Black Moshannon State Park PA

Black Moshannon State Park, PA

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TOPIC: Abies balsamea - a southern disjunct populatiom - sort of
http://groups.google.com/group/entstrees/browse_thread/thread/55d5a418079c1999?hl=en
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== 1 of 2 ==
Date: Sun, Aug 17 2008 9:11 pm
From: "Edward Forrest Frank"

ENTS,

Today I went looking for a disjunct population of balsam fir on the southern end of its range in central Pennsylvania. I found them - sort of. The tale started with a note on the website for Black Moshannon State Park. http://www.dcnr.state.pa.us/stateparks/parks/blackmoshannon.aspx
http://en.wikipedia.org/wiki/Black_Moshannon_State_Park

Background:
Perched Black Moshannon State Park covers 3,394 acres of forests and wetlands, and includes 1992 acres which are protected as the Black Moshannon Bog Natural Area. The bog in the park provides a habitat for diverse wildlife not common in other areas of the state, such as carnivorous plants, orchids, and species normally found farther north. This bog is the largest reconstituted bog/wetland complex in Pennsylvania with the Black Moshannon Lake and the associated bogs are held behind a dam on Black Moshannon Creek, The CCC-built dam forming Black Moshannon Lake was replaced in the 1950s by the current structure. The park is atop the Allegheny Plateau, just west of the Allegheny Front, an escarpment which steeply rises 1,300 feet (400 m) in 4 miles (6.4 km), and marks the transition between the Ridge-and-Valley Appalachians to the east and the Allegheny Plateau to the west. The lake within the park is at an elevation of about 1,900 feet (580 m), and the park itself sits in a natural basin. The basin and the underlying sandstone trap water and thus form the lake and surrounding bogs. The higher elevation leads to a cooler climate, and the basin helps trap denser, cooler air, leading to longer winters and milder summers.

Black Moshannon Lake

The Hint:
Star Mill Trail: With fine views of the lake and opportunities to see wildlife, this trail travels through pines, a climax forest of beech and hemlock and an UNCOMMON STAND OF BALSAM FIR. Look for evidence of Star Mill, a sawmill which was built in 1879. (1.1 mile, 2.0 full loop, flat, hiking, cross-country skiing)

If you look on a map of the distribution of balsam fir, there are several disjunct populations trailing off along the Appalachians southward from the primary range into West Virginia and Virginia.

I wanted to see what the species looked like near the southern end of its range. Some people have looked at the populations in West Virginia and determined they may be a separate subspecies of balsam fir - a "bracted" variety, A. balsamea (L.) Mill. var. phanerolepis, more closely related to the typical balsam fir A. balsamea (L.) Mill. var. balsamea than to Frazier Fir Abies fraseri (Pursh) Poir. West Virginia Seed Sources of Balsam Fir http://ohioline.osu.edu/rb1191/1191_17.html.

I stopped at the park office and spoke to the park manager Chris Reese. My question was whether or not these were truly a disjunct natural population or a planted population that was naturalizing. The answer was that he was unsure, because different people have suggested both options. After talking to him I headed to the Star Mill Trail. The area was essentially timbered flat in the late 1800's and I expected to see second growth forest associated with regrowth from that period. I found that. The other thing that really jumped out was the large population of exotic conifers ranging from red pine plantations planted by the CCC in the 1930's to a variety of different spruces growing among a hemlock and red maple dominated second growth forest. I found some trees along the trail that were pretty good size. I measured a Hemlock with a girth of 9' 4".

Large Hemlock

This was not then only hemlock of size. It looked old, so did a number of other specimens of hemlock along the trail. They likely were spared from logging as they were not prime timber. I also found some large red oak trees one was 9' in girth and 95 feet tall, the second was 9' 9" in girth and 103 feet tall. These could very well post date the lumbering operation. There were a number of twisted but fat white pines along the trail also.

