Sounds like an oxymoron, but the pine white butterflies (neophasia menapia) are back in large numbers. Not good news for our trees, especially the ponderosa pines. Looking at the whole mountain you can see where last year's invasion killed a number of trees.
Early last week I took a hike with the dogs on the north side of our place, and once I got into the trees, I was brushing off what I first thought was many, many cobwebs, but on a closer look were the butterflies' caterpillars dangling from the branches by their individual silk strands. An entomologist said in a local newspaper article that she was in an area of the forest that had so many of the caterpillars in the trees, that as she was walking under them as they were pooping (peeing?) it felt like rain. Luckily, I didn't have that experience, but wound up waving my hiking pole in front of me to knock the silk out of the way.
Over the last several days, the butterflies have begun to emerge and there are more every day. Last year at their height, there were so many flying in and around the trees that in the same spot on the north side of our property, you could hear their wings flapping. At the time that was fascinating, but that was before we knew they could be destructive.