Hemlocks Natural Area, 9/16/04   Dale J. Luthringer
  Jan 09, 2005 14:25 PST 
Bob, Ernie, ENTS,

I apologize for taking so long to write this post on my trip to Hemlocks
Natural Area. I’ve just been too busy with work lately to put serious
time aside to make a worthwhile effort which this site so richly
deserves. The Hemlocks Natural Area is located in the Tuscarora State
Forest of south central Pennsylvania (north of RT22 and west of
Harrisburg) along Hemlock Road near Big Spring State Park. This natural
area consists of 120 acres of mainly old growth E. hemlock in a narrow
steep boulder filled ravine about 1.5 miles long. There are also
representatives of very old black gum, tuliptree, cucumbertree, black
and yellow birch, and N. red and chestnut oaks.


Hemlock wooly adelgid (HWA) has hit this area very hard resulting in an
almost completely open canopy. I was there on a very sunny day, and
noted very little shade underneath the heavily dominated hemlock
cathedral. Forestry has released predator beetles here and is currently
involved in a long term study to monitor their effects. It appears that
some trees are hit worse than others. This is just my personal
estimate, but I think we’re looking at close to %50 mortality at this
site, if the predator beetles are not successful. Understory consists
mainly of black birch and tuliptree, with some N. red oak, red maple,
and black gum.

The largest and most impressive trees appear to be on the uppermost
section of the drainage. This is where the tallest hemlocks were
located. Impressive tuliptrees were also located in this section. The
lower section of the drainage is dominated by younger hemlocks with much
fuller canopies. Impressive black gums both in height and girth are
located here also. The tallest black gum we’ve found to date in the
northeast is located here, along with my personal best girth forest
grown specimen. I regret not getting a crown spread for this tree. It
probably would have been in the top 3 overall largest black gums
documented in the state.

I did not record heights for most of the trees due to lack of time and
the overall sensitivity of the site. Most trees were measured directly
from Hemlock Road which overlooks the steep small boulder, moss covered
ravine of this site. I easily could’ve used 3 interns down at the
bottom of the ravine to hop from base to base of each tree. I did make
an attempt to record girth measurements for the more significant big
tree finds of the day.

The day’s stats as follows:

Species                        CBH     Height   Comments

Am. basswood               N/A       83.5
Am. basswood               N/A       96.1
Am. basswood               N/A       113.4

Black birch                    N/A       75
Black birch                    N/A       94.7

Black gum                     N/A       87.5
Black gum                     10.7      96.4      personal girth record,
ancient tree            40 15.032N x 77 38.145W
Black gum                     6.3        104.2
Black gum                     8.6        109.5    tallest recorded in NE
40 15.327N x 77 37.979W

Black locust                  N/A       96.3      by road

Chestnut oak                 9.8        >80       severe crown damage,
chunky tree
Chestnut oak                 N/A       102.8

Cucumbertree                N/A       98.1
Cucumbertree                N/A       100.1
Cucumbertree                N/A       110.4
Cucumbertree                N/A       111

E. hemlock                    12.1      113.7    new 12x100 club
E. hemlock                    N/A       114.9
E. hemlock                    N/A       118.4
E. hemlock                    N/A       119.1
E. hemlock                    N/A       121.8
E. hemlock                    N/A       123.3
E. hemlock                    N/A       123.8
E. hemlock                    N/A       124
E. hemlock                    N/A       129.1
E. hemlock                    N/A       130.1
E. hemlock                    ~8        130.7
E. hemlock                    11.8      132.5    forestry study tree
E. hemlock                    9.6        134.4    forestry study tree
E. hemlock                    N/A       134.9    poor shape from HWA
40 14.404N x 77 38.469W
E. hemlock                    9.8        137.9    forestry study tree
tack#209                    40 14.160N x 77 38.618W

N. red oak                     N/A       90.9
N. red oak                     11.4      105.1
N. red oak                     N/A       105.3
N. red oak                     N/A       106.6
N. red oak                     N/A       111.1
N. red oak                     N/A       119

Red maple                     N/A       115.5

Tuliptree                        N/A       116.8
Tuliptree                        N/A       118.1
Tuliptree                        N/A       126.1
Tuliptree                        N/A       127.5
Tuliptree                        ~10.6    137.2    balanced precariously
over cliff, measured ˝ girth w/tape, multiplied x2
Tuliptree                        N/A       138

White ash                     N/A       104.1

Yellow birch                   N/A       83.1

Hemlocks Natural Area Rucker Index as follows:

Species                        CBH     Height   Rucker Index = 114.75

Tuliptree                        N/A       138
E. hemlock                    9.8        137.9
N. red oak                     N/A       119
Red maple                     N/A       115.5
Am. basswood               N/A       113.4
Cucumbertree                N/A       111
Black gum                     8.6        109.5
White ash                     N/A       104.1
Chestnut oak                 N/A       102.8
Black locust                  N/A       96.3

The Hemlocks Natural Area Rucker Index of 114.75 ranks it #7 out of 19
sites so far surveyed in Pennsylvania. I believe with more time we
could find a taller representative white ash and Am. basswood. It would
be nice to find another species taller than the black locust that I
found along the road, to kick that out of the statistics.

