Basswood Bark - photo by Ed Frank

Basswood Leaves - photo by Ed Frank

Basswood (Tilia Americana). Most people can not identify basswood. It
is an unremarkable tree known more for the fact that its wood is soft
and easily carved than for any other reason. My mission today was to
collect a cross-section slab or a “cookie” from a downed basswood tree
that had fallen across the Slippery Rock Gorge Trail in McConnell’s Mil
State Park in western Pennsylvania. Three of us were on the trip,
myself, Carl Harting, and Anthony Kelly. All are members of the Eastern
Native Tree Society (ENTS). The tree had fallen around five years ago
and park employees had used chain saws on the log to clear the path for
the trail. Last summer on a measuring trip to the area we paused and
counted the rings on the exposed chain-sawed end of the tree, At 19.2
feet above the base of the tree we counted 178 rings. All the rings
were close together, growing with even finer bands near the outer bark.

Downed basswood log - photo by Ed Frank

The question we ask ourselves was how long can basswood live? Nobody
really knows. It is generally thought of as a short lived tree reaching
maybe 100 to 150 years old. Here was a specimen that was much older
than that. A search of the International Tree Ring Database found no
listings for American Basswood, nor were there any listings in the
OLDLIST or the Eastern OLDLIST tree ring databases for the species. Dr.
Neil Pederson, a dendrochronologist from Eastern Kentucky University
emailed me some additional information: “My class did core a basswood
this fall that was solid, believe it or not. I recall the age was in the
180 yr range. It has not been crossdated, so will not be listed anywhere
any time soon. I hope to go back with another class next fall. Perhaps
we can pick up a new age then. But, no, I haven't found any [published]
ages.”   The more I thought about it the more interested I became in
this particular dead tree. I applied for a permit from the PA DCNR to
collect a section and received approval. After a number of delays,
today we were finally going to get the specimen.

photo by Ed Frank

photo by Carl Harting

Carl, Anthony, and I met at the main parking lot at McConnell’s Mill mid
morning, consolidated vehicles, and drove over to the jumping off point
for the hike. The hike started a half mile or so back from back from
the edge of the Slippery Rock Creek gorge. I borrowed a long crosscut
saw and a peavey for the trip, so we loaded up and hiked to the bottom
of the gorge. It was a bright sunny day. The leaves were out on the
trees, but still retained some of the spring colors. Mayapple flowers
and violets lined the path through the forest. Anthony, Carl, and a few
others have been working at documenting the giant trees in the park for
several years. Five species found in the park are either the tallest of
their species known in Pennsylvania or in the entire northeastern United
States. An American basswood in the immediate vicinity of the downed
tree, at 127.1 feet tall, is the tallest accurately measured specimen in
Pennsylvania and is within a half foot, effectively tied for the tallest
measured for the species.

photo by Carl Harting

The cookie was between 28.5 and 31.5 inches in diameter without the bark.  The bark would add another 1.5 inches to the diameter - photo by Ed Frank

The fallen tree looked bigger than I remembered when faced with the
prospect of cutting and removing a cross-section. After five years there
was some decay on the tree and its upper surface was covered by lichens
and moss. The bottom of the gorge was distant from the outside world.
The water rushed in the creek a few feet away, the wind blew through the
trees, birds were singing, and a cardinal was flitting among the bushes
on the edge of the creek. The original plan was to remove a short
section from the exposed end of the tree where it had been cut to clear
the trail. However, the end of the tree was beginning to decay, so I
opted to cut a section from the intact trunk seven feet above the base
of the tree. Carl, Anthony, and I took turns pairing up on the
cross-cut saw and fairly quickly we had cut a 2 inch thick “cookie” from
the soft wood. The sawdust smelled sweet in the warm spring air. The
slab was beautiful. The center point of the tree rings was slightly
off-center from the edges. Different ring widths could be seen
throughout the life of the tree. Wider rings marked periods of quick
growth, likely when the area was more open, and finer rings marked
periods of slower growth. Anthony did a quick field count of the rings
and conservatively counted 187 rings. That means this tree first
sprouted around 1815.

