Thursday, February 28, 2013

Shipping out the 2012 Crop

Loading pecans in a hopper-bottom truck
   The 2012 pecan crop at the Pecan Experiment Field ended up being the largest crop we have ever harvested in history. We loaded out a full trunk load (50,000 lbs) last week and have a partial load to go out this week (photo at left). If we only had a little more rainfall during last summer our total tonnage would have been even greater.

   The down side of the 2012 crop year has been the total collapse of the pecan market. Prices started low and fell further as the season progressed. Just like Wall Street, the pecan industry periodically goes through a market correction following years of inflated inshell prices (2010 & 2011). Growers blame the shellers. Shellers blame the banks. Banks blame the Government. But in the end, extreme price fluctuations hurt the entire industry.

Our pecans were fed into a belt elevator
    The crop years of 1990-1993 was last time the pecan industry passed through a period of extreme price fluctuations. When the dust settled, we had fewer but larger growers. The number of shellers decreased dramatically, but the remaining processing plants increased in size and efficiency (one air cracker replaced 10 mechanical crackers). Only one thing is for certain, the pecan industry will continue to evolve and present new challenges for everyone involved.

Thursday, February 21, 2013

Tips for cutting pecan scionwood

   When ever we get decent weather during the month of February we are outside cutting pecan scionwood. The best quality scions are collected from young, vigorous-growing trees (photo at right). A close look at this 'Lakota' tree and you'll find it covered with one-year-old shoots that are 18 to 24 inches long. This kind of shoot growth makes great scions but removing every one-year-old shoot from this tree will also remove the entire 2013 pecan crop.
    As you can see by the shucks that still remain, this 'Lakota' tree produced a good crop of nuts in 2012. So to prevent crop production losses due to scionwood collection, we have developed a scionwood orchard.
   Trees in the scionwood orchard are spaced close--15 ft apart in the row and 30 feet apart between rows. The trees are pruned heavily every year to force the production of long vigorous shoots (photo at left). Each tree now produces hundreds of high quality scions.
    While cutting scions the other day, I thought it would be a good idea to show you a few tips on scionwood collection. Lets start with the perfect piece of wood (photo at right). Great scionwood is relatively straight and has well-formed, prominent buds that are widely spaced along the stem. At each bud node you can see a large primary bud with a smaller secondary bud below. An even smaller tertiary bud can be seen below the secondary bud and just above the leaf scar.
    In forcing strong shoot growth on our scionwood trees, we often collect wood that have stalked buds (photo at left). If you come across any stalked buds on your scions, prune them off before putting the wood into refrigerated storage. This kind of wood still makes good scionwood because of its innate vigor and the fact that there are large secondary buds under each stalked bud.
     When cutting scions, you might notice that the buds near the base of the one-year-old shoot are often smaller and less prominent than buds on the middle portion of the shoot. This occurs most frequently when you cut one-year-old shoots are over 2 feet in length. In addition, the small primary buds found near the base of the shoot are easily knocked off during handling (photo at right). These lower buds are less tightly held to the stem because of apical dominance that was expressed during the growing season by the more prominent buds found near the terminal of the shoot. You can still use this kind of wood to make a successful grafts but you'll find that only secondary buds will break bud and new growth from the scion will take longer to appear (7 to 10 days longer).

    Now lets look at the terminal portion of the shoot. In the photo at left, note the furrows in the stem marked by the red arrows. These furrows tell me that this portion the the stem has a very large pith with only a thin layer of wood under the bark. This kind of wood is never good for grafting. If is difficult to carve and percent take will be poor.  In cutting scions, I always discard the terminal portion of the shoot.

   One problem faced by pecan growers is collecting scions from mature trees. Once a tree goes into full pecan production, new shoot growth is often limited to 4 to 6 inches in length (photo at left). The buds on these shoots are close together and the shoot length is so short its impossible to carve . If you want to collect scions from a mature tree its always best to prune a few limbs the previous year to force vigorous shoot growth. However, in a pinch let me show you a technique for harvesting scions on trees with short one-year old growth.
    Here's a twig I cut from a mature tree. Note I cut off a twig with both one and two-year wood (photo at left). Also note that the one-year wood has prominent buds, while the buds on the two-year wood are long gone (they fell off along with the catkins last spring). However, the two-year wood is larger in diameter providing me with a better spot more making grafting cuts.
      In preparing this scion, I start by pruning off one half of the forked twig and discarding it (photo at right). One interesting thing to note is the pedicle on the end of the discarded twig. This pedicle held a cluster of 3 nuts last fall.
    Next, I cut off the terminal of the shoot and discarded it (photo at left). Cutting off the terminal effectively removes any pistillate flowers that might emerge once the graft takes.
    This leaves me with a crooked scion but one that has plump, healthy buds on the upper end and a good, thick area to make my cuts on the lower end. This scion is not ideal--the two year wood has too many leaf scar bumps in the way of making smooth cuts but I could make this work for a bark graft in a pinch.

Wednesday, February 20, 2013

More dormant pecan pruning

   Some pecan trees are just more difficult to train than others. In previous posts, I've shown you my approach to dormant pruning on a neglected pecan tree and again on trees that receive regular summer pruning. Recently, I received an email with photos of a single pecan tree taken from four different directions (photos above). This was a great idea. Viewing the tree from all 4 sides really helps in visualizing the tree as a truly three dimensional object.

