college of AG said:
Animal, I have some questions.
My folks have some old mature papershell pecans my grandpa planted. No idea how long ago, and could be wrong, but think I remember 70 years ago.
The last 5 or so years they aren't producing any (less than 5 uncracked gallons). They using to produce truckloads.
Is there anything we should do? Have they outlived their productive life? How can I take a cutting or something to reproduce them for other members of our family?
Trees won't make crops without nutrition and water.
My guess is they are stressed from inadequate water.
Send a soil sample to TAMU soil lab. Indicate you want to grow pecans.
Follow the instructions for taking the sample.
Fertilize per the soil test results for your soil.
My guess is all you'll need is nitrogen. Either ammonium sulphate 21-0-0 or urea 41-0-0 in 3 split applications.
Follow soil test recommendations not my educated guesses.
Irrigate to provide adequate water. That will be equivalent of 2" per week, depending on soils ability to store water. You have to provide water biweekly.
That's why pecans grow best on deep alluvial soil, well drained yet excellent water holding capacity.
My pecan trees are growing in Norwood silt loam that I know is at least 16 feet deep of topsoil based on recent excavation to bury an old frame house.
It is an historical watercourse of the Colorado River.
Here is an excellent Aggie Horticulture reference for pecan water needs.
https://aggie-hort.tamu.edu/newsletters/hortupdate/hortupdate_archives/2001/sep01/art4sep.html#:~:text=To%20a%20home%20owner%2C%20this,can%20endure%20without%20being%20damaged.Pecans tree set nut crops based on carbohydrate production and storage. Otherwise they drop nuts.