Root Features and Functions

By DEAN HOLLINGSWORTH / The Dallas Morning News

A tree's root system can be as large as five to six times its canopy. Damage during construction and a home's location can adversely impact trees over time. Here's a look at the root structure of trees.

Transport and Support Roots These long, rope-like roots transport water and nutrients from the absorbing roots to the above ground portions of a tree. They are relatively few in number and serve like the arterial streets in a city. Tap Root This downward growing root is the first or primary root. Absorbing Roots Absorbing roots are soft and non woody. They consist of two kinds that intimately intermingle. Both are necessary for extracting water and 14 essential elements from the soil. Trees and Construction Tips on protecting the roots and trunks of trees that are to remain on site. Incorporate tree protection into plans to assure that construction is a safe distance away.

Creat protection barriers to prevent soil compaction, injuries to bark and limbs, and spills of harmful materials.

Require a 4 inch layer of chip mulch or 6 inches of pine straw where machinery must cross throught the protected zone.

Suggest root pruning along limits of land disturbance. Cut roots will produce a flush of new root growth and reduce the chance of rot.

Recommend tunneling instead of trenching for the installation of utilities. Tunneling 2 to 4 feet beneath the surface avoids cutting most roots.

Suggest aeration systems over root zones that must be covered with fill.

Tree death often rooted in past damage

Impact of construction can lead to slow demise for seemingly healthy plant

08:29 PM CDT on Friday, August 17, 2007
By ALLEN HOUSTON / The Dallas Morning News
ahouston@dallasnews.com

Trees that survive through new construction may not be out of the woods yet, according to several local arborists.

A home's location and root damage during construction can adversely affect trees over time. So 10 to 15 years down the line, what was believed to be a healthy tree can die.

The bulk of a tree's roots system is in the top 18 to 24 inches, while its larger roots are there to provide structural support. The heavy equipment from construction can cut the roots severely or compact the soil so much that the root system declines because of a lack of oxygen. A tree's root system can be as large as five to six times its canopy.

On smaller lots, construction can affect the health of the trees next door.

"Trees don't know property lines," said Phil Erwin, acting chief arborist for the city of Dallas. "If a house is built on a property line within a few feet of a neighbor's house, there is a good chance it's going to be impacted by all of the construction going on."

Harold Spiegel, consulting arborist for Preservation Tree Service in Dallas, said many builders and developers were becoming more conscious of saving trees. Proper protection can be time consuming and costly, he added.

"Dallas has become more aggressive than it used to be," Mr. Spiegel said. "But it lags very far behind the Northeast, California and some other parts of the country. I don't think we have learned that we have old-growth trees yet. In many ways, we still have a prairie-city mentality about our city."

Justin Regan, the arborist for Justin's Tree Service, works with builders and said much of tree protection depends on education.

"There are a lot of good builders that perform their due diligence and take care of trees the way that they are supposed to," he said. "Unfortunately, there are also developers who know that they will be long gone before construction damage shows."