Re: Tree butchery and some better ways of ding things.

Bracey Tiede wrote:
> Moira,
>
> Kiwis are no worse than Americans.  I drive around the SF Bay Area
> sadly noting the wholesale deformation of all kinds of trees.  In
> some neighborhoods that haven't undergrounded their utility (power,
> phone, cable tv) lines, the power company has come through and
> created big vee-shaped holes in the middle of street trees to keep
> them out of the power lines. There is a Chinese elm down the street
> that will probably just split in half this year because the majority
> of the tree is hanging out over the street and not over the trunk.
> Palm trees are beheaded.  It's horrendous.
>
> Our MG group is thinking of having an 'Ugly Tree' contest this winter
> so we can post photos of what not to do on our website.

I do notice men seem more keen than women to perform drastic surgery on
their trees, maybe in many cases they get carried away by the heady sense of power when they pick up a chainsaw!

Some women go to the opposite extreme, begging you to go easy on pruning because they hate to hurt the plant. I remember a few occasions particularly, when I was faced with a rose bush full of weak and dead wood and had quite a task to persuade the owner that a drastic clearout was actually going to do the bush good. Fortunately in most cases when I came back the next year, after the bush had had a much improved flowering season, there was no more argument!

Some of the more intelligent pruning is still marred by the tendency to leave stubs. As you knowledgeable folks will know by now, side branches have a collar region at their base. This is usually marked by a basal swelling, but this is not present in all species and in such cases leaving behind about half an inch of tissue is usually sufficient. With largish branches one might maybe leave an inch to be sure. This allows for proper internal sealing of the cut, so even if there should be a small amount of surface rotting on the wound site it will not penetrate more than a very short distance and eventual barking over of the scar is assured. Conversely if the collar region is cut off by slicing too close in to the main trunk a rot may start in the wound before it can bark over and there is nothing to stop it spreading into the heart wood of the tree -a common cause of hollow trunks.

However over-cautious amateurs are more likely to leave a distinct stub up to three or four inches long. This can look remarkably unsightly. There is at present in a nearby street an Atlas cedar which has had its lower branches all removed, but at least three inches of each has been left so the stem now looks like some odd sort of peg ladder and really quite hideous. With conifers this will not get any worse as they do not normally sprout, but any deciduous tree or shrub treated like this will almost always have dormant buds on the stub and the next season will grow a whole bunch of shoots where the single branch was removed, so the last state is always worse than the first.

As I said. conifers mostly do not resprout after drastic cutting as their older wood does not retain active buds. This also applies to some other evergreens, especially the Proteaceae. Like so may rules this has its exceptions; yew trees retain live dormant buds even on the main stems and so does Protea cynaroides, which can be cut nearly to the ground and will be rejuvented by lots of new shoots. You folks will doubtless know of others. If you are not sure whether wood on any species will resprout it pays to be cautions, first shortening some small not-very-prominent side branch and observing whether it sprouts or not.

I have always tried to emphasize when giving pruning courses a set of "cutting rules" which go something like this :-

If you want to remove a shoot so it will never grow again you most cut it out at the collar. One thing I would reccommend is that if you want to raise the crown of a deciduous tree you do it early in its life when the branches to be removed are still small. I was just looking at some red oaks at my neighbour's from which he removed several bottom branches several years ago, when they were aleady quite large, maybe as much as 7 or 8 inches in diameter, or maybe even larger. He did it very properly, leaving the collars and taking all precautions not to tear the surrounding bark. The cuts are long healed and the bark growing in from the sides, but the large wounds can still clearly be seen and do marr the appearence of the trunks.

if you want to strengthen a shoot you should shorten it back to one or more nodes with their dormant buds. and in general the more you shorten it the stronger new growth you can expect, while shoots left entirely alone will grow the slowest and produce fewest side branches.

With fruit tree shoots (including main leaders) shortening by a third or less will tend to produce moderate new growth. Shortening by half or more will usually produce very vigorous new growth. Any removal of the teminal bud generally stimulates more than one dormant bud on the shoot to become active.

The highest bud on a pruned upright shoot will always tend to grow straight up, as will the second bud down, but any further down still will tend to grow out approximately horizontal, so they can be trained as side branches. If you don't want to have the leader forking every time it is pruned you must either destroy the second bud from the tip or be prepared to go round later and cut out the extra upright shoots which develop. With apples and pears at least knocking off the second bud at pruning time is a very easy and neat solution. (By the way the different growth habit of side branches is related to hormonal messages passing between the buds.)

I still have a series of diagrams I made for my classes. Among other general pruning informtion they show how to shorten back stems both upright and horizontal so as to discourage unwanted growth without seriously affecting the tree's health and at the same time to achieve as far as possible an "natural" and "uncut" appearence. If there is enough interest I can scan them and arrange to have them posted on my web site.

Moira
--
Tony & Moira Ryan,
Wainuiomata, North Island, NZ.     Pictures of our garden at:-
http://mywebpages.comcast.net/cherie1/Garden/TonyandMoira/index.htm
NEW PICTURES ADDED 4/Feb/2004

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