Well, Bob, I didn’t find any hemlock that would make it into the
prestigious 140ft class for PA here, but there were some close ones.
The tallest hemlocks were near the top of the drainage. I was
pleasantly surprised to find hemlocks in the upper 130ft class though.
I believe I measured the tallest hemlocks and tuliptrees to be found at
this site. The tall and fat black gums were definitely an added bonus.
I haven’t researched any age studies for this site, but that fat black
gum should easily go over 250 years old. I’d like to say 300+, but
these can be tricky to age and I just haven’t cored enough of them to
get a good feel for their age/bark character relationships.

Hemlocks Natural Area is in Perry County. Here is a great set of
directions. If from page 55 of Chuck Fergus’ book, ‘Natural
Pennsylvania: Exploring the State Forest Natural Areas’, copyright 2002
by Stackpole Books. I’m not sure if you remember Chuck, but he’s the
one who wrote virtually all the ‘field notes’ of every PA wildlife
critter for the Pennsylvania Game Commission. He now lives up in
Vermont… matter of fact, I just recently met him at the last ENTS
rendezvous at MTSF. He was doing a feature article on the gathering.
Sorry, I ramble… Here’s his directions:

“TO GET THERE. Drive west from Blain on PA Route 274 for 10 miles.
Turn south (left) onto Hemlock Road. After 2.2 miles, you enter the
natural area; after a total of 3.8 miles, you come to a parking lot on
the left with access to the Hemlock Trail.

From the PA Turnpike (I-=76), exit at Willow Hill and go north on PA
Route 75 for 10.9 miles. Bear right on Route 274 just beyond
Doylesburg. After 4.8 miles, turn right on Hemlock Road and follow the
directions in the proceeding paragraph.
Request a free brochure with trail map from the Tuscarora State Forest
district office.”

The Tuscarora State Forest District Office address is:

RR1 Box 42A
Blain, PA 17006


RE: Hemlocks Natural Area   Phil LaBranche
  Jan 09, 2005 18:01 PST 

       Speaking of the HWA, if the predator beetles are successful will the
Hemlocks be able to recover? Or will they just maintain the condition they
are in?

RE: Hemlocks Natural Area   Ernie Ostuno
  Jan 09, 2005 18:49 PST 


Great job, and I am sure the state forest people will appreciate your
info. Their brochure on the site (as of 5 years ago) gave the maximum
height of the tallest hemlock as 123 feet. You found one about 15 feet
taller. Not to mention that Black Gum!

The soil conditions at that site seemed better than most of the OG
hemlock sites I had visited in PA and the trees appeared correspondingly
larger and more impressive. The greatest girths I ever measured for
hemlocks in PA (both living and dead) were at that site. The soil wasn't
as thin and rocky as some areas like Sweet Root...and maybe that will
help some of the hemlocks survive the adelgid onslaught a little better
than at Sweet Root.

BTW...after a warm, rainy spell on Wed-Thu, it looks like next weekend
will finally see the Arctic air return to the NE US, and hopefully the
cold snap will do in some of those little adelgids.

Hemlocks Natural Area   Dale J. Luthringer
  Jan 10, 2005 17:22 PST 

Well, we certainly hope the hemlock will recover. A number of agencies
have spent a lot of time, money, and effort to hopefully save the
eastern hemlock from this onslaught. I believe that some have been hit
so hard by HWA for so long that they have probably used up their
reserves and will not come back even if the HWA are gone. Others may
have enough reserve left and other resources to be able to make it
through. The only thing though, is that it’s not just HWA that’s been
affecting Pennsylvania hemlock as late. Droughts, mites, and fungus all
take their collective toll. HWA is just another ‘pathogen’ on the list.

Drought, you say? Well, the last year was the rainiest we’ve had in
Pennsylvania for a long time, and the trend has continued well into
January so far. The drought problem though was before our overabundance
of rainfall, we had 3-4 years of very dry weather. Hopefully this
year’s rain will perk things up a bit for the hemlocks.

My fingers are crossed.