Eastern Hemlock (Black Diamond) Traditional Cache

The Hemlocks along the trail are small and not common. Maybe due to the Invasive Woolly Aldelgid?

The cache is hidden by one of the small trees. The coords had a wide spread. I hope the average will take you to the right tree.

22. EASTERN HEMLOCK ;

hemlock-spruce

Tsuga canadensis (Linnaeus) Carriere

Eastern hemlock is a valuable forest tree very widely distributed throughout the state, particularly common on northern exposures, shaded gorges, steep mountain slopes, and borders of deep swamps.

The wood is light, not strong, coarse-grained, brittle, not durable, splinters easily, and is light brown in color. It is largely manufactured into construction lumber and is also in demand for mechanical pulp.

Bark - reddish to grayish brown in color, with shallow, broad connecting ridges; inner bark bright cinnamon red in color. The high tannin content of the bark is of commercial value in tanning leather.

Twigs - slender, yellowish to grayish brown in color, rough when needles are shed.

Winter buds - very small, reddish brown in color, not resinous-coated.

Leaves - borne singly, twisting to appear 2-ranked with a third row pointing forward on top of the twig; with distinct short stalk, flat, 1/2 inch long, rounded or notched at the apex, dark green in color above, paler below with 2 white lines, persistent from 2 to 3 years.

Fruit - a cone, stalked, pendant, 3/4 inch long, ripening in a year, grayish brown in color when mature, falling during the winter following maturity. Cone scales - with rounded entire margins. Seeds - in pairs, winged, light brown in color, 1/16 inch long, ripening in September.

Distinguishing features - needles with tiny stalks; small cones.

Tsuga canadensis (L.) Carr.

Eastern Hemlock

Pinaceae -- Pine family

R. M. Godman and Kenneth Lancaster

Eastern hemlock (Tsuga canadensis), also called Canada hemlock or hemlock spruce, is a slow-growing long-lived tree which unlike many trees grows well in shade. It may take 250 to 300 years to reach maturity and may live for 800 years or more. A tree measuring 193 cm (76 in) in d.b.h. and 53.3 m (175 ft) tall is among the largest recorded. Hemlock bark was once the source of tannin for the leather industry; now the wood is important to the pulp and paper industry. Many species of wildlife benefit from the excellent habitat that a dense stand of hemlock provides. This tree also ranks high for ornamental planting.

Habitat

Native Range

The northern limit of eastern hemlock extends from outliers in northeastern Minnesota and the western one-third of Wisconsin eastward through northern Michigan, south-central Ontario, extreme southern Quebec, through New Brunswick, and all of Nova Scotia. Within the United States the species is found throughout New England, New York, Pennsylvania, and the middle Atlantic States, extending westward from central New Jersey to the Appalachian Mountains, then southward into northern Georgia and Alabama. Outliers also appear in extreme southern Michigan and western Ohio, with scattered islands in southern Indiana and east of the Appalachians in the middle Atlantic States.

The range completely overlaps that of Carolina hemlock (Tsuga caroliniana), a closely related species limited to the slopes of the Appalachians from Virginia and West Virginia into Georgia.

Commercial volumes of eastern hemlock have been greatly reduced by harvesting. In Michigan, for example, sawtimber volume decreased 69 percent and growing stock volume decreased 71 percent between 1935 and 1955 (10). Both the type area and volume are continuing to decline because of harvesting and failure to regenerate, particularly in the western portion of the range. The remaining sawtimber is concentrated in the Northeast and the Lake States.

Climate

Eastern hemlock is generally restricted to regions with cool humid climates. In the northern areas January temperatures average about -12° C (10° F) and July temperatures about 16° C (60° F). Precipitation ranges from less than 740 mm. (29 in) in heavy snowfall areas of the north to more than 1270 mm (50 in) per year, about one-half occurring as summer precipitation. In the more productive areas near the Atlantic coast and southern Appalachians, January temperatures range as high as 6° C (42° F) and annual precipitation exceeds 1520 mm (60 in). The frost-free period is less than 80 days at the northern limits and nearly 200 days in the eastern and southern portions of the range.

Fully stocked stands of eastern hemlock tend to develop similar microclimates because of their dense canopy, dense shading, deep duff layer, and subsequent retention of moisture and uniformly low temperatures. In the few stands in which understories do develop, the type of vegetation tends to be similar to other forest types in the area although fewer species become established.

