[ SCOURGE ]
Death of a Hemlock Stand
Since its arrival in southern New England during the mid-1980s, hemlock woolly adelgid (HWA) has
significantly affected hemlock forests throughout the region. Though its effects were initially greatest
in lowland regions, in recent years it has been increasingly widespread in the higher elevations of
These views show hemlock ravines with HWA infestation in central Massachusetts in early 2016
matched with images that were taken from the same vantages in 2003, before HWA arrived or became
significantly established. The sites are located roughly 10 miles east of the Connecticut River at
elevations between 400 and 700 feet. The insect slowly kills trees over a 4- to 10-year period, so to see
the dramatic effects over this longer timeframe is striking.
The ecology of these rivers and streams, which are an important component of central New England’s
landscape, will likely be significantly altered by HWA. Soil erosion and nutrient leaching may adversely
affect water quality, which is a concern as many of these waterways feed public water supplies. Increased
water temperatures and continuing tree mortality will also affect brook trout, stream salamanders,
and many other wildlife species that are dependent on these habitats.
The unfortunate reality is that scenes like these may become increasingly prevalent in northern New
England as HWA continues to advance. Cold winter temperatures in northerly locations may temporarily
slow the spread of HWA, but then there are winters like we had this past year.
Amethyst Brook is a major tributary of the Fort
River, which is a water supply for Amherst and
Hadley, Massachuetts, and ultimately discharges
into the Connecticut River.
Buffam Brook is a cold-water stream with a
series of cascades above its confluence with
Amethyst Brook. A conservation area protects the
watershed where the two brooks meet.
The Middle Branch of the Swift River, seen
here at the Bear’s Den waterfall in New Salem,
Massachusetts, is one of the largest tributaries of
the Quabbin Reservoir, the water supply for roughly
2. 5 million residents of eastern Massachusetts.
Amethyst Brook 2016
Amethyst Brook 2003