Increment Borers

[DMc]

I would like to get one and could use some feed back from those that are familiar with their use. Burnham, you just mentioned in the resistograph thread that you use them. What can and can't they do? Are the smaller sizes .169" or .200" large enough to get readable cores? What about the "2-thread" to "3-thread" pros and cons.

I'm thinking this could be a very viable alternative to the Resistograph. I know it is "old school" but there is a lot of history in its use and I'm not particularly stressed by pulling a slightly larger hole and breaking boundaries if it will get me good, readable information. With a clear core I should be able to photograph and have a hard copy fact sheet for the client with a lot less expense.

The core could also be labbed to id any particular decay organisms.

I'm interested in anybody's feedback on experience with these tools.

Dave

 

[flushcut]

I was thinking the same thing so I am along for the ride.

 

[Paul B]

I got one off Ebay a few years ago, about $80 I think, for a Suunto 18", 9/16 core, in darn good shape.

 

[sotc]

They would provide useful info. The one thing they would not do so well is document the size of a cavity.

 

[Paul B]

no?

 

[sotc]

Not really. You could run a wire in to the end of the hole and compare against the plug if you dont break it. Still not truly documented. I'm not bashing it as they are handy and perhaps more important than the cavity is that it can document the shell thickness.

 

[stig]

Only thing I know about them is that if you break one in a 4800+ years old bristlecone pine, you can get permission to cut the tree down.

 

[Burnham]

The first thing you need to understand about increment borers is that they are a delicate instrument that takes a certain amount of skill to use without damaging beyond repair. The cutting tip on the bit is quite thin and brittle. It is very easy to nick or chip that edge by bumping it against any metal object, especially the open end of the handle when returning the bit inside for storage. The bit shaft itself is somewhat brittle, too...rather like any drill bit. I have seen them snapped in two by ham-fisted operators, allowing themselves to introduce sideways pressure when driving the bit.

Frequently, if not properly maintained, a piece of the core will lodge just inside the tip when the extractor (commonly called the spoon) and core are pulled free from the bit. NEVER attempt to dislodge this from the open end of the tip with any metal object, like the end of the spoon, a small screwdriver, etc...the chances that you will chip the cutting tip are close to 100%. If any damage whatsoever occurs to that cutting edge, the increment borer will not produce a clean, retreivable, usable core. Instead, push the offending piece out from the rear, using something skinny and stiff. I use a length of stainless steel car radio antenna.

One problem with increment borers is that when you drive the threads into rot or a cavity, it can be hard to get it to back out...the threads don't have anything to bite. There are a few tricks that can work if all the stars align, but once in a great while a tree keeps a borer.

The smaller diameter borers do indeed produce readable cores. I much prefer the small diameter...it's easier to drive and remove, and does less damage to the tree.

Three thread style is easier to drive, and generally cuts more cleanly since the borer drives less deeply with each turn of the handle than does the two thread style.

In my experience, there are significant differences in how well the products of different manufacturers perform. Look for thin, sharp edges on the threads...some are broader and more dull, just don't engage and drive or remove as efficiently.

It's usually a good idea to put some sort of pulling handle, in the form of a loop of cord or a turk's head knot, on the end of the spoon, to make extracting the core easier.

Invest in a set of special sharpening stones...a cone and flats. If you do ding up the cutting edge, some companies provide professional rehab/maintenance service...but too big a chip will put the borer beyond help. Replacements of all parts are generally available, if on the spendy side...but that's the case with a good quality increment borer anyway.

Forestry Suppliers has a Tech Tips doc for increment borers...here's a link.

http://www.afoa.org/PDF/ci0111_b.pdf

 

[Bounce]

You are a hard act to follow Burnham. I think you nailed all the most important points.

 

[DMc]

Great stuff, Burnham, thanks so much! What immediately caught my attention was the difficulty in removing the borer from an open cavity. This was to be one of my primary uses, the determination, size location of open cavities, post core extraction with the use of a borer scope. Corings could be made with compass point references and plotted. This with a visual inspection from the inside should give a pretty definitive reading on the extent of internal, hollow decay pockets.

As fun as that sounds, its not going to work very well if every time I core I have to wait for the stars to line up to get it back out. So whereas I am still interested in getting the increment borer, I may have to rethink the above strategy a bit.