Soils and Topography

The soil requirements for eastern hemlock are not exacting. They are universally characterized as being moist to very moist but with good drainage. In the Lake States the species grows on upland sandy loams, loamy sands, and silt loams, often with an abundance of ground or coarse rocky material throughout the upper profile deposited from glacial or fluvial material. In Canada and the northeastern States the soils under eastern hemlock tend to be shallow loams and silt loams, often over granite, gneiss, and slate bedrock (Typic, Lithic, and Entic Haplorthods of the order Spodosols). Typically, most soils are highly acid, particularly in the upper horizons, but some are near neutral. The heavy, slowly decomposing litter fosters podzolization or leaching as the stand increases in age. On sites in which eastern white pine (Pinus strobus) is a major component, the soils tend to be of a sandy texture, well mixed with humus, moist, and well drained (Alfic Haplorthods). Scattered patches of hemlock also occur on the finer glacial tills as well, but in general these soils have less hemlock than the coarser soils.

Eastern hemlock grows from sea level to about 730 m (2,400 ft) in elevation in the northeastern and northern portions of the range. Most commonly it is found on benches, flats, and swamp borders, provided the peat and muck soils are shallow.

On the Allegheny Plateau, especially in New York and Pennsylvania, most of the hemlock grows between 300 and 910 m (1,000 and 3,000 ft). In the southern Appalachians the most frequent occurrences are at elevations of 610 to 1520 m (2,000 to 5,000 ft) and often are restricted to north and east slopes, coves, or cool, moist valleys. Outliers tend to be severely restricted by a combination of edaphic and climatic factors.

Hemlock woolly adelgid (HWA) (Adelges tsugae) is a small aphidlike insect native to Asia that is now threatening eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana).

Origin

Hemlock woolly adelgid, Adelges tsugae, is an invasive insect in eastern North America.

DNA evidence suggests that the invasive eastern U.S. population came from Japan and not the western United States, where the species feeds on western hemlock (Tsuga heterophylla [Raf.] Sarg.) but is believed to be native and is not a pest.

Impacts:

HWA threatens hemlock trees, genus Tsuga. It feeds on the tree’s food storage cells. The hemlock “walls off” the area where the HWA is feeding, causing a disruption in nutrient flow and, eventually, killing the needle. Needles will dry out, gray, and fall off. Over several years, whole limbs will die back, killing the host tree from the bottom up. Stressed hemlocks are more likely to become infected with mortality typically occurring within 4 to 10 years after infestation by hemlock woolly adelgid.

Life Cycle

Hemlock woolly adelgids are small in size and to the naked eye only their woolly coverings are easily visible. The insect has two generations per year and growth occurs from fall through late spring. Insects in summer are inactive and scarcely visible at the bases of needles as black dots. Woolly masses (the sign allowing the species to be recognized) develop in October and are present thereafter through June of the following year.

Identification:

Appearance: Adult HWA are 2mm long with a black, oval-shaped soft body. 

Nymphs: Also called crawlers, they cause the most damage to host trees as they attach specialized mouth parts to the base of hemlock needles leading to leaf loss. Pictured above are HWA nymphs in their dormant phase which occurs during most of the summer months. They are tiny, flat, black and oval with a ring of white “fringe” around their perimeter.

Distribution

In the eastern USA, Adelges tsugae is killing eastern hemlocks (Tsuga canadensis [L.] Carrière) and Carolina (Tsuga caroliniana Engelm.) in large numbers from Connecticut south along the Appalachian Mountains. From Massachusetts north, or at high elevations, tree mortality has been restrained by higher rates of mortality of adelgids in winter due to low temperatures.

Control Efforts

A biological control program is in progress against this pest, based on specialized predatory beetles that feed only on adelgids, collected in western North America (Laricobius nigrinus Fender) or China/Japan (species of Laricobius and various Scymnus ladybird beetles). To date, releases have not demonstrated any reductions in adelgid densities from predators. Populations of L. nigrinus have become well established and abundant in some areas of western North Carolina

CONTROL/ MANANGEMENT

MANUAL

 Stress on infested hemlocks can be reduced by pruning dead or dying branches and watering trees during dry periods. This will reduce chances of infestation by HWA. Note: Avoid fertilizing hemlocks with a nitrogen fertilizer as it will encourage HWA reproduction and survival.

CHEMICAL

 Individual trees can be treated with a systemic insecticide, applied as a soil drench or basal bark spray. Once applied, the treatment can provide years of protection for the tree.

 Hemlock foliage may also be treated with horticultural oils and insecticidal soaps as long as the trees are small enough to be saturated, ensuring that the HWA has been exposed. NYS Hemlock Initiative: HWA Management

BIOLOGICAL

 Several HWA predators, including beetles and fungal pathogens, are being tested for effectiveness in treating infested hemlocks on a large scale. While more research is needed to assess long-term feasibility, studies have shown this to be a promising method of controlling HWA.

The cache is a tied in, camoed, “micro” pill bottle, that you have to push hard to open and close. Please BYOP and leave things as you find them, including the camo. Make sure the SWAG doesn’t push the log up, so the cap won’t close tightly. No SWAG to start.