Farm Forestry New ZealandIntermediate pruning the easy way
NZFFA Information leaflet No. 8 (2005).
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
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.
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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