Tuesday, January 31, 2017

Removing a narrow-angled branch

   In pruning my young pecan trees, I came across a tree with a large branch attached to the trunk at a narrow angle (photo at right). Look carefully and you can see that a bark inclusion has already formed at the attachment site on the trunk. A  narrow crotch is structurally weak and prone to breakage. This branch needs to be pruned off--the sooner the better.
    In pruning off a narrow-angled branch of this size, I employ the 3 cut technique of limb removal (photo series below).  The first step in the process is to use a chainsaw to carve a undercut on the limb. This cut is made to eliminate the possibility of the bark tearing down the trunk when the weight of the limb is cut from the tree. The second cut is made above the undercut and is used to remove most of the limb from the tree. That leaves me with a short stub that can be easily carved off the tree with my saw. Because of the narrow branch angle, I plunge cut into the side of the branch to remove the stub. The plunge cut technique allows me to achieve the proper angle for branch removal without damaging the main trunk with the saw.  

Monday, January 30, 2017

Dormant pecan tree pruning

   I took advantage of some mild winter weather to prune some of my young pecan trees. This year I continued the process of trimming limbs to eventually create a tree with at least 8 feet of clear trunk. But remember,  lower limb removal  is a multi-year task. This year, I'll be trimming off 2 limbs from the tree pictured at right.Lets take a closer look.
    In pruning this tree, I will concentrate on two areas on the main trunk (photo at right). The lowest whorl of branches was located at about 3 feet above the ground (arrow labeled #1). You can see a pruning wound and a single branch left on this section of the main stem.  Higher up along the stem is a second whorl of branches (arrow labeled #2) with 3 branches growing out from the trunk. This year, I will remove the lowest branch (#1) and one branch from the second whorl (#2).

   Before I show you new pruning cuts, I thought it would be interesting to show you how a tree heals over previously made pruning cuts (photos above). Three branches originally grew from the lowest whorl of branches. Walking around the tree I could see the scars where I pruned off limbs in 2015 and 2016. The 2015 pruning wound has grown over completely by the smooth bark of callus tissue. A deep split in the bark marks the location of the pruned off limb.  The 2016 pruning scar demonstrates how a tree seals over a pruning wound. Callus tissue grows fastest to the right and left of the wound. Callus forms to a lesser extent below the pruning wound but barely grows above the cut. By the end of the 2017 growing season, the pruning cut I made in 2016 will be fully enclosed just like the 2015 pruning cut.       

   The first pruning cut I made this year was to remove the lowest limb left on this tree. In the photo at right, you can easily see last year's pruning wound but this year's cut is a little more difficult to see. Along the right edge of the trunk note that I made a angled cut to remove the low limb.

   I then moved up to the second whorl of branches. In the photo at left, note that there are three branches growing from this section of the trunk. During last year's pruning effort I had removed a branch from this area. The pruning wound is marked by an orange arrow on the photo. This year I removed another limb from this area (red line). I choose this limb to prune because it was located on the opposite side of the tree from the limb I had just cut from lower down on the trunk.

    Two cuts with a chainsaw and I was done pruning this tree for 2017. Two low limbs remain on this tree. I'll remove one in 2018 and the last one in 2019. One these limbs are removed I should have 8 eight of clear straight trunk.

Wednesday, January 25, 2017

A historical perspective

     One of my hobbies has been collecting antique books--not just any books but books about nut growing. Within the pages of "The Nut Culturist", published in 1896, is a line drawing of a shellbark hickory labeled Hale's papershell hickory (photo at right). The author of this book, Andrew S. Fuller, describes the tree as being unique among the shellbark hickories in having a shell almost as thin as a pecan. In 1894, Mr. Fuller described the tree as being being over 75 feet tall and nearly 2 feet in diameter. He estimated the tree to be at least 100 years old.
    The Hale's hickory was discovered during a time in our history when grafting nut trees was deemed nearly impossible. Standard fruit-tree grafting methods had been tried with little or no success. Outside the report in Mr. Fuller's book, all trace this historic hickory tree has disappeared. Most likely the tree was cut down long ago and turned into axe handles.
     But I've always been fascinated by this story of a outstanding hickory tree lost to history. You see, the Hale's hickory tree was located near the Saddle River in Ridgewood, NJ. I grew up is this area and spent hours of my childhood exploring the banks of the Saddle River. We looked for anything that would float, launching it into the rushing water and watching it swirl down stream. We found plenty of sticks and acorns in the wooded areas along the river but I never remember finding any baseball-sized shellbark hickory nuts. By the mid 1960's, had all the hickories disappeared from the Saddle River floodplain?
    In the 1890's, Ridgewood, NJ was a farming community producing fruit, vegetables, and dairy for nearby New York City. Hickory, walnut, and oak were valuable native trees producing both nuts and outstanding hardwood (white oak acorns were used for hog feed).  Today, Ridgewood is wall to wall Mc-Mansions built for the executives of major corporations. The native timber was cleared long ago and replaced with trees that won't litter manicured lawns with large nuts. The corporate executive has no need for a good piece of hickory wood.

