March 5^th                   “ Caldwell Colossus”            Caldwell Fork, NC, GRSM

March 31^st                 “Cheoah Hemlock”              Ammons Br. , NC, Wright Tract

April 27^th                    “Winding Stair Loner”          Winding Stairs Br., NC, GRSM

May 17^th                     “Woolly Mammoth”              Kalanu Prong , TN , GRSM

May 18^th                     “Tom’s Tower”                       Lowes Creek, TN, GRSM

July 16^th                     “Jim Branch Giant”              Jim Branch, NC, GRSM

September 9^th           “Yonaguska Hemlock”        Winding Stairs Br., NC, GRSM

September 14^th         “Rough Fork Hemlock”       Rough Fork, NC, GRSM

December 17^th          “Dunn Creek Hemlock”      Dunn Creek , TN , GRSM

December 18^th          “Buckeye Creek Hemlock” Buckeye Creek , TN , GRSM

Monocular

We used a monocular to measure the volumes of two of the ten tallest known
eastern hemlocks. Those trees, the East Fork Spire and Ellicott's Rocket,
both grew in a formerly spectacular grove on the East Fork of the Chattooga
River in the Ellicott Rock Wilderness in Sumter National Forest, SC. This
grove had five trees over 160' tall and was fully infested with HWA in 2004
(HWA was discovered in this grove in December, 2001). We returned, expecting
total mortality, but were surprised to see some trees looking quite healthy,
although heavily reinfested with HWA. Three of the tall trees were dead,
including the second tallest, the East Fork Spire. We chose to use the
monocular on the two tallest trees since they were young and exhibited no
complex structures. Error would be minimal due to excellent visibility,
consistent trunk taper, and a presumably round stem cross-section. Also,
climbing the dead and breaking up East Fork Spire was not a safe option!

Plots

We have found a great deal of variation in the vegetation plots surrounding
the target trees. The closest thing to a common denominator would be the
presence of rosebay rhododendron and mountain silverbell in or around all
plots. Distance to surface water varies considerably. The trees in crown
contact with the target trees are typically much shorter. Age of surrounding
trees and basal area vary widely, as does diversity of trees and shrubs in
the plots. Incidentally, we have now measured 1,912 shrubs in the shrub
plots, of which 1,207 were rhododendron!

Tall trees

2006 began with 24 eastern hemlocks known to reach or exceed 160'; fifteen
within GRSM[1]. Considering a sample population of several hundred measured
over 40 combined years of intermittent ENTS searching, this is a small
percentage. The dedicated searching of the Tsuga Search has allowed for more
time and focus on these forests, yet by November the number of 160's had
only grown to 27 trees. But in one memorable December day on Big Fork Ridge
in Cataloochee, this number jumped by five to 32 trees over 160'!. Even more
exciting though was the discovery in this grove of one slender tree that
appears to exceed 170'- a height threshold that although arbitrary, has been
regarded as the "Holy Grail" for eastern hemlock height measuring. Three
separate laser height measurements average 171.6 feet. If so, this will be a
new record height for the species. Unfortunately, this tree and the other
160 footers surrounding it are dead or in such exceedingly poor condition
that treatments for HWA are likely futile. We intend to climb it in early
2007 before it breaks apart. Due to its exceedingly slender trunk we have
named this tree "Yuhgi" (yuh-ghee), which is Cherokee for "needle". It will
be by far the smallest tree in the project in terms of volume. Table 1 lists
the ten tallest known trees as of 12/31/2006 and how they were measured.
Some volumes are estimated:

Table 1:  Tallest known eastern hemlocks December 2006.

Big trees

The crowning event of the 2006 large tree discoveries was the climb of the
Cheoah Hemlock on March 31st, 2006. This tree was significant in many ways,
not the least of them being a new record volume of 1564 cubic feet! The
climb of this tree included the first application of the "frame mapping"
technique described in the October 2006 Tsuga Search Progress Report. The
technique proved extremely successful and was later applied to two more
trees. We were shocked that a tree outside of GRSM and at over 3800'
elevation would snatch the title of the biggest hemlock away from the park.
Climbed just a few weeks before, the 1385 cubic foot Caldwell Colossus was
the previous title holder.

The Cheoah Hemlock, with its huge, multi-forked and reiterated crown, was
far larger in volume than the next biggest, and seemed free from challenge
by a larger tree. However, Jess had a big hemlock in his notes from a
Greenbrier, TN trip in 2004. This tree near Laurel Branch had dimensions
warranting a visit and a monocular estimate of volume. The solid 18 foot
girth and impressive height of 153' quickly grabbed our attention. The
monocular estimate indicates this tree may contain nearly 1600 cubic feet of
wood! If so, the Smokies will once again lay claim to the largest known
eastern hemlock. Fortunately, being in relatively good vigor, this tree can
recover and will be treated this winter. Rain thwarted a scheduled climb in
late December, but it is high on the priority list for 2007. Regardless of
its actual size, it is a new National Champion and will be nominated to the
National Register of Big Trees.