Sounds like a second set of threads would sure be a nice way to prevent pocket suck.

Dave

 

[Burnham]

You can tell them how to get a hung borer to back out, Sean .

 

[Burnham]

Since Dave is online and thinking this might be a problem, I'll go ahead, Sean...sorry .

Really Dave, most times you won't have a problem. Anyone with a decent feel for how things are going, a touch if you will, can usually tell when the threads quit biting. The borer won't be advancing any more as you turn, and the tension on the handle drops off. If you keep turning the bit at that point, the treads strip out what fiber is there and trouble looms, but if you stop at the first indication that the tip is in rot, it usually can be backed out after you pull the core.

Carefully applying pulling power to the handles as you begin to back the borer out is very helpful. And the last trick in my bag is to loop a doubled small diameter cord over the handle and around the bit and tie it off around an anchor that is both at the same elevation and directly in line with the borer shaft (that's the star alignment part of it )...as you turn the handle the loop tightens and exerts strong pressure pulling the threads back into sound wood.

I bet for your purposes (not having to carry the thing through the woods), a U shaped frame could be fabbed up that would brace it's legs against the tree, leaving just enough room for the handle to swing inside it, with the cord tied off to the peak of the U...it would work a treat for retreival.

 

[Bounce]

I like your idea of using a twisted tether to help back the thing out. But in a nutshell, the trick to getting a borer unstuck is to avoid getting it stuck in the first place. Unfortunately this makes it kinda difficult to use for determining the extent of decay because the moment you hit a pocket of decay you have to stop boring. If you keep boring because you want to see how much of the tree is decayed, then you will strip out the holes and literally be screwed. The best advice I ever got when working with one of these was to pretend you are turning an steel bolt into an aluminum nut.

 

[DMc]

...as you turn the handle the loop tightens and exerts strong pressure pulling the threads back into sound wood.

I bet for your purposes (not having to carry the thing through the woods), a U shaped frame could be fabbed up that would brace it's legs against the tree, leaving just enough room for the handle to swing inside it, with the cord tied off to the peak of the U...it would work a treat for retreival.

Once again, good stuff. I'll let that tumble around in what used to be my brain for awhile.

Dave

 

[Burnham]

You also asked what an increment borer can and can't do...some further thoughts.

When I use the increment borer to evaluate the condition of suspected hazard trees, I generally bore three spots evenly spaced around the trunk. I stop boring when I hit soft wood. I extract the cores and by checking them, can tell how much solid rind the tree has, on average, and can compare that to the DBH and make a judgement on how stable it is. I will sometimes bore closer to the ground as well as up about chest high. I don't really care how much is truly hollow, or rotten... knowing the extent of sound wood is what I'm after.

But obviously, if you know how much is sound, you know how much is not.

.

 

[sotc]

Not nessasarily. especially on hardwoods. Incense cedar, Western red cedar, hemlock, pretty often you would be right.

 

[Burnham]

Well, I'll happily defer...I'm a conifer boy, y'all know that .

 

[Mr. Sir]

Haha, "conifer boy"

I like that, it has a nice ring to it.

 

[SkwerI]

 

[Mr. Sir]

I bought an increment borer a few years back; haven't actually used it yet. :roll:

 

[thattreeguy]

i have one i got from baileys
while assessing trees at a school some boys took it from my bag a few trees away and were sword fighting with it
lil brats bent the spoon......just a touch....bowed is more like it
now as i try to core a tree it pushes the spoon back and i cant remove the core cleanly like i used to

is it because of the bent spoon or does something else cause that

i used to used it a few times a quarter

 

[DMc]

Not nessasarily. especially on hardwoods. Incense cedar, Western red cedar, hemlock, pretty often you would be right.

Can you defend that statement, Willie? Just askin'.

 

[sotc]

How many trees have you cut down that had decay pockets, fractures etc but were otherwise sound wood? Butt rot in cedar and hemlock very often leaves just a shell that is pretty consistent around the tree. Not sure which part you want defended so trying to cover all bases.

 

[sotc]

Heres one such scenario, the only pic I have but i'd chalk that up to there being nothing special about a small pocket of decay making it not very picture worthy

 

[Burnham]

Good example, Willie.