No. 8 Intermediate pruning the easy way
NEW ZEALAND FARM FORESTRY ASSOCIATION INFORMATION LEAFLET
Our property is located between 360 and 450m altitude on the boundary
of Egmont National Park in North Taranaki. It consists of a series of
parallel hills and steep-sided valleys aligned north-south, which is
generally at right angles to the prevailing winds.
About 10 years ago we made the decision to switch to a sustainable
regime and converted the tractor-contour land to dairy grazing. In
addition, over the next 6 years, we planted about 20ha of pines in the
gullies. This has proved to be a win-win situation because pine trees
do not thrive on the more windy and exposed grazing land, but have
really taken off in the sheltered gullies which are too steep and
dangerous for your average dairy herd.
Until last year, pruning was easy, with form pruning and first lifts
both simple ground-standing operations. Over the last year, however,
our main blocks of trees reached the age and size for intermediate
pruning. We were faced with the alternatives of bringing in a pruning
crew, doing it ourselves the normal way, or finding a method that was
more appropriate to those of us who are not as young as we used to be.
When I had my sixtieth birthday I was not greatly amused when my
workmates bought me a membership in Grey Power.
It is pleasing to be able to record that our pruning is up to date with
nearly 10ha of trees pruned to 5m. Our pruning technique is not only
safer than conventional methods but is much less arduous, and perfectly
suitable for those of us with full time jobs and only weekends
available for pruning.
The solution
The advantages
The solution
We bought an orchard pneumatic pruning lopper with a 3m extension
powered with 125psi air. The gun hooks onto a branch and a plastic
piston built into the handgrip powers the cutting knife.
It was my original intention to get a small petrol-powered compressor
and mount it on the quad, but as our core activity is pruning trees,
not maintaining air compressors, this idea was abandoned in favour of
conventional scuba-dive bottles filled at the local dive shop. These
are filled to 3000psi and last around 3 hours for a $5 fill. The basic
set-up is to carry a loose air bottle among the trees and, leaving it
on the ground, prune about a dozen trees using a light weight air line
about 20m long. The bottle is not heavy and readily moved to the next
spot even on steep hillsides.
You could carry it on your back using the normal scuba backpack but why
carry it when you don’t have to? For trees on easy slopes the bottles
can remain on the quad rather than having to be hand-carried.
The advantages
This pruning method has many advantages:
- Cost: Gun + extension +
airline hose + regulator + two
second hand
scuba bottles cost about the same as a new chainsaw. The operating cost
of compressed air is not much different from the cost of chainsaw
petrol. Maintenance costs are almost zero.
- Safety: You stand on the
ground for all heavy work and you
cannot
fall out of a tree if you are not up it. There is no chainsaw to hurt
yourself with, and with the cutting knife being over 3m away from you,
you cannot get your fingers near it.
- Noise: There is no noisy
2-stroke, no need for ear
protection and no
exhaust fumes.
- Sawdust: One of the most irritating aspects of pruning with
either
hand or chainsaws is getting windblown sawdust in your eyes. Pneumatic
pruning guns produce no sawdust.
- Quick and easy: There is
a limit to how much high-level
hand pruning
your arm joints and shoulder muscles can take. There is nothing easier
than standing on the ground and pulling a pistol grip with one finger –
transforming previously hard work into a pleasant outdoor activity. I
have not carried out any time trials compared to conventional methods
but using the gun is quick and easy.
- Weight: The gear is very
light, weighing less than half the
weight
of a small chainsaw, and you hold it in two hands. Despite being so
light it will still remove branches up to about 6cm in diameter. Nor is
there any problem cutting as close to the stem as you would normally.
- Division of work: One of
the main but less obvious
advantages of
this method is that the work is split into two separate operations. To
control DOS it is necessary to get the big branches off on time. For
quality control it is also necessary to remove the epicormics and stem
needles. With conventional pruning, once you have a ladder up the tree
it makes sense to do all these operations at the same time. With gun
pruning, there is no ladder required to do the heavy work and as
removing the fluff is not strictly necessary for DOS control, it can be
deferred for a few months until all the trees on the property have been
gun pruned. It is still necessary to use a ladder to go up most trees
and do a final clean up, but this operation is very simple and takes
less than a minute per tree. This splitting of the activity into two
parts takes away a great deal of mental pruning pressure.
While this method was principally intended for intermediate pruning,
the gun has been used to final prune a couple of blocks as well. To do
this, you need to stand on a low ladder, although there is no reason
why this could not be avoided by buying a further extension. This would
also have the advantage of keeping clear of falling foliage.
There is no restriction on pruning height, and up to around 6.5m is no
trouble.
I mentioned this method of pruning to a couple of local contractors but
their response has been one of ill-concealed derision – presumably
because it does not conform to the macho-man image that forestry gangs
seem compelled to portray.
For those of you who wish to prune your own trees and have better
things to do than wrecking your shoulder joints and collecting chainsaw
injuries, I can strongly recommend this approach.
(top)
This article by John de Bueger appeared in the August 1999
issue of the New
Zealand Tree Grower. For more information you can
phone John on (06) 759-6300
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