Red Oak

White Pine

I did find the balsam firs. The largest were in the neighborhood of 5 inches in diameter and perhaps 40 feet tall. The largest and oldest were in the central portion of the grove. Scattered and generally progressively younger firs were found up to 150 yards from the central portion of the balsam fir grove. Now for the kicker. The largest and oldest firs, and I am not very familiar with the age characteristics, were associated with a linear series of arborvitae of similar size. It was my impression these arborvitae had been planted along a lane. The juxtaposition of the arborvitae and the oldest and largest of the balsam firs, the fact that they were comparable in size, and the fact that the arborvitae were planted lend credence to the idea these balsam fir were also a planted population.

I searched the area for older trees and failed to find them. This group was found along the southern end of the Star Mill Trail in on a strip of land lying west of Beaver Road and an east of an arm of Black Moshannon Lake. I did find a single balsam fir on the east side of the road uphill from the site, but there were no additional seed sources uphill of this individual. The USDA Silvics Manual reports: "Seed Production and Dissemination- Regular seed production probably begins after 20 to 30 years. Cone development has been reported for trees 15 years of age and younger and only 2 m (6.6 ft) tall. Good seed crops occur at intervals of 2 to 4 years, with some seed production usually occurring during intervening years. These are about 134 seeds per cone. The period of balsam fir seedfall is long and dissemination distances vary. Seedfall begins late in August, peaks in September and October, and continues into November. Some seeds fall throughout the winter and into early spring. Most of the seeds are spread by wind-some to great distances over frozen snow-and some are spread by rodents. Although seeds may disseminate from 100 m (330 ft) to more than 160 m (525 ft), effective distances are 25 m to 60 m (80 to 200 ft) (1,11,28). Many seeds falling with the cone scales land close to the base of the tree." I would suggest that the seeds may also be dispersed by animals and birds beyond that range. In any case it certainly is feasible that the entire population was propagated from a single seed source. If balsam fir were planted in conjunction with the arborvitae, there may have been multiple sources for the current population.

The first question to my mind is how do you tell if this is a regrowth of a native population or one derived from a planted seed source? I don't know if there is a way to tell indisputably. Looking at the evidence you have: 1) a fairly young population, 2) a population that appears centered on a single area, 3) the age distribution appears to get progressively younger away from the center, 4) the species has not spread a great distance from the center, 5) the center of the population is associated with a planted population of arborvitae, 6) Superficially the arborvitae seems comparable in age to the oldest of the balsam fir.

Chris Reese told me that there was a single older balsam fir of unknown origin near another park building. I have yet to check this specimen out. Aside from this, there does not appear to be any additional balsam fir in the park. I would think if this was a native population that was reestablishing itself after being cut down, that there would be more than one locality with the species in the park. There are other, more southerly populations of the species. Clearly looking at things such as the pollen record, firs were present in the area during the end of the last glaciation. So this is within the potential range for a disjunct population. Mr. Reese told me that the district forester had concluded that this was a planted population that is naturalizing in the area. I would based upon the evidence found also conclude that this is most likely a planted population that is naturalizing on the site. A potential way to shed more light on the question is to determine the relative ages of the oldest fir present and the arborvitae. If they both date from the same time frame this would lend more credence to the idea they are derived from a planted population. Mr. Reese gave me verbal permission to core some specimens. I tried to core one specimen, but the wood was soft and plugged my corer. I decided to pursue this coring effort another time.

A second question has been bothering me about this population. If this population is derived from a planted specimen and is vigorously naturalizing in the area, should it be considered a naturalized species or a native species? Looking at the past history of the site, it supported balsam fir in the past, but I am unsure of how long it has been since the species was present. Since the species is naturalizing prolifically, it suggests that the species could exist, or even thrive there at the present time. Was the species lost from the site from a slow progression of change, or was it persisting as a remnant population that was lost in a single event? This is a prospect faced by our island pockets of preserves. If a species is lost through some set of circumstances, there may be no sources left to regrow the lost species population. So is this a case of naturalization or simply one of reintroduction of a species to a disjunct portion of its range? I know someone will post a set of technical definitions with everything spelled out, but I am wondering about the core nature of the concepts of native, naturalized, and reintroduced rather than the compromises required of most technical definitions.

