After a few thousand years, the tundra slowly turned to boreal forest, or taiga. The climate warmed slightly, and confiers grew into rich forests. Spruce, larch, and fir trees are the dominant plants in this forest, although smaller herbaceous plants, mosses, and grasses can be found. Lakes and other smaller water bodies are also abundant in the boreal forest. Today, boreal forest is the largest biome in the world. These forests make up 29% of all forest cover. Boreal forests are still found in the Adirondack Mountains.

Fossils of boreal mammal species are the most abundant in the Ice Age collections of the State Museum. American mastodon fossils are found in sites across the state as well as species like giant ground sloth, peccary, stag-moose, giant beaver, and even California condor. These fossils show that the boreal forest was very diverse.

Castoroides ohioensis 
One of the largest rodents that ever lived, this extinct beaver grew to 8 feet (2.4 m) long and weighed as much as 275 pounds (125 kg)—about the size of a modern black bear. Like modern beavers, this extinct beaver had long incisor teeth. But they were not sharp and could not have cut down trees.
 

Platygonus compressus
A distant relative of pigs, this extinct peccary grew up to 3 feet (0.91 m) long. With long legs, it was probably a fast runner. Today, three species of peccaries live in the southwestern United States and tropical America. This peccary’s canine teeth point straight up and down. In pigs, the canines are at an angle. 

Megalonyx jeffersonii
Unlike modern sloths, this extinct sloth lived mainly on the ground. It reached high into trees to eat twigs and branches.

Cervalces scotti 
Only a little bit larger than moose, the stag-moose lived in New York until approximately 11,700 years ago. The stag-moose reached 8 feet (2.5 m) in height and a weight of 1,562 pounds (708.5 kg). Its antlers could reach 6 feet in length. Like modern moose, the stag-moose lived in the Pleistocene’s wetlands, forests, and woodlands.