Thursday, December 1, 2011

Ice storm recovery update

    Its been 4 years since the pecan groves around Chetopa,Kansas were hit by a massive ice storm. Once the leaves have fallen from the trees you can still see the scars of limb breakage left behind in the canopies of our trees. In the photo at right, you can see that vigorous new shoots have developed where limbs were torn from the tree by the weight of the ice. With each passing year, our trees are filling out their canopies, increasing the area where nuts can be produced.
    But where are the nuts? It seems that the native pecan trees that did not set nuts on undamaged limbs, didn't set a crop on the new shoots either. In contrast, native trees that did set a crop (photo at left) produced pecans on both old and new branches.  What we are seeing at this point is that the new shoots developed in response to ice-induced limb loss are now fully mature (able to produce a nut crop) and synchronized with the entire tree.
    If you take a closer look at the regrowth associated with ice-storm-related limb breakage, you can see that an over-abundance of new shoots have developed in many areas (photo at right).  Note that these vigorous branches have also developed numerous lateral shoots. As the trees continue to grow, competition for sunlight among these new shoots will eventually lead to the  natural thinning of the most heavily shaded limbs (the so called self pruning process).
   Squirrel damage has also led to some much needed limb thinning on ice-damaged trees. I've been shaking trees this harvest season only to find several branches that have developed since the ice storm on the ground (photo left). Note the dried leaves still attached to the shoot indicating that this shoot was injured by squirrels last summer.
    If you look at the base of the shoot you can clearly see that the bark had been stripped back by squirrels feeding on the cambial layer of the shoot. A combination of summer winds and harvest tree shaking snapped these dead shoots out of the tree.