Ed Frank

Miscellaneous Links on Balsam Fir:
USDA Silvics Manual
http://www.na.fs.fed.us/pubs/silvics_manual/volume_1/abies/balsamea.htm

USDA Plant profile Abies balsemea
http://plants.usda.gov/java/profile?symbol=ABBA

Balsam Fir pdf
http://www.fpl.fs.fed.us/documnts/usda/amwood/234balsa.pdf

Conifers.org Balsam Fir
http://www.conifers.org/pi/ab/balsamea.htm

Plant profile for Abies balsemea
http://plants.usda.gov/java/profile?symbol=ABBA&mapType=Large&format=Print&photoID=abba_003_ahp.tif

Nearctica - Balsam Fir
http://www.nearctica.com/trees/conifer/abies/Abalsam.htm

West Virginia Seed Sources of Balsam Fir
http://ohioline.osu.edu/rb1191/1191_17.html

http://www.fs.fed.us/database/feis/plants/tree/abibal/all.html

Pennsylvania County Distribution Map
http://plants.usda.gov/java/county?state_name=Pennsylvania&statefips=42&symbol=ABBA

Balsam Fir Thrives in State's Bogs
http://www.sungazette.com/page/content.detail/id/505706.html?nav=5013

Abies balsemea - Wilkepedia
http://en.wikipedia.org/wiki/Balsam_Fir

Conifers.org reports:

Big Tree
Height 30 m, dbh 120 cm, crown spread 14 m; in Fairfield, PA (American Forests 1996).

Oldest
A tree-ring chronology covering 245 years, presumably based on living tree material, was collected in 1996 at Lac Liberal, Canada (470 m elevation, 49° 4'N, 72° 6' W) by C. Krause and H. Morin (NOAA 1999).

== 2 of 6 ==
Date: Mon, Aug 18 2008 5:56 am
From: ERNEST.OSTUNO@noaa.gov

Ed,

Thanks for the very interesting report. All I remember about "Black
Mo" was the huge old hemlock stumps left over from the logging era,
lots of porcupines, and lots of beaver-gnawed trees near the lake.

As for Balsam Fir, have you been to Bear Meadows Natural Area? Dale
Luthringer has a nice write up on that place:

http://www.nativetreesociety.org/fieldtrips/penna/bear_meadows.htm

I also have video of Bear Meadows from 1999 that you posted on youtube
last year. The area has been studied by the PSU Forestry people, but
I'm not sure if Black Moshannon has. I am guessing not, since it was
almost totally cut over. You could ask Marc Abrams at PSU about that.

Ernie

== 3 of 6 ==
Date: Mon, Aug 18 2008 8:32 am
From: "Jess Riddle"

Ed,

What jumps out at me from your description and photos is that Black
Moshannon SP does not look like typical habitat for balsam fir at the
southern edge of the range. In New York outside of mountainous areas,
balsam fir is restricted to swamps and a few areas of thin limestone
soils. Bear Meadows in PA fits that same pattern. The Black
Moshannon stand looks fairly well drained and does not appear to have
any unusual soil conditions. Hence, the habitat also seems to
indicate the population is not naturally occurring.

Jess

== 4 of 6 ==
Date: Mon, Aug 18 2008 9:35 am
From: "Edward Forrest Frank"

Ernie,

Yes, I know about Dale's report and posted your video. I wanted to go to Black Moshannon SP because it was someplace different that had not been reported on before. The two things that stood out in the blurbs from the park were the unusual stand of balsam fir and an unusual stand of hawthorns. I did not see the hawthorns but got a good location. They really aren't that big or old according to Chris Reese, but form what is pretty much a monoculture stand of the species in one area of the park. On their species list the only hawthorn species keyed out is dotted hawthorn Crategus punctata - the same species we found in the Allegheny River Islands Wilderness. I will check it out on a future trip.

