For the moment, I came up with a way a smooth over relations between Gran and her new in-laws. Tree produces a plethora of pine cones every year, most of which simply fall to the ground and don't do anything. Tree's shade keeps any of the seeds from producing survivable saplings, so the cones just end of being a waste of her resources. She's probably the only tree in the world who possesses emotions, and in this case she experiences deep frustration.
I'd learned that squirrels love pine cone seeds which are rich in nutrients that squirrels require, so when I heard about Gran's problems I put the two things together. Fenton and I gathered in a wheelbarrow about 75 pines cones beneath Tree's branches, and carted them over to Mr. Squirrel's tree (where Gran lives now). I tied a big bow around the wheelbarrow with a tag reading "From Dorothy Kindle-Squirrel" and the in-laws were invited over. Fenton and I left, but I heard later that their mood improved dramatically.
While Tree knew that the seeds inside the cones would be eaten and that they wouldn't produce progeny, she was glad that they were being put to use and not just rotting in the dirt. She's conscientious that way.
Today's question: Being all the same species, do humans have conflicts with in-laws?