Wednesday, August 12, 2015

Nut thinning Lakota pecan with a trunk shaker

  When we first released the Lakota pecan cultivar, I warned growers that, when this tree matures (20+ years old), it tends to over-produce. Over-production reduces nut quality at harvest and limits return bloom the following year. To combat over-production, we used our trunk shaker to remove a portion of our Lakota crop by lightly shaking the tree during the water stage of nut development (photo at right).
   Before shaking, I checked the stage of kernel development of our Lakota trees by slicing open several nuts. Today, Lakota was not at full water stage by close enough for tree shaking purposes (photo at left).  As we moved through the orchard, we discovered that some Lakota trees were far more over-loaded than other trees. By watching each tree during the shaking process, I can remove more nuts on the trees that are severely over-loaded and fewer nuts on trees with a lesser crop load.
    When thinning a pecan crop with a tree shaker, it is important not to judge the amount of thinning needed by looking at the number of nuts shaken to the ground (photo at right). If seeing a bunch of green nuts on the ground makes you nervous, I would strongly advise not grafting Lakota in your pecan grove. Lakota may not need nut thinning every year but you will need to thin nuts off of this cultivar during years of heavy nut set.

   To judge how much thinning is enough, it is best to look up at the canopy to see how many nuts are left in the tree after shaking. It is hard to capture crop load with a camera but the photos above show the exact same area of tree canopy before and after tree shaking. We aim at shaking the tree long enough to reduce the Lakota crop down to about 60% fruiting shoots. When nut thinning, we have found it best to have the shaker operator directed by a canopy spotter trained to judge the crop load left in the tree.