The original Chetopa pecan tree (KS112)
 In 1954, Franks Brewster purchased an eighty acre tract of land in the Neosho River floodplain near Chetopa, KS. At that time, the land supported a combination of native pecan trees and native grass hayfields. Upon purchasing the land Mr. Brewster set about numbering each native pecan tree on the farm so he could record nut production information on each tree. Within his native pecan grove, he found a small tree (6 inches in diameter) and labeled that tree #112.  By 1956, he noted in his farm records that the 112 tree bore unusually large nuts for a native tree.
     In 1962, Frank Brewster donated his pecan farm to Kansas State University for the express purpose of developing a pecan research facility. The Pecan Experiment Field we know today, originated from this donation.
    I arrived in Kansas in 1981. By that time, the 112 tree had grown to 17 inches in diameter and was proving to be a reliable producer of quality nuts. Today, the original tree is 28 inches in diameter and still producing nuts annually. 
   In 1983, we decided to graft a new block of pecan trees using scions from the 112 tree  and scions from Giles (Giles originated from a native tree 1.5 miles from the Experiment Field). Early results from this trial were promising--so promising that we decided to give the 112 tree a proper cultivar name. We called the tree Chetopa, after the Osage Indian Chief that lent his name to the nearby town.
    We've watched this block of Chetopa and Giles trees grow and produce nut crops for 33 years. We've learned that Chetopa may be an outstanding native pecan, but like most pecan cultivars it has some negative attributes. Chetopa is susceptible to scab, although not as susceptible as Giles. Chetopa trees are prone to limb breakage in wind and ice storms. And finally, inner-shell packing material is often trapped in the dorsal groves of Chetopa kernels. On my own farm, I have not grafted any Chetopa trees because I'm concentrating on grafting only scab resistant cultivars with outstand shelling characteristics.
   Given the history of Hale's Hickory, it makes me wonder if Chetopa will disappear in 100 years time. Will anyone remember the story of its discovery, how it got its name, or why it lost favor with pecan growers? I hope so.

Friday, January 13, 2017

Branch growth pattern: Gauging the potential for native pecan productivity

    Recently, I took a short drive down the gravel roads in the Neosho River bottom to take a look at native pecan trees in mid-winter.  I passed native groves that have had a history of intensive management and then further down the road I came across groves that receive minimal or no inputs during previous growing seasons.  As I studied the canopies of native trees on this cold clear day, I noted striking differences in branch structure between well-managed and un-managed trees (photos below).

    The first tree I stopped at was located in a well manage native grove. What I mean by well managed is that this native stand has received fertilizer applications, both Fall and Spring, for well over 15 years. The grove is also sprayed regularly to control pests and the ground cover is both grazed and mowed. Choosing a tree at random within this grove, I looked upwards and photographed a portion of the tree’s canopy (above right).  Immediately, I noticed the numerous shucks that still hung from the branches. This tree produced a good crop of native nuts in 2016. But, I also noticed a vigorous branching pattern. The twigs within the canopy were long, thick, and light grey in color. This healthy growth pattern can only be appreciated after being compared to the branches of an un-managed native pecan tree.

    Down the road, I came to one of those native pecan groves that suffer from a lack of attention. If the trees in the grove look to be producing a few nuts, the orchard gets mowed and raked just before the harvesters come in to collect a meager crop of nuts. This grove has been starved of soil nutrients but is occasionally sprayed for pecan weevil control.  Again I picked a tree at random and took a photo of the tree’s branch structure (above left).  There was little evidence that this tree produced a nut crop in 2016.  The tree had short, thin branches that appeared dark in color. In comparing the canopies of managed and un-managed trees, it is almost hard to believe they are both the same tree species.

    After taking the photographs of tree branch structure, I used a pole pruner to cut a sample of twig growth from both trees (photo above). In the photo, the two dark twigs to the left of the ruler came from the un-managed grove. To the right of the ruler, I set down a single light-colored twig from the well managed grove. The reason I photographed two twigs from the un-managed grove is to give you some idea how poorly this tree bore nuts. Of the four terminals pictured from the un-managed tree, only one terminal had a pedicel attached indicating the formation of a nut cluster. Based on the size of the nut attachment scars on this one pedicel, I guarantee that all the nuts in this cluster were aborted by mid-season due to scab infection. In comparison, the branch from the well-managed tree displayed prominent pedicels on both terminals.  This twig had borne two nut clusters in 2016.

But the twigs pictured above have an even greater story to tell.  Note the diameter of the shoot growth. Un-managed twigs are thin and spindly. The twig cut from the managed tree has shoots that are longer and thicker. And here’s why this all matters. I can look at the branches of any native tree and predict its future productivity.  Branch growth is a reflection of total tree vigor. Vigorous thick shoots indicate that the tree will have the internal reserves to produce an abundant pistillate flower crop in the Spring.  Short, small-diameter twigs may produce a lot of catkins but female flowers will few in number.

