Saturday, April 25, 2020

First day of pecan grafting

    I might have been able to start grafting earlier, but last week's frost caused me to delay carving scions until I could see how my trees recover from the frost burn. Turns out, my bigger trees (bark grafting size) have grown out of the frost burn quickly, pushing out new leaves and numerous catkins. The bark slipped nicely allowing for the easy insertion of a scion (photo at right). Today's cool weather was ideal for grafting but with 35 mph winds, photographing my grafting process was not possible. Over the next week, I'll be grafting every day so I'll be sure to capture my methods on film to share on this blog.
   None of my smaller trees (3-flap size) were ready to graft today. These were the trees most seriously affected by last week's frost. The photo at left shows a typical seedling tree. New green buds are only now starting to emerge. When I apply a 3-flap graft to this sized tree, I like to see a little more new growth on the stock tree before placing a scion.

   Let's take a closer look at the terminal buds on seedling tree pictured above. In the photo at right, you can see a frost-killed bud at the apex of the shoot. Below the dead bud, new buds have begun to swell and enlarge. If we get a few more days of warm sunshine, this tree should grow rapidly and be ready to accept a scion.   

Monday, April 20, 2020

Spring frost burns emerging pecan shoots

Frost burn on Kanza
    At first I didn't think it got cold enough last Saturday morning (18 April 2020) to give cause for concern. Our thermometer, read 30 degrees F at dawn. That shouldn't be cold enough to injure emerging pecan shoots. From past experience, 28 degrees F (or below) seems to be the temperature that freezes pecan tissue.
    But as temperatures began to warm  early this week, I started to notice signs of frost damage (photo at right). It is now clear to me that temperatures out in my pecan grove must have dropped lower than 30 F  for at least a short time during the early morning hours of April 18th.
    I looked at a lot of pecan trees in my orchard and made two important observations: (1) Damage appeared more severe on lower limbs and was nearly absent on upper limbs, and (2) outer leafs were damaged but the shoot's main growing point remained still green and viable.

    I cut limbs from a Kanza tree at two heights above the ground. In the photo at left,  the shoot on the left was cut from a branch only 8 feet above the ground. In comparison, the shoot on the right was cut from a limb 20 feet up into the canopy.  Note that the catkins on lower shoots are brown and dead, while catkins are healthy higher up in the tree. Both twigs showed evidence of viable shoot growth, however, the twig gathered from a lower limb looks like it is struggling to survive.
    I would not be surprised that, when the 2020 harvest season rolls around, the majority of my nut crop will be held in the upper 2/3 of the trees' canopy.

    The photo at right is typical of the growth I have observed on many of my pecan trees. The first few leaves created by a new shoot shows signs of frost burn. But if you look carefully, you will see the apex of the new shoot is undamaged and ready to unfurl new leaves. As the season progresses, pecan trees will probably abort all frost damaged leaves.

    The frost we experienced last Saturday is called a radiation frost. The earth radiates its heat into a clear cold sky. This results in temperatures that are colder near the surface of the soil as compared temperatures at higher elevations. So when I checked on some pecan seedlings that I was planning to graft this year, I found total freeze kill to emerging buds (photo at left). This will not kill the tree, but the shock of freeze injury means that I will need to wait until secondary buds start to grow before even attempting to graft.

Saturday, April 11, 2020

Spring fertilizer application

    Over the past week, a stretch of dry weather has allowed the soils in my pecan grove to dry up enough to permit making my annual Spring application of fertilizer. With rain in the forecast for Easter Sunday, I rushed over to my local farm Coop to pick up a fertilizer buggy filled with N, P and K. This Spring, I broadcast a total of 69 lbs. nitrogen, 29 lbs. phosphorus and 38 lbs. potassium per acre. I made this application by mixing 2 parts Urea with one part DAP and one part Potash then spreading this mixture at the rate of 250 lbs./acre. 
   Remember, this spring application is only one half of the total fertilizer I apply to my trees each year. This past October, I spread N, P, and K on the trees just before harvest. 

Wednesday, April 8, 2020

Can curly grain pecan wood be grafted?

    It seems like I've been waiting forever to be able to work in my pecan grove this Spring. Above average rainfall for the month of March has meant that even now, in early April, the grove has just too many wet spots.  However, I have plenty of shop projects to keep me busy.
   Just before I retired from K-State, we removed a large Osage tree that had serious trunk damage. Instead of throwing the log on a brush pile to burn, I had the trunk sawed up into lumber. I was anxious to learn how the graft union would appear in the wood's grain. I let the wood air dry for 2 years then started to mill the rough cut lumber. What appeared in the wood grain was amazing (photo below).

    There was a distinctive line across the wood that marked the location of the graft union. Wood color between the seedling rootstock and Osage scion was obviously different but what stood out to me was the curly grain pattern visible in the Osage wood (horizontal stripes). You will note that the curly grain is present only on the left side of the board. This side of the board is quarter sawn, meaning the growth rings are at a right angle to the face of the board. 
   Figured or curly grained wood is highly prized for making custom furniture projects. This board will be made into a hall table but I'll be leaving the graft union right in the middle of the table top.  That will give me the chance to talk about the art of pecan tree grafting all while bragging about my woodworking skills.

Curly Grain in pecan wood

   This is the first piece of pecan lumber that I have noticed a curly grain pattern in the wood. Do trees grafted to Osage always make curly grained wood? Or is this just a lucky find on my part? That's a question that will take 30-40 years to answer. For now I'll just enjoy the wood.