Relationship Between Stand Development and Spruce Mortality on Great Cranberry Island, Maine

New Release

New Release (continued)

Relationship Between Stand Development and Spruce Mortality on Great Cranberry Island, Maine

Stand Level Disturbances and
Tree Disease

Maine’s Mid-Coastal Islands

Hypothesis

Sample Area

Sample Design

Plot Measurements

Relationship Between Stand Development and Spruce Mortality on Great Cranberry Island, Maine

Dead Basal Area
80% in high mortality plots; < 30% in low mortality plots

Red Spruce:

White Spruce:

Balsam Fir:

Stand Age Class Distribution
Both stands have trees originating over 100 years ago
More frequency of younger ages in high mortality plot could be due to death of the older trees

Tree Regeneration
Abundant red spruce regeneration in low mortality plots
Little regeneration in high mortality plots

Ground Plant Composition
Grasses/sedges most abundant type in high mortality plots
Mosses most abundant type in low mortality plots

Deer Browsing

Hypothesis:  High mortality site developed from an abandoned field

Hypothesis:  Low mortality site developed from a red spruce forest

Conclusion

Thanks to the residents of
Great Cranberry Island