   If you are still grumbling about a poor crop in 2016, take the time to go out and look at your trees this winter. If you don’t see vigorous branch growth, your native grove is not on the path of good annual nut production.  To increase annual nut production your first step should be to apply enough nitrogen fertilizer to stimulate the growth of strong, thick twigs. If the grove has been un-managed for several years, it will take several years of annual fertilizer applications (both Fall and Spring) to see a response from large native trees. Eventually, you’ll see better shoot growth and subsequently much better nut production.

Monday, January 9, 2017

In the eye of the beholder: Kanza and Pawnee

     Kanza and Pawnee are the two most popular pecan cultivars being propagated for northern pecan growers (photo at right).  The decision growers make to graft one or both of these cultivars is largely based on the expectation that the nuts they produce will command top dollar in the marketplace. However, the way growers look at pecan cultivars may be entirely different than the way consumers judge pecans.
   Consumers are visually oriented. Given the choice between several, in-shell cultivars most consumers will be attracted to the largest nut and immediately ask if the nut is a "paper shell". It doesn't seem to matter if a quality kernel actually resides inside the shell. Given the choice between Kanza and Pawnee, most in-shell buyers will choose Pawnee based solely on its larger size.

   Everything changes when the nuts are cracked (photo at right). Once a consumer can see the kernel, different visual cues come into play. Kernel color makes the greatest impression. In the minds of the consumer, a light, straw-colored kernel is associated with freshness. Dark or mottled kernels are associated with off-flavors even if the kernel is actually top quality.
    Kernel appearance is where Kanza really shines. A bag of cracked Kanza nuts is filled with plump, light-colored kernels. Cracked with a modern pneumatic pecan cracker, Kanza kernels not only look pretty but entire kernel halves are often freed from the shell.
    In comparison, Pawnee kernels vary widely in appearance, even when harvested from a single tree. Some kernels have a nice golden color while others appear mottled (photo above). This causes the consumer to pause and ask if the mottled kernels have something wrong with them. Offering a taste sample may be the only way to convince a consumer that a mottled Pawnee kernel tastes just fine.
   Its unfortunate that taste, that one human sense that should guide consumers,  is rarely used to select pecans within the marketplace. Both Kanza and Pawnee have excellent flavor, although their flavors differ. Kanza kernels taste sweet and oily while Pawnee kernels have a distinctive buttery flavor. Personally, I like the flavor of both nuts and I find it refreshing to switch up a recipe by simply using a different pecan cultivar.  

Tuesday, January 3, 2017

Stratifying pecan seed

   The beginning of a new year usually inspires folks to make plans for the future. I can't think of any better plan then to plant more pecan trees. So the very first thing I did in 2017 was to start stratifying pecan seeds that I plan to grow into new trees this summer.

   Stratification is the method we use to promote uniform seed germination. The process involves getting the seed nut fully hydrated then storing the moist seed in temperatures between 32 and 40 degrees F (0 to 4 degrees C) for 90 to 120 days. I started the process of stratification by placing some Giles pecans (2016 crop) into a 5 gallon bucket (photo above right).   

   I then added enough water to float the nuts inside the bucket (photo at left). To make sure the seed inside the shell becomes fully hydrated, I like to soak the nuts for 24 hours .

   To keep the nuts that float wet during the entire 24 hour soaking period, I placed a second 5 gallon bucket inside the first bucket and on top of the nuts (photo at right). By adding water to the upper bucket, the weight of the upper bucket presses down on the nuts below and keeps all seed nuts fully submerged.

    After 24 hours, I drained off all water from the seed nuts. As a precautionary measure, I added some Captan fungicide to the wet nuts and stirred the nuts around until each nut was coated with the white powder (photo at left). The fungicide will act to prevent kernel rotting fungi from destroying seeds during the cold stratification process.

    I use plastic storage boxes for seed stratification. I start by placing a layer of potting soil in the bottom of the box (photo at right). The potting soil is damp (not dripping wet!) and about 1.5 inches deep. By using damp potting soil, I ensure the nuts stay fully hydrated during the entire cold storage period.

  Next I add a single layer of nuts to the box (photo at left).

   I then add another layer of moist potting soil over the top of the nuts. At this point my small storage box was full and ready to be refrigerated. I you choose to use a deeper storage box, multiple layers of nuts can be added to the box. Just make sure to add potting soil between each layer of seed.

   One reason I like to use storage containers for stratifying seed is because the lids fit tight enough to prevent moisture loss during cold storage.  I place a label on each box with the cultivar name and the date the nuts begin stratification (photo at left). To achieve uniform germination pecan seeds need at least 90 days of cold temperatures. I use a standard household refrigerator to treat the seed and set the temperature to 34 degrees F (1 degree C).
    By April 2nd, these nuts will have had 90 days of cold treatment. However, I don't like to plant seed into pots until the danger of frost has passed. At my location, the average frost free date is April 20th. With an extra couple of weeks in the cold, these seeds should pop up quickly after planting.