Thursday, September 29, 2011

Of Droughts and Trees - Continued

Sunday in Evansville, Indiana, brought with it an otherworldly experience. It was raining when I awoke. It was raining after breakfast. It was raining before and after lunch. It was raining before and after dinner. It was raining when I went to sleep. Steady, continuous, life-giving rain. The locals could not understand why I walked around all day with a smile on my face.

Tuesday, on my drive home, the stretch from Texarkana to Dallas brought a return to Dante's Inferno. The ground was parched. The grass was dry or blackened from fire. The watering holes were shriveled. More trees than I could count were dead or dying, with leaves brown and withered, way too early in the season to be the normal signs of autumn.

Recently, I blogged about the effects of this drought on the trees of Houston, Dallas and Richardson. After the jump, an update.

City of Dallas arborist Phil Erwin told us that Houston is in the midst of its worst drought in its 175-year history. It expects to lose 66 million trees in the next two years. The latest news totes up one small cost of the drought. Houston's Parks and Recreation Department has requested $4.5 million to remove 15,000 dead trees from city parks and streets. That's 13 times the average yearly amount. The damage to trees from the drought is considered to be "way worse" than the damage from Hurricane Ike.

The Dallas Urban Forest Advisory Committee (UFAC) advised the Dallas City Council that "2011 was the second worst summer drought in nearly 500 years." UFAC advises the city to water trees, not grass, and to redirect mowing funds to watering trees.

UFAC reinforces Phil Erwin's advice not to give up on trees: "The more trees we lost - the hotter it will be." The drought may be taking its toll on our trees, but the benefits that trees provide are, if anything, even more valuable during droughts than during mild weather.

On its "Tree the Town" website, the City of Richardson offers homeowners good advice on how to ensure those benefits are preserved:

15. What's the best way to care of my tree during the drought?

Extended droughts can cause health issues for both young and mature trees. It's best to apply water before the tree canopy begins losing foliage than to wait until symptoms advanced. The following are steps you can take to help the health of your trees:
  • Trees take in water by their roots, so it is important to adjust sprinkler heads down to water the soil.
  • Do not water near the trunk unless you've planted the tree within the last four or five years. Instead, water the area under the drip-line (edge of the branches) where the tree's root system extends.
  • Water slowly to allow saturation of the soil.
  • Do not prune live branches in a severe drought. Removing live tissues forces the tree to expend energy to defend against the pruning cuts. Removing live foliage also reduces the capacity of the tree to grow once rains return.
  • Do not fertilize trees in extended drought since this pulls water from the roots and forces the tree to expend precious energy to process the fertilizer.
  • Do not dig under the canopy of the tree in drought. Digging under the tree kills the small roots that absorb water, thus reducing the tree's capacity to uptake water.

What Richardson's "Tree the Town" website omits to say is what the city itself is doing to balance its own emphasis on planting new trees with a concerted effort to protect the trees the city already has. I hope the silence is merely a communications lapse. Despite the welcome recent break from the triple digit temperatures, the drought remains a serious threat and is only getting worse the longer it lasts.

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