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Classic-Marsupial126 t1_j5uaxc0 wrote

What's the oldest fire you have identified?

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Prof_Fire OP t1_j5uc0dl wrote

In terms of published studies, the oldest fires I have found so far are in the 1600s. However, we have work underway in Florida that shows fire activity in the 1500s! We are limited by how long the trees live. However, if we collect a very old stump that was cut down over a 100 years ago, we can get back further in time. In some places, with longer-lived tree species, fire history can go back beyond a millenia!

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amirghajari t1_j5ue578 wrote

But does it mean that you should cut those old trees down to see the rings and check for fire marks?

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Prof_Fire OP t1_j5uiy81 wrote

In my own research, I do not sample live trees for fire history. Because fire scars can occur on any side of a tree, we generally need a full cross section (sometimes called a tree cookie) for the fire-history work. We focus on collecting these cross sections from snags (standing dead trees) and stumps. There is a tree-ring method of sampling live trees without them - a pencil thin core is extracted using a tool known as an increment borer. However, this method is not useful for fire history; it’s used in studies that examine things like tree age and climate-growth relationships. You can check out cool photographs of working with stumps and live trees on my research website:

https://sites.google.com/view/monicarother/photo-gallery

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LowInFat t1_j5uhd49 wrote

You can take small cores from live trees without harming them. They don't need to be cut down. Here in the Pacific Northwest, I've cored a 400 year old Douglas fir.

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