By Tobias Carroll There aren’t many living things on the planet that one could describe as being as old as the pyramids. When it comes to the bristlecone pines that are found in just three states, however, that’s exactly the kind of longevity you’re looking at. These trees have stood for thousands of years, with one of the oldest reaching the age of at least 4,700. And now, unfortunately, they’re at risk. Last month, a Los Angeles Times report explored a pair of threats faced by bristlecone pines. Both an invasive species — in this case, a kind of beetle — and the drought conditions that have …