The true-to-title version: I found a fire-scarred birch on the hill above our house and cored it to see how long it’s been since the last forest fire here. It was surprisingly long ago.

The fire regime in the Interior is an important part of boreal forest ecology. Natural, lighting-caused fires are common in the region in the summers, with some years being quite bad. This past year, for example, was the second-worst fire year in history, with over 5 million acres burned across the state (that’s as big as the entire state of Massachusetts). The worst was in 2004, when over 6 million acres burned. But with good fire protection within the Fairbanks North Star Borough’s residential areas, it has clearly been many decades since our neighborhood woods last went up in smoke. I often wondered just how long it had been.

A venerable relic of a birch with fire scarring at its base

In meandering around the woods this summer, I noticed that a venerable old relic of a birch had some fire scarring at its base. It had undergone a lot of growth since that bygone day, and a big lobe of the post-fire growth overlaid the scarring in such a way that it would be easy to get an age on it. So the next time I went out I carried a tree increment borer and took a core. It turned out to be one of those cores that is challenging to get an accurate count on. I’ve now counted that sucker about ten times in different light, with different lenses and magnifications, with sanding, and even oiling. Bottom line? 120-130 years. That was a surprise. It’s no wonder that I hadn’t seen signs like this before. When spring arrives I may go out and find some more and narrow down the date.

A close-up, with a lens cap for scale on a lobe of post-fire overgrowth.