Eastern Hemlock
Scientific Name: Tsuga canadensis
— pronounced SOO-guh ka-na-DEN-sis
— Tsuga, Japanese for hemlock; canadensis, of Canada.
Pine Family (Pinaceae): over 200 species, including spruce, and fir.
Other Common Names: Canadian Hemlock
Eastern Hemlock needles are about 1⁄2” long and grow in a flat plane along the branches. The undersides of the needles have two parallel white stripes.
— pronounced SOO-guh ka-na-DEN-sis
— Tsuga, Japanese for hemlock; canadensis, of Canada.
Pine Family (Pinaceae): over 200 species, including spruce, and fir.
Other Common Names: Canadian Hemlock
Eastern Hemlock needles are about 1⁄2” long and grow in a flat plane along the branches. The undersides of the needles have two parallel white stripes.
Photos by David Rosher
The mature brown ovoid cones are about 3⁄4” long and hang from the twig tips. The bark of young Hemlocks is scaly and becomes furrowed as the tree matures.
The mature brown ovoid cones are about 3⁄4” long and hang from the twig tips. The bark of young Hemlocks is scaly and becomes furrowed as the tree matures.
Bark Photo by David Rosher
For more photos and ID help: VA Tech dendrology.
This hemlock doesn’t have any needles or cones because it’s dead. It was killed by an invasive insect—the Hemlock Woolly Adelgid, which was introduced from Japan to Virginia in the early 1950’s and has since spread north to Maine and south to Georgia. The insect can be recognized by the presence of a wooly, white waxy substance on the underside of young twigs. This “wool” covers the insect in all but its earliest life stages. The wax-covered adelgids look like tiny cotton balls.
For more photos and ID help: VA Tech dendrology.
This hemlock doesn’t have any needles or cones because it’s dead. It was killed by an invasive insect—the Hemlock Woolly Adelgid, which was introduced from Japan to Virginia in the early 1950’s and has since spread north to Maine and south to Georgia. The insect can be recognized by the presence of a wooly, white waxy substance on the underside of young twigs. This “wool” covers the insect in all but its earliest life stages. The wax-covered adelgids look like tiny cotton balls.
Photo by David Rosher
Injury to the tree occurs as a result of the insects sucking the sap and probably injecting toxic saliva while feeding. Damage from accumulated injuries causes the needles on infested branches to dry, turn a grayish-green color, and then drop from the tree. Dieback of major limbs progresses from the bottom of the tree upwards. Trees weakened by the Hemlock Woolly Adelgid often succumb to diseases and wood-boring insects and are readily broken and thrown by wind.
Eastern Hemlocks are scattered throughout the Preserve, and all are infested with the Hemlock Woolly Adelgid. Many, like this one, have died.
Injury to the tree occurs as a result of the insects sucking the sap and probably injecting toxic saliva while feeding. Damage from accumulated injuries causes the needles on infested branches to dry, turn a grayish-green color, and then drop from the tree. Dieback of major limbs progresses from the bottom of the tree upwards. Trees weakened by the Hemlock Woolly Adelgid often succumb to diseases and wood-boring insects and are readily broken and thrown by wind.
Eastern Hemlocks are scattered throughout the Preserve, and all are infested with the Hemlock Woolly Adelgid. Many, like this one, have died.