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  • From: "Frances and David" <fdnokes@hotmail.com>
  • To: "permaculture" <permaculture@lists.ibiblio.org>
  • Subject: Re: [permaculture] fruit trees
  • Date: Mon, 24 Dec 2012 09:57:29 -0800

Very interesting discussion/contribution.
Bill is not talking through his hat.
His middle name is authenticity.
Having run a traditional cider press for decades, he has seen many apples and talked with many growers.
He has also been custodian of a heritage orchard. When I am back in the area (traveling at moment), I can talk more with his assistant who is a friend.
However, my understanding is that he has acted on this information in tending to the orchard, including thinning, harvesting, and pruning...
Here is how his explanation goes: right around the time that the apples are the size of ping pong balls, the trees hormonal system will send out the message re: how many buds to set up for the following year. So, by thinning at this time, yes, larger apples are achieved, and certainly apples with a greater sense of personal space, but also, the trees hormonal system knows that it won't be exhausted by sheer numbers, and can set up to have a good number of buds for the following year.
A lot of people around where we live refer to this cycle as being on again off again... Every two years repeating. Hence, the sense in the explanation. When the year is sparse, the hormonal system of the tree sends out a message that there is ample energy for a large harvest.
Conditions where we live are generally acceptable, having had an enormous amount of rain most winters...
What can make (or break) are the spring conditions, and whether the flowers are out at the same time as the bees happen to be around...
If they come with a frost, then it's a poor season. However, where we live there are also sundry mini climates, and so, someone always has better or worse conditions.
Fran


-----Original Message----- From: loren luyendyk
Sent: Sunday, December 23, 2012 9:18 PM
To: Permaculture Listserve
Subject: Re: [permaculture] fruit trees


Very interesting thread. From an economical perspective, the issue of alternate bearing is indeed important to fruit farmers, as it seems that all trees of the same variety in a certain area will follow the same pattern seasonally. In my experience, avocados (Hass) typically have "on" and "off" years which is represented regionally, and this trend can affect market price significantly. An "on" year creates a glut and low market prices, as everyone has a bumper crop that year. (this trend is more complicated now with the importation of foreign fruit) Alternate bearing can be pretty extreme with avos, with harvests ranging from 15,000 lbs/acre to 2,000 lbs/acre.

However, if you had Hass avocado trees (the variety is important in a commodity market) that were unaffected by alternate bearing, you would be a happy farmer. You would have above average harvests during "off" years and your crop would demand a higher price, as a result of limited supply. I imagine plant breeders have tried to get around this one, but I am not sure (anyone know?).

The process of "thinning"- removing small fruit- is very common with most stone and pomme fruits, mainly because if you remove 1/2 to 2/3 of the fruit you will get larger fruit (and we all know that bigger is better :) Thinning is not feasible with avocados as the trees are usually too tall, and they tend to drop excess fruit during the year on their own accord. I have never heard that thinning was an attempt to disrupt alternate bearing. Also, in my experience thinning is mainly practiced on deciduous trees.

From and evolutionary biology perspective, I am not too convinced of the predator satiation hypothesis- this appears to be a Darwinian approach based on competition. I agree that the more fruit a tree produces the more the animals will plant it (not just squirrels but birds), and it would be a "reproductive advantage" to have more fruit every year.

I think alternate bearing (in some trees at least) is based more on weather (and possibly that the tree simply needs rest after a big year). Here in Southern California we can tell if we are going to have good winter rains if the coast live oaks set lots of acorns. The trees seem to know that there will be good conditions for their fruit to grow into new trees and they pump them out.

Loren Luyendyk
805-452-8249
Permaculture Design and Education
ISA Certified Arborist #WE-7805A
www.sborganics.com
www.globalpermaculture.com
www.surferswithoutborders.com


Date: Sun, 23 Dec 2012 14:19:01 -0800
From: ben.martinhorst@gmail.com
To: permaculture@lists.ibiblio.org
Subject: Re: [permaculture] fruit trees

>
> OK, Ben - I'll go along with that (although a reference to a study
> confirming the specific relationship you describe would make the thesis
> even more convincing).
>

Sure. In general, you can look up the Predator Satiation Hypothesis. For a
brief account in the mainstream press, see
http://www.nytimes.com/2011/12/03/nyregion/boom-and-bust-in-acorns-will-affect-many-creatures-including-humans.html?_r=0,
regarding last years low acorn crop in the US northeast.

For a more technical discussion, see "The evolutionary ecology of mast
seeding in trees"<http://www.jonathansilvertown.com/Site/Research_publications_files/Biolog%20Jour14(1980)%20.pdf>
by
Silvertown, "Predator satiation and recruitment in a mast fruiting
monocarpic herb" <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3043937/> by
Tsvuura et al, or the more nuanced "Prolonged diapause of specialist
seed-feeders makes predator satiation unstable in masting of Quercus
crispula"<http://link.springer.com/article/10.1007/s00442-003-1381-6/fulltext.html>
by
Maeto and Ozaki.

I should note that it does look from a quick review of the literature that
irregular cycling of mast production is a fair bit more complicated than
I've presented it, with factors like hormonal variability, annual climate
variation, and insect predation playing major roles (although it looks like
evidence for the predator satiation hypothesis is stronger for oaks and
weevils than it is for oaks and rodents).

Moreover, it's still far from clear to me that irregular fruiting cycles in
apples, etc, are affected by predator satiation dynamics. I haven't yet
found anything to suggest that it's even been researched, but since I'm
looking through some of the literature anyway, here's a review of what
general consensus is about alternate bearing in a number of crops,
including apples: "Alternate bearing in fruit
trees"<http://www.crec.ifas.ufl.edu/academics/classes/HOS6546/materials/Hort_Reviews.pdf>,
by Monselise and Goldschmidt.

Fun stuff.

-Ben
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