Journal Quilt for January - practice pieces

In the quest for the perfect tree bark, I seem to have purchased a lot of variegated threads in the brown tones -- the one I actually used for this piece is a King Tut, which is still on the machine, not in this picture. . . and I have 2 more varieties coming from Connecting Threads. Fortunately, I love autumn shades and will eventually find uses for all this I'm sure, but I can see that I'm going to have to rein myself in somewhat, somewhere, somehow - if I buy 15 spools of thread or so for every element of every journal piece I attempt, I'll soon be in the poorhouse! Tried this tree on muslin, basic quilt sandwich - muslin front & back with Warm & Natural in between. The tension is too tight for thread play, came out very puckery. So, trying to think back to a class I took with Julie Hocker several years ago, I think I either have to monkey with the bobbin tension -- something Ricky Tims says I shouldn't be scared of! -- or as I recall in her class, rather than a quilt sandwich for the thread play, we used a stabilizer under the fabric - which I am sure I still have some of around here. So for the next practice piece, that's what I'll try - I think the tension issue would be lessened with only fabric and a stabilizier. But once I started on this one, I had to keep going even though I wasn't thrilled with the results, just to practice the technique for making the tree itself. Now, off to pour a cup of coffee and do morning pages. . .