Ed

== 5 of 6 ==
Date: Mon, Aug 18 2008 9:42 am
From: "Edward Forrest Frank"

Jess,

The general area overall has been a swampy since the last ice age. The current impoundment behind the reservoir is not more than a few feet lower than the trail through the stand, and no more than a stones throw away. The area of the stand specifically appears to be well drained, and the oldest portion of the stand is upslope perhaps another ten to twenty feet higher in elevation than the trail. Without soil borings I can't really say if the soil immediately below the surface detritus is drained well or not.

Ed

== 6 of 6 ==
Date: Mon, Aug 18 2008 12:53 pm
From: ERNEST.OSTUNO@noaa.gov

Ed,

I remember there being quite a few small underground springs bubbling
up on the periphery of the reservoir. In fact I have video somewhere
of a few of them.

Also, I remember reading somewhere, maybe the park brochure, that the
water table was greatly affected by the clearcutting during the
logging era. I don't know enough about forestry or hydrology to know
if this even possible.

Ernie

== 2 of 7 ==
Date: Tues, Aug 19 2008 6:01 am
From: dbhguru@comcast.net

James,

Western New York has several counties with very low population densities. In fact, New York has an amazing amount of open space. When you consider the human zoos that have developed in the Northeast (New York, Boston, Philadelphia, etc.), the western NY countryside is just great. I love New York state, but I avoid the Big Apple and the other human termite colonies if at all possible.

Bob

== 3 of 7 ==
Date: Tues, Aug 19 2008 7:13 am
From: turner

Ed. Thanks for post on the Balsam Fir. It will energize me to visit
several of our stands in West Virginia which I have been meaning to
do. I have been told that between heavy deer browsing and HWA most of
them are not doing to well. Locally they are called Blister Pine - is
that name used in PA? Also thanks for the link to the OSU research
paper. Very informative and I had not seen it before although I was
aware that the Christmas tree growers really liked the Canaan Valley,
Tucker County, WV seed source.
TS

== 4 of 7 ==
Date: Tues, Aug 19 2008 9:05 am
From: "Edward Forrest Frank"

Turner,

As far as I know HWA does not attack balsam fir nor Frazier fir. There is a similar organism a Balsam Wooly adelgid that does attack them. The following is an excerpt from an overview/introduction to the Third Symposium on the HWA by Fred Hain:

Third Symposium on Hemlock Woolly Adelgid Presentations -Hain

BALSAM WOOLLY ADELGID: ADELGES PICEAE AND HEMLOCK WOOLLY ADELGID: A. TSUGAE (HOMOPTERA: ADELGIDAE)

It is interesting to compare the initial significance and spread of hemlock woolly adelgid (HWA) and balsam woolly adelgid (BWA). BWA was found in natural stands of balsam fir in 1908 and in Fraser fir of the southern Appalachians in 1955. Severe mortality was immediately apparent. HWA was found on ornamental eastern hemlock in 1952 or '54 in Richmond, Virginia, and was not considered a serious pest because it was easily controlled with pesticides. HWA became a pest of concern in the late 1980s when it had spread to natural stands. Since then it has caused widespread mortality. Neither adelgid is considered a pest in its native range. BWA attacks all fir species, but Fraser fir is one of the most susceptible. Usually, mature trees in natural stands are attacked, but trees in Christmas tree plantations are also attacked. The insect can be found on all parts of the tree, but it primarily infests the trunk. Old-growth Fraser fir stands are virtually eliminated, but individual trees still survive. In many cases, vigorous Fraser fir reproduction has replaced the old growth, begging the question what will happen to these trees as they approach the age of maximum susceptibility to BWA. Early research on BWA emphasized biological control. Six European predators are known to be established. They are Laricobius erichsonii (Coleoptera: Derodontidae), Pullus impexus (Coleoptera: Coccinellidae), Aphidecta obliterata (Coleoptera: Coccinellidae), Aphidoletes thompsoni (Diptera: Cedidomyiidae), Cremifania nigrocellulata (Diptera: Chamaemyiidae), and Leucopis obscura (Diptera: hamaemyiidae). However, there has been no clear demonstration that any of the predators have had a significant impact on BWA populations. Current research on BWA is emphasizing host factors. BWA presentations at this conference will deal with impacts in the southern Appalachians, host interactions, chemical composition of wood and infested bark, metabolite profiling and microarray analysis of infested and uninfested fir species, and an artificial feeding system development for both adelgid species. Unlike BWA, HWA will attack all ages of its host in natural stands and, consequently, represents a more serious threat to hemlock than BWA does to fir. Eastern and Carolina hemlock are very susceptible to HWA, while the western and Asian species are not. The basic challenge that we face is to understand why the western and Asian hemlocks are not impacted by HWA the way Eastern and Carolina hemlocks are: is it biological control, host resistance, a combination of the two, or something else? Perhaps the information presented at this conference will begin to answer this question.

