Over a lifetime of a species, on the order of millions of years, long term temperature changes come into play. Any species that can't cope with some variation in temperatures is not a species whose fate we need to be concerned about right now, because it no longer exists. Everywhere on the surface of the earth temperatures fluctuate.

 

How did the trees of an ancient world cope with warmer temperatures? They did so by migrating or staying put and adapting. They could manufacture special proteins, they could change their metabolism, things like that. But thermal tolerance can be costly by requiring energy and time. Warming today is taking place at least ten times faster than it did at the end of the last glaciation, about 12,000 years ago. Things are moving too fast for slow acting forces to keep up.

 

Some tree species such as spruce, birch, fir and aspen will disappear completely from their current growing range. Global warming is mostly seen as a threat to cold loving species and these trees are adapted to cooler conditions.

How many tree species overall will be capable of moving fast enough remains an open question. In the coming decades we are probably going to learn the answer whether we want to or not.

 

Predicted Minnesota survivors of climate change:

• Oaks
• Hackberry
• Eastern Cottonwood
• Boxelder
• Honeylocust
• Black Locust
• Red Mulberry
• Silver maple
• Hybrid Elms (ie: Patriot)
• Eastern Red Cedar

For more information on trees adapting to steadily warming climate.

It is likely that our north woods of pine, fir, aspen and birch will not survive the warming climate. Pictured here is a white pine stand along the Mississippi river in Minnesota. These will eventually be replaced by a mix of other trees like oak and hackberry.

 

Oaks have evolved a higher tolerance for drought. Healthy trees can better defend themselves against most native insects and diseases.