Hollowed Oaks - How to tell?

[Canyonbc]

This thought has been bugging me all day. When looking at a Oak tree, that is dead but has no obvious cavities or anything gapping holes...how you do know if its hollow.

If it shedding bark is this a sign?

Are there other techniques to figure out if its hallow or not???

 

[Magnum783]

I use a couple when I suspect something of this nature, not sure if all are totally correct but they both seem to work well. I hit it with a sledge or splitting maul and listen for a timpanic sound or hollow sound. Or even a sound that sounds different than a normal thud. The second method my most preferred method is to use an auger bit on a cordless drill. Like a bit that one would use to install cables with. I drill a few holes a different heights and that gives me a fool proof determination at least at the place where I drilled the holes as to wither the tree is rotten or not. Now the only catch to using a drill is yes you are taking away valuable wood from the tree and you making a slight week spot. My drill bit is only 1/2" so I am too concerned. Also if you have a really wide tree it will be difficult to find a bit long enough to go at least half way. You will however have to have a really huge tree. You are able to drill almost 24" with my bit using an extension. Now I know I am not a pro but I am learning and this what a pro passed on to me as advice as to how to check. Good luck and if you have any doubt just don't climb it and find out for sure some way or another.
Jared

 

[Canyonbc]

Thanks Jared,

I am not a pro either, how to be one, some day but not there yet. I had similar thoughts to what you were thinking..but wanted to ask everyone and try get some different ideas.

I think the safest thing though, is just like you said...if your not confident, then dont climb it.

Thanks for the tips though,

Mike

 

[Stihlboy088]

Hollow

Bang on it and listen for unusual resonance, or get an increment borer. I bought one several years ago it's used to extract core samples,age and soundness of the tree. They are a bit pricey but i've used it enough to find it a worthwhile investment. Check out Ben Meadows.

 

[Canyonbc]

Bang on it and listen for unusual resonance, or get an increment borer. I bought one several years ago it's used to extract core samples,age and soundness of the tree. They are a bit pricey but i've used it enough to find it a worthwhile investment. Check out Ben Meadows.

Thanks

I will look into Ben Meadows

 

[John Paul Sanborn]

A 1/8 drill bit will suffice, you just need to look at the frass off the bit. Color will tell and you will notice resistance changes. 20% holding wood is usually OK to climb for me.

Thumping is good to, I do it all the time.

What I like less then hollows, is visible root rot.

I had an ash the other day that I was trying to get a throughball into, and pulled it out of the root plate. I had to step to the side a bit since it was 35-40 ft tall.

 

[kkottemann]

When buying hardwood timber I tone every tree in my plot. I use 9 Oz ballpin hammer and hit all around the base of the tree. With a little pratice you will be able to tell which ones are hollow, doddy (sort of hollow) or solid. If the hammer goes through the trunk, then you have a problem.

 

[Canyonbc]

Alright thanks for all the tips. and information.

 

[Dadatwins]

I agree with JPS, more concern with root plate and stability than hollow. A hollow tree can stand and be climbed, if the root plate is decayed the whole tree is a risk to fall over. I climbed a box elder one time that was so hollow the spike hole were visible on the inside of the tree. Be more concerned with decay and root rot at the base. Rope test is good test, just be sure if the tree fails the test and falls over, there is room to fall.

 

[Canyonbc]

I agree with JPS, more concern with root plate and stability than hollow. A hollow tree can stand and be climbed, if the root plate is decayed the whole tree is a risk to fall over. I climbed a box elder one time that was so hollow the spike hole were visible on the inside of the tree. Be more concerned with decay and root rot at the base. Rope test is good test, just be sure if the tree fails the test and falls over, there is room to fall.

Thanks thats huge...

Crazy info.

When you say rope test...providing there is room...how much pull do you want to do put on it.

 

[John Paul Sanborn]

just be sure if the tree fails the test and falls over, there is room to fall.

This is the most recent one for me. I was going to climb it tied into an adjacent tree just from the look of the basal flair. Then i saw it moving in the wind and was "concerned".