Finding the status of the balsam fir populations in West Virginia and Virginia would be a worthwhile undertaking. If you visit them please report to everyone on what you find. ENTS doesn't have any accounts from these stands.

Ed Frank

== 5 of 7 ==
Date: Tues, Aug 19 2008 9:29 am
From: "Edward Forrest Frank"

Turner,

Regarding the name Blister Pine - I don't really know. I am not a forester and have never been part of the forestry or lumber industry community, so I don't know if they call it that or not. Locally the species is not present so local people really do not call it anything. They are sold as Christmas Trees and landscaping plants, but I believe they are just called balsam fir. My knowledge is from guidebooks and academic papers which call it balsam fir. So I don't really know.

Ed

== 6 of 7 ==
Date: Tues, Aug 19 2008 3:00 pm
From: Lee Frelich

Jess, Ed:

There are also balsam fir stands in Iowa and southeast Minnesota, in what
is otherwise a prairie climate. These fir stands are on algific talus
slopes with cold air ventilation throughout the summer. Behind the talus
slopes there are caves that fill with ice from groundwater seepage during
the winter, and it takes all summer for the ice to melt, allowing cold air
to seep out between the rocks during summer. These stands also have boreal
understory plants.

Most southern outliers of conifers at this time are actually not relics
from the last glaciation, but rather advanced populations form southward
migration which was in progress from about 7000 years before present until
the early 1900s. They were responding to the natural cooling trend after
the Mid-Holocene warm period. In some pollen records the conifers disappear
and then reappear in the last few thousand years. Now with global warming
tree species are moving rapidly in the other direction.

Lee

== 7 of 7 ==
Date: Tues, Aug 19 2008 3:26 pm
From: "Edward Forrest Frank"

Lee,

If they are part of an advancing front, how did they make the jump from the present boundaries of their common range to their present positions tens to hundreds of miles from the next known population to the north? In the case of Black Moshannon, I think the trees are naturalizing from a planted specimen, but there is another population in southern Centre County (I have not visited it yet) far from the populations in northern PA. There are also pockets in West Virginia and Virginia. These seem to have some significant genetic differentiation from the general population of balsam fir. This would suggest to my mind that they are an older population that has been isolated for some period of time, rather than the front line of an advancement. I am not familiar with the specifics of the pollen record, but say 12,000 years ago there was a mass of Abies sp. in PA through the southern Appalachians. Now there is Frazier Fir [Abies fraseri (Pursh) Poir] in the south, these isolated pockets of balsam fir in West Virginia and Virginia [A. balsamea (L.) Mill. var. phanerolepis] also known as Canaan Fir - a favorite among many Christmas Tree growers, these small patches in PA, and the a generally wide ranging mass that extends from northern PA into Ontario and westward to Manitoba (maybe Alberta?). How would the advancing scenario work to explain this distribution of fir pockets? Do you have some maps or diagrams you could post and references providing more details?

