The maple sugar industry is suffering because of the fluctuations in seasonal temperature patterns. While the surface impacts of this are on the sugar farmers, it is clear that there is also a change in the physiological patterns of the trees, since it's their reaction to temperature that enables the maple sugar industry to function.
In addition, a study published in the journal Global Change Biology indicates that over the course of fourteen years (1989-2002), the duration of the green canopy of the Hubbard Experimental Forest in the White Mountains of New Hampshire, has increased by ten days. This finding includes the Sugar Maple, American Beech, and Yellow Birch.
New York Times article
Daily Climate article
Global Change Biology article