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Oak Wilt
- How Was It First Controlled
KEEP TREES FREE OF DISEASES BY TAKING CARE OF THEM FROM
THE START.
Trees give us so much, oxygen, shade, beauty, shelter
and value to our
property, it makes good
sense to do all we can to protect our trees from harm.
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c)
2001 Frank Oberle
All Rights Reserved |
Native Wisdom |
Fire - giving life to the earth
Native American
knowledge of historical land-management practices.
All life comes from fire. The
first fire is the sun giving life to the earth.
First,
sunlight energizes a tree, then humans cut the tree down, burn
it and release the power of the sun once again, This is the
second fire.
Call it photosynthesis. Call
it solar radiation, if you like. It’s all about life-giving
energy.
Throughout history, native
nations used and were aware of traditional ecological
knowledge for land-restoration practices. They burned prairies
using fire as a tool to encourage good growth and
productivity. Tubers, seed plants and medicine plants all
germinate after a fire. Native nations have used seasonal
burning techniques for hundreds of years to enrich the soil
and grow plants with high nutrient value. They understood and
lived in harmony with the natural creation and benefits caused
by forest fires.
Buffalo, The Lords of the
Prairies |
At one time, the
prairie was a supermarket for native peoples. They
worked in harmony with the seasons to obtain a steady
supply of food. To prepare for winter, the people burned
prairies behind them as they went into the woodlands for
warmth. Since the prairie was no longer a source of
food, buffalo migrated to the woods as well. They became
food for people during the winter months.
In
the spring, the natives would migrate to the prairie
that had been burned in the fall. They would find new
growth and food high in nutrients as a result of the
fire. In working with nature, natives kept what is
called “fuel loading” — an overabundance of flammable
vegetation — to a minimum. |
Insect & Diseases Control
When left to nature, a mature forest gradually
declines until a natural disaster such as insect infestation,
disease, windstorm or fire, ushers in a period of renewal.
Another less familiar aspect
of forest protection involves the detection and control of
insects and diseases such as oak wilt, forest tent
caterpillars, armillaria root rot, and canker diseases.
Minimizing the destructive impact of insects and diseases on
the forest is an important aspect of forest management.
A pest management program has
been created by the Texas Forest Service to monitor and
respond to insect and disease outbreaks. If an infestation
occurs, it is surveyed and when possible treated
appropriately. The use of improved management techniques plays
a key role in the prevention of forest tree diseases.
Oak
Wilt
- The History
Oak Wilt, Ceratocystis
fagacearum, is an aggressive native disease of oaks. It
spreads from tree to tree by insects feeding on wounds or
through roots connecting diseased trees with healthy ones. The
fungus causes spores and Vascular system becomes plugged.
Therefore, the foliage wilts and falls.
Oak Wilt began to receive
increased attention just after 1940 because of the damage it
caused in shade, wood-lot and forest oaks in IA, WI and MN. It
is not known how long it has been in the U.S. An epidemic
observed in WI and MN about 1913 was ascribed to various
causes (climatic conditions, insects, other diseases), but
investigators of the WI Agricultural Experiment station and
the USDA who established the fungal nature of oak wilt in
1942, believe that the disease may have been responsible for
some of the earlier mortality of oaks in that area. The
development of the aerial scouting technique and the discovery
of the disease in the Appalachians brought greatly expanded
survey activities in 1951. Besides the States already
mentioned, this disease was found in MI, WV, KY, TN, VA, MD,
NC and Continued survey found many new locations in this range
of States, with a notable increase in the known centers of
infection in TX,OH and PA. Although
the disease is widely scattered through much of our State, the
percentage of trees infected is low however, and losses are
significant but the situation could become a catastrophe
should an efficient vector for the fungus appear.
Guardians of The Forests
The Power of The Second Fire
Oak wilt has continued to spread throughout Texas
at almost alarming rates and has now expanded from 55 counties
to 68 counties. This spread is primarily in high density
populated areas. The increase spread of oak wilt is also
continuing in the northeast and California.
Oak wilt, has damaged and
killed live oaks, red oaks, and other oak species in central
Texas for over 30 years. The fungus
infects the water-conducting vessels in the
oak, producing a toxin that causes the tree to wilt and then
die--often within a year after being infected. The disease
spreads through interconnected root systems at rates of up to
100 feet per year. To stop the advance of infection, barrier
trenches are installed to sever root connections in advance of
the fungus.
Fires are still used in
forest management today for control of insects infestation,
disease and to reduce fuel loading of the understory, but with
the increase in areas of dense human population, intentional
fires now pose a greater risk. The accidental fire also
provided a chance to marry the wisdom of the Native American
culture and the knowledge of modern technology.
Most people don't realize
that some fire is good for the forest, we've almost oversold
the message of forest fire prevention to the point that people
think all fire in the forest is bad, and it's not. Whether
lightning-caused, wildfires were once quite common occurrences
throughout the grasslands and forests of the region. These
frequent fires maintained an open forest structure in the
forest and prevented expansion into the grasslands.
Prairie
Grass over shoulder high |
Can you imagine east Texas with
the great pine forests and central Texas as grassland
with grasses reaching shoulder high and the total
absence of mountain ashe cedar and mesquite trees. The
perimeters of these open grasslands areas were shared by
post oaks, black jack oaks, Texas red oaks or Spanish
oaks and motts live oaks, and numerous massive live oaks
trees. Along canyon ridges were lacey oaks, wild
cherry, and chinquapin oaks along the creek sides. Other
native trees and shrubs like the madrone, texas pistache,
mountain laurel, persimmon and agarito bush as well as
other native plants all blended in with the grasslands
and scattered forest areas. That was Texas just over 100
years ago. Keep in mind that the forests were kept clean
of dead wood by the native nations and early pioneers as
the dead wood provided a source of firewood for cooking
fires and to heat their homes. |
A century of human expansion
in the Northeast, and Central Southwest has significantly
decreased the incidence of high-intensity natural surface
fires. The spread of oak wilt has been on the rise for the
last century due to the population increases and the reduction
of natural forest fires and controlled prescribed burns.
Nature usually provides checks and balances to control
insects, diseases, and undesirable plant growth such as the
invasive cedars and mesquite trees, but when man interferes,
nature can not adapt or respond quick enough to maintain these
checks and balances.
Only after the human
populations moved into the forest areas, the natural forest
fires were on the decline due to preventive measures, did we
notice the progressing and spread of oak wilt. The Second Fire
was the natural control for oak wilt, other diseases, insects
and unwanted growth of the understory and provided the balance
of forest regeneration in nature. To day ranchers and
landowners can not risk control burns of range land
areas, which can endanger livestock, wild game, homes and for
the liability risks to their neighboring ranches.
The scientists are now
monitoring the growth of the plants and collecting data to
determine which species survive best. If native plants thrive
and beat out the competition of other vegetation, it will
bring back an excellent food source for wildlife and help
control insect infestations and diseases. Research in all
aspects of this disease continues in hopes of finding better
answers to deal with this problem.
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On
an oak savannah, Burr Oak trees survive these
fires because
they have extremely thick bark, preventing the
fire from damaging
the tree. Other trees were destroyed by these
fires periodically |
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Native Americans made frequent use of fire in their
stewardship
of
oak and conifer woodlands. There are numerous
accounts of
burning by native Americans in woodlands to enhance
habitat for
game
species, to improve access for hunting and gathering
acorns,
and
to maintain plant materials in an appropriate with
form for crafts
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Burned
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Unburned
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Photo by
Schoolyard LTER Workshop teachers, Konza Prairie
Environmental Education Program |
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