General warming in the Northern Hemisphere has been recorded since the end of the 1800s following the Little Ice Age. Records of glacier retreat during the last 100 years over the entire globe independently confirmed the recorded trend in global temperature rise. