Proceedings
of the Fourth Urban Forestry Conference
ST. LOUIS, MISSOURI, OCTOBER 15-19, 1989
Edited by: Phillip D. Rodbell
Sponsored By: The American Forestry Association
Treating the Treaty Oak
John Giedraitis
City Forester
Austin, Texas
The Treaty Oak is a living symbol of history.
Since its poisoning early this year, the heroic efforts to save
it have proved to be the challenge of my career.
This is an intriguing story of an historic tree, its malicious
vandalism, how the art and science of forestry and arboriculture were
applied to try to save it, and how this great tree’s sacrifice can be a
message for each and every one of us.
Our Chamber of Commerce estimates the Treaty Oak to be over 600 years
old. Most foresters settle
on about 300, but once you have seen the majesty of this tree, it’s not
hard to believe the Chamber of Commerce.
In fact, the live oaks (Quercus virginiana) that grow in
the chalky, dry limestone soils around Austin have a peculiar habit of
root sprouting, that is, throwing up genetically identical clones from
the roots; given this, it is possible that its current four-foot
diameter, 50-foot height, and 90-foot spread may only be the latest
sprout off of a common root system dating back thousands of years.
Whatever its age records show that it has had important
historical associations with the residents of Texas.
Historians tell us that the Treaty Oak is the last of a grove of
fourteen trees known as the Council Oaks.
The original Texans regarded it as a Tree-God, a temple of
worship for the Comanches and Tonkawa Indians.
In the shade of the oaks’ wide-spreading branches, the natives
would meet to dance the war dances, smoke the peace pipe, and celebrate
feasts and religious ceremonies.
Myths and magic surrounded the tree.
Indian maidens believed that a sauce made from its acorns, if
taken by warriors on the eve of battle, would bring their loved ones
safely back.
The Treaty Oak has also played an important and romantic part in the
history of the Lone Star State.
One legend has the Father of Texas, Stephen F. Austin, signing
the first boundary treaty with the local Indians under the tree, and
hence its name. While there
is little proof of this, the grove was an accepted boundary between
Whites and Reds. In fact,
in 1841, the first county judge of Austin went past the grove in search
of stray cattle and was killed by Indians.
As the capitol of Texas developed into a burgeoning city, the members of
the Council Oaks fell one by one, and by the 1920s, the Treaty Oak
itself was threatened. A
cry went up throughout Texas to save the oak, because, as Mrs. W.C.
Stoner wrote in the Texas Garden Federation News at the time, “No
massive building, no marble shaft erected by man could ever compare to
the beauty and grandeur of this natural, living monument planted by our
Maker himself, and no hand should cause it to be brought low except the
hand of Him who gave it.
This mighty oak should be a tree of peace to all Texans and the tender
sacred sentiments it arouses should inspire all posterity.”
In 1922, it was added to the American Forestry Association’s
compilation of famous and historic U.S. trees.
Such was public sentiment that on August 11, 1937; the Treaty Oak was
purchased from Mr. T. J. Caldwell, a banker, rancher, and state senator.
In an area hard hit by the Depression, the one-quarter acre lot
was purchased by the city of Austin with donated and public funds.
The lot was sold with the stipulation that the city could not
destroy the tree or use the land for any other purpose so long as the
tree remained alive. In
recent years, as the city has grown up around it, the tree has been the
site of picnics, weddings and other important personal events including
this forester’s proposal of marriage.
On March 2, Texas Independence Day, the Treaty Oak was the last stop on
a local tree conference tour.
As the bus emptied and the group gathered under the tree, we
noticed that there was a band of about three to four feet of dead grass
around the base of the tree.
In addition, there was what looked like a circle or arch going
out from the base of the tree on the East Side.
We supposed that it was caused by a city employee’s careless
application of a chemical grass edger during routine maintenance.
However, no further thought was given to it since these chemicals
rarely damage trees. It was
not until the first of June when a woman who works nearby the tree
called the city forester’s office after noticing some brown leaves.
The first report was that the tree was showing signs of oak wilt, a
fungal relative of the Dutch elm disease that has destroyed more than
10,000 oaks in Austin over the past two decades.
When we investigated, however, we found leaf symptoms more
typical of chemical injury than disease.
We moved quickly and asked our State Department of Agriculture
and Texas A&M University for assistance.
Soil samples were taken and within several days we had excavated
six to eight inches deep and injected both activated charcoal to bind
the chemical, and active microbes to digest it.
