AN FOREST UNRAVELING ?

Eastern Hemlock

* Extremely Shade Tolerant

* Long-lived; often >400 yrs.“Redwood of the East” “Old Growth”

* No Ecological Equivalent

* Distinctive Ecosystem & Biodiversity

* Drought Intolerant

* Pennsylvania State Tree

Hemlock woolly adelgid

Dying hemlock tree

Complicating Factors in the Causes of Hemlock Decline

• Local Human Impacts– fragmentation, soil compaction & erosion, salt

• Air pollution – acidic deposition, excess N (favor HWA)

• Climate change – drought stress, mild winters (favor HWA)

• Other forest “pests”– elongate and circular hemlock scale, hemlock

borer beetle, gypsy moth defoliation

Blackburnian warbler

Black-throated green warbler

Blue-headed vireo

Birds Strongly Linked to Hemlock Forests

Hemlock streams are 3 times more likely thanhardwood streams to support brook trout

ALIEN PLANTS INVADING

• “Tree-from-hell”

• Japanese barberry

• Japanese stiltgrass

• Garlic mustard