July 12, 2009 - Today I revisited Marion Brooks Natural Area in Elk County, PA.  I first visited the site on January 1, 2009 and posted about it to the ENTS list:  http://www.nativetreesociety.org/fieldtrips/penna/20090101-marionbrooks/marion_brooks_natural_area.htm.  In the latter part of the 1800’s the entire region had been logged.  By around 1912, the area was a wasteland of barren and eroding hills.  Repeated fires took place among the branches, brush,  and tree tops left behind after the logging operation. These frequent and intense fires burned across the area and devoured even the organic materials in the soil, leaving behind a mineral soil with virtually no organic content.  It was in this soil that a few pioneering species, like paper birch were able to establish a foothold, where nothing else would grow.  As a result of these fires the area is today occupied by an almost pure stand of paper birch (Betula papyifera).

 

 

 

The view that greeted me today was far different from that scene in January.  In the midst of winter the vista was one of stark white tree trunks growing from little clumps extending across the hilltop.  Today the white trunks were topped by masses of green leaves.  The floor of the woods was covered by a carpet of green bracken and blueberry.   It is a place whose face changes dramatically with the season.  I need to return in the fall when the green leaves turn to yellow.

 

 

On the initial trip I measured nine species of tree in the ten to twenty acres immediately adjacent to the parking area.  This was the purest section of the paper birch stand I found.  One species that was reported to be present was Serviceberry (Amelanchier arborea?).  I could not be sure of the identification in the winter.  Serviceberry was indeed present and red berries were growing on the trees.  Overall in the purest stands around 90% of the mature trees present were paper birch. 

 

Small serviceberry tree - photo by Edward Frank

 

Patch of sassafras trees - photo by Edward Frank

 

Beyond that the most common trees present were sassafras (Sassafras albidum) and serviceberry.  I was surprised at the number of sassafras present.  It usually is not that common of a species in the forests around here.  Sassafras was also commonly present in the shallow herbaceous layer.  Other trees that were relatively common were red maple (Acer rubrum), red oak (Quercus rubra), and witch hazel (Hamamelis virginiana).  Scattered small white pine (Pinus strobus) grew here and there.  Less commonly found were black cherry (Prunus serotina), white oak (Quercus alba), and pitch pine (Pinus rigida).  I found a single cucumbertree (Magnolia acuminata) just as I was leaving.  There were no hemlock (Tsuga canadensis) present in the area of the purest paper birch, but some specimens were located nearer the edges of the stands.  Small Norway spruce starts were present here and there, likely seeded from some large specimens along the run below the site.

 

Low sweet blueberry on the left and common bracken fern on the right - photo by Edward Frank

 

The herbaceous layer is similarly depauperate with only four species commonly found there.  Across the entire site is a two foot high mass of common bracken fern (Pteridium aquilinium).  In most of the area there also are blueberries.  The Elk County Natural heritage Inventory identified them as low sweet blueberries (Vaccinium angustifolium). There does seem to be two distinct sizes of the bushes, and I am not sure if these represent two separate species of blueberry or not.  Also common on the forest floor under the bracken ferns are teaberry (Gaultheria procumbens?) Also present in some areas are numerous sassafras shoots rarely more than a couple feet tall.  Around the edges of the site are also found some mountain laurel (Kalmia latifolia).  The largest was just over ten feet tall and 8 inches in girth.  Most were much smaller.  A wider variety of other herbaceous species were reported present in the swampy area along Page Run below this portion of the site. These areas were not investigated this trip. 

 

 

 

The overall distribution pattern of the trees is very patchy. The cluster of paper birch near the parking area occupies about 10 acres.  Surrounding this area dominated by paper birch are areas of trees where oaks and maples are more common and generally larger in size. In other areas the ground is open with only an occasional tree.  These are generally occupied by blueberries and to a lesser extent by bracken ferns. 

 

Open area with a carpet of blueberry and bracken fern and a hawthorn tree - photo by Edward Frank

 

In the large open area approximately 600 feet north of the parking lot there are some hawthorn trees growing in the open amongst the blueberries.  In the areas where the paper birch is dominant, the trees are generally more stunted than elsewhere.  All of the trees in the area are generally undersized because of the poor soil; it is just that some areas are more stunted than others.   On a broader scale there are clusters of nearly pure paper birch scattered here and there separated by bands containing larger numbers of other species. 

 

On this trip I completed a Rucker Height Index for the birch stand adjacent to the parking area.  The RI value of 63.36 reflects the stunted nature of the trees in the area and the general lack of diversity overall.  Previously I calculated a RI for a larger portion of the site that included areas of less stunted trees, but it was still only 72.77 with taller examples of pitch pine and white pine replacing the shorter examples from the birch dominated stand.  I am sure a broader exploration of the natural area would lead to some marginally higher numbers, but the RI will still reflect a generally short forest.

