gave way to newer
environmental crises du jour: deforestation in the rain forests of Brazil, old growth logging, the spotted owl controversy of the Pacific Northwest among them. Meanwhile, the
solitary red spruces of the Northeast continued to suffer, whether or not the public was
A pleasant surprise
Paul Schaberg was still paying attention. A plant physiologist for the U.S. Forest Service’s
Northern Research Station, he remembers a watershed moment nearly 15 years ago: he
was riding a Vermont ski lift, when rising over a crest and looking out over the landscape
he noticed something strikingly wrong.
“I was aghast,” he says, recalling the hundreds of crimson red spruces punctuating the
landscape. “It wasn’t until we got up high in the air that it hit me just how bad it was. It
was really quite striking.”
That was in early 2003, at the tail end of a bone-chillingly cold winter. Frigid arctic air
and stinging winds had zapped the new foliage of nearly every red spruce tree in sight.
Up to that time, Schaberg had been tracking the condition of red spruces and researching
the effects of acid rain, calcium deficiency, and repeated winter injury on tree health, but
he’d never seen a sight as dramatic as this.
He moved quickly to encourage his colleagues to examine the extent and severity of
the damage. The Vermont Department of Forests, Parks, and Recreation conducted an