Pruning- An Academic Primer

This will not be of interest to everyone, but may be to serious hobbyists and professionals.


Or academic types?

The document discusses many important pruning concepts. Should help everyone that takes the time to read it. Your aware I don’t prune anymore than what is necessary. The document discusses methods I use such as “Pruning reduces yield” as well as “Pruning encourages vegetative growth rather than reproductive growth in young trees” . It also discusses size pruning which I do not follow but many do in the “Pruning is a dwarfing process” section because of their particular orchard needs. Thanks for posting this it supports my current methods I’m using. I’ve read different things and some people disagree completely with methods I follow. One important concept the document discusses is fruit sugars in regards to pruning which is not an issue I have experienced but may be an issue in other places. The document helped me understand why people in cooler climates prune trees more than I do. Other peoples pruning methods make a lot more sense to me now. Fruit color, ripening, high sugar levels are never a problem in my area because we reach temperatures of 100+ and have excess 90 degree days in the summer which other locations do not have. The other areas are pruning more severely to ripen their fruit earlier and to concentrate sugars. Those concepts I did not understand in improving fruit quality by pruning because we ripen our fruit early as it is. We ripen Bartlett in July some years which is September in other locations.

That’s funny you point out the statement that “all pruning reduces yield”. I consider that to be fundamentally incorrect- and even beyond the usual level of such absolute statements that some academics sometimes enjoy making. Apple trees on relatively vigorous rootstocks seem oriented to create excessively thick canopies and given that less than 33% of exposure to light renders a leaf to be an energy sink, it is obvious that removal of internal wood containing such leaves will not reduce yield as there is often no fruit coming from parts of the tree with so little light. Energy wasted on such leaves ultimately have to reduce the trees capacity to produce fruit- at least in some cases. The tree is likely genetically programmed to develop such an inefficient canopy to prevent competition from establishing underneath.

Sunlight also is used by fruit trees to feed vegetative growth when it reaches vegetative wood while that reaching spurs feeds fruit and flower production. I don’t know if research removing vegetative shoots in mid to late spring has ever been conducted, but expect that this practice would intend to counter biennial production and encourage the spur leaves to send the message that "we’re good not only to produce this season’s fruit but next season’s as well. It should also direct more energy to fruit size. Research has recently shown that leaves deprived of sun for a short time lose their photosynthetic ability permanently- which is why summer pruning is sometimes counterproductive- it comes too late to serve spur leaves.

And then there is the removal of diseased and dead wood which is certainly a form of pruning that cannot possibly reduce yield. .


The idea of Pruning reduces yield could be better worded to say unnecessary pruning reduces yield. I believe that is what the author intended to convey when they wrote that section. Many people trim off their bud wood. I just saw a neighbor removing their fruit bud wood again recently. They have not had a crop of apples in 5 years now and it was a highly productive tree. What I said was I don’t prune any more than what is necessary. Crossed branches, diseased branches, narrow crotches etc. need to be removed. In other words I’m not a height pruner rather a problem pruner. I believe height should be controlled by rootstock rather than pruning.

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Clark, you are such a positive person. I am a born critic. Your wife is luckier than mine.

I wasn’t commenting on your pruning in any way, though. Just throwing in my 2 cents about that statement. I actually think it was an act of mental laziness that it was not edited from the article.

I have brought unproductive trees into productivity by developing and opening to light spur wood on trees pruned by arborists probably partially in the manner you describe. If you waited for the trees to come into fruitfulness by neglecting them it would take about 4 years for productive wood to develop outside of a previously annually stubcut canopy- often over 30’ above the ground, but unproductive, shaded, weeping spur wood can be turned around the first season of proper pruning.


My favorite pruning book is out of print, although there are some copies still circulating in libraries around the country so may be sourced that way. It is titiled “Training and Pruning Apple and Pear Trees” published by the American Society for Horticultural Science. I’m amazed how much it now costs to obtain considering I got my copy at a NAFEX annual meeting for about 8 bucks a couple decades ago. Mine is falling apart from excessive reading and the poor original binding. That may contribute to the rarity of used copies. A used copy would be worth the price to any small commercial growers, IMO.

Is this the same text, @alan and, if so, why is it your favorite?


Wow, thank you so much- now any of us can download this invaluable primer.

It’s my favorite because it is thorough, written in relatively plain and easy to understand language, accurate, with very helpful illustrations. I would advise all members interested in pruning methods to download this free treasure.

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