Researchers have found compelling evidence that Vikings reached the Americas about 500 years before Christopher Columbus, based on a study of tree species in Greenland. The study, published in the journal Antiquity, shows that Norse colonists in Greenland (985–1450 AD) used imported timber from North America for shipbuilding and construction. The timber, including species like hemlock and jack pine not native to Greenland or Europe, suggests regular trips by the Vikings to North America for resources.
  

Key Points: 

1. Evidence of Viking Presence: The discovery of non-native tree species in Greenland, used by Norse colonists, supports the theory that Vikings traveled to the Americas long before Columbus.
2. Timber Import from North America: The Vikings imported hemlock and jack pine, tree species indigenous to regions like New England, Nova Scotia, Quebec, and Ontario, for use in their Greenland settlements.
3. Routine Voyages: The study implies that Vikings made regular voyages to North America, extracting natural resources and establishing trade routes across the medieval North Atlantic world.
4. Analysis of Wood: Researchers analyzed the wood from various Norse construction projects, concluding that a significant portion of the timber was imported or collected as driftwood.
5. Norse-Greenland Settlements: The study sheds light on the extent and nature of Norse settlements in Greenland, highlighting their advanced navigation and resource utilization capabilities.

Source: https://www.popularmechanics.com/science/archaeology/a45823574/vikings-in-america-before-columbus-new-discovery/#