Thanks for the information about the fir stands in southern Minnesota and Iowa. This is the kind of unusual mechanisms I want to ENTS document. Are these populations genetically consistent with those of the general population in northern Minnesota and Wisconsin? I would love to be able to document many of the unusual assemblages of trees and plants you are commenting on from Minnesota both at the fringe of the glaciations, and on the edge of the forest prairie transition. It would be great if you could do some short descriptions of these locations with photos for the ENTS list. maybe you could recruit some additional ENTS members from out your way, perhaps among your cult followers there in Grad school.

As always I appreciate these gleanings from your forest repertoire.

Ed

==============================================================================
TOPIC: Abies balsamea - a southern disjunct populatiom - sort of
http://groups.google.com/group/entstrees/browse_thread/thread/55d5a418079c1999?hl=en
==============================================================================

== 1 of 2 ==
Date: Wed, Aug 20 2008 6:17 pm
From: Lee Frelich

Ed:

On a long time scale fir clearly was abundant across the east, including PA
12,000 years ago, and then disappeared (having moved to northern Quebec)
and came back in the last few thousand years. In MN the pattern is similar
except that fir was not as abundant 12,000 ybp, and did not a readvance,
probably because of droughts and fires, until the last 1000 years. Its
always possible that some populations persisted through the mid Holocene,
but given the rate of southward movement in the last few thousand years, it
seems likely that most naturally established spruce and fir sites along the
southern margin of the species ranges were established in the last
1000-2000 years. Not all of these sites have a sedimentary record, so there
is still a lot we don't know.

There is only one genetics paper on the topic by Shea and Furnier which
compared isolated populations in IA and MN to populations in the central
part of the range, which showed that the isolated populations have lower
diversity, which could be consistent with a recent founder effect or loss
of genes through long term isolation.

We know almost nothing about long distance dispersal by plants during
migration.

Lee

== 2 of 2 ==
Date: Wed, Aug 20 2008 6:33 pm
From: "Edward Forrest Frank"

Lee,

Thanks. I am thinking that perhaps the populations in WV and VA may be remnants simply because of the differentiation from the genetics of the population farther to the north.

The situation you describe for the populations in MN with the lower diversity is analogous to what was found in the Caribbean. http://www.caves.org/pub/journal/PDF/V60/V60N2 -Frank-Paleontology.pdf One of the consideration of diversity in Caribbean Islands was if they were slowly populated over time by animal species rafted to the island they would have a low initial diversity that increased over time. If they were part of an isthmus connected to the mainland that became separated into islands by raising relative sea level, then the initial species diversity would be high - equivalent to that of the mainland - and this diversity would generally decrease over time as species were lost.

In this case an advancing population would be established based upon the genetic make-up of the first or first few examples that reached the area. Thus a low diversity. If it were a remnant population from retreat the main body of the population then it would have a higher initial diversity in the population, and frankly it is hard to get rid of diversity without it being replaced by a genetic change that is better suited for the environment.

Ed

== 2 of 2 ==
Date: Thurs, Aug 21 2008 3:24 pm
From: "Edward Forrest Frank"

Lee,

I am interested in your opinion on the matter, so I was trying to find out what you think rather than demanding that my opinion be accepted.

The Ohio Report http://ohioline.osu.edu/rb1191/1191_1.html and http://ohioline.osu.edu/rb1191/index.html Reads:
"The taxonomy/identity of the Abies species in the eastern United States and Canada has been confusing. Taxonomists have traditionally recognized two species as being native to eastern North America. Balsam fir (Abies balsamea (L.) Mill.) has an extensive and more or less continuous natural range through Canada and southward into Minnesota, Wisconsin, Michigan, New York, and northern Pennsylvania, with disjunct distribution through central Pennsylvania and northern West Virginia and Virginia, while Fraser fir (Abies fraseri (Pursh) Poir.) occurs only at higher elevations in the mountains of southwestern Virginia, eastern Tennessee, and western North Carolina (Figure 1). The most prominent taxonomic feature used to distinguish between balsam and Fraser fir has been the relative length of the cone scales and bracts. For balsam fir, the bract is much shorter than and is fully enclosed within the cone scale, while in Fraser fir the bract is much longer than the cone scale and is exserted from the cone and reflexed downward. Attempts have also been made to differentiate between these two species on the basis of numbers of lines of stomata on the leaves and internal leaf anatomy, but individual variations make interpretations using those characteristics uncertain.

