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General Forestry => Ask The Forester => Topic started by: palmerstreeservice on January 30, 2005, 06:56:55 PM

Title: Checking the middle of the tree
Post by: palmerstreeservice on January 30, 2005, 06:56:55 PM
I have customers frequently ask if the middle of their tree is hollow... As a general rule the trees outer appearance gives me a good clue because they don't call unless they notice a potential problem which generally means its too late.

I have seen what I would call a hand crank drill bits for checking the inner part of the tree, however this looks time consuming.

Can I do the same thing with a long narrow drill bit and then stick a wire in the hole and find out if the middle is soft.

Also no matter which way you go about this is there a specific spot this should be done at and should I put Pruning Sealer on it when finished

Kyle Palmer
Title: Re: Checking the middle of the tree
Post by: Jeff on January 30, 2005, 11:03:15 PM
You can go to forester suppy and look for an increment borer.
Title: Re: Checking the middle of the tree
Post by: Eric_Jensen on January 30, 2005, 11:34:41 PM
Rubber mallets work well for initial inspection.  They are easier on the arms ;D, and also won't break a CODIT barrier on trees not slated for removal.
Title: Re: Checking the middle of the tree
Post by: Texas Ranger on January 31, 2005, 10:21:19 AM
Or, you can do the Missouri Butt Pat to determin interior condition.  Some what of an art, but the sound varies when the trunk is hit with an object, and you ear is hard up against the stem.  Solid stem has a hard sound, hollow, well, a hollow sound. 

We are successful most of the time with the butt of a knife, tapping the stem.
Title: Re: Checking the middle of the tree
Post by: palmerstreeservice on January 31, 2005, 10:26:28 AM
so if you do actually tap it, can you use just a long deap bit with a cordless drill or will the speed somehow damage the tree, and then do you still seal it?
Title: Re: Checking the middle of the tree
Post by: Larry on January 31, 2005, 03:12:45 PM
I learned that Missouri Butt Pat thing on telephone poles long time ago.  Not as easy on trees though.  If I found one suspect I would take a cordless drill (fresh battery) with 1/4" electricians bit for proof positive and then plug the hole with a dowel.  No idea if this is approved practice or not.

Increment borer things are for checking growth rings and age??  Seemed like they are pretty pricy to as I saw a forester throw a little tantrum when he broke one off in a tree. ???
Title: Re: Checking the middle of the tree
Post by: Texas Ranger on January 31, 2005, 04:09:45 PM
Increment borers will also get stuck in a hollow tree, and then you have a hollow tree with a spigot.

A drill will work, then you have to probe to see if it is hollow, and on a 20 inch tree or bigger it gets kinda dicey. 

Either way, do not plug the hole, the tree will grow over it the first year.  1/4 inch drill at the most, you should feel it when you break into the hollow section.

Hardwoods can be interesting, hollows may have pressure in them, fluids, let me correct that, smelly fluids, that will flush out under pressure when you hit the hollow.  Brightens your day .

Missouri butt pat is my way, I smell better at the end of the day.
Title: Re: Checking the middle of the tree
Post by: Larry on January 31, 2005, 04:42:30 PM
Quote from: Texas Ranger on January 31, 2005, 04:09:45 PM
Hardwoods can be interesting, hollows may have pressure in them, fluids, let me correct that, smelly fluids, that will flush out under pressure when you hit the hollow.  Brightens your day .


I was helping some guys log a tract that they were behind on one day.  I was sorta being a PITA and was carrying on about wanting a big tree to cut.  After lunch we went to a new place and the boss said "there is your tree Larry".  Huge black oak...sure wasn't any worries about it being a leaner.  Bored straight in with the 066 fast as I could and this huge geyser of stump water came shooting back out. >:(  Turned around and the boss along with couple other guys were rolling around on the ground laughing. ;D :D ;D

Decided to be a little bit more reserved the rest of the day. ::) ::)

Thanks for the tip on not plugging the hole Don.
Title: Re: Checking the middle of the tree
Post by: Eric_Jensen on January 31, 2005, 10:37:38 PM
Kyle, I haven' t used an increment borer in years, so had to crack the books. 

Pirone's Tree Maintenance page 191 discusses these decay testing tools  http://www.fujikura-westbury.co.uk/speciality/products/decay/index.html   (hope I'm not breaking any rules posting the link)

Shigo in A New Tree Biology cautions against using increment borers.  Page 548 "Studies on the injuries made by increment borers....showed that the wounds caused long columns of discolored and decayed wood.  Some holes were plugged with wooden dowels, and others were filled with all types of wound dressings and wound sealants.  There is no doubt , the borer wounds do injure trees, and may start cracks.....I do not trust the results obtained from a few cores."  Page 555 "Keep increment borers out of trees that are wanted for high quality wood."
Title: Re: Checking the middle of the tree
Post by: Furby on February 01, 2005, 12:28:33 AM
Quote from: palmerstreeservice on January 30, 2005, 06:56:55 PM
I have customers frequently ask if the middle of their tree is hollow... As a general rule the trees outer appearance gives me a good clue because they don't call unless they notice a potential problem which generally means its too late.
Kyle Palmer

