Friday, January 28, 2011

Cutting scions

Our annual January thaw came around this week, so we took advantage of some beautiful weather to cut pecan scion wood. One of the best ideas we've had when it comes to growing high quality propagation wood is to develop a scion wood orchard. In the photo at left, long, one-year-old shoots are cut from specially grown scion wood trees. Its nice to have a hydraulic lift for this type of work but most of the scions could be reached with a pole pruner.
     In the photo at right, you can see one of our a scion wood trees with all the scions removed. Note that we leave lots of stubby branches on the trees to provide ample places for the tree to sprout new vigorous shoots next summer.
    Even when these trees are butchered annually they still produce a few nut clusters (note shucks on still on the tree). We collect the first nuts produced by each tree in our scion wood orchard and verify that the cultivar is true to type. We then  paint the green ring on the trunk (green=good to go) to indicate that the tree is ready for scion wood production. The trees in the scion wood block are planted 15 feet apart in rows 30 feet apart.

 Once we collect the scion wood branches, we cut the wood into ~8 inch long bud sticks and place them in plastic boxes (photo at left).  Inside the boxes we also place some dampened paper towels to ensure high humidity inside the box during storage.  We store the wood at 35 degrees F until it time to ship out the wood in early April.

What's wrong with my pecans?

   I often receive pecan samples from home owners that have a pecan tree or two in their yard with a note simply saying--"Whats wrong with these pecans?". So I thought it might be a good idea to describe how I determine the problems associated with these type of samples. The sample pictured above came from a gentleman from the Wichita, KS area. The note that came with the sample stated that the pecans produced by his tree rarely fill well and some nuts have an "off" flavor.
    The first step to determine the cause of poor pecan performance is to determine if the nut comes from a grafted tree. These nuts were smaller than most cultivars and the thick shell confirmed the nut to be a seedling. Before cracking the nut open, I noticed that the shell markings that are normally dark black on a pecan were lighter and reddish on the submitted sample. This told me this pecan did not receive a long enough growing season to complete normal nut development. I cracked open the nut and found more evidence that this pecan is not adapted to the Kansas growing season.  Three kernel defects were present--hollow kernels, kernels that don't extend the full length of the shell, and brown fuzz adhering to the kernels. All 3 of these defects indicate that this tree ran out of time (length of growing season) to fill the kernel properly.
   The "off" flavor of some kernels were caused by stinkbug feeding. This problem shows up as darkened areas on the kernels. A full explanation of this malady can be found in a previous post call "black spots on kernels".
  So now its time to make recommendations. There are no remedies for poor genetics. The tree that produced the pecan pictured above likely originated from a seedling tree (or nut) collected in Texas and moved to the Wichita area. During years when we experience a longer-than-normal growing season the nuts will fill better. Stink bugs can be controlled in the commercial pecan orchard setting but the chemicals used are not compatible with application  within suburban neighborhoods.
   This nut sample provides yet another example of why proper cultivar selection is critical for successful pecan production in the North.

Friday, January 21, 2011

Natives bounce back


   I will always remember the devastation our native groves suffered following the 2007 ice storm. Broken tree limbs were everywhere. It took nearly six months to clean up the mess. While watching the huge piles of debris burn,  I kept wondering if the native pecan yields we had worked so hard to achieve would ever return. In the graph above, you can see that our yields, like our trees, are regrowing. Let me recap some history. The 2007 yield was record low because we lost most of our spring flush of terminal growth to the Easter Freeze in April. We had just finished our meager harvest in Dec of 2007 when we were hit by the ice storm. The crop in 2008 was slightly better that 2007 even with more that 1/2 the limbs gone because 2008 should have been an  "on" year (a result of the spring freeze in 2007). Yields dropped in 2009 as the trees seemed to put all their energy into growing new branches. In 2010, we were back "on" but this time some of those new limbs produced a few nuts. I'll predict the 2011 crop to decline slightly and then in 2012 we'll be back to the 1500 lb average we harvested during the years prior to 2007. 

Pecan Breeding Project

This past fall we collected the first pecans from our pecan breeding block. Pictured at left is a seedling that produced a clean beautiful kernel. It really stood out among all the samples we collected. This medium sized nut had 57% kernel. The pecan pictured below was 52% kernel, about the same size as Kanza and is scab resistant. At this point in our evaluation, I'm looking for kernel quality and scab resistance for any clone that will move into advanced testing. Nut size can change as the trees get larger (see Nuts on young trees). So, I will wait a while before deciding if a seedling is too small to be considered for release.
     One thing I have noticed so far is that our heavy use of Pawnee as a parent has meant that many of the seedlings are producing nuts with that fine black speckling on the surface of the kernel that is so characteristic of Pawnee. These black speckles give the kernels a grayish caste that you can see on the nuts pictured above right.
    If I find a high quality and scab free pollinizer (type 1) for Kanza (type 2) in our breedling block, all that hand pollination and tree planting will be worth it.

