Logic Masters Deutschland e.V.

Another Christmas puzzle, which shares some minor similarities with both of my previous Christmas puzzles.

Please also try these if you have time:

Merry Christmas!
Loopin' around, the masyu tree...
Kropki-Masyudoku

If you've seen the one I made last year, you'll know which part of this year's puzzle has been loopin' around my mind for a full year... ;)
(Although as per usual I only started setting about a week ago and just finished it in time today. I really need to start a bit sooner with these things...)

The rules of this one may seem long, but I think they shouldn't be too hard to understand.

I'm not entirely sure about the difficulty of this one, probably about 4 stars.
Feel free to post a comment if you have any questions about the puzzle. Other comments, ratings and solves of any of my puzzles are also highly appreciated.

Have fun, and Merry Christmas!

Rules:

Normal sudoku rules apply.

Draw a single closed loop in the grid moving orthogonally through the centers of cells without branching or crossing itself.
The loop mostly stays in the tree and can only exit it for at most two cells in a row before going back into the tree.
Digits along the loop alternate between odd and even.

Place some circles into the grid. Circles are either big and in a cell or small and on an edge between two cells. Small white circles can be anywhere in the grid, all other circles can only be placed in the tree (not even on the edge of the tree). The given star counts as a yellow circle.

Clues outside the grid indicate how many circles of each color are to be placed in the corresponding row/column. The colors are yellow, white, red and blue, clued in that order, as reminded by the letters in the upper left corner of the puzzle.
(Feel free to use different colors, as long as you don't confuse yourself too much by doing so)
A - is simply not given as a clue and can be ignored.

Big yellow circles contain a digit that is greater than all orthogonally adjacent digits which are not in a big yellow circle.
Small yellow circles sit between digits with a difference of at least 3.

Big white circles are always on the loop and the loop goes straight through big white circles and turns in the cell before or after.
Small white circles sit between consecutive digits.

Big red circles contain odd digits and are never on the loop. Small red circles connect cells with an odd sum and are never on the loop.

Big blue circles contain even digits and are never on the loop. Small blue circles connect cells with an even sum and are never on the loop.

Play here on CTC.