Something I think we need to clear up in terms of what is and is not on-topic, are questions where the user asks something that is not a biological question and then attempting to justify it being here because they have included a reference to a living thing.
For example, in this original version of this question the user asks why there is variance in the temperature of the shadows cast by trees.
Ultimately this boils down to a physics problem. For example, if we were to assume that it is only because of variance in transpiration rates of plants (clearly its more complex than this), the question would be "Why does the temperature of the shadow cast by two objects which transpire at different rates vary?" In my eyes, that's physics.
The user who posted that example question has edited that question to make it more on topic, and this is not meant to be a direct criticism of that post (I'm delighted to see someone fix a question and be open to feedback) - it just prompted me to make a meta post that I have been meaning to do for a while because this is not the first time I've had a discussion like this.
Similarly, we get people posting medical questions, then attempting to defend it by writing "This is a biology question so don't close it." Saying "Its a biology question" does not make a question biology.
Other hypothetical examples (because searching for these in the old, and probably closed, questions will take forever):
"If I drop an elephant and a mouse out of a plane which will land first?" It's physics, it's about animals, but it is physics.
"If someone eats four kilos of carrots everyday will they turn orange?" Probably health, not Biology.
"If someone eats four kilos of carrots everyday will they turn orange? This is not a personal medical question, its biology, so don't close it." Still health, still not Biology.
"Why does eating four kilos of carrots a day (references 1,2,3...) cause skin to turn orange?" Probably OK for biology.
"How do I plot a graph of response to a hormone treatment in my experiment on mice using R?" Stack overflow.
My suggestion: We have to do a better job at critically analysing what the problem at the heart of a question is, and deciding whether it is biology or something else, and make clear to (new) users that not all questions that feature living things are biology questions. I don't see many users doing this.