Centennial Woods is an old-growth Eastern Hemlock forest. This is because they can withstand the cold temperatures and low sunlight of Vermont winters, and, while nearly every other tree in the area was clear cut for sheep grazing in the nineteenth century, it is theorized that many Eastern Hemlocks were spared for their use in leather tanning.
Other native species that dominate the forest are second-growth Yellow Birch, Black Cherry, Sugar Maple, Red Maple, Eastern White Pine, and Northern Red Oak trees. Nearly all of these trees are approximately 130 to 160 years old as they were intentionally planted in successful attempts to reforest Vermont.
Invasive plant species also dominate these woods, including Buckthorn and Phragmites (that have taken over native goldenrods in the wetland area).
Because the forested area of Centennial Woods is dominated by tall trees, little sunlight reaches the forest floor, disabling smaller understory trees and flowering plants from growing. However, a power line runs through the wetland area, requiring trees to be trimmed annually to prevent interference. This allows understory trees to dominate the area, letting more sunlight reach ground level and supporting many smaller and flowering plants than the rest of the woods.