Watering the trees just now I found my one single pine tree was lying completely out of the pot, and most of the substrate was also out, so the tree's roots were lying in the hot sun and had been there a while. The tree was sitting right under the bird feeder, so I guess that some seeds had fallen into it and been dug out by some creature - maybe the chipmunk in the previous message.
I brought it inside, put more substrate in the pot, took it into the kitchen, and soaked it. Now it is still there, out of the sun. I think it has had enough.
My guess is the tree is dead, and it will take a long time to tell, since it is a pine.
Obvious question: anything else to do? I was thinking tomorrow take it to the window that gets lots of sun but is in the air conditioning, and then the next day take it outside in the heat (highs 85-90 F, 30 or so C). Maybe in the front of the house to get only a little sun for a while. And, of course, no fertilizer until new growth appears (or everything turns brown).
