Exciting stuff going on there. Big changes to the par 3s, especially number 8. It will be much shorter, but trickier, with the barranca coming into play on the left. Not sure what they are going after with removing several of the fairway bunkers and all of the greenside bunkers on #4 and #5, and all but one on #3. That's kind of the signature stretch. The devil will be in the shaping of the run-off areas in lieu of the greenside bunkers. #7 looks fantastic. I don't think the drawings do #9 justice. I'm betting that will look great, as will #13 and #16. The new heart/shamrock shaped greens on 8, 9, 11, 12, 13, 14 and 16 will create some tucked pins at the back right/left and narrow spots at the front. It will be interesting to see the shaping of those new greens and if they add contours/ridges/bowls. Colonial's greens are relatively flat by tour standards, but I would expect that will change a little with these new greens. Distance control will be even more critical with these changes, it looks like. It has always been one of the biggest defenses, but these changes seem designed to amplify it.
As happens to most courses as they age, the greens rise up after decades of top-dressing. I suspect that's the primary motivator for lowering a few. Many of the greens have lost their shape -- they've rounded out over the years due to mowing. Looks like they've addressed that on most of them and then adjusted bunkers to fit. The shaping of many of the bunkers is certainly going to be a new look. Those, too, had become sort of generic in shape. They'll have some visual character to them now.
As for the tree removal, this is very modest in the grand scheme of things. It's about 3 trees per hole. Looks to be strategic, and mostly to allow for air flow at greens, which is needed for the bentgrass greens.