Eastern hemlock
Eastern hemlock (Tsuga canadensis), also known as Canadian hemlock, Canada hemlock, Hemlock, or Hemlock spruce, is an evergreen conifer tree which is native to southeastern Canada, the northeastern United States, and along the Appalachian mountains, stretching into north Alabama. It is the only hemlock variety native to Alabama.
The hemlock is noted for tolerating more shade than other evergreens and thrives on north-facing slopes, in deep ravines, and along streams, where it finds moist soil. When grouped in stands of hemlock, their dense foliage can create microclimates with very little sunlight reaching the surface of the ground or streams.
The tree grows into an upright pyramidal form with a thick furrowed reddish-brown trunk, branches extending to the ground. The flattened needles are about 1/2" to 3/4" long, paired, growing in two rows along each sprig. The small seed cones, rarely reaching an inch long, emerge as tight green ovals and mature to open gray-brown cones in mid-October, releasing small seeds to be dispersed by wind. The seeds are vulnerable to drying and germinate best in warm, moist soils. Seedlings are vulnerable to root rot fungi if present.
Hemlock lumber is a medium-brown colored coarse-grained softwood. It is used in making paper, railroad ties, pallets, crates and framed buildings. The bark is rich in tannins and was formerly used to tan hides. Its historic range has been reduced in the mid-20th century by over-timbering. More recently, eastern hemlock has been affected by infestation by the hemlock wooly adelgid (HWA), an invasive aphid-like insect. Affected trees are unable to maintain their needles, which turn brown and fall, weakening the tree and making it more vulnerable to other threats. Infestations usually result in death within 3 to 5 years.
The southernmost stand of eastern hemlock is believed to inhabit Village Creek Canyon below Bayview Dam in western Jefferson County. Alabama's "Champion" eastern hemlock, first recognized in 1992, is 120 feet tall with an average diameter of 25 feet and a trunk diameter of 48.4 inches. It is located in the William B. Bankhead National Forest in Winston County.
References
- Angel, Josh (2023) "Trees of Alabama: Eastern Hemlock." Alabama's Treasured Forests. Alabama Forestry Commission, Vol. 42, No. 3, p. 32