A few weeks earlier I had walked form it as the last tree of the day, I had gaffed up a few feet and looked down an was very uncomfortable.

This time I did a pull with 2mm ZingIt with this result.

 

[tree md]

I had a large removal about a month ago that had a large cavity at the base. It was a Silver Maple about 2 1/2' dbh. I looked the tree over, sounded it out and assessed that it was sound enough to climb. When I got 60' up in a leader I found that the leader was hollow through and through. It was 8" diameter at 60' and had a knot hole that I could stick my fist in. I needed to go up another 15' to about 5" diameter to make my cut. I needed to go that high because it was over the high lines and needed to get up there to clear them with a free fall. If I could have tied into another leader I would have went ahead and done it but the only tie in point would have swung me into the lines if I were to swing. I decided against it. I took a rotten piece of core wood that I dug out of another knot hole, went to the home owner, explained the situation and told him I would need a crane to proceed with the job. I also explained that it would cost a considerable amount more. Thankfully he was an understanding customer and told us to go ahead and do it along with 2 other larger trees with the crane. Turned into an excellent job. However, I learned a lesson there. I look them over really close now and have even started using binoculars to glass for cracks and hollow spots before I give an estimate or climb.

 

[Canyonbc]

I had a large removal about a month ago that had a large cavity at the base. It was a Silver Maple about 2 1/2' dbh. I looked the tree over, sounded it out and assessed that it was sound enough to climb. When I got 60' up in a leader I found that the leader was hollow through and through. It was 8" diameter at 60' and had a knot hole that I could stick my fist in. I needed to go up another 15' to about 5" diameter to make my cut. I needed to go that high because it was over the high lines and needed to get up there to clear them with a free fall. If I could have tied into another leader I would have went ahead and done it but the only tie in point would have swung me into the lines if I were to swing. I decided against it. I took a rotten piece of core wood that I dug out of another knot hole, went to the home owner, explained the situation and told him I would need a crane to proceed with the job. I also explained that it would cost a considerable amount more. Thankfully he was an understanding customer and told us to go ahead and do it along with 2 other larger trees with the crane. Turned into an excellent job. However, I learned a lesson there. I look them over really close now and have even started using binoculars to glass for cracks and hollow spots before I give an estimate or climb.

Wow, one heck of a story you got there...def. agree you did the right thing of going to the customer, and luckily he was gracious enough to agree with you.

Congrads on getting the other trees, and a job done well/safe.

 

[newguy18]

I don't know about oaks in california but the oak trees down here are almost always rotten.the signs to check for rot I go by besides smacking the trunk are if there are any dips in the trunk espically around the root crown area or sinc most of them in my area have crotch unions at about 10 to 20' off the ground I rope up and inspect those because if a tree is rotten down here with out a cavity then there is almost always a hole in the crotch union usually about the size of a 1/4 " drill bit.

 

[Canyonbc]

Sounds like a good plan.

I don't have to much experience with Oaks, but getting more and more...so just trying to gain as much info as possible

 

[Dadatwins]

When you say rope test...providing there is room...how much pull do you want to do put on it.

Really depends on the situation, sometimes the wind will show movement and listen for sounds in the tree. As for pulling I am pushing 250 lbs and can get a pretty good pull on a tree, but sometimes better to have someone else pull while one person stays near the base and looks for movement. If the tree is that questionable and you are just not comfortable, find another way instead of climbing it or walk away. That is the best advice anyone can give. Be careful.

 

[Canyonbc]

Really depends on the situation, sometimes the wind will show movement and listen for sounds in the tree. As for pulling I am pushing 250 lbs and can get a pretty good pull on a tree, but sometimes better to have someone else pull while one person stays near the base and looks for movement. If the tree is that questionable and you are just not comfortable, find another way instead of climbing it or walk away. That is the best advice anyone can give. Be careful.

Thank you,

I had a feeling that is what you meant (person pulling), but wanted to confirm.

I whole hardly agree, 110% "If the tree is that questionable and you are just not comfortable, find another way instead of climbing it or walk away." - Totally agree, cant say it enough.

but thanks again for the info

Canyon