Some taxonomists have recognized two varieties of balsam fir, A. balsamea (L.) Mill. var. balsamea, the "typical" balsam fir and a "bracted" variety, A. balsamea (L.) Mill. var. phanerolepis Fern., which is distinguished from var. balsamea on the basis of the relative length of the bract and awn to length of the cone scale and by a slight variation in cone size. The range of var. phanerolepis has been identified as occurring within the range of var. balsamea at higher elevations in the mountains of the northeast, at lower elevations in Maine and the maritime provinces of Canada, as well as the small, isolated stands in the mountains of northern Virginia and West Virginia (Perry 1931, Fernald 1950, Little 1953).

Classification of the small populations of fir at higher elevations in northern West Virginia and Virginia (Figure 1) has been particularly confusing. Trees from those populations have cones similar to balsam fir as well as trees with exserted and reflexed bracts characteristic of Fraser fir and intermediate-appearing forms (Figure 2). These populations have, at various times, been identified as A. balsamea (Millspaugh 1892, Core 1934, Core 1940), A. fraseri (Millspaugh 1913, Zon 1914, Brooks 1920, Fulling 1934, Wyman 1943), and A. balsamea var. phanerolepis (Perry 1931, Fosberg 1941, Fernald 1950, Little 1953, Strausbaugh and Core 1964), while Fulling (1936) and Core (1934) suggested that they might represent a separate species, A. intermedia, which was of hybrid origin between balsam and Fraser fir.

A number of studies have attempted to clarify the status of the Abies species in eastern North America. Oosting and Billings (1951) suggested that during the most recent glacial advance (Pleistocene), spruce-fir forests extended from Canada, south along the Appalachian Mountains to North Carolina and Tennessee, with a clinal pattern of phenotypic variation within that range. Since the glacial retreat, populations have become separated and have evolved to their present phenotypic expressions. Mark (1958) proposed that as the climate warmed, fir populations at lower elevations in the southern part of the range were replaced by other species, leaving only isolated stands at higher elevations. The gap between the A. balsamea and A. fraseri populations prevented gene flow from the northern populations, resulting in a reduction in the gene pool of A. fraseri during the recent xerothermic period, with genes responsible for phenotypes similar to A. balsamea being eliminated.

Myers and Bormann (1963) studied phenotypic variation in trees of A. balsamea var. balsamea and A. balsamea var. phanerolepis in response to altitudinal and geographic gradients in cone scale/bract ratios to measure intergradation between the two varieties. Their studies found a complete series of morphological forms connecting the two, with two clines within the A. balsamea population - one from lower to higher altitudes in the mountains of the northeastern United States and one at lower altitudes from coastal regions toward the interior of the continent. Based on their data, they questioned the taxonomic validity of separation of A. balsamea into two varieties and also suggested that A. balsamea and A. fraseri represent closely related and recently separated populations. Studies by Robinson and Thor (1969) and Thor and Barnett (1974) compared various characteristics of trees from the "intermediate" populations of fir growing in northern West Virginia and Virginia with those of trees of Fraser fir from Virginia, North Carolina, and Tennessee and balsam fir from Pennsylvania and New York. They concluded that the "intermediate" populations were not of hybrid origin but rather are relicts of a once continuous fir population having clinal variation along a north-south gradient.

Thor and Barnett (1974) also proposed that only one species of Abies be recognized in eastern North America, with three varieties: var. balsamea, var. phanerolepis (including the northern Virginia and West Virginia populations), and var. fraseri.