 

Rucker Index

Number	Name	Species	Girth	Height	Date	Measurer	Method
1	Northern Red Oak	Quercus rubra	7' 11"	80.15	1-Jan-09	Edward Frank	ENTS
2	American Beech	Fagus grandifolia	2' 11"	57.03	1-Jan-09	Edward Frank	ENTS
3	Black Cherry	Prunus serotina	5' 3"	81	1-Jan-09	Edward Frank	ENTS
4	Sassafras	Sassafras albidum	3' 11"	58.56	1-Jan-09	Edward Frank	ENTS
5	Red Maple	Acer rubrum	6' 6"	85.03	1-Jan-09	Edward Frank	ENTS
6	White Pine	Pinus strobus	3' 9"	35.08	1-Jan-09	Edward Frank	ENTS
7	Paper Birch	Betula papyifera	3' 10"	74.83	1-Jan-09	Edward Frank	ENTS
8	Pitch Pine	Pinus rigida	2' 9"	36.43	1-Jan-09	Edward Frank	ENTS
9	Serviceberry	Ameliancher	2' 6"	54.52	12-Jul-09	Edward Frank	ENTS
11	White Oak	Quercus alba	4' 10"	71	12-Jul-09	Edward Frank	ENTS
	Rucker Height Index			63.363
10	Mountain Laurel	Kalmia latifolia	8"	10	12-Jul-09	Edward Frank	ENTS
12	Cucumber Magnolia	Magnolia acuminata	na	~40	12-Jul-09	Edward Frank	ENTS
13	Witch Hazel	Hamamelis virginiana	11"	16	12-Jul-09	Edward Frank	ENTS

 

I am unsure of the history of human utilization of the area after the initial logging operations and subsequent fires.    There was some activity as evidenced by old overgrown roads leading off from the current roads.  There are some patches of Norway spruce and European larch along Losey Road where it crosses Page Run.  However I believe this human utilization was limited.  The soil is so poor that farming was unlikely to have taken place.  Perhaps there were some hunting camps, or some cattle grazing taking place in some areas adjacent to the natural area. 

 

Multitrunk paper birch trees - photo by Edward Frank

 

The paper birch trees are mostly splaying multitrunk clusters of trees.  This likely indicated that after the paper birch first sprouted after the initial wave of intense fires, another fire took place.  This second fire was less intense but burnt the newly growing paper birches off at ground level.  Afterwards they resprouted from the surviving roots forming these multitrunk clumps.   Some reports have suggested that the paper birch are dying out as they are reaching the end of their natural life spans.  There are open areas within the paper birch dominated area where birch trees have died and fallen.  There are fallen tree trunks on the forest floor.  I do not believe that they are dying because they are reaching the end of their normal life span.  There is the normal thinning of the trees over time.  Some are dying for a variety of reasons.  It is also common for individual trunks in a multitrunk clump to be lost over time as the other trunks become more dominant.  Many of the larger trees seem completely healthy.  There are single trunk trees growing that also appear to be doing well.   

 

The problem seems to be not that the paper birch colony is dying from ld age, but that they are not being replaced by younger trees.  Indeed none of the trees currently growing regardless of species are being replaced by younger trees.  Most of the trees in the stands are in the 80 to 100 year old rage.  The youngest trees growing I would guess are at least thirty years old.  Given the stunted nature of the trees overall they could even be older.  What would normally be the sapling “layer” of the forest is generally empty.  What trees that are present are some serviceberry, some sassafras, and witch hazel and these for the most part appear to be mature if small trees.  I do not know what has changed and why the trees are not being replaced.  Clearly they grew initially after the fires creating the forest seen today.  Why are they not sprouting new trees today?  Could it be because of the dense layer of bracken ferns and blueberries?  Could it be over-browsing by deer? Something different is happening, I just do not know what.

 

Fat witch hazel trunks for a cluster - photo by Edward Frank

 

Pitch Pine trees are quite common in the area outside of the paper birch stands, mostly in the 50 to 60 foot tall range.  Within the paper birch stands they are absent or relegated to the very edge.   Witch hazel is present in some areas.  One specimen may be ten years old or so, but many of them appear to be older.  One cluster had several stems in the 8’ to 11” girth range, which is quite large for the species in this area. 

 

 

Blueberry - photo by Edward Frank

 

Hawthorn leaves - photo by Edward Frank

 

Hawthorn was present in the open area north of the entrance patch of paper birch.  There were several trees.  They were not measured but were in the 4 to 6 inch diameter range and 15 to twenty feet tall.  It is a different species than the dotted hawthorn we have been finding along the Allegheny and Clarion Rivers.    It has a much broader and deeply toothed, double saw-edged leaf.  Hawthorns species are difficult to distinguish.  It is definitely Crataegus, and my best guess as to species would be Fanleaf Hawthorn (Crataegus flabbelatta, also listed as Crataegus macrosperma.).    

 

Bear oak? - photo by Edward Frank

 

On the closer view air photo of the site provided by MapQuest.com, Losey Road crosses Page Run in the upper right hand corner just below a sharp 90 degree bend in the road. A hundred yards past this point there is a blue blazed trail leading to the east further into the Quehanna Wild Area.  This loop is to be left for another trip, but I did walk a short distance down this trail.  Again the landscape is covered by patchy forest and open areas.  There are several large single trunk paper birch, maple, and oak trees.  One bent tree 15 feet tall caught my eye as it looked different from the other oaks I had been seeing.   I have tentatively identified it as bear oak (Quercus illcifolia).  I am not personally familiar with the species but it is present  in the Scotia barrens to the south in Centre County, and elsewhere in areas impacted by the logging and fire sequence that created this landscape at Marion Brooks.  There is much more to do here. I have been concentrating on understanding what has happened in one small area of the 900+ acre natural area.  I also want to explore further along the trail leading into other areas of the Quehanna Wild Area.

 

Edward Frank

 

"The most beautiful thing we can experience is the mysterious.
It is the source of all true art and all science." - Albert Einstein