Washington, D.C. ? Ice-covered Greenland really was green a half-million or so years ago, covered with forests in a climate much like that of Sweden and eastern Canada today.

An international team of researchers recovered ancient DNA from the bottom of an ice core that indicates the presence of pine, yew and alder trees.

The researchers, led by Eske Willerslev of the University of Copenhagen, Denmark, say the findings are the first direct proof that there was forest in southern Greenland.

Included were genetic traces of butterflies, moths, flies and beetles, they report in today’s edition of the journal Science.

The material was recovered from cores drilled through ice 1.2 miles thick at a site in south-central Greenland. Ice cores from another site did not yield any DNA.