Problems Caused By Weeds In Forestry
Forestry is a large user of
herbicides. Competition between forest trees and
weeds for light, nutrients and water is probably
the main problem caused by weeds in exotic
forests. This effect is of most importance
during the first few years of the life of the
forest, as the trees are most susceptible to the
effects of competition at this stage. If
competition is severe enough, trees can be
killed during the first year after planting. If
trees do survive the first year, major checks in
growth at this stage can cause a delay in the
development of the trees. Research has shown
that trees are affected by the initial check in
growth for quite a few years afterwards, causing
a delay of several years before the trees will
reach a harvestable size.
EcoCover Case Study.
A trial in which there was no weed control
for the first year then excellent control
for the following two years resulted in the
mean volume per tree being 3180 cm3
after three years. In comparison, trees
which had good weed control for all three
years had a volume of 8674 cm3,
2.7 times that of the other trees.24
Although scrub weeds can be very competitive
in establishing forests, perennial grasses
can be just as damaging.
Loss of moisture is a problem
to new planting as is frost damage in certain
areas. Dense weeds around young trees can reduce
air movement and thus increase humidity, which
many lead to disease problems. Weeds can also
attract pest and disease organisms into forests
and lead to problems. Weeds can also make
maintenance more difficult and forests more
vulnerable to damage by fires.24
Photos 1
Massey University Pinus radiata weed trials
comparing four different treatments. 36
Period 1 - at planting.
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Bare soil |
EcoCover |
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Polythene |
Fluted
cardboard |
Photos 2
Massey University Pinus radiata weed trials.36
Period 2 - 6 months+
after planting.
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Bare soil |
EcoCover |
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Polythene |
Fluted
cardboard |
Radiata seedling without a mulch competing with
weeds for light, nutrients and moisture
See more examples on the
Landscape Mulch page. |