Sorry, but I guess I'm missing the point. If there are no noticable signs, what does it mater if you are not taking down the tree anyways? Are they going to have you remove the tree just because it's hollow? Trees can live a very long time hollow, and stay standing long after death. Lots of solid healthy trees can be more likely to fall over or break off. Why damage a the tree for really no reason?
Title: Re: Checking the middle of the tree
Post by: chet on February 01, 2005, 01:24:53 AM
 :)  Furby, you said what I been thinkin'.   ;D
Title: Re: Checking the middle of the tree
Post by: Ron Scott on February 01, 2005, 11:00:24 AM
Watch for the wildlife use being made of the tree. Hollow trees make good den, snag, or cavity trees and may have that value if you enjoy viewing wildlife.
Title: Re: Checking the middle of the tree
Post by: Tom on February 01, 2005, 03:32:22 PM
You never know just what kind of strange being you'll find in a tree cavity. :D
Title: Re: Checking the middle of the tree
Post by: SwampDonkey on February 01, 2005, 05:31:50 PM
I've seen white pine forest stand long after a fire passed by. The new forest grew up around the old white pine stubs that still stand to this day after the new forest has matured. White pine trees take a long time to decay, same as hemlock. I've got a large balsam fir tree behind the house. I'm afraid it will come down soon. It's been dead for 3 years now and rocks away in them wind storms. Fir tends to snap off and doesn't uproot that often unless the site is wet.
Title: Re: Checking the middle of the tree
Post by: palmerstreeservice on February 01, 2005, 06:01:52 PM
I agree by letting it be if there are no tatle tail signs however, (no offense to the older croud) old people freak out about trees.  They call all the time just to have them checked and this and that.  Always worrying.  I look at them tell them they are fine but several people have said, "don't you have a way to check the middle." So I guess that is why I am checking into the boring.  I'm not sure but I may be putting my neck on the chop block, if I tell someone the tree looks ok and they request I check the middle, don't and then the wind blows it over on their house, I would guess I am making myself liable for telling them it is ok.
Title: Re: Checking the middle of the tree
Post by: Frickman on February 01, 2005, 08:07:46 PM
PalmersTreeService,

A doctor has alot of different tests, x-Rays, CAT scans, etc. he can do on you to see what is going on in your body, but sometimes he has to open you up to see what is really going on. I figure trees are the same way, you can tell alot by looking at the outside but sometimes might have to open them up to see what's there. I'm not an advocate though of drilling into trees, except to make maple syrup.

You can use your experience and external signs to give your customers an educated guess as to what's inside the tree, and use the above analogy to avoid drilling into the tree. And just like a doctor's patient, that tree can blow down or die at anytime and there's not alot you can do about it. They will have to understand that like a medical doctor, you're not a miracle worker and cannot will a tree to live when it's time has passed.

Title: Re: Checking the middle of the tree
Post by: SwampDonkey on February 01, 2005, 08:28:56 PM
A few years back I was asked to have a look at a couple of Carolina poplar on a lawn. The neighbor was scared the trees where gonna come down on the houses. The trees were 40 plus inches. One tree I inspected had some conk at the butt the other looked sound but had a large crown. I  recommended removing them before the wind knocked them down. I know hese trees have been there along time and you wouldn't think they would blow over in the next big storm. But, low and behold a NEaster blew in a couple weeks later and the tree with the conk was broke off at the infection and the tree that was sound was uprooted. Luckily the wind blew those trees away from the buildings and out across the road. It knocked out the power but the houses were spared. I can only imagine what the owner felt after the trees fell over. I wonder how hostile her neighbors where after me being there in their presence to suggest taking them down?  ::)
Title: Re: Checking the middle of the tree
Post by: palmerstreeservice on February 01, 2005, 10:58:24 PM
I really like the doctors example I think I will use that.  THanks
Title: Re: Checking the middle of the tree
Post by: rebocardo on February 02, 2005, 11:35:32 PM
> I wonder how hostile her neighbors where after me being there in
> their presence to suggest taking them down?

Unless they offered to split the costs I hope they weren't hostile  ;)
Title: Re: Checking the middle of the tree
Post by: SwampDonkey on February 03, 2005, 06:29:36 AM
As I recall a nieghbor was interested in helping with the cost, but the landowner didn't want to part with her trees so much.  Even her own son wanted her to remove the trees. ::) It's not really the responsibility of the neighbors to share cost removing your trees, but danger trees may make a nieghbor look at things a little different.  ;)
Title: Re: Checking the middle of the tree
Post by: leweee on February 04, 2005, 01:16:32 PM
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. :o
Title: Re: Checking the middle of the tree
Post by: rebocardo on February 04, 2005, 08:10:38 PM
> 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.
Title: Re: Checking the middle of the tree
Post by: Phorester on February 04, 2005, 09:59:33 PM
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".
Title: Re: Checking the middle of the tree
Post by: chet on February 04, 2005, 10:25:48 PM
Quote from: Phorester on February 04, 2005, 09:59:33 PM

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.
Title: Re: Checking the middle of the tree
Post by: Andy Henriksen on February 07, 2005, 03:05:33 PM
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.
Title: Re: Checking the middle of the tree
Post by: Larry on February 07, 2005, 03:57:16 PM
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?
Title: Re: Checking the middle of the tree
Post by: Phorester on February 07, 2005, 09:05:41 PM
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.
Title: Re: Checking the middle of the tree
Post by: Phorester on February 07, 2005, 09:11:53 PM

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.
Title: Re: Checking the middle of the tree
Post by: Andy Henriksen on February 08, 2005, 08:49:50 AM
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.