Check scionwood for winter injury

This winter has been a little colder than normal (whatever normal is in SE Kansas). Temperatures dropped to near 0 F on two consecutive nights in mid-January. As a general rule, we usually don't see serious cold injury until temperatures drop below -10 F even on our most cold tender cultivars. However,  the past season's crop load does influence cold hardiness. If a tree bears an excessive crop in the fall it becomes very prone to winter dieback. 
In the photo above, you can see two pecan twigs that have had the bark scraped off. The top twig was taken from a Maramec tree while the bottom twig came from a Kanza tree. Note take the interior bark and cambial area of the Kanza twig is clean and green with no indications of cold injury. In contrast, the Maramec twig  shows the signs of internal browning that are associated with cold injury. Last fall both these cultivars had a full crop load of nuts but only the cold sensitive Maramec  has been injured by the cold. Susceptibility to cold injury is one reason Maramec is not recommended for propagation in northern pecan states.
    In a month's time, you should start to collect scionwood in preparation for next spring's grafting season. When you do, slice into a twig and check for winter injury. Significant internal browning translates into scionwood that will not perform well in the field.

Wednesday, January 19, 2011

Shipping Out Pecans

    It wasn't that many years ago that shipping out pecans meant spending all day carrying 140lb burlap bags of pecans into a semi truck box trailer and stacking them 5 bags high. It was exhausting work and I'm so glad the industry has moved to a bulk handling system. Today, most pecan growers store their crop in super sacks that can hold 1300-1700 lbs of pecans (large white bag in photo above). With that much weight in the sack only a front end loader (pictured above), skid steer, or forklift can handle lifting and moving a super sack.  These bags feature a spout on the bottom that can be opened to dump the nuts out of the sack.  When it comes time to ship out the crop we use a belted tube elevator to lift the nuts up into a standard semi-truck grain trailer (photo above). The pecan industry's move to bulk handling has been a real labor saver for both growers and shellers. A grain truck can move around 48,000 lbs of pecans a load.    

Wednesday, January 12, 2011

Jayhawk's kernel defect

When we first started to evaluate Jayhawk, we were hoping that this cultivar would represent and improvement over its parent cultivar, Giles. Well, the data is now coming in. The first thing we noticed about Jayhawk was that it was scab resistant, while Giles is not. Nut size and yield of Jayhawk and Giles are very similar. Unfortunately, after cracking out nut samples we found that Jayhawk kernels suffer from the same defects we see with Giles kernels. If Jayhawk or Giles nuts suffer from a lack of moisture during kernel fill (late august to early sept) nut meats take on a mottled appearance (photo above) and become very dry tasting.  How disappointing! I was so enthused about the scab resistance of Jayhawk that I almost overlooked the importance of a cultivar being able to produce a quality kernel under a wide range of weather conditions.

Wednesday, January 5, 2011

Time to Thin Trees

   With the temperatures pushing 50 F  and the ground nice and dry, I decided today was a perfect day to started some long planned thinning operations.The orchard pictured above is 25 years old and the limbs of adjacent trees were getting very close if not touching. The original orchard was planted with trees 30 feet apart in a square pattern (see diagram above, right). To thin the orchard, we removed every other tree in first row (tree number 2,4,6,8, etc). For row two, we switched to removing the odd number trees (tree 1,3,5,7, etc).  For row three, its back to removing the even numbered trees.
To avoid confusion, clearly mark the trees you plan to remove with flagging tape (if you look closely you'll see yellow tape around the trunk of the sawed trees in the photo above). 
  After thinning the remaining trees should still be arranged in a square pattern with trees 42 feet apart but the squares are now shifted 45 degrees. Sometime in the future this orchard we be thinned again to achieve the final spacing of 60 x 60 feet. 
   One the worst decisions you can make is to delay the thinning process until the time the trees become so crowded that you start seeing significant limb loss and a decrease in yield. It looks like we are having a pretty good winter to make some firewood so don't miss this opportunity to crank up the chainsaw..

Harvest 2010

  The ground dried up in December, and the harvest season really kicked off in the Neosho River Bottoms. We had the first decent crop since the disastrous ice storm of 2007. For us the 2010 harvest went smoother than any year in recent memory. No mud, a decent ground cover to pick from, and the nuts seemed to fly across the cleaning table (very little junk to pick out). But best of all, our pecan harvesters made it through the entire season with out any major break downs. We met our target for getting all our nuts picked up by Christmas and the crop cleaned by the 1st week in January. Now all we have to do is get the crop shipped out.
   We did have one set back during the December harvest season. Our building was broken into with chainsaws and pecans stolen. I personally spent a lot of time with the sheriff's office trying to catch the thieves but it seems our laws are designed to protect the bad guys while making the victims of the crime (the Pecan Field) spend money we can't afford to replace essential equipment. Looks like we'll also be investing in additional security systems.