When do you prune lichee trees for fruit production?

[islandguy]

My two young lichee trees haven’t given fruit yet but are already getting big enough to need pruning (about 5 years old). Looked up pruning methods for lichee and it seems you want to prune headers timed so that the cold they require to set flowers will happen when flowers are just starting to form. So my question is, what month do local people prune lichee (in Chiang Mai area)? I realize that the process of picking the fruit usually involves snipping off the ends of the branches, so that may be all the pruning people do, and that would have me a month behind schedule already. Thanks for any insight.

[drtreelove]

You’re right, lychee trees are usually shaped/reduced at time of harvest. But it’s not too late for essential pruning: structural corrections, cleaning, thinning and light shaping of your young trees.. Be conservative and don’t do heavy thinning or major crown reduction for the wrong reasons (or for no good reason except that someone says you should cut).

 

I like a statement from one of the first books I read early in my arborist career: “The best time to prune is when your saw is sharp.” (John Haller, Tree Care 1957).  Of course this needs to followed with some other considerations. But it’s true, light pruning (cleaning of deadwood, structural corrections, directional training, light thinning and shaping can be done most any time. Heavy pruning can create physiological stress, excessive vegetative growth response, disrupt growth, flowering and fruiting.

 

Be careful of seeking advice from commercial growers for your landscape trees, because there are some differences in techniques and objectives for home orchards and landscape fruit trees.  You may find value, as I do, in preserving the natural form and beauty of the trees as well as managing for high quality, nutrient dense fruit production for home use. Lychee are incredibly beautiful and naturally well-formed trees, one of my favorites. With moderate pruning, along with good soil and water management, you will likely get more fruit than you can use, preserve and gift to friends.

 

Commercial growers often prune heavily with an objective of stimulating new growth for maximum yield.  This is often done without consideration of the physiological effects and stress factors that affect tree health and structural integrity.

 

Over thinning and especially heading cuts, exposes woody branches and trunks to sun scald of bark and the underlying growing layer.  This can open a path for wood decay fungal infection which can affect growth and create branch dieback, and can attract borer-beetle infestation.

 

Lightly clean and thin the foliar crown, remove dead-wood, breakage, stubs and crossing branches, preserve stable alternating branch structure, use central leader or “modified central leader” system, not “open-center” or other extreme heading styles. Preserve the full shading of the woody structure and the shading of the soil beneath the crown; don’t raise the canopy too much, therefore allowing the sun to beat in, drying the soil and sun-burning the lower tree trunks. Shape lightly but don’t top the trees. Branch end-weight reduction and height reduction can be done with “drop-crotch” method as needed.  Contrary to a common practice, I never top fruit trees for easy pickings. Climb or use a ladder and pole-pruner.   

 

Best management practices for high quality, nutrient dense fruit production is mostly about good water management and soil fertility.  Consider mixed species cover cropping as is being promoted by regenerative agriculture, soil-food-web and eco-agriculture advocates.

[islandguy]

Thanks for your good advice. My challenge is that our fruit tree area was created to concentrate abd minimize the space used so as to emphasize flowering species elsewhere, so we need to either take out half the fruit trees or prune to keep smaller. One of our friends has the biggest lychee tree I’ve ever seen and it is a real beauty. Last year it had abundant fruit and this year very little. I’ll take your advice to lightly prune the lychees for now, and see what next year brings.

[drtreelove]

21 hours ago, islandguy said:

Thanks for your good advice. My challenge is that our fruit tree area was created to concentrate abd minimize the space used so as to emphasize flowering species elsewhere, so we need to either take out half the fruit trees or prune to keep smaller. One of our friends has the biggest lychee tree I’ve ever seen and it is a real beauty. Last year it had abundant fruit and this year very little. I’ll take your advice to lightly prune the lychees for now, and see what next year brings.

Take out trees or prune to keep smaller, this is a hard choice. But I would vote for the removals, to make adequate space for the remaining trees to grow into maturity.  I have multiple reasons for this opinion, besides my love of natural form and beauty of trees, and abhorrence of over-pruning and the distorted, excessive growth reactions.  Also, there is the pysiological stress created by over-pruning and the excessive growth that results when the trees have to refoliate and use stored sugars. And it increases your pruning frequency cycle. 

From a paper on lychee growing:   "heavy pruning should be avoided as it induces profuse vegetative growth instead of floral growth."

 

Your property is kind of borderline for good lychee fruiting isn't it?  They need a chill factor.  I know most of the orchards I've seen are at higher elevations. There are various varieties and that may make a difference. 

The CMU Site B orchard on Doi Pui is just below the summit at about 1200m. 

 "Lychee is observed to thrive at elevations ranging from 1,000 to 1,380 meters above sea level."