photo by Ed Frank

Now the big problem – getting the cross-section back to my van. I had
stupidly not thought to bring a dolly or anything else to help carry the
slab. Taking turns we briefly carried and mostly rolled the specimen up
out of the gorge and back to the van. This was a strenuous process and
I must salute my fellows on their superhuman efforts. I am sure they
moved the cookie far greater distances than I. As we made our way back
to the vehicles the estimate of the weight of the cross-section went up.
Later I found the weight to be 71 pounds. Eventually we reached the
vehicles, loaded the cross-section, went our separate ways, and I
headed home. The section was not any worse for the wear of the long
roll up out of the gorge. The plans at this point are for me to sand the
cross-section with progressively finer grit sandpaper. This will enable
a more a more accurate ring count and I will able to obtain a truer age
for the specimen. After this preliminary processing the sample will be
sent to Dr. Pederson for further examination.

Of the three hundred fifty species of trees found in the eastern United
States, perhaps four dozen have had any cross dating. Most people doing
tree ring research, and there are only a few in the United States, are
interested in determining the history of a particular site, so obviously
they select the trees with the longest life spans. Generally seven or
more core samples are required from an area to do cross dating. This
process involves comparing the differences in ring widths among the
specimens to determine if there are rings missing, or if there are extra
rings present in individual samples. Then a composite corrected tree
ring sequence is compiled from the samples. It is much more accurate
than simple ring counts of specimens. The shorter lived trees, like
basswood, are only sampled occasionally and the results are rarely
published as there are seldom enough samples collected to do cross
dating.   Even for the species for which there are cross dated tree ring
sequences, these sequences in many cases do not include the oldest
specimens for a species, or provide information on the maximum ages that
a species can reach. Given the general lack of information on the
maximum ages various tree species can reach, efforts like this
collection of a single sample of an individual old tree can help fill in
the gaps in our knowledge of this species and of the area in which it
was found.

I will be taking the sample to Dr. Pederson in mid-June when I attend
the First Kentucky Old-Growth Conference. There are some really old
basswoods in the park. Likely several older than the downed one we
sampled. It would be an ideal place to do a series of cores and develop
a cross dated reference for the species, but I don't think we can find a
dendrochronologist to undertake a more detailed analysis.

Edward Forrest Frank

After we parted ways at 5:30 or so I went back to the park and walked a part
of the Slippery Rock Gorge Trail that I hadn't been to for about two years
-- before I had my laser  or much experience spotting old trees.  I went
from the covered bridge down to almost Eckhert Bridge.  I came across many
more old basswoods a ways down stream.  I also found a number of
old-looking, though not very large hemlocks.

I also walked a ways along the rim of the gorge downstream from the log
cabin that sits on top of the gorge above the covered bridge.  I found yet
another chunk of private land that dips down into the gorge that has
recently been logged, I'd say about 5 or so years ago.  A number of nice old
trees were taken.  I found one old hemlock stump with lots of really tight
rings.  After hauling that cookie out of the gorge and up to your van, I was
too spent to sit there and meticulously count all its rings. There were a
number of other stumps whose rings I'd like to count.  That will have to
wait for another day.

Tony

The other Basswood on the list is at the Awbury Arboretum in Germantown.  It too is a multistemmed trunk, planted tree from the late 1800's.  No one has ever submitted a large single stem to the list to my knowledge.  I would like to have one listed to show max height and forest habit.

Sw

-------------- Original message --------------
From: "Edward Frank"

Scott,

 

What can you tell me about the National Champion Basswood? http://www.pabigtrees.com/trees/species/tilia_basswood_linden.htm  from the photo it looks like a triple tree with several midgets used for scale.  We were just down at McConnell's Mill State Park Yesterday and cut a cookie from a downed basswood that had fallen across the North Country Trail.  It looks to be about 190 years old.

 

Ed

An interesting adventure, can't wait to hear the results of the
aging. Field count verses lab.   

Larry