The following information is from Stepping Stones Volume 14.3.

When Lumber Was First in Warren County by Bruce A. Smith

Rich stands of hemlock along the Tionesta Creek initiated a timber exploitation, which in the relatively brief span of 75 years, brought about the final and complete depletion of Pennsylvania’s last virgin forest.

A prime factor in this activity stemmed from the need for tannin, an organic chemical used in leather manufacture. This substance, so richly present in hemlock bark, was a most prized resource to the tanning industry. Greatly assisting movement of leather manufacture into the area was the completion of the Philadelphia & Erie Railroad, east-west through Sheffield, in 1864.

Webb and Walter Horton, tanning industrialists, came to the Sheffield wilderness in 1864 and immediately began the purchase of hemlock forest land. The tanning company property eventually extended from Kinzua country to as far south as the Clarion River and, of course, encompassed most of the area that is now the Allegheny National Forest.

Tannery production set up an insatiable demand for hemlock bark in vast quantities. Records divulge that the Tionesta Tannery in Sheffield, an average-sized plant, processed 8,500 cords of bark per year in production of leather, a rate approximating 29 cords each working day. This rate of consumption may have gone as high as 50 cords per day for some tanneries. With the average tree yielding one cord of bark, the number of trees required to supply this tannery for a full working year comes to the sum of 15,000. Most tanneries, however, operated intermittently, thereby rendering it difficult to come to an exact bark consumption figure. Nevertheless, the fact that there were six tanneries within the immediate Sheffield neighborhood lends evidence of rapid forest diminution.


Hemlock “bark peeling season” occurred during the period of sap flow, from early spring to mid-summer, depending considerably on weather conditions. Bark was removed from the trees in four-foot two-inch lengths, seasoned for a time, and then transported to tannery sites for storage. Bark storage stacks typically extended several hundred feet. The bark was built up to a form of gabled “roof” on which the final layer of slabs was placed in the manner of shingles to provide rain run-off. Storage was in quantities that anticipated production needs for the ensuing year.

In the earlier time of little regard for hemlock lumber, after bark removal, nothing further was done with the grounded trunk. Harvesting trees for bark only was referred to as “slash cutting.”

Transportation of bark from the wood in the amounts required presented to tanners a problem of great magnitude. This transportation was, at first, accomplished through the media of horse-drawn sleds. To provide suitable grade for these sleds, planks were sometimes laid on earthen roads over considerable distances. One such grade reached eight miles from Sheffield through Saybrook into Cherry Grove country. West Main Street of Sheffield is still occasionally referred to as “Plank Road.”


Courtesy of the Warren County Historical Society