It is in itself a biome.
The main lowlands ecosystem is spruce-fir-northern hardwood forest. There are spruce bogs and some other forest types to be found. As you go up in elevation, you will find subalpine spruce forests and eventually the Alpine zone which occurs above treeline and consists largely shrubs, moss, and lichens. There is a terrific guide book that was recently published (The Plants of Baxter State Park) which might help you pinpoint where you want to go, if you are interested in particular ecosystems.
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