Environment News Service 20 Feb 12;
COLLEGE STATION, Texas, February 20, 2012 (ENS) - At least 5.6 million trees that once shaded homes, streets and parks in communities across Texas now are dead as a result of last year's drought. These dead trees represent as much as 10 percent of the total number of trees that make up the state's urban forest.
Texas Forest Service urban foresters calculated their loss over the past month as they surveyed tree mortality in cities and towns across the state.
"This estimate is preliminary because trees are continuing to die from the drought," said Pete Smith, Texas Forest Service staff forester and lead researcher.
"This means we may be significantly undercounting the number of trees that ultimately will succumb to the drought," said Smith. "That number may not be known until the end of 2012, if ever."
After one of the driest years on record, many shade trees went into dormancy as early as August 2011, dropping their leaves and branches in a "desperate act of self-preservation," the Texas Forest Service says. Pine trees with normally thick, green crowns turned red with dead needles while foliage on cedar trees turned brown.
Much like the drought, tree mortality is not uniform across Texas and can vary from one yard to another.
The study conducted by Texas Forest Service, a member of The Texas A&M University System, focuses on tree mortality in the urban forest. The trees that line streets, shade homes and grow in local parks are all considered to be part of the urban forest.
To determine how many urban trees have been lost to the drought, foresters studied satellite imagery taken before and during the drought, counting both live and dead trees in randomly selected plots on both public and private land.
All cities and towns in Texas were included in the study with the exception of the Trans Pecos region, where tree mortality was determined to be a result of a February 2011 cold snap; not the drought.
The Texas Forest Service says that because the drought-killed trees are in populated areas, many threaten public safety and will need to be removed at an estimated total cost of $560 million.
The estimated loss of economic and environmental benefits once provided by these dead trees is roughly $280 million per year. When alive, they cut heating and cooling bills, cleaned the air and water and increased property values.
