The Christmas tree itself acts like a fortress. That is, cells that are part of the Christmas tree must contain digits which are strictly large than digits in adjacent cells which are not part of the tree. There is no restriction for two adjacent cells which are part of the tree. Where there is potential ambiguity as to whether a cell is part of the tree, I've filled it with a pale yellow glow.
Each piece of tinsel on the tree indicates an ascending sequence of digits in the cells that it covers. it's up to you to determine in which direction. Hopefully it's clear where the tinsel is going. Please note that some pieces of tinsel are going diagonally between cells.
Finally the tree is decorated with some baubles and a star. These have no significance other than to provide givens for the puzzle. Upon test solving in paint, I found these decorations to be somewhat distracting. I should also add that I haven't tried printing this, so hopefully I've chosen a shade of green that doesn't come out too dark. Then again you'll have to live with this. It's a Christmas tree, see.
Oh, and this one isn't for the faint hearted in terms of its difficulty. But not so hard that you'll need to guess. But hey, you've all got tons of free time on your hands, right? Merry Christmas, Dearest Reader, and as always, Enjoy!
#225 Christmas Tree Sudoku – rated hardAll puzzles © Tom Collyer 2009-12.