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These glaciers destroyed any vegetation in their path, and cooled the climate near their front. Pre-existing natural communities remained largely intact south of the glaciers, but saw an increase in dominance of pine and a now-extinct species of temperate spruce , ( Picea critchfieldii ).
The most heavily forested regions of the U.S. are Maine, New Hampshire, American Samoa, the Northern Mariana Islands and West Virginia; the least heavily forested regions are North Dakota, Nebraska, and South Dakota. [2] The U.S. had a 2018 Forest Landscape Integrity Index mean score of 6.65/10, ranking it 67th globally out of 172 countries. [6]
On land, North America's vegetation included plants like conifers, cycads, ferns, ginkgoes, and horsetails. [46] The Triassic vegetation of the east coast indicated swampy conditions in the local rift valleys. Arizona was home to a great forest that would later leave behind the area's famous petrified wood. [51]
The United States began expanding beyond North America in 1856 with the passage of the Guano Islands Act, causing many small and uninhabited, but economically important, islands in the Caribbean Sea and the Pacific Ocean to be claimed. [4] Most of these claims were eventually abandoned, largely because of competing claims from other countries.
The Great Plains is a broad expanse of flatland in North America. The region is located to the east of the Rocky Mountains , much of it covered in prairie , steppe , and grassland . They are the western part of the Interior Plains , which include the mixed grass prairie , the tallgrass prairie between the Great Lakes and Appalachian Plateau ...
Age of the bedrock underlying North America, from red (oldest) to blue, green, yellow (newest). Seventy percent of North America is underlain by the Laurentia craton, [5] which is exposed as the Canadian Shield in much of central and eastern Canada around the Hudson Bay, and as far south as the U.S. states of Michigan, Wisconsin, and Minnesota.
For reasons that are unclear, approximately 500 years ago, aboriginal populations declined significantly throughout Eastern North America and more broadly throughout the Americas. … Thus, by the time the first European observers were reporting the nature of the vegetation of the region, it is likely to have changed significantly since the ...
The Massachusetts Bay Colony French settlements and forts in the so-called Illinois Country, 1763, which encompassed parts of the modern day states of Illinois, Missouri, Indiana and Kentucky) A 1775 map of the German Coast, a historical region of present-day Louisiana located above New Orleans on the eastern bank of the Mississippi River Vandalia was the name of a proposed British colony ...