Malcolm - That is a good question about trunk caliper size.   I agree that over time, a lateral could get quite large.    I've not recently refreshed my memory on all of the research I did a few years ago on this topic.   However, from the many photos that I have seen, I do not recall seeing any of these production plants with large girths.    From other bits and pieces that I have read, I think that a fig tree, after a certain age, may start loosing its productiveness.    I think that I read that even in regular orchards (California for example), that after x number of years, trees are ripped out and they start over.  Is this correct?

    If it is correct, my assumption is that in the intensive fig production areas (Japan, Korea and one spot in Australia), production is the all important factor.   I think that older (unproductive) trees are removed and new ones are put in their place.   That would probably explain the lack of any photos showing large trunk and lateral girth size.

    This makes me think of another question - how completely are trees removed from the greenhouses, outside orchards, etc?   Do they pull out all of the roots?    What about the soil?   Is some of it excavated in the greenhouses and replaced?    Mineral salt build up in the soil might be a good reason to do that.   We are slowly putting the pieces together for this cultivation method.

 
   Thanks for posing the question.     Any other explanations for this?

Byron (Ingevald)

Malcolm, if the biggest problem I have is that the horizontals get so thick that they start touching the ground, I can live with that. Can always just dig a little trench underneath if I have to.

Byron, I am sure that the growers remove any tree that becomes unproductive for any reason, including old age.  There must be an age at which the production declines to the point where it's advantageous to start over with a new tree, even though it will be a few years before it gets to peak production. I have no idea what this age would be, and I suspect it's dependent on a number of factors, including growing conditions, etc.

I don't think you can effectively remove all the roots.  But no big deal, just pull the stump up and any roots left will naturally decay over time and add to the organic matter in the soil. 

The Japanese greenhouses appear to be opened up during the summer, so rain should flush out any mineral salts accumulated.  If somehow you set up a system or lived in a climate where there was never any rain or other source of flushing, then you would definitely have to watch out for this issue over time. 

Hi,
Cutting branches year after year will probably make nests for diseases to appear.
I'm still curious of seeing such a tree after 10 or 20 years of production.
I've seen old vines ... Perhaps fig trees are just as smart, growing new buds out of the blue.
A fig tree that is pruned won't grow a thick trunk, because she has to rebuilt the branches each year.
If the roots are constrained, the tree won't grow such a big trunk.
I don't think that aging is a problem when dealing with fig trees.
Perhaps big fig trees exist in such a production, but you're laking the pics ...

Rob - Thanks for your thoughtful reply.   I really appreciated your comment about the possibility of the Japanese greenhouse roofs being opened up to deal with salt build up.    I've spent some time thinking about that issue a lot and do not have any solid information on how watering and mineral build up is dealt with in their system.  A roof that can open seems to be a very good solution.   A good flushing via rain would really make a big difference.     

  I am curious about their regular irrigation method - the amount of water used per plant and how it is delivered (subsurface irrigation, surface drip, etc).   I do know that mulching is part of the plan - either artificial or organic materials.    In the greenhouse the mulch is effective at reducing humidity and keeping moisture in the soil for the plant.

Jdsfrance - Thanks for your thoughts also on this issue.    It is possible that pruning could introduce disease.   I've seen many photographs of these heavily pruned trees and assume that disease is not a big issue although in a closed up greenhouse there potentially be a problem.    The biggest solution to avoid diseases spreading is to sterilize the pruning equipment from tree to tree.

    I've seen photos of heavily pruned fig trees, including one that a neighbor of mine grows that has a very thick trunk.   I have posted a picture from a French nursery that I collected several years ago that shows a thick fig tree in a container with a constrained root area.    I do not know the age of the tree - perhaps 40 years or so.    I don't have direct evidence at hand, but think that the heavily pruned espalier figs in Japan would get thick trunks over time - except that the productivity likely diminishes and then they are replaced.   I could be completely wrong about this but hope to get a definitive answer someday.

Take care,
Byron (Ingevald)
 

Byron,
I don't think that build up of salts would be a problem with regular fertilization schedule and normal watering since they are in ground. The organic mulch and soil microbes will also be playing their part.

I have no knowledge of the non productive age of the espaliered fig trees but Ken Love mentions in his description of Fig Culture in japan, http://www.hawaiifruit.net/Figs-Japan.htm, that,

Pete - thanks for your informative reply!   I do remember coming across those fertilizer proportions.    They are different from some other recommendations I have come across. I think that I have been using the 3:1:2 ratio fertilizer.   Anyway, I may do some experimentation in that department!  Thanks for the Peters recommendation.

  I just got a note from a friend in Japan regarding the age of fig trees and soil sickness issues in greenhouses.   In greenhouses, soil sickness (mineral and salt build up issues) are apparently a serious concern.   I've come across documents about this, written in Japanese, that I will get some help translating for better understanding.    My friend found information in a book that said the Masui Dauphine matures in 2 to 3 years, becomes fully productive between 7 and 15 years and then weakens.     I seem to have come across similar information but will need to find time to dig up that information, buried deeply in a pile of files on the computer...

