The August issue of Onsite Installer included an editor's column asking for practitioners' comments about the wisdom of leaving trees near onsite systems. There were two basic questions: Do trees near the system lead to root intrusion and blockages? And do excavations that cut roots ultimately weaken and kill the trees? Here are the responses:

20 feet clear?

I have been involved with septic systems since 1981 as both a designer and regulator. During this time I have had many experiences with tree roots clogging leaching areas. The worst one was when the owners never cut down the brush over the system for about 13 years.

Lots of smaller trees had taken root along with an understory of woody brush plants. Also, several large pine trees were about 15 to 25 feet to the side of the excavation for the trenches. We found that the first two trench distribution pipes were completely clogged, the stone had a mat of roots from beginning to end, and the distribution box was infested with even more roots.

Unfortunately, the owners had to pay for re-engineering the system due to a regulatory change that had taken place during the 13 years. After a permit was obtained, a new soil absorption system was installed.

Most people do not want to cut down large trees on their property, even when I relate this story. We do see many systems during inspections that have root intrusion, but not as widespread as the case I described. Commonly the distribution box is invaded.

I recommend that all trees and stumps be removed for 20 feet around the soil absorption system, but people at times will not allow this. Building tree wells to accommodate higher grades without killing an existing tree is a typical method during system replacements at existing homes.

Christopher J. Knuth, R.S.

Director of Public Health

Leominster, Mass.

Tree was fine

In my work as a regulator for the past eight years, I've had limited feedback from installers or homeowners about issues with trees and soil absorption systems here in Nebraska, but I do have a little experience with sewer work at my home in Lincoln.

The sewer main for our block runs between us and the neighbor. Two years ago, my neighbor's clay tile sewer succumbed to the roots from a very large silver maple tree on our property. Unfortunately, the sewer main runs about 10 feet on our side of the property line and is about 15 feet deep where the neighbor's sewer line connects.

The edge of the hole they dug to hook up the new sewer pipe was no more than three feet from our mature flowering crab, which is also within the maple's drip line. It has been a little over two years now and the flowering crab seems to be doing fine.

Gary Buttermore, P.E.

Environmental Engineer IV Supervisor

Onsite Wastewater Unit and Operator Certification Program

Nebraska Department of Environmental Quality

Always saved trees

I've been installing septic systems since early 1987 and I've always saved trees when I could. Unless you have to install a sand bed around the leaching area, I see no reason for not leaving as many trees as feasible.

If you're using schedule 35 piping, I've never seen roots adversely affect it. If you're using concrete or plastic galleries, I've never seen roots adversely affect them, either. I've cut roots right up to the trunk and installed the gallery, and both system and tree have been OK for many years – and are still OK as of this writing.

However, if you were cutting the roots in such a way to make the tree more likely to fall upon anything like the house, power lines or driveways, in a storm or a good wind, then I would consider removing the tree.

They tell us trees can die if you fill around the trunks, but I've seen trees thrive very well years after fill has been placed around them. I've also seen them die as a result of the fill, so I usually let the homeowners make an educated decision. I hope my comments help.

Bob Aillery

Stright Company

Stamford, Conn.

Roots intrude

I read your piece about saving trees next to septic systems with great interest. I was curious about the concern for the health of the trees since I've never noticed any problems with trees near leachfields in more than 45 years working around septic systems. Quite the contrary, the problems I've seen are generally with the septic systems because of root intrusion.

While problems can occur with any septic system, and even with poorly joined pipes in municipal sewer lines (of which I have dug up several), the problem appears to be greater with septic systems for vacation homes. Because of my concern for this, I wrote an article that Onsite Installer printed back in August 2004 explaining my experiences and concerns with root problems.

I think your trees are going to be fine, but it's the septic system that will need watching.

Russ Lanoie

www.RuralHomeTech.com

Conway, N.H.

It's very simple...

I just read your article about trees and onsite systems. I am an installer in Pennsylvania, and have been installing for 28 years. It's very simple: Root systems of trees are drawn to water, and what do drainfields contain? Need I say more? I hope everything works out!

Ronald DiGregorio

Delaware Valley Septics

Upper Darby, Pa.