Tuesday, February 22, 2011

Moving in a new orchard

     I drove by V.O. Morgan's pecan farm today and noticed that he had 2, truck-mounted tree spades moving seedling trees out into rows. Like every native pecan grower, V.O. has a ready supply of sapling trees growing in fence rows and field margins (you can see the native trees behind the truck). The trucks are moving trees that average 1 to 2 inches in diameter. The open fields of this farm are filling up fast with young trees and it will be interesting watch this new orchard grow.
     From past experience, we know that using a tree spade to move trees requires a large commitment to post transplanting aftercare. The area around each tree needs to be tilled all summer long to make certain the seam between transplanted root ball and the surrounding soil doesn't open up during dry periods. In addition, the trees will need water during the heat of the summer. Both watering and tillage are necessary to keep the transplanted root ball from drying up and killing the young tree.
    Eventually these trees will need to be grafted. Grafting should not be attempted until the transplanted tree overcomes transplant shock and begins to make at least 2 feet of new growth in a year's time. Only when the tree is ready to accept a graft will you find success in propagating pecan cultivars onto transplanted trees.

Monday, February 21, 2011

Pruning lower limbs

    With all the snow melted and temperatures in the low 70's (F), I spent this past weekend pruning trees in our pecan breeding block. I do most of my trimming with a chain saw. I use the nose of the blade to plunge cut limbs off at just the right angle as to leave the smallest possible wound. The pair of photos above shows the textbook case of a branch attached to the trees with a pronounced branch collar. To remove this branch, I approached the limb from the side holding  the chainsaw's blade at the same angle as the branch collar. I then plunged the nose of the chainsaw into the branch, cutting it off quickly and cleanly. Note that the branch collar is still present and the pruning wound is minimized.

    When working out in the field, you'll find that nature doesn't always follow the illustrations in textbooks. In the photos at left you will note that this lower limb is attached to the trunk without a prominent  branch collar. In this case, you can see a partially formed branch collar on the upper side of the branch attachment but the collar is non existent along the side of the branch. I just had to pick an angle and plunge cut away. Was it the right angle? It looks good to me and I'm glad I removed this limb before the apparent bark inclusion seen in the photos became a major problem.

    Sometimes a tree can provide you with multiple pruning challenges. In the photo at right you can see I was faced with the typical forked tree, but this tree also had a small limb growing at a right angle from the fork. The pecan in the photo was placed in the tree's fork by a bird, storing away the nut for a late winter snack. My ultimate goal for pruning this tree to to remove the fork and encourage the development a single trunk. Pruning this tree required two steps. First, I removed the small side branch and cut the weight off one half the tree (above). Pruning off the weight helps prevent bark tearing.

   To complete the pruning of this tree, I needed to remove the stump I left after pruning off most of one side of a tree's fork. In the photo at right you can see the well developed bark inclusion and the total lack of a branch collar. At this point I just picked an angle that looked right (this is definitely an art) and plunge cut off the stump.
    And if you are wondering, the pecan tasted pretty good!

Friday, February 18, 2011

Notes on Mandan

Mandan is one of the newest pecan cultivars released by the USDA pecan breeding program. We have had only a couple of years experience with this new cultivar and have yet to fruit Mandan at the Pecan Field. I was able to get a fresh sample of Mandan from a grower in Oklahoma so we could look at kernel quality. The photo above has Mandan kernels (top row) compared to Kanza kernels (bottom row). The Mandan kernels are obviously larger but the kernel color is darker and more "veiny" than the Kanza kernels. You will also note that the dorsal groves of Mandan are narrow (can hold packing material) as compared to Kanza. In the past, I've found it hard to market nuts with ugly kernels even if those nuts have good size. Less that perfect kernel quality is one of the major reasons I can't get excited about grafting Mandan.

  Mandan does seem to have good cold hardiness. Last week, temperatures at the Pecan Field dropped to around -15 degrees F. This morning, I collected some branches from our Mandan grafts, cut into the cambial zone and found only healthy green tissue (photo at left).
   When they released Mandan, the USDA indicated that this new cultivar has good scab resistance. Unfortunately we have found scab on Mandan trees at Chetopa, KS and New Franklin, MO. Scab is easily spotted as black, sunken lesions on the twigs during the dormant period. You can see 3 scab lesions in the middle of the twig pictured at above, right. The number of scab lesions I have seen on the stems of Mandan are similar to the number I see on Pawnee but less than the number of lesions found on a very scab susceptible cultivar like Colby  

Thursday, February 3, 2011

February 1st Blizzard

At first the weather man said we might get up to 1/2 inch of ice followed by 9-10 inches of snow, but fortunately, all we got was 19 inches of snow! (2nd highest snowfall on record).  Fortunate for the trees, that is! Today, after spending all day yesterday digging out both home and office, I had the chance to photograph the beauty of a snow covered native pecan grove (above). It was especially beautiful because I couldn't see any broken limbs following the snow storm that packed 40 mph winds. Looks like the snow will be around for a while allowing temperatures to fall well below normal. This morning I woke up to -9 F.  Additional sub-zero weather is forecast in the coming week. Once we are able to get back out into the field, it will be interesting to see if any more cold damage shows up in the cambium of one-year-old pecan branches.