One a day, plus iron

So in the previous post, we discovered that logs 26" in diameter were like 40% bigger than logs 22" in diameter. Is there a point where a 4" increase in diameter makes the log 50% bigger? Heck, what is the relationship of 4" difference in trunk diameter as the overall size of the tree increases? How can we find out? (Yeah, it's maths. Look, this is not my fault. I just go where the current interests take me. Probably this all stems from the "half a dog" bullshit from badly-written homework at the beginning of the month. What can you do?)

( Everyone wants to read about maths, right? )