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Frequently Asked Questions:

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Why are these Eastern Hemlock trees unique?
The north-facing bluffs around Swift Creek provide a relatively cool and most environment which supports a variety of vegetation unusual to this area. This includes Eastern Hemlock trees (Tsuga canadensis) thriving more that 200 miles from their typical habitat in the Appalachian Mountains. During the last glacial period 18,000 years ago, much of the northern United States was covered by huge ice sheets. Although these did not extend into North Carolina, temperatures in this region were considerably cooler than they are today.
Fossil evidence indicates that plant and tree species - like spruce, fir, hemlock and jack pine - now found in the northern conifer forests and in the mountain regions were widespread across the Piedmont during this period. Most of these plant communities disappeared with the retreat of the glaciers, but the hemlock trees of Hemlock Bluffs remain as a unique relic of that ancient world.
How were the bluffs formed?
Most of the rocks that underly the Preserve are 500 to 600 million years old, and originated as volcanic material. About 220 million years ago, large faults formed in the Earth's crust. Some of these, like the one that runs parallel to the bluffs, filled with quartz deposited from hot water passing through the fractured rock. During the Pleistocene era, the climate was much cooler and quite wet, and Swift Creek was a much larger stream. It eroded the softer volcanic rock, leaving the harder rock along the bluffs. You can see large white blocks of quartz near the top of the bluffs.
Why a nature preserve?
Uncommon vegetation is not the only thing that makes Hemlock Bluffs unique. The Preserve also serves as a vital wildlife habitat and breeding group for local salamander populations. The Town of Cary has designated this 150 acre area as a nature preseve to protect this very special ecosystem. A system of trails, boardwalks and overlooks allow visitors access to the area without disrupting the fragile micro-habitat.