Wednesday, September 20, 2023

Strong thunderstorms roll through the area

      During the summers of 2022 and 2023 we suffered through extremely dry conditions in our area. However, last night we finally received some much needed relief. This morning I dumped 2.98 inches of water out of my rain gauge. Unfortunately, the strong thunderstorms that brought us the rain also came with extremely strong winds. Besides waking up to rain puddles and mud, I discovered several trees had broken limbs. In most cases, the wind broke just a single limb (photo at right). With a single limb broken, corrective pruning was simple; I just cut off the damaged limb at the point it was attached to the trunk.

   However, not every tree was easy to fix. The top of this tree (pictured at left) fractured and broke in 2 places, completely removing all leaf and nut bearing limbs. I could prune off the broken limbs but I'd be left with nothing but the trunk. Even if the exposed trunk resprouts new shoots next year, I've found that naked trunks quickly get attacked by wood-boring insects and wood rotting fungi. Ultimately, the tree would never regain a healthy condition. So in this case, I'll remove the entire tree and replant with a new tree this fall.
     Most of the limbs that broke out of my trees were one half of a narrow branch angle (photo at right). This fall I cut off the broken half of the narrow crotch but left the other half to mature its nut crop. With harvest a little over a month away, I want to maximize the number of nuts I collect this fall. The standing half remains in a much weakened condition which means that after harvest I'll need to prune out the rest this damaged branch. If left un-pruned,  the standing half has a high probability of snapping off during the next strong storm.

   Damage to the entire orchard was light. I took the photo above to show you the task I was faced with this morning. You'll note one severely broken tree and one with a single broken limb. However, the remaining trees in the background did not suffer any limb breakage. It took me about 3 hours to drive around and prune off broken limbs on 30 acres of pecan trees. Once the soil dries up, I'll go back with my tractor and grapple to pick up pruned limbs and haul them off to the brush pile.

Saturday, September 16, 2023

Earlton: First cultivar to ripen in 2023

Earlton, 15 Sept. 2023

     It has been a long hot summer with just barely enough rainfall to produce a pecan crop.  Our dry summer weather has created smaller than normal pecans with some kernel filling issues. However, this year my pecans seem to be ripening normally. As expected, Earlton was the first cultivar in my orchard to split shuck (photo at right). Earlton originated from my pecan breeding project and is the result of a controlled cross between  Pawnee and Greenriver.

    The first pecan tree to ripen in any pecan grove often suffers from immense wildlife pressure. While I was collecting a nut sample from Earlton, I spotted the tell-tale signs that a bushy-tailed thief had stolen a pecan right out of the shuck (photo at left). Note that a portion of the shuck was chewed off to allow better access to a fully ripened pecan (now gone).

    On closer inspection I noted a pile of shucks at the base of the tree (photo at right). Squirrels often cut off an entire nut cluster then bring the cluster down to the base of the tree to remove the shucks. Once they free a pecan from the shuck they scamper back up the tree with the pecan to eat the nut or cache it away for future use. They definitely don't take the time to eat the pecan while on the ground; That would put them in danger of being eaten themselves by a hawk, owl, or coyote. Note that you can't see any shell fragments amonst the green shucks. It clear all these pecans where taken elsewhere.

   I will be checking nut ripening 3 times per week this fall. It will be interesting to see how the other cultivars in my orchard split their shucks in comparison to previous years.

Thursday, April 27, 2023

Observing pecan budbreak

     After a long winter, Spring finally arrived to the pecan grove. This year, I decided to photograph pecan bud development and leaf burst as it occurred during the month of April.  Each week, I snapped photos of pecan shoots on a Kanza tree (protogynous flowering) and a Liberty tree (protandrous flowering).

   On April 5th, the buds on Kanza trees had broken open their outer scales and were starting to show swelling green buds (photo at right).  


      On the same date (April 5) Liberty buds had swollen in size but had yet to split open their outer scales (photo at left).  

     One week later (April 12) Kanza buds were showing the first stages of leaf burst (photo at right). At this point, the two lateral buds that flank each vegetative shoot are still tightly closed. These lateral buds will eventually produce catkins.

   As a protandrous cultivar, Liberty displays its catkins first as buds start to open up in the Spring (photo at left, April 12). The vegetative bud has emerged but leaves have yet to burst forth.

       By April 18, Kanza leaves have unfurled and catkins are now visible (photo at right). You should note that Kanza catkins are long and narrow which is typical of catkins produced by protogynous cultivars.

     By the same date (18 Apr.), the leaves of Liberty have begun to expand but the catkins are still the dominate feature of this cultivar's new growth. Note that pollen sacs are already quite large on each catkin (photo at left). The short and wide catkins of Liberty are typical of cultivars with a protandrous flowering habit. 


    One week later (April 25),  the new vegetative shoots on Kanza trees have grown 4 to 5 inches in length (photo at right). The extremely long catkins have reached their final length. At this date I could still not detect the formation of a pistillate flower clusters at the apex of new shoot Kanza shoots. Hopefully that will come soon.

     On April 25, Liberty leaves have expanded but shoot length lags behind adjacent Kanza trees. However, Liberty catkins are now fully formed and will be ready to shed pollen about the same time as Kanza pistillate flowers appear in early May. (photo at left).

    On April 25, I searched long and hard for any signs of pistillate flower formation. After last year's extreme drought, I'm extremely curious to see how my trees will flower this Spring. I did find a single Caney terminal that displayed the early stages of pistillate flower development. In the photo at right, look carefully between the youngest emerging leaves. Note the oval-shaped structure nestled in the shoot's growing tip. That's the first sign of a pistillate flower cluster.


Monday, February 6, 2023

Looking inside a pecan graft union

      Whenever I remove a pecan tree, I like to save the portion of the trunk that contains the graft union. After drying a few weeks, I slice open the trunk with a band saw hoping to reveal the anatomy of the graft.  This winter I got lucky. In the photo above, you can see every step I took in placing a bark graft on this tree.

     As you look at the photo, note that the color of the wood is distinctively different between scion and stock. Wood growing from the scion is lighter in color than the wood of the stock. A distinctive color boundary between scion and stock extends across the entire trunk. Even though scion and stock grow together seamlessly, they remain genetically separate and never mix. This is graphically illustrated in the photo by the sliver of light-colored scionwood that dives deep into the stock. This inclusion of scion into the stock is exactly where I inserted the grafting wood under the bark of the stock (even the staples are visible).  

      I've always been fascinated by the grafting process and how that process is reflected in the grain of the wood. The photo above shows a hall table I built using pecan boards cut to reveal a graft union. The left side of the table is Giles rootstock while the right side is the cultivar, Osage. Note the distinctive brown line that cuts across the table indicating the boundary between scion and stock. In this example, the rootstock wood is lighter in color than the Osage wood grafted on top.