Dec. 8, 2011 - Recent rains have been especially helpful to Texas fruit tree production.
Amidst a severe drought, fruit trees' root systems have been under significant stress. Luckily rain and cooler temperatures arrived just in time, as trees now need crucial chilling hours, in addition to moisture.
"I don't know what it is going to be like... If there is sufficient soil moisture to keep the tree healthy over the wintertime, then I think it will be fine," said Keith Hansen, Texas AgriLife Extension Service horticulturist.
Trees may have been stressed from this year's summer weather, the drought in particular, especially those on non-irrigated land.
"We have been getting some pretty timely rains recently, and if it keeps it up, then I would speculate that we would probably be in fairly good shape," Hansen said. "But, that is a hard thing to predict."
Still, the increase in wet weather is promising for most,
"What I can say is that it's a decent start to overcoming a huge soil moisture deficit," said Jim Kamas, AgriLife Extension pomology and viticulture specialist. "We are still many inches behind normal and every rain we get counts. Fall is a crucial time for root growth and if there is no or limited soil moisture, it greatly affects trees from growing roots."
If conditions become dry again, the situation could become problematic again.
"I'm not sure I really want to think about it, because it's not good," Kamas said. "I mentioned root growth, well it's more than that. Trees under drought stress are far more susceptible to cold injury than trees well supplied with water. Trees are already weakened by the greatest statewide drought in history. Continued drought will only make things worse."
"We just need to continue to get some timely rain so that the soil profile has some moisture in it," Hansen added. "We don't want flooded soil, but neither do we want the soil to get bone dry again. If we keep on getting an inch or so every couple of weeks as far as soil moisture is concerned, with most tree fruits we should be in good shape. Pecans, I think, are going to need a lot more than say peaches, plums or blueberries for example, because they just have a more extensive, deeper root system and it is going to take a lot of rainfall to recharge soil moisture."
Experts are crossing their fingers for nice, cold and moist fall and winter seasons.
"Dormancy is a fairly complicated phenomenon," Kamas explained. "We start counting chilling in the fall with first freeze and in some years can accumulate significant chilling prior to January and February.
"We count chilling hours, traditionally temperatures below 45 degrees Fahrenheit," he continued. In reality its temps in the 30s and 40s are the best and very deep freezes do little to overcome dormancy. Its not just ambient air temperature either, overcast or rainy days are much better than clear days when the sun's energy can actually warm the tissue inside peach buds much higher than we record the air with a thermometer."
While chilling hours begin accumulation during the fall months, they can be interrupted by warm bursts which can offset the accumulated hours. So, chilling hours in the months of January and February are especially important.
"I think the experience that some research has shown the January and February weather, you know the temperatures during those two months leading up to bud break are what is the most critical," Hansen said. "In other words, you could have a really good chilling in November and December and early January, and have a heat wave in January, February, and even if they had gotten what they needed early on, the warmer weather would possibly negate what was accumulated."
Though the future is unclear, it's possible fruit trees in Texas can still flourish.
"Canopies were smaller because of the drought, so our production capacity has been somewhat diminished for next year," Kamas explained. "But, with a good chilling season and a return to near normal rainfall, we could bounce right back. It's amazing how resilient fruit trees are."