   Japanese fig orchards that are outdoors, likely do not have the soil sickness issues but it is still interesting that I have not encountered photos of large girth trees.  Your quote from Ken Love would seem to work well in outdoor orchards.   It is understandable that trees in greenhouses would meet this fate but am still interested to know if there are some open roof type greenhouses to help cure or manage soil problems via some good rainfall.

   I have also seen information about hydroponically grown figs.   I think that I posted some links about that many years ago.   That would probably be one solution for avoiding soil sickness but of course brings on a new set of complexities...

  On we go - Lots of interesting information to share and discuss.

Thanks - 

Byron (Ingevald)   

Byron, Baud had recommended that the potassium should be higher than the nitrogen for production of figs, 7-3-10 and 6-3-10 (the later one would be used after spring).  The potassium does help but this is my first year trying this so it was not a great year to see the affects.  Next year we will see how it works, but this is also for organic production, the ratios i don't think should change much, I believe what ascpete is doing is very similar to these ratios and may be easier to obtain what he is using.

Byron,
Thanks for the info.

I've also been using a combination of Organic fertilizers with a water soluble 3-1-2 ratio fertilizer and the results have been very good. I tested several different fertilizers as part of my fertigation and hydroponic experiments this year and the Hydroponic Fertilizers were the favorite, but their cost would be prohibitive.

Soil tests and cover crop rotational planting would help to resolve any problems with excess soil minerals for in ground trees. If you look at all the pictures of the fig orchards you will note barren or mulched soil between the rows and trees, this is actually unhealthy for the structure and microbes. The Japanese fig orchards are operated as commercial ventures and as such are geared towards production of figs and not the health of the soil, as are most commercial farms. Healthier "Organic Farming Practices" which ensure healthy soil microbes and soil structure could resolve some of the problems, but it would mean reduced production.


Chivas,
Thanks for posting the Baud formulas.
I used Espoma Garden-Tone 3-4-4 and supplement with Water soluble fertilizers, for a combined ratio with Peters 20-20-20 (1-1-1 ratio) of 4-5-5.

Bauds fertilization schedule reflects the current practices for hydroponic vegetable production, maintaining separate "Growing" and "Fruiting" fertilizer formulas,<with increased Nitrogen in the "Grow" and decreased Nitrogen in the "Bloom" stages of growth. With the combination of Organic Solid Fertilizers and Water Soluble Fertilizers the Grow/Bloom stages can be accomplished by simply stopping the liquid fertilizer mid season or after the figs have formed.

BTW, One of the Hydroponic fertilizer tested has a Grow ratio of 2-1-3 and a Bloom ratio of 1-3-3. >
<Edit>

Pete - I am very interested in a healthy living soil and not interested in creating a dead zone requiring chemical inputs to subsidize plant life.    I am interested someday in growing figs in a greenhouse but am trying to get a grip on various soil issues, hoping to be able to figure out a system that will be mostly sustainable, relying on a functional healthy soil ecosystem, etc.  

  Related to the healthy soil concept, I've also read about charcoal / biochar.  There seem to be some positive results from adding this to the soil.  It provides a home for the microbes, improving the soil's health and giving more back to the plants both moisture and nutrients (a simplified statement, but papers that I have read indicate positive results - more long term experimentation is needed, but looks good).

I am not quite understanding your comment about the "barren or mulched soil between the rows and trees."    I think of mulch as a good thing, it decomposes on the lower layer and more can be added.  It holds moisture, stabilizes soil temp, etc.   Is mulch in this context a problem because of other factors?   Just trying to understand.   (Is this the plastic sheet mulch??)  I've seen the barren areas you are talking about and understand that issue related to soil health.    

The cover crop rotational planting concept is a very good idea.   Something else to consider in regards to long term soil health.

Thanks!

Byron

Byron,
For my existing in ground fruit orchard (Apples, Pears, Plums and peaches) I apply fertilizer only once in the early spring, to get the soil microbes off to a good start. The trees are mulched with a layer of compost topped with organic matter (plant stems wood chips etc). The existing cover crop, Annual Grasses, Vetch and Comfrey are allowed to grow and are used as chop and drop mulch. I could just as easily stop the early spring fertilizer routine, but it has helped increase the season length by waking the fertilized orchard earlier that the adjacent unfertilized areas.

The Japanese Fig Orchards are Mono culture raised beds that are mulched with Straw that's layered to prevent decomposition, basically the orchards are set up to rely on the added fertilizers for all the needed nutrients. Most pictured orchard areas are devoid of plant growth which is normal commercial farming practice which directs the available nutrients and moisture to the cultivated crops. Mono cultures have been proven to be detrimental to the soil in the long term since plants use nutrients differently and plant pathogens can get established easier due to the decrease of beneficial soil microbes in the cultivated barren soil.

Pete - Thanks for the clarification and describing the soil care in your orchard.  As I was finishing up the previous post, I was thinking that it was the non-decompositional mulch that you were talking about.   I understand.  A healthy living soil is the goal.

Byron

Pete,

Ahhh... thanks for posting that link.  That makes much more sense.  It also answers the question whether or not one should have one or two horizontals does it it not?