Trees Found, Implication Ignored

They've found trees under the ice, and somehow missed the point:

Melting glaciers in Western Canada are revealing tree stumps up to 7,000 years old where the region's rivers of ice have retreated to a historic minimum, a geologist said today......

...There have been many advances and retreats of these glaciers over the past 7,000 years, but no retreats that have pushed them back so far upstream as to expose these trees.

Obviously, the ice hasn't retreated to an historic minimum. The trees grew there. The article doesn't find it noteworthy that there were no glaciers there at one time, but concludes with:

The age of the tree stumps gives new emphasis to the well-documented before-and-after photographs of retreating glaciers during the past 100 years.

"It seems like an unprecedented change in a short amount of time," Koch said. "From this work and many other studies looking at forcings of the climate system, one has to turn away from natural ones alone to explain this dramatic change of the past 150 years."

Again, I'll ask, what was man doing 7000 years ago to warm the planet enough for trees to be growing there in the first place?