We then waited to see what would happen.
A few days later the analysis came back from the laboratory.
We were startled to learn that Velpar, an herbicide made by the
DuPont Corporation in LaPorte, Texas, had been used.
We had assumed that a chemical had been applied accidentally, but
if it was Velpar (hexazinone), it was no accident, and we were faced
with the first recorded intentional poisoning of an historic tree.
Velpar is used commercially by the pulp and paper industry to clear land
of undesirable species, including oaks, when they grow among pines being
raised for pulp. Pines arc
tolerant of Velpar whereas most other species are not.
It is used locally in our Central Texas area by ranchers to
control mesquite and other brush on rangeland.
The discovery that Velpar had been used could only mean that
someone had tried to kill the Treaty Oak.
But who and why?
An investigation was started by the Austin Police Department.
Soon after, DuPont responded to the misapplication of their
product by offering a $10,000 reward.
The Texas Forestry Association upped this by another $1,000.
By the end of June, Paul Stedman Cullen, a 46-year-old unemployed
feedstore worker, had been arrested.
Reports say that an informer told police that both he and Cullen
had driven around Austin looking for a tree to poison.
News reports also say that it was done to rob the spirit of the
tree as part of a ritual to protect a woman from another man.
He has been charged with criminal mischief by causing damage of
more than $20,000 and a second-degree felony punishable by two to 20
years in prison and a fine up to $10,000.
However, his previous record of twice being imprisoned for
burglary could enhance the crime to a first-degree felony.
If the jury agrees and he is convicted, the maximum punishment
could be life in prison.
Today, he remains in custody unable to raise a $20,000 bond.
The label for Velpar suggests that for best control the chemical should
be spot sprayed at the base of the tree.
For the Treaty Oak, a lethal dose would have been about five
ounces. We assume that some
portion or all of a one-gallon container was used.
This would be roughly 25 times the amount needed to kill the
tree. We also estimate that
the poisoning occurred sometime in early February or before.
If that is true, then the tree had remained in highly
contaminated soil for some four or five months before symptoms were
noticed on the leaves.
Moisture is required to activate Velpar in the soil.
It is drawn into the plant with water and transported to the
leaves, where it is concentrated as water evaporates.
It acts by blocking a key step in photosynthesis thereby
preventing the tree from manufacturing food.
As the leaf becomes more and more contaminated, it turns brown
and is shed by the tree. The
tree responds by pushing out new leaves that, in turn, are also
contaminated by the poison and are lost.
This cycle continues until the tree has used up all of its energy
reserves and cannot produce more leaves.
This is when the tree dies.
Live oaks in Austin can put on more than one set or flush of leaves each
year. In fact, after the
annual shedding of leaves this past spring, many live oaks put on two
flushes. When we first
noticed the leaf symptoms in early June, less than 40 percent of the
first flush was damaged and the second flush was still healthy.
Several weeks later, however, much of the first flush had browned
and fallen, and the second set was starting to show symptoms.
We knew then that our initial excavation and injection
treatment had not been successful.
When we saw the second set of leaves becoming symptomatic, we decided to
expand the treatments and call in additional experts to help us.
It was then, just like in an old-time western movie; the Calvary
came over the hill to save the day.
In our case, it was Mr. H. Ross Perot, a Texas industrialist and
billionaire who let us know that whatever it cost, however long it took,
he would support our efforts to save this icon of Texas history.
After several days of phone calls, we brought together the Treaty
Oak Task Force, a group of 22 Ph.D.’s and practitioners from around the
country. For one day, they
reviewed what was known about Velpar, what treatments had been done to
date, and discussed possible treatment alternatives.
When they were gone, we were left to implement their
recommendations.
The experts all basically agreed on three points.
First, lower the stress on the tree so that the tree could fight
the effects of the chemical without dealing with the heat of summer.
Second, collect more data to find out how much poison was in the
soil and how much was in the tree. Third, remove the contamination from
the soil and the tree.
One-two-three save the tree.
There was only one small detail.
While tens of millions of dollars had been spent to bring Velpar
to market for its intended use of controlling trees, no one had ever
tried to save a tree that had been treated.
We were in uncharted territory without a guide.
Reducing stress, our first treatment goal, was easy to talk about but
difficult to do. How do you
create an open-air intensive-care unit to keep a 50-foot patient cool in
a climate where there are more than 100 days a year over 900F?
The answer was water and shade.
First, we installed an “irrigation system in the sky.”
