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Our neighborhood is filled with oaks, and I have at least 6 or 7 on my relatively small property (~0.3 acres). I've always wondered how old they are, and if they pre-date the house or not (this house is just under 20 years old).

My neighbor recently cut down one of her oak trees due to disease (I don't know the details). It was similar in size to mine - some of mine are smaller and some of mine are bigger, so I figure its age is a rough average for the age of my trees. I checked the recently cut cross-section near the base of the tree, and while I can clearly see some rings on the inside, they are only distinct for about the inner third of the tree. I've successfully "aged" other trees like this, so I'm not sure what is going on here (the lack of discernible rings doesn't seem like it is caused by the chainsaw). In case it helps I'm in North/Central Florida.

Upon further inspection: The original and very indistinct photo of the tree was from when it was freshly cut down a week ago. I just took another picture today and the outer rings stand out substantially more, although now I'm more confused. Some sections in the middle are still very indistinct, but the outer rings appear substantially larger than the inner rings. Is this normal? I could understand differences in age/climate making tree growth more favorable, but it appears to be a factor of 2 or 3 difference, which makes me wonder if these outer rings are something other than annual growth rings. Presuming that the large outer rings are normal annual growth rings, then I think I can find at least 30 distinct rings. There are areas where there are obviously rings but I can't see them, so I'm guessing it is about 40 years old.

Any guesses as to how old this tree is? Am I "interpreting" it properly? I've also embedded the pictures below, but doing so required shrinking them. The above links will take you to the original, higher resolution images.

enter image description here

  • The year rings are not good visible in this picture probably due to light. The white stuff in the middle is probably the disease (looks as fungus). The trunk does however have rings, you can see them a little bit at around 10 O'clock. Also the brown parts in the middle show some ring structure. – benn May 14 at 7:06
  • @benn I'm not sure if lighting is the problem. I couldn't see them any better in person. I was in shade, but this was in midafternoon on a sunny day. The light doesn't really get any better. – conman May 14 at 11:17
  • I think you should lime away some dirt. Glossy surfaces are easier to read. Do you know the species? To me this tree does no seem old. Maybe 20 years? In your climate maybe also less. – Giacomo Catenazzi May 14 at 13:13
  • @GiacomoCatenazzi lime away some dirt? I still have the stump (the neighbor obviously didn't want it and I figured I'd find a use for it) so if there is something I can do to figure this out I'm up for it (preferably involving common household materials). Indeed, that's why I asked if it is possible to determine the age of the tree - techniques to help are welcome as an answer, even if you can't tell the age of the tree from the photo. – conman May 14 at 13:16
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    @GiacomoCatenazzi by "lime" do you mean rasp, file, plane or sand away some surface wood to make it smooth and easier to evaluate? Lime in a garden context usually means a white calcium compound. If the latter, what function does the lime powder provide? Thanks. – Colin Beckingham May 14 at 15:04
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One way you could go about attempting to verify your age is by estimating the tree's age based on its growth factor. Just figure out the diameter of the tree and then multiply by its growth factor. The growth factor for the Oak is 3. This will give you an approximation for the age of tree which you could use to compare with your other approximation, GL!

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    I've never heard of that method before - thanks! – conman May 14 at 17:01
  • @conman NP, have fun! – Rob May 14 at 17:02
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    Can you add a reference to the growth factor that you quote? Thanks! – kevinsky May 14 at 17:19
  • @kevinsky Ugh, always making things complicated. It's going to require more than that because it depends on the variety of the oak but of course you knew that didn't you? – Rob May 14 at 17:26
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    @Rob I was hoping you could refer to a web link, preferably from a university, arborist which showed the growth factors, thanks! – kevinsky May 14 at 17:56

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