Trees and extreme cold and heat

How do trees survive this freezing weather? Are they just super tough or do they have anti-freeze in their veins? Here is a Phytophactor article with good information on this remarkable adaptation. It suggests that there may be a little bit of both going on out there.

http://phytophactor.fieldofscience.com/2010/12/why-dont-trees-freeze.html

There are other questions that arise when talking about trees and weather that take the discussion in a different direction. Questions such as: How are trees going to survive our overall warming trends resulting from climate change? Should we be planting warmer weather species in anticipation of the changes?

There is no clear consensus on this but what I can comment on is the fact that some urban forest managers have modified their tree planting lists to accommodate for trends that they and scientist observe and anticipate. In Washington DC, for instance, it was common to include sugar maples among the street trees to be planted, but the arborists there have dramatically cut down on this particular species. There are certain locations with suitable microclimates where sugar maple might be a good choice, but in typical DC planting locations there are better options.

I have also read that the City of Chicago has removed the white oak from its planting list for similar reasons. It is a marginal species as is and the anticipated warming makes it too risky. Current conditions may allow a newly planted white oak to survive its initial transplanting and even a few summers that follow, however by the time it matures and begins to provide its ecological benefits the urban environment is likely to be too harsh.

Many say planting warm weather species may be jumping the gun a little bit. Damage caused by harsh winters may counter-balance the benefits of a species’ heat tolerance. For now I recommend maintaining a diverse pallet and consider eliminating certain species that are proving to be problematic with summer heat and drought stress. And always remember that despite overall trends conditions can be highly variable from location to location. Consider the micro-climate and soil environment where you intend to plant and think “Right Tree, Right Place, for the Right Reason.”