Tsuga Search introduction   Will Blozan
  May 16, 2006 18:30 PDT 

Many posts will be forthcoming regarding a project called the "Tsuga
Search". I want to take this opportunity to introduce it and set the context
for the work I am doing in the southern Appalachians.

As most of you may know, I am passionate about trees and have a particular
fondness for eastern hemlock. I spent three years working for the National
Park Service mapping old-growth hemlock forests for Great Smoky Mountains
National Park (GRSM). The project was helping resource managers prepare for
the arrival of the dreaded hemlock woolly adelgid (HWA). This tiny insect is
fatal to the eastern hemlock and threatens to extirpate it from the natural
forests in the GRSM. (HWA kills Carolina hemlock as well but that species
does not occur in GRSM.)

Well, HWA was confirmed in GRSM in 2002 and has begun its deadly march into
the old-growth hemlock forests- some of the most extensive and pristine in
the southern Appalachians. The park contains many thousands of acres of
ancient hemlock forests and hemlock is a crucial and common component of
many of the other 500,000 acres of GRSM. The devastation will be cataclysmic
in the pure hemlock forests, some of which can cover over 100 contiguous
acres. The higher elevation hemlock forests have already experienced nearly
complete loss of American beech to beech bark disease and any remaining
trees of other species will likely be physically crushed and/or damaged by
the huge, falling hemlocks. Ecosystem collapse can be expected as well as a
complete conversion to another vegetation type of yet to be determined
composition. Exotic plant encroachment will be a concern as will issues of
water quality and the viability of invertebrate, amphibian and avian

Fortunately, GRSM has a full-time and aggressive team out combating the HWA
using several tactics in an attempt to preserve some forests. The primary
control method is a soil application of a systemic insecticide that is
highly successful but somewhat costly. Foliar sprays are also employed as a
control on easily accessed sites along roads and near buildings. Biocontrol
has been ongoing for several years, with two species of predatory beetle
released that feed exclusively on HWA. Positive results have yet to be
observed from the biocontrol methods but chemically treated trees and groves
are recovering. Unfortunately, funding is tight and HWA is winning the race
to the more remote forests. Soil treatments are most effective when the
trees are in good vigor, which is not the case for most of GRSM. However, I
am confident that the treatments will make a huge impact on preserving some
forests for people and wildlife to visit and utilize in the future. I
commend their efforts and will sincerely appreciate the end result.

NPS staff has routinely drawn upon the experience of ENTS members in the
area and as such we experience a positive working relationship. Michael
Davie and Jess Riddle are particularly well-traveled and knowledgeable of
GRSM hemlock forests. My tree care company has been contracted to complete
extensive soil treatments in the backcountry of the Cataloochee District
(arguably the "epicenter" of eastern hemlock development) and as such have
the working knowledge and practical experience of large scale old-growth
hemlock preservation efforts.

My interest in big trees is obvious and I have been documenting the giant
hemlocks of GRSM beginning with my first climb of the tallest recorded
eastern hemlock, the Tsali Hemlock (169'10") in 1998. I wanted to take this
interest one step further and blend my passion for big trees with a desire
to save these trees and forests for the future. My personal mission is to
leave both a living legacy of exceptional hemlock forests for future studies
and to gather benchmark data of a species and its environment on the verge
of ecological extinction.

The recent loss to HWA of the tallest known hemlock forest ever documented
(East Fork Chattooga River, SC) hit home like a spear through my heart. I
had to do something. The window for preservation was quickly closing- I had
to do something now. Thus was born the "Tsuga Search". With the advice of
Dr. Lee Frelich, Dr. Robert Van Pelt, Bob Leverett and Jess Riddle we
proposed to GRSM a study of the superlative hemlock forests of GRSM and
other known groves of exceptional trees.

The general gist of it is: to locate, document and preserve exceptional
specimens of eastern hemlock within GRSM. Searches for exceptional trees
would be in areas known to hold good growth potential, and trees already
discovered would be relocated and measured. Vegetation plots would be
established and sampled around the trees and environmental parameters
assessed. The trees would be climbed, measured for volume, photographed and
treated with appropriate control measures to combat HWA. Core samples would
be pulled from surrounding trees to evaluate stand age and perhaps
disturbance history. The selected trees and surrounding groves would be
treated for HWA in complement to the extensive preservation efforts of the

To date, the project has been entirely funded by my company, Appalachian
Arborists, Inc. Resource managers at GRSM have just submitted a proposal for
a matching grant to offset some costs. The acceptance of this grant hinges
on the incorporation and non-profit status of ENTS, another effort in the
works. Once ENTS is established as its own entity with grant receiving
potential, the Tsuga Search and other projects proposed by fellow ENTS can
be funded. The project design can be adapted to other threatened species as

The development of the macroscope volume technique was a direct result of
the Tsuga Search, as the search for big trees naturally involves volume
determination. We performed our first entire tree test of the technique last
week. The macroscope volume was 1223 ft3 for a giant tree on eastern Winding
Stairs Branch in Cataloochee. I climbed the tree and measured it "by hand"
to 1180 cubic feet, a 3.5% difference. Jess and I were striving for ground
based estimates to be within 5% of a climb. Of course, there is no way to be
sure exactly how close the macroscope values are since the climb data are
not an exact representation either.

Jess and I delivered a poster at the recent old-growth forest conference
that summarized the findings since October 2005. I will send a progress
report to Ed to post. Check back soon on the "Hemlock Search" link on the
ENTS website for the abstract, updates and photos.

Will Blozan

May 2006