From large tanks placed in a parking lot next to the park we
pumped Texas spring water that had been donated and delivered free.
The water was pumped through a three-inch line by an electric
pump to the tree, where it split up into smaller lines that crisscrossed
the tree’s three main branches ending in sprinkler heads above the
crown. During July and
August, we pumped nearly 1,500 gallons a day.
We used an automatic timer to pump every half-hour for 60 to 90
seconds during the heat of the day.
The goal was to cool the crown and not wet the ground.
We also installed a series of screens around the east, south, and west
sides of the tree to lower heat stress.
The city-owned Electric Utility Department bored 12; 10-foot deep
holes every 20 feet and dropped in 70-foot wooden poles.
They cabled the tips together and added three lightning rods.
Along the side of each pole, they ran a steel cable from eight
feet off the ground to 55 feet in the air.
To this were attached the screen panels made of plastic-coated
nylon screening, similar to what is used on tennis court fences.
Aircraft cable was sewn into the edges of the panels for
strength. The entire panel
was joined to the cable on the pole and to the panel above and below by
clips resembling rock-climbing carabiners that could be closed and
locked shut. Each screen
was made up of five panels connected together.
To the top of each screen a rope was attached so that the screens
could be raised and lowered through a pulley at the top of the pole.
When the screens were up and the sprinklers were on, it could be
ten to fifteen degrees cooler under the tree.
Other measures taken to reduce stress included fertilization and
aeration. We have fertilized both by spraying the foliage and injecting
the soil. A dilute solution
of one-tenth strength Rapid- Gro fertilizer was used several times to
try to replace nutrients lost as a result of successive leaf falls.
We also aerated to reduce compaction under the tree and promote
better air exchange in the soil.
Since the entire park is filled with roots, we marked out a grid
of painted dots on a three-by-three-foot spacing and augured a
three-inch diameter hole, 24 inches deep at each dot. We removed the
original soil and added a light textured back-fill mix of sand, peat
bark and soil microbes. A
golf course aerator was also used several times to help lessen the
impact of the workers’ heels as the treatments were being done.
Our second goal was to find out how much poison was in the soil and how
much was in the tree.
Immediately after the Task Force meeting, we used a soil auger to sample
to four foot deep at various locations around the tree.
The results from the laboratory showed that there was Velpar at
lethal concentrations down to three feet.
With this information, we completely removed the soil around the
base of the tree. The
samples of root, trunk, twig, and leaf tissues, taken over a four-month
period, have shown only a small drop in Velpar concentration within the
tree. This high level of
poison, despite the removal of contaminated soil and the shedding of
contaminated leaves, has not been encouraging.
To date, over $25,000 of the $100,000 spent to save the tree has
been spent to process soil and tissue samples.
Removing the contamination, our third treatment goal, has called for
some novel approaches because it was generally felt that flooding to
remove the contamination would activate the Velpar and worsen the
situation. We began by
re-excavating our initial treatment area and hand-digging to a depth of
two feet and eight to 15 feet out from the trunk.
Two feet down, we started to hit a mat of smaller roots that made
digging time-consuming and difficult to do without serious damage to the
roots. To solve this, we
called in a pumper-truck crew from the Austin Fire Department.
They connected to a fire hydrant and laid out several high
volume, low pressure lines for our workers to sluice away the last foot
of soil. We then sucked up
the mud slurry into a vacuum truck ordinarily used by our Public Works
Department to clean out storm sewers.
The slurry was then pumped into a tanker truck, treated with
activated charcoal, and disposed of at a city waste-water treatment
plant. At 36 inches, the
fertile dark soil around the tree gave way to a sandy bottom, a probable
reason why very little of the water soluble Velpar was found at deeper
levels.
By the middle of July, the third set of leaves was damaged and the
fourth set was ready to break bud to replace them.
There was a general consensus among the Task Force that the
levels of Velpar were still toxic and it was time to neutralize or flush
the poison from the tree.
Given the chemical nature of Velpar, a very strong acid or a very strong
base would have been needed to change its chemical makeup and neutralize
it; either one of these would have killed the tree. The other approach,
to flush the poison, seemed to hold more promise.
The idea was to push the weakly charged Velpar out of the xylem
cell walls, and into the fourth set of leaves, by displacing it with
another ion--in this case, potassium from a dilute solution of potassium
chloride salt. About 35
gallons were injected into the root flare.
