Pecan


#483

Thanks for sharing. Positive thoughts for you guys!


#484

You are doing the right thing. When our fire struck some 8 years ago I had placed bales of straw to the W side of my trees, to act as a windbreak for the winter. The possibility of a fire was not on my radar then. That straw just cooked (literally) the trees when the fire came through. Clearing out the mulch and undergrowth around your trees is a very good idea.

May you and your trees come through this unscathed.


#485

Thank you! I had a heavy mulch on most of the trees.


#486

Mulch is good… until fire comes along. I’m working on getting mulch applied to my trees. Hope this turns out alright for you.

I found several very interesting articles on L.J. Grauke’s USDA tab. Further searches turn up some finished documents. https://www.ars.usda.gov/people-locations/person?person-id=2086


#487

Survived the fire. Back fired less than a 1/4 mile from the house. Some damage to some trees from rotor wash from a Chinook type helicopter dipping into the pond 1000 gallons at a time.


#488

Awesome pics. Air assault!!


#489

This is a Mullahay I grafted 3 years ago fighting the wind

, hope it does not snap off. One Warren 346 may be lost.


#490

Hey man, congratulations!!! I’m real happy for ya.

Sincerest regards,

Dax


#491

Thanks man!!!


#492

Yo!!!


#493

I’ve been thinking and studying the pecan dormancy question and came up with a few more useful items. I do NOT think I have all of this correct, but I am reasonably certain that I have enough of it right to test the thesis and prove the mechanisms involved.

Dormancy is induced by low temperatures, generally defined as a certain number of hours below 45 degrees F within a (not well defined) period of time. Hours of temps below freezing are weighted more heavily than hours above 32 but below 45 degrees. Temps above 45 do not appear to induce dormancy. Number of hours required to induce dormancy are variety dependent, i.e. Kiowa has a relatively low number of hours required as compared to Stuart. There is an element of daylength sensitivity that can also trigger dormancy. This shows up in Kanza which drops leaves up to a month before Stuart when planted near the gulf coast.

Breaking dormancy has two major and one minor components. The tree must have been exposed to sufficient hours of temps below 45 degrees to break the internal dormancy, then it must be exposed to sufficient hours of temps above 60 degrees to trigger bud break. A tree might for example require 300 hours below 45 to satisfy dormancy plus 100 hours above 60 to initiate bud break. If that tree gets 500 hours below 45, it will still require 100 hours above 60 to initiate bud break. If it gets 200 hours below 45, then it may need 160 hours above 60 to trigger bud break. There is a strong relationship between hours of chilling and hours of heat required on a per variety basis. There is a reset effect where one night of abnormally low temps may delay bud break significantly more hours by “resetting” the number of heating days. This would explain why Elliott breaks buds even when temps are too cold while Stuart holds off until warmer weather is more likely. Elliott has relatively low cooling hours to satisfy dormancy and has relatively low heating hours to initiate bud break. I suspect Elliott also does not strongly respond to the “reset” stimulus of a night of low temps. The minor component is day length. I see clear evidence that a phytochrome moderation system contributes both to inducing dormancy in the fall and breaking dormancy in the spring.

Male and female flower buds have different requirements for both chilling and heating hours to break dormancy. The knock-on effect of this is that heterodichogamy must be an expression of chilling and heating requirements of a given variety. This clearly explains why a variety may be protandrous in one location and protogynous in another. Kiowa, as an example, can flip from protogynous to protandrous in tropical areas where it does not get enough hours of cold temps to break dormancy properly. Darryl Sparks noted several varieties that flip from protandrous to protogynous and vice versa in his book. I suspect that day length has a strong influence on dichogamy but have not found any studies that would support this.

What is needed to prove the above? Monitoring stations in several pecan orchards scattered across the U.S. that record hours of daylight, hourly temps, rainfall, light exposure levels (cloudy vs clear and sunny), and wind velocity could be analyzed to determine variety specific values. With a bit of work, a regression formula should be capable of predicting bud break for any given variety in any variation of climate the trees are grown in.

Edit: correcting spelling of Kiowa


#494

Well researched.

Thank you for sharing.

Dax


#495

I potted up 4 more seedlings this morning bringing the total to 145. There are still a few germinating that might bring it up to 150. I don’t expect much from these late seedlings. I will probably set them out on my land and let them grow a year or two to get to grafting size.

We have 3 or 4 days of wet weather forecast. I’m going to set some buds and see if I can get a few more seedlings worked over to cultivars. I particularly want a few more Lakota and Kanza trees.


#496

I have a small potted pecan and am trying to decide the best place to plant it and any others I may get. The choice: in an old open pasture with full sun but winter winds or in an old fence row with some sun but some protection from wind and maybe better soil for trees. Any suggestions?


#497

They get big quickly. Either spot sounds good but I’d lean to open pasture & full sun as the #1 priorities.

Should you have the room, space them 50-60 feet apart.

Dax


#498

I potted up 2 more seedlings this morning replacing 2 that were not thriving. I’ve found that if a seedling does not get off to a good start it will eventually either die or be so weak it will never be useful.

I fertilized the seedlings again with 24-8-16 giving each plant about 1/3 teaspoon and then watered it in. The trees are showing very dark green color and are growing fairly well. At least a dozen trees are over 1/4 inch diameter at the base and are producing new growth and new leaves. My best estimate is that between 70 and 100 will be big enough to graft. I’ll know for sure in about 3 months.

My Adams #5 tree has a good crop again this year. I expect to harvest about 5 pounds of nuts in shell. I expect it to produce 30 or more pounds of pecans per year within the next 3 years. This presumes I continue to fertilize it heavily to encourage growth as well as nut production.


#499

The pecan genome project is moving slowly forward. Per Jennifer Randall, they have an early version that has very little resolution. A second run is in the works that maps genes to chromosomes. Based on progress, it will take at least 3 more years to get to a gold standard level of mapping.

http://pecantoolbox.nmsu.edu/


#500

I set buds on several trees today. These are young seedlings about 2 years old so are done with coin purse buds with 2 buds set on each tree. I’m going to put a couple more on this afternoon.


#501

Is there a way to tell what variety of pecan trees are in my yard thanks


#502

If they are named varieties then a person with extensive knowledge can often ID them from a nut sample. I don’t have that level of knowledge yet though I can ID about a dozen varieties like Stuart, Desirable, and Elliott. From your zone, I suspect your trees are more likely to be natives or seedlings of improved varieties. Wes Rice’s books on pecans have pictures of over 100 varieties. If yours are named varieties, comparing to his book might give you an ID.