Generally, if you are talking about the smaller streams of the Allehgeny
National Forest region, even the ones that are way oof the beaten path are not
as good wild trout streams as what you would find simply by falling out of your
car into a stream to the east or south in the Potter/Lycoming/Cameron county
region.

Nobody I have talked to about this knows why, not even PA's fisheries people.

There are a lot of theories though. The region is largely capped with
sandstone with very little bedrock that has much if any buffering capacity.
There are a number of undistrubed ANF streams that hold Ph's in the mid 5's,
even at low flows.

Another thing is the somewhat goofy mineral rights/public lands policies of the
ANF that have existed since it was designated many decades ago. The public does
not hold the mineral rights to a lot of this land and episodic disruption by
timber, oil and gas ops means that few watersheds in the region go undisturbed
for any more than a few years at a time. So, there are a lot of episodic
fisheries where wells might have been drilled five years ago and now things are
healing and trout pops are on the increase and bang, in comes another drilling
op.

Having fished the region for nearly 4o years, my vote for primary depressing
factor goes to acidification and low Ph.

If it is any help, you can divide the ANF up into three drainages, Clarion
River, Tionesta Creek and all other direct tribs to the Allegheny River and
their watersheds.

The Clarion basin is by far the most acidic. Streams that enter Tionesta Creek
from the south are the next worst. Those from the north are better. The least
acid impacted are the streams of the direct Allegheny tribs group.

There are of course, some exceptions. But not that many. By and large, your
best small stream prospecting will be in the Kinzua drainage and streams that
flow to the Allegheny Reservoir.

But beyond that, drive another 50 miles east and you are into better geology
and much better fishing.

Hope this helps..