   The primary problem with this tree is that it lacks a strong central leader. The tree has far too many lateral shoots that are producing upward growing shoots (photo at left). The first step in pruning this tree is to identify the shoot you wish to promote as a central leader. The shoot I would choose is identified by a red arrow. Since my goal is to stimulate the central leader, my next step would be to remove the leader's closest competitor (yellow arrow). Take this limb off all the way back to the trunk. Next, start making bench cuts on all other lateral branches. I've pointed out just one of these cuts in the photo, but many more bench cuts should be made to remove all upward growing shoots on lateral branches. Keep in mind that you should limit the amount of wood removed during dormant pruning. Only cut what is necessary to stimulate the growth of the central leader. Excessive dormant pruning leads to uncontrollable regrowth most often in a strongly upward direction (this is how this tree developed so many upward growing laterals in the first place). The dormant pruning cuts made on this tree should be followed up by directive summer pruning cuts made as spring growth emerges.  Summer pruning has proven to be the most effective way to define and keep a strong central leader in the long run.

    One major factor in tree training that is often overlooked is the impact of the strong southerly winds we endure all summer here in the central plains. I often joke with folks that you can tell its a northern pecan by the fact that a young tree seem to point north (photo above). The fact is, pecan trees seem to grow more upright on the south side of a tree for two reasons--the wind and full exposure to sunlight. In the photo above I've circled in red all the upright growing limbs on the south side of this tree. All of these limbs should receive bench cuts during the dormant season and careful directive pruning during the summer months. The fight against upward growing shoots is always hardest on the south side of the tree. Be patient, don't cut too much at one time, work with the tree as best you can.
     In the first photo of pruning this tree, I pointed to a limb that needed pruning to release the leader to grow more vigorously. In the second pruning photo, the yellow arrow points to the same limb that needs removal back to the trunk. From this photo angle, you can see just how competitive that limb is towards the central leader and why it needs to be pruned out. Also, the green arrow points to a fork in the central leader. One half of that folk needs to be removed before it grows into a more difficult pruning problem.

Saturday, February 16, 2013

Collecting scions from mature trees

     Have you ever wanted to collect propagation wood from a favorite old native tree? You stare up into the tree's canopy searching for nice, long, one-year-old shoots only to find short stubby growth covered with closely spaced buds (photo at left). Short shoots can be used for grafting in a pinch but your success rate will be reduced.
    A better solution for collecting scions from a mature tree is to force the tree into growing vigorous scions for you. This takes some advanced planning.
    Last year we stubbed back some branches on the south side of a mature 'Canton' tree to promote vigorous sprouting. In the photo at right, you can spot several places where we cut tree limbs back, leaving one inch diameter stubs. Note that, even after pruning, the branches remained in full sun. These dormant season pruning cuts promoted strong regrowth last summer and now, this tree has at least one small area from which we can collect high quality scions.

Friday, February 15, 2013

Pecans at Colonial Williamsburg

Large pecan tree, Willimansburg, VA
    I had the opportunity to travel to Virginia and speak to the Virginia Biological Farming Conference. What a great group. I had lots of great discussions that I hope will lead more Virginians to plant northern pecan cultivars.
    While I was in Virginia, the wife and I traveled to Colonial Williamsburg to experience 18th century history. However, it seems we spent most of our time looking at fruit plantings in the gardens of the restored colonial town (see photos below). I was also glad to find several mature pecan trees planted around the village (photo above, right). When I asked the locals if they were able to harvest any nuts from these giant trees, they assured me that the trees do indeed produce nuts but an army of gray squirrels steals the crop long before the shucks open. (The historic Kings Arms Tavern needs to add squirrel stew to their menu of 18th century dishes).

Fig trees trained as an espalier, Williamsburg, VA
    Pecan is not native to Virginia but the tree grows well in the tidewater region of the State. Both Thomas Jefferson and George Washington planted "Louisiana nuts" (pecans) at their plantations in Monticello and Mt. Vernon over 200 years ago but pecan has yet to become a commercial crop in the state. The reason may be as simple as poor cultivar selection.

Apple trees trained as a 4 arm espalier, Williamsburg, VA
    If you look at a map, you'll find that Chetopa, KS and Richmond, VA are at roughly the same latitude, ~37 degrees N. Both locations have around 200 frost free days (temps above 28 F) and experience hot summers. Based on climatic data, land owners in VA should be establishing northern pecan cultivars such as Kanza, Lakota, and Pawnee rather than traditional southern cultivars that are often planted (such as Stuart, Desirable, or Schley).  With better cultivar selection and a good squirrel trapping program, Virginia could be an excellent place to produce quality pecans.

Friday, February 1, 2013

Oswego pecan - 2012 results

   When I was collecting pecan samples from our cultivar trial last fall, I came across our Oswego trees and, frankly, I was little disappointed. The nuts were small and not that well filled (sample from Chetopa at right). It wasn't until I collected samples from our cultivar trial at New Madrid, MO that my faith in Oswego as a cultivar was restored (photo at right). The New Madrid sample had the size and kernel quality that spurred the naming of this seedling in the first place.  
   I've talked about the effects of tree size and drought on nut size, nut shape and quality in previous posts. Here we see similar results. The Oswego nut from New Madrid was produced by a tree that was irrigated all throughout last summer's heat and drought. In contrast, The Oswego nut from Chetopa was produced by a young tree that was not irrigated. I'm so glad I decided to set up multiple sites to test pecan cultivars.