During the last week of April, we finally received some warm night-time temperatures that have stimulated the buds on our pecan trees to finally push open (photo at right). In my last post, I mentioned that I discovered some freeze damage to buds from the
April 16th freeze. Now that the trees are finally starting to grow I can see the extent of that damage.
The first thing I noticed was a wide degree of variation in bud break over the entire tree's canopy. With some trees, freeze damage was pronounced on lower limbs while higher in the canopy the buds were breaking normally. The photos above are examples of bud break on the same tree. In the lower portion of the canopy, terminal buds were killed and you can see green buds pushing out from the base of last year's shoot. Twenty five feet up in the air, bud break appeared normal. The difference in damage due to height within the tree canopy is due to the fact that on April 16th we experience a radiation freeze. During these types of freezes, temperatures are coldest closer to the ground.
I discovered that most cultivars suffered only limited cold damage. On many trees, bud break on lower limbs appear almost normal, except if you look closely, the terminal buds are stunted and not growing normally (photo above). Buds just below the terminal are growing new shoots.This type of damage becomes obvious when you compare the lower shoot to one growing higher in the tree. Note that the terminal buds on the upper shoot are growing strait up from the terminal of last year's growth, just like they should.
Since the vast majority of nuts are produced in the upper portion of the tree's canopy the impact the the April 16th freeze will be minimal. However, we won't know for certain until pollination season rolls around later this month.
