an forest unraveling ?. eastern hemlock * extremely shade tolerant * long-lived; often >400 yrs....
Post on 21-Dec-2015
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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