Checking the middle of the tree

[leweee]

Kyle... if you use the doc  analigy make sure you have Mal-practice insurance...... at least a wavier for the client to sign . most certified arborists do this to CTA.

[rebocardo]

> find out if the middle is soft.

I do not think you need a wire or borer to find out. If a tree is punky on the inside what the drill bit extracts will be self evident because it will be smelly, brown, and decayed ... or nothing at all.

You can tell just by feel because when you hit a bad spot there will no resistance like there is trying to drill the green sapwood. A 18v drill usually has a very hard time going through green oak, that much I know using a 1/2" bit.

Usually all the punky stuff falls down to the bottom of the tree along with the water.

My favorite way of testing if a tree is punky before I cut it down is to take a long screwdriver and small sledge hammer and see if I can drive it past the bark in a soft spot or where there is no bark.

Usually if the tree is that bad, I skip the tree and tell them to get a professional arborist or tree service in to take it down $.

I have a problem with drilling holes in trees even if the person wants to, because I know something as simple as three months worth of vine growth on a tree can give enough foot hold to termites, beetles, mothes, or grubs to doom the tree.

imo, A 1/4 - 1/2" hole directly into the middle of the tree, especially unsealed or blocked with something solid is nothing but a meal ticket to a termite or carpenter ant.

Here in GA where I live, just having an ivy vine going up a tree is enough to doom a red oak (white oaks seem to hold up better).

I had a vine grow up a tree during the winter and three months later when I went to clean up the yard again it was enough to give a termite colony a foothold in the tree. I nuked them with Raid, but, I think the tree is probably a goner now if they managed to make it to the middle.

I would avoid drilling a tree unless I was pretty sure it needed to come down and if I needed to drill the tree I would use a drill bit they use for drilling rafters for wires about 18" long.

[Phorester]

Kyle, I examine several yard and street trees every year, as that is part of my job as a Virginia Service Forester.  If the homeowner is concerned that they are hollow, I use a hand axe and 'sound' them as Texas Ranger describes.  You can begin to tell the difference yourself by sounding an obvious hollow tree and one that looks solid.   But..........

As other posters are saying, if it is not obvious by looking at the outside of the tree, it's hard to tell if it is hollow or not unless you drill it, and even that is not foolproof especially if your drill/increment borer doesn't reach to the center of the tree. As one poster said, just because a tree is hollow doesn't mean it is not safe.  We've all seen obviously hollow trees stand for decade after decade.  And of course, if it is punky in the center instead of hollow, it's just as structurally unsound as if it was hollow, but harder to determine.  It's also hard to explain that to a concerned homeowner because they think it's a simple matter for an "expert" to determine.

I always follow up my visit with a written letter so there will be no misunderstanding as to what I told the homeowner if something happens to the tree later. I also include the following statement in each letter where the homeowner asks if the tree is in danger of blowing down:  "It is impossible to predict how long any tree will stand.  Even a perfectly healthy and windfirm tree can blow down in the next thunderstorm if the wind is strong enough".

[Chet]

I always follow up my visit with a written letter so there will be no misunderstanding as to what I told the homeowner if something happens to the tree later. I also include the following statement in each letter where the homeowner asks if the tree is in danger of blowing down:  "It is impossible to predict how long any tree will stand.  Even a perfectly healthy and windfirm tree can blow down in the next thunderstorm if the wind is strong enough".

Phorester,
I do the very same thing. I also point out other trees in the area, that are more likely to come down for a host of different reasons.

[Andy Henriksen]

I've just read through this thread and have a few comments.  While it is true you can't predict when a tree will fall, there are standards for assessing whether a tree is generally sound.  The structural integrity of a tree CAN be calculated if a few variables are known - diameter of tree, diameter of sound wood, size and types of external defects, etc.  I believe ISA has a publication on this.  Also,  USDA publication NA-TP-03-03 "Urban Tree Risk Management: A Community Guide to Program Design and Implementation" has a great guide in chapter 3 - How to Detect and Assess Hazardous Defects in Trees.

The bottom line is there is a science to this, perhaps an ever-evolving science, but a science nonetheless.  If, you are "eyeballing" it, and you are wrong, you have nothing to back you up should a client decide to sue you. 

I'd highly encourage anyone making these assessments outside of their own backyards to join ISA, and become a certified arborist, and familiarize yourself with the industry standards of hazard tree assessment.

Finally, drilling (with a small diameter bit) is common and acceptable, but should only be done when there is reason to suspect heartrot, as there is a slim chance that the drill hole coudl become a conduit for disease.

[Larry]

Couple of questions.

I am well acquainted with utility poles.  Just because a pole is hollow does not mean it needs to be replaced, as most of the strength comes from the outside couple of inches.  Would this be the same for a tree?

When some of the tree service outfits find a hollow tree they want to fill em up with re-bar and concrete.  I sorta suspect this hastens the demise of the tree alone with being hard on my chain when I take it down.   Comments?

[Phorester]

Yes, it is the same for a tree as a hollow utility pole.  Maybe even more so because the tree is still alive and will contribute new wood every year on the circumfrence of the tree, thus increasing it's strength.

Concrete and rebar was once an accepted practice to "strengthen" a hollow tree many decades ago.  It was found, however, that concrete doesn't bend and sway in the wind, as every tree does.  Therefore, a tree with a concrete plug in it will eventually crack around the concrete as the tree moves and the concrete doesn't.  So in the long run, concrete in a tree will actually cause the tree to weaken as it splits and cracks apart around the concrete.

[Phorester]

ANDYHIX,  I agree with your opinion of ISA certification.  I'm also an ISA Certified Arborist, and am impressed by the entire certification process.  The initial certification test was one of the hardest tests I've ever taken.  The requirement of continuing education credits every 3 years adds to the integrity and credibility of the designation.

Anybody in the tree service business should become certified by ISA, then promote the heck out of it.

[Andy Henriksen]

Larry, for trees, assuming no other defects (cracks, etc.), a tree is considered sound if there is at least 1" of shell thickness for every 6" of stem diameter.  i.e. 1/3 of the diamter should be sound wood.