I have finally got back to this. I have now finished the tree and started on decorating it. Initially I failed to read the instructions for the gold garlands properly and did the first row in backstitch only. I was thinking you couldn't really see them very well, then I read that I was supposed to use stem stitch, so I went back over them adding a stitch from the middle on one side of each backstitch across to the middle on the other side of the next stitch to try and get the stem stitch effect. It came out looking good, and in fact almost better than the row above which is just stem stitch, partly because I have trouble getting my rows of stem stitch to go where I want them, so doing the backstitch first solved that problem for me.
Here are two photos of it - the first with just the backstitched garlands, and the second 'fixed' with the next row. To be honest, you probably won't be able to see any difference. Also - don't compare the pine needles to the pattern - I think I managed to get the main branches where they were supposed to go, but most of the needles just happened.