Hello Dr. Trout;
                
Sorry to take this long in trying to answer your questions but simple questions do not always have simple answers, and time to discuss all these things is in short supply also, but the work to solve these things is important, so we try to keep working.
                

I asked some of the researchers at the Allegheny National Forest Lab for their knowledge on stripped maple and acid soils and below are some of their comments.
                
My comments are that if no acid rain had ever fallen and if no acid soils were a problem there would still be cases of over browsing and of selective browsing by deer.  

For years I have seen stripped maple thrive in areas and also seen stripped maple over browsed in areas. These are in areas of the same ph for miles around in McKean County.  

pH differences seem to make little difference in stripped maple abundance, while deer browsing does impact it.  I saw this when deer were kept inside inclosures.
Inclosures with high deer densities and even with deer starvation had heavily browsed stripped maples but some of it withstood the heavy browsing and still had thick stands of stripped maple and almost no other young trees or shrubs, wildflowers or vines.

Yet on the same soil pH site in the very same area many other trees, shrub, wildflowers and vines made a comeback with no pH increases by only having less deer on them, and the stripped maple thrived along with a variety of other plants.
                

I do believe acid rain and acid soils do contribute to changes and to problems in forests and affect what grows and what does not grow.

However, in many sites where the soils is acidic in Elk and McKean County even the plants that do well in acid soils such as Mt. Laurel,Rhododendron, white pine , hemlock , and aspen are browsed so heavily they disappear from the forest regeneration.  

Then we put up a fence and these same plants start to come back, and in places , even thrive, in these same acidic soils.  

In areas that are not fenced, but some factor lowers the deer population such as harvests or low reproduction, etc, we see the same thing.
                

So, even though we believe that acid rain has bad effects on the soils, trees and environment, we also see where deer browsing impacts can be heavy also, even on plants that do not seem to have any soil problems.

If one starts to look at other states that have little acid rain and much higher pH soils, they still find examples of over browsing by deer.

State like Wisconsin, Minnesota, and Arizona come to mind.
                

I hope this will help others understand that here are many factors, including deer browsing, that are being studied and learned about.
                

That's all for now, some comments from others below.

John P. Dzemyan
PGC Land Manager

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Comments from: Some personnel from the US Forest Service Research Lab near Warren, PA visited some sites in the Catskills in the early 90s, looking for sites for a potential deer study that ended up not starting.

Upon their return, they shared the information that in the Catskills, people were reporting that where striped maple thrived, that was an indicator of low deer impact.

We were only somewhat surprised, as we'd often described deer preference as a little bit like human preferences at a buffet table - what deer prefer is a function in part of what choices they have.

In almost all the sites we've worked in in Pennsylvania, striped maple is moderately well-preferred, but extremely resilient.

Even where striped maple is very dense, one often observes that it has been browsed repeatedly, but it survives pretty heavy browsing pressure.

Again, in the sites we've observed in Pennsylvania, oaks -- from acorn through seedling - are both at least equally preferred and less resilient.

The possible exception is oak seedling plants that have in some way developed a very strong root system, at which point their resilience to browsing appears to improve. this creates a pretty complex situation - in our study of liming effects on forest regeneration on the Susquehannock State Forest, for example, in the early years, striped maple was both more abundant and taller inside the fence.

But as the complex interactions of preference, resilience, and plant species competition worked themselves out, with deer more successfully removing other species, striped maple became the dominant species outside the fences, to a statistically significant extent.

On the other hand, we have little evidence that striped maple is in fact benefited by acidic soils.

The only study to that effect that I know was a 6 day study in foam cups at Penn State in 1994 (Demchik, M.C; Sharpe, W. E. 1999.

The effect of calcium/aluminum ratio on root elongation of twenty-six Pennsylvania plants.

In Sharpe, W.E.; Drohan, J.R. eds. Proceedings of the 1998 PA Acidic Deposition Conference, Vol 1. Environmental Resources Research Institute, University Park, PA).

In the same long-term study, where 10 tons per acre of dolomite limestone were added to forest soils, no measure of striped maple showed any response to the resultant changes in soil chemistry in either the short run (the first three years, 1986-1988) nor in the long run, looking at the forest 15 years after the lime was applied.

These results have not yet been published, but the publication is "in process" literally as I write this e-mail.

I hope that this is helpful to the participant in Dr. Trout's discussion.
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--Last edited by Dr Trout on 2007-08-22 14:28:16 --