Studies by Clarkson and Fairbrothers (1970) using serological and electrophoretic investigations of seed protein of trees also concluded that A. balsamea var. balsamea and A. fraseri are closely related and recently separated taxa and that A. balsamea var. phanerolepis (from the mountains of northern West Virginia and Virginia) is more closely related to A. balsamea than to A. fraseri and is not of hybrid origin. Studies by Jacobs et al. (1983), using electrophoretic study of seed proteins, came to similar conclusions; their study also found that electrophoretic patterns for seed of "bracted" sources from Canaan Valley, West Virginia, and Mt. Desert Island, Maine, were identical. "

This is the sum of the genetic information I have found on the internet, and as you can see much of it is older data. There may be more recent findings than these in the literature. The bulletin was published in 1999.

Edward Frank

Literature Cited
Brooks, A. B. 1920. West Virginia trees. West Virginia University. Agr. Exp. Sta. Bulletin 175. 242 p.

Brown, J. H. 1983. A "new" fir for Ohio Christmas tree plantings? Ohio Report. 68(4):51-54.

Brown, J. H. 1998. Bud break and frost injury on three sources/varieties of balsam fir. Christmas Trees. 26(2):24-27, 29.

Brown, J. H. 1998. Nitrogen fertilization of a Canaan Valley seed source of balsam fir. The Ohio State University. Ohio Agricultural Research and Development Center. Special Circular 159. 14 p.

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== 2 of 4 ==
Date: Fri, Aug 22 2008 3:30 pm
From: Lee Frelich

Ed, Ernie:

To see whether the quote by Abrams et al regarding presence of fir for the
last 10,000 years is true, I would have to see the paper they cite from
Pennsylvania Academy of sciences:

Kovar, A.J. 1965. Pollen analysis of the Bear Meadows bog central
Pennsylvania. PA Academy of Sciences Publication No. 38., pp 16-24.

The academy does not have old publications on their website, so I can't
check it, and I wouldn't take the authors of the Abrams et al paper word
for it either.

I can summarize what I think at this point by saying that for the most
part, fir disappeared during the mid-Holocene and then came back in the
last few thousand years over most of the landscape, although there is a
chance that some survived in bogs or high elevations. Its likely that the
southward march of fir from the main range swamped local expansion. This
pattern was much more exaggerated in Minnesota because climate changes are
all exaggerated due to being in the center of the continent. I don't think
there is enough genetic information yet to reconstruct what happened from
that type of evidence (such as Jason McLachlan of Notre Dame University has
done for beech).

Lee

== 3 of 4 ==
Date: Fri, Aug 22 2008 5:12 pm
From: DON BERTOLETTE

Lee/Ed/Ernie-
As a former GIS person, I recall a great resource for those wanting to check known species locations...notice that it was listed in the bibliography below, but am supplying a link for it, including balsam fir:
http://esp.cr.usgs.gov/data/atlas/little/

-DonRB

== 4 of 4 ==
Date: Fri, Aug 22 2008 9:29 pm
From: "Edward Forrest Frank"

Lee,

Thanks for the discussion on this subject. I had always heard of these populations being referred to as remnant populations from the ice ages. Now I see that it may not be that straight forward. I had been thinking the WV an VA populations were likely remnants because there had been some time for genetic differentiation. But by my own arguments, if they were part of a once advancing front, this also could have led to the genetic difference. If they were part of a limited population as part of an advancing front, with a low initial genetic diversity, then any minor variant, expression of a uncommon genetic trait, or even a favorable mutation could more quickly spread among the entire population than would be possible for a larger population with a higher initial diversity. I am not sure what to think about the issue now, but the discussion has been very instructive. As you said the genetic character of the populations, "could be consistent with a recent founder effect or loss of genes through long term isolation."

You mention the idea of "long distance dispersal by plants during migration." Perhaps that is what is needed as with global warming the plant climate ranges could be moving northward faster than the plant can follow. The presence of some long distance dispersal mechanism might be needed for the trees to just keep up.

Ed

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