Zoar Valley
In the far southwestern tip of New York State, the Cattaraugus Creek cuts a deep canyon through the shales of the Portage Escarpment in its path from the Allegheny Plateau to Lake Erie. Thousands of years of erosion and deposition have built up a series of streamside terraces along the bottom, where deep layers of fine sediments over a bed of river cobbles shelter the roots of the tallest forest in the northeastern US.
The favorable microclimate and sheltering topography enable many tree species to compete in the canopy and reach exceptional heights. There are few trees of great diameter here, but with nineteen species stretching over 120' in height including seven that rise over 140', Zoar Valley stands above the rest in its diversity of tall trees.
Common Name: American Elm
Scientific Name: Ulmus americana
Common Name: Eastern Cottonwood
Scientific Name: Populus deltoides
Common Name: Tulip Tree
Scientific Name: Liriodendron tulipifera
The age of the forests in Zoar Valley has long been a point of controversy. Conflicts developed when the NYS DEC announced a plan to harvest timber from the forests deep in the canyon, which were believed by many to be remnants of the region's original old-growth forests.
A lengthy citizen's campaign led to the designation of the forests within the canyon and along the rim as the Zoar Valley Unique Area, protected from logging and development, and the passage of a state law defining and protecting old-growth forests.
Dendrochronology work carried out since that time identified the stands within the deepest part of the gorge as unlogged primary forest and illuminated the successional processes still taking place there as the riverbed shifts from year to year. At the same time, forests in the canyon's south branch that include some of the largest and tallest trees present have been shown to be regrowth following cutting in the 19th century.
Within these younger forests a Tuliptree rises 163.5' to pierce the surrounding canopy of Maples and Basswoods, making it the tallest broadleaf tree in all of North America north of the 40th parallel. This fast-growing individual stands on a trunk with a DBH of just 32 inches. A few steps from its base is a hollow structure built of stacked stones- a lime kiln. Less than two centuries ago, the original forests that shaded that stretch of canyon were cut and fed into that kiln to be cooked down into ash.
Used in the manufacture of chemicals, wood ash was in that period more profitable and easier to transport than lumber. Even here, on the steep slopes and dry ridge-lines high above the river, there are gnarled and ancient specimens of Hemlock, Chestnut Oak, and Eastern Red Cedar that have always been out of reach.
In the old-growth landscape of the main canyon the tallest trees are also still growing. An American Sycamore at the edge of one terrace continues to grow at a rate of more than 0.5' every year. An annual measurement in June 2020 confirmed that this tree had finally passed an incredible milestone: at 160.2' tall, becoming the first of its species to be measured over 160' outside of the Southern Appalachians.
Not too far away grows another tall sycamore with the top of its crown long ago blown out. While hollow, a core sample with 271 rings in the outer wall showed this tree to be well over 300 years old, an elder of its kind. These stands are difficult to access except in the lowest flow periods of summer. No doubt this is why they remain so intact.
Common Name: Sugar Maple
Scientific Name: Acer saccharum
Common Name: Common Juniper
Scientific Name: Juniperus communis
Common Name: American Sycamore
Scientific Name: Platanus occidentalis