Diario de gingerventi

The pictures attached show a shrub with purplish grey bark and short stubby alternate branches. A couple are located at the edge of the swamp behind our yard. The trunks and branches are dotted with small pockmark-like lenticels. One has only one trunk, the other has 3. There were a few dark red shriveled fruits about 1/2'” in diameter, left on one shrub. There is a single leaf bud at the end of each twig or branch. On 2/25 a leaf bud at the end of one branch had started to open. Temperature was about 41 degrees, sunny and windy. I was surprised to see a leaf opening so early in the year and even more surprised to notice that while I held the branch in my fingers, the leaf began to open more. This leaf was responding not only to sunlight but also to warmth. There was at least one other leaf starting to open on this day but when going on subsequent days, after colder weather with temps mostly below freezing, I did not seen any open leaves. Did they fall off in the freezing weather? In trying to identify the shrub in the Sibley Guide to Trees, I am guessing that it is a sweet crabapple. In the guide it is not shown to grow in Massachusetts but only as far east as New York. If I have identified it correctly, its range must have spread east. Or else, my guess is incorrect. The leaf is finely toothed and the twigs are rough looking with numerous closely stacked rings at their ends. Does each ring represent a year?
I clipped the branch with the opened leaf and put it in water. Ten days later, 3 of the twelve buds on this branch have opened displaying not one, but 5 oval leaves or leaflets clustered around 2-4 tiny unopened (as of yet) leaves in the center. The opened leaf buds are staggered between unopened leaf buds. I had expected the leaf buds to open simultaneously or to open in an ascending order. Perhaps a simultaneous opening would be too draining of energy. And the staggered openings may occur to allow more light to reach the young buds?