Several three-gallon garden sprayers filled with the solution
were pumped to 20 pounds of pressure and connected to a harness of tubes
and T-shaped injectors adapted from Elm Research Institute equipment.
The oak took less than three hours to take up the solution.
While leaf samples taken immediately before and after the
injection showed that a significant amount of Velpar was pushed to the
leaves, subsequent tissue samples still showed very high levels within
the tree. Our attempt to
flush out the poison had been only partially successful.
About one month later, in the beginning of September, most of the fourth
set of leaves were brown and falling, and the fifth set was beginning to
push out. Members of the
Task Force, who were familiar with the effects of Velpar on oaks, had
told us early on that oaks generally go through five or six sets of
leaves until running out of energy.
We knew that there was still toxin inside the tree and that its
energy reserves were running low.
We reasoned that if we could replace some energy while the tree
still had leaves, the tree would be better able to overcome the poison
by either neutralizing it by some unknown enzymatic action over the
winter or by physically shedding the poison with each successive set of
leaves. We decided to
inject “tree food” into the tree.
We were now into a new fourth phase of treatment and one that had very
little support from research.
After checking with tree physiologists from around the country,
we determined that a dilute solution of sucrose injected into the tree
would probably not damage it.
However, very few researchers thought that it would be of much
benefit either. Using the
salt injection technique, but slightly higher up on the trunk, we
injected about eight pounds of sugar in 65 gallons of distilled water; a
fungicide was also added to check any microbial growth.
In all, it took about 32 hours to complete the infusion.
The benefits, if any, of this injection, will probably never be
known.
The current outlook for the Treaty Oak is guarded.
When we analyzed wood samples taken from the drill bit used for
the sugar injection, we found that there were still extremely high
levels of Velpar in the tree. Today we remain cautiously optimistic.
As the tree goes dormant this winter, we will be waiting until
this spring’s new leaves to see if the Treaty Oak will survive.
Could the Treaty Oak die? A
tree that has survived centuries of scaring summers, dusty drought, and
whistling ‘winds seems immortal to us--a symbol of strength and
permanence in an age of increasing vulnerability and change.
When it became clear that our efforts to help the tree rid itself
of the poison were not as successful as we had wished, we started to
hope for the best but plan for the worst.
In the past month, we have taken over 500 twig cuttings and 50
root cuttings. Our goal now
is not only to save the existing tree in the park, but to preserve the
Treaty Oak by replication.
If it is possible to grow a new Treaty Oak from a cutting, it may also
be possible to tissue culture, or clone, this tree.
There is the potential to create hundreds of thousands of Treaty
Oaks. In fact, corporate sponsors have already lined up to fund this
effort, and commercial nurseries are being contacted to see if they are
interested in a license to grow and market Treaty Oaks.
It may be that, in the not-too-distant future, you will be able
to go to your local nursery and purchase a Treaty Oak for planting in
your front yard.
It is comforting to believe that this majestic tree will survive.
With all of its worldwide fame, the Treaty Oak has truly become a
symbol of our time. Its
poisoning begs us to consider not only the reality of its desperate
plight but also the larger truths it represents.
Just as many cultures have held the tree to be a symbol of
knowledge and life, we today are being asked to believe in the tree once
again; to believe that billions of new trees will give us Global ReLeaf.
But tree planting is also a symbol of a larger truth.
While there are many symbolic and practical reasons for tree
planting, perhaps the best is that it reminds us that we are part of the
world. It reminds us that
each of us must change our own prodigal behavior to stop the poisoning
and begin to repair the damage to the thin skin of life covering the
planet we call home.
In conclusion, I would like to extend thanks, to all those who have
given support to our efforts to save the tree: to Mr. Perot for his
financial support, our mayor, Lee Cooke, and council, and especially
council member George Humphrey for his leadership with our Austin ReLeaf
efforts; to the dedicated scientists both corporate, government, and
private who unselfishly gave us both their time and expertise,
especially Dr. Arthur Costonis of Systemics Incorporated, Dr. David
Appel of Texas A&M University, Dr. Jerry Brand of the University of
Texas, and Dr. Thomas Perry of the University of North Carolina; to the
dozens of city workers who patiently met every demand put on them; and
lastly, to the tens of thousands of well wishers from around the globe.
I have been moved by their outpouring of love, sympathy, and
compassion.
 1930's |
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  2004 |
 2009 International Society of Arboriculture Texas Chapter Work Day at Treaty Oak |
 2010 grafted Treaty Oaks |