A practical
approach to the burning of beetle infested trees
The burning of trees affected
by the Asian Longhorned Beetle in a confined residential area
by means of S-Series air
curtain burners
by N. Fuhrmann
Literature and guidelines from
government agencies, schools and industry organizations on the subject of the management
of trees and other vegetation infested with the Asian longhorned beetle and, for that
matter, other tree destroying beetles, pests or fungi, are plentiful. Once affected or suspected trees
have been identified, it is generally accepted that the optimal method of containing and
eradicating the pest, that is, preventing the colonization of the beetles in areas of
healthy trees, is to fell and burn the beetle infested trees.
But how can burning be accomplished in
a confined area, possibly a quarantined residential district, without causing a menace or
endangering the well-being of the public, as transporting the affected wood waste to other
more suitable location is ruled out?
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Air Burners, LLC Model S-127:
Tree Disposal in Alaska |
Many experts suggest to chip the trees and then
burn the chips, without any advice where and how to burn them. Grinding or chipping may
make the wood waste more manageable for transport to remote locations for disposal or
incineration by whatever means, but it is only one step towards the goal of complete
destruction of the trees.
It is also sometimes suggested that chipping is all that is needed to eradicate the
beetles, because it will result in the total elimination of them, as the mechanical trauma
inflicted will kill the beetles and none will survive. No conclusive scientific evaluation
of this premise can be readily obtained, and common sense may dictate that many, if not
most adult beetles could well be killed by the mechanical chipping procedure, but eggs or
larvae and some mature beetles may quite certainly survive the ordeal and result in
re-populating of the pest in the same or other locations, if the produced chips were
transported off site and then stored or disposed.
The optimal and most cost effective solution to the
apparent dilemma is to incinerate the infested trees on site in sections as large as
practical in an S-Series air curtain
burner without any costly prior grinding or chipping. An
S-Series machine is a portable refractory walled incineration system or
mechanized burner with a fire box that
is usually 21 or 27 feet long, capable of accommodating large sections of tree trunks. After
felling a tree, it only needs be cut into suitable chunks which are immediately introduced
into the burning chamber of the S-Series machine on site or nearby by means of a front
loader or excavator. At a loading rate of approximately 8-15 tons or more per hour
(throughput depending on type of system used and factors, such as
make-up and moisture content of waste stream, etc.) this process is efficient and
economical.
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Air Burners, LLC Model S-127:
Shown in full operation - No visible smoke! |
The system controls smoke quite effectively,
and its emissions are regulated by EPA provisions for air curtain incinerators. High
velocity air is introduced into the burning chamber in such a way that over-oxygenation of
the fire is achieved, resulting in temperatures of about 2,000 to 2,500
degrees Fahrenheit (!) and
particulates are trapped under the air curtain and effectively combusted.
The patented S-Series is being manufactured by Air Burners,
LLC. of Palm City, Florida and can be
procured directly from the manufacturer. The largest portable machine costs
slightly more than $100,000 FOB factory. S-Series machines are also available for contract work or lease from
a number of environmental or recycling companies, and for larger
projects, also from the manufacturer.
What makes the S-Series machines the only practical
machines for burning trees in quarantined or otherwise confines areas, especially close to
occupied dwellings, is the fact that they are totally portable for quick and easy
deployment to trouble spots. They arrive fully assembled and, with the
right kind of trailer, require no crane, but only a
winch, for loading and unloading. An S-Series System machine is powered by a Diesel
engine, and it needs no external electric power or natural gas to achieve combustion, as
it feeds on the very waste that is introduced into it. Operation as near as 100 yards to
occupied dwellings is usually permitted, as the menace from smoke and emissions is very
controlled. It is again the extremely high temperature that causes most particulates to be
rapidly combusted within the chamber.
But it is this very high temperature that also
assures complete sterilization of the beetle affected wood waste (or for this matter, any
other combustible waste, such as pathogen-ridden diseased animal carcasses), leaving
absolutely no chance for re-colonization, re-infestation or spreading. The residual ash is
actually a beneficial soil amendment for certain clay-like soils and can be safely and
with confidence applied to the land.
That is not true for any other remedy, especially
affected tree management by means of grinding, mulching or chipping. That method should be
avoided altogether in favor of S-Series incineration.
Other considerations along the same line:
Municipalities that opt to acquire an S-Series
machine will find applications for it at operations, such as municipal landfills, for the
economical reduction of wood waste consisting of yard waste or certain demolition debris,
including hard to manage stumps, reserving the scarce and costly landfill space for other
waste deposits. S-Series units are being employed for such purpose at landfills where they
are operating day after day for many years.
This incineration option has gained significance,
as the chipping of wood waste has often not been as desirable a solution as it was
suggested to be. This has been recently shown again with respect to storm clean-up
measures in the Florida Keys, Alabama and other locations that suffered from hurricane
storm damage in recent years.
If stored in the open, wood chips will start to
decompose and leachates from them may adversely affect the water table. In addition, the
chipping itself is quite expensive, because the grinding equipment may cost several times
that of an S-Series unit, and related transportation and possible disposal cost of the
resultant chip piles are high as well. The chips frequently cannot be marketed for
beneficial re-use and must be taken to an appropriate landfill at significant cost.
Subsequent burning in an S-Series machine, as is often requested, is not
very practical. Only
chunks of wood waste without any prior grinding or chipping can be efficiently handled by
the S-Series incinerator.
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