I settled on satin stitch for the big leaves and couched straight stitch for the pine-needles, but wasn't happy with either the satin stitch or the lattice I had experimented with for the snow.
My next step was to try split back stitch. I was much happier with this than with the satin stitch.
Although I left my earlier experiments with the leaves and with the snow lattice in place, like a sampler, I thought the satin stitch snow so horrible I pulled it out.
I am going to leave the lattice example and the vertical one in - treat it as a sampler. I might try a double layer of satin stitch in the next quarter - horizontal over vertical perhaps.
I also worked the breasts of the birds in split back stitch, but the wings in satin stitch.
I have a few more variations in mind to try on the other three sides!