Our initial hope of locating ten trees over 1300 cubic feet was beginning to
feel too ambitious. The more we learned about hemlock sizes the more we
realized that a 1300 cubic foot tree is HUGE. The trees we were scouting
with the monocular were typically 1100-1200 cubic feet. 1300 cubic feet was
elusive. Now, at year end, we have reconsidered since the tenth largest tree
is the 1262 cubic foot "Woolly Mammoth", and the one others under 1300 cubic
feet fall shy by only six cubic feet. Hemlocks 1300 cubic feet or larger
still appear to be very rare, but based on the success of this December,
more are bound to be found.

In fact, December alone yielded three trees scaling ~1300 cubic feet or
more. This resulted in three previously climbed trees dropping off the "top
ten" volume list. One of these trees, with a girth of 18'10", is a new girth
record for a living hemlock in the Smokies. One snag off the Gabes Mountain
Trail was measured to 19'1" in girth, and would have been one of the largest
hemlocks if still standing.

As data mounts, we anticipate having more than 30 trees climbed by next
fall. This will result in a HUGE dataset for eastern hemlock in GRSM and a
few sites outside of the park. At this time GRSM contains nine of the top
ten trees in volume and eight of the top ten trees in height. It appears
likely that only two trees will provide a "two for one special" with regard
to being both a top ten large and tall tree (asterisked below). However,
with more finds next year one of these trees may drop to a lower position
and out of the ranking. Table 2 is the current ranking of the largest trees:

Table 2:  Largest known eastern hemlocks December 2006.  

Achievements

2006 was a monumental year for not only eastern hemlock finds but also field
methodologies we have developed, and the commensurate refinements of our
search image. We can claim the most accurate volume and height estimates for
eastern hemlock ever collected. This is due to the techniques described in
our Tree Measurement Protocols of the Tsuga Search Project, submitted in
September 2006. Below are some highlights:

Frame mapping

The most revolutionary new technique, frame mapping, has allowed for very
accurate examination of the fused trunk sections and greater accuracy in the
volume calculations. Its application on previously climbed trees has changed
the ranking of the big trees and allowed for an accurate determination of
the immense wood volume in the Cheoah, Yonaguska, and Dunn Creek hemlocks.

Monocular interpolator

The monocular technique described in the February 2006 Tsuga Search Progress
Report has been further refined by Jess' creation of an interpolator for
"missing" distances. Formerly, we had to get a lasered distance to every
point on the tree that we measured with the monocular scale. Intervening
tree branches and limbs on the target tree often did not allow an accurate
distance to be taken even though the trunk was visible to the eye, and thus
we were limited in the number and selection of suitable measurement points.
Now, with just two points measured on the target tree - the top and a basal
reference - we can interpolate the distances to other obscured portions of
the tree by using the angle to the selected spot. The interpolator program
is based on an assumed straight trunk between the measured points. The
result is more measurements are taken in less time.

Base mapping

The sinuses, bulges, and other convolutions associated with roots emerging
from the base of a trunk on a slope greatly complicate the calculation of
the large volume of wood at the base of a tree. We have been selecting a
point above the trunk flare that we feel would best represent the volume of
the portion of trunk from there down to the midslope point. This shortcut is
employed due to the complexity of the lower section and to expedite the
remote field efforts. However, our western advisor, Dr. Robert Van Pelt,
felt we were introducing significant errors by ignoring the base. After all,
we went to extraordinary efforts in the aerial portion by employing the
frame mapping technique.

In response to Dr. Van Pelt, we started to take some basal measurements
using a modified version of the frame mapping technique. To date we have
only mapped a handful of trees. This is primarily because the process is
terribly tedious, time-consuming and disturbs the area around the base of
the tree. Our intention is to gather more data (selecting dead trees when
possible) and develop a regression curve to apply to the climbed trees.
Tearing up the soil around the target trees poses an especially great
problem since the insecticide is applied to roots near the trees' bases.
Based on the mapped trees so far, our standard shortcut has both under and
overestimated the wood in the lower trunk, but has never changed the final
volume more than a fraction of a percent.

Special thanks

In addition to those listed in the October Progress Report, we would like to
thank the additional NPS staff members who have helped with the vegetation
plots and treatments of these great trees. Also, great appreciation goes to
those individuals who have donated funds to the project, including the great
ENTS webmaster Ed Frank and ENTS co-founder Robert Leverett.

The Tsuga Search and climb of the Cheoah hemlock was written up in the
September/October issue of Blue Ridge Country Magazine (Volume XIX Number
9/10). Author Elizabeth Hunter is a great ambassador for hemlocks and a loud
voice for us that reaches untold thousands of people through her work and
dedication to documenting the plight of our hemlocks.

_____

[1] Two trees previously listed over 160' were climbed in 2006 and
discovered to be just under 160' tall.