The last few weeks of december were really warm... one of my maple's buds look like they are starting to extend... it is the middle of winter. The tree was not in a green house.. I had set it in a raised garden bed, but didn't really do much... what can I do now?... the next few weeks should have some frost here and there.

same here. I let nature run its course. Last year all my maples leaved out, and then I got -4c nights, for 3 days in a row. Not a single leaf was damaged (!)

some I've talked to recommend keeping trees in a darker spot, what are your thoughts on that?

Daylight is one of the triggers that trees use to get out of dormancy (Next to the length of cold season and the time since going dormant). It might make a difference.

On the other hand.. Buds that are moving are not opening.

In general I find people worry too much about their trees. They can take a lot more than many gve them credits for.

Last year my elms started popping leaves out January 6. I repotted, etc., and continued to other trees as they started. Then in April when everything looked like spring it dropped to 20F/-7C. I carried them all I side the garage close to the outside door where it would not be too warm and left them until it warmed up to over freezing. Everything was fine.

Trees have lived without central heat for millions of years. They don't need much help.

I'm not considering taking it inside, or something like that, I was wondering what some of you have experienced. And what, if anything you've done.