Vol. 15—1961 - NorthEastern Weed Science Society

518.
The possibility o:rusing controlled burns to remove small dense understory
brush and prepare a seedbed should always be considered in site preparation
work. Where sufficient logging slash or needle duff from overstory pine
is present in the ground litter to carry a hot .fire, controlled burning
followed by planting may be the cheapest solution to reforesting the land •
. .
Occasionally, where there is not enough litter, but where susceptible
species are prevalent, it is possible to use herbicides to set up an area
for controlled burning. The chemical is applied at the beginning of the
growing season as soon as foliage has reached full size, and the burning is
done at the end of the growing season or the following year when foliage and
stems are dead and dry. Planting or seeding should be done immediately after
the burn to take advantage of the release obtained.
More work needs to be done on this chemical-fire combination treatment
to determine the idSal time to use the controlled' burn. Following chemical
treatment too closely with fire will not allow sufficient time for translocation
of chemical to plant roots. '!he result will be vigorous resprouting from
the root collar which can cause severe competition to newly planted trees or
seedlings.
It is interesting to note that the main reason for the brush hardwood
problem on millions of acres of valuable pine land in this country today is
largely due to the intensive fire control now in practice. If controlled
burning can be substituted for the wild fires ot the past, brush can be
temporarily controlled and planting sites can be prepared fairly econonncally.
Once a desirable species has been established on a site, fire and
mechanical clearing can no longer be used. Selective techniques that favor
one species over another are required. These are release situations and are
ideally suited to herbicide programs. As a general rule, the greatest return
from money spent on a single herbicide treatment will be realized on areas
where desirable species are already established and release is needed.
For the remainder of this discussion let us consider the specific
herbicide techniques that may be used' in these release programs.
A. FOLIAGESPRAYINGBY AIR
The use of aircraft to appl~~ herbicides for conifer release in this
country is a firmly established prac~ice. The technique is most economical
on areas in excess ot .500 acres. Most of the work is done by helicopter
aircraft, using li-2 pounds per acre Of" lC?wvolatile ester of 2,4,.5-T in
2 quarts of oil and 4 gallons of water .5}(1) • Examples of low volatile esters
in use today are the- btttoxy ethanol and propylene glycol butyl ether esters.
Timing of aerial sprays should coincide with full toliage development on the
weed tree species and should be appl~d atter the new growth on conifers has
hardened off. Soil moisture should be sufficient for good growth and relative
humidi ty should be high. For unifQrm coverage, swaths should overlap on 30
to 40 foot centers and should be nagged. Boundaries of sprayed areas should
be clearly marked. Three points need emphasis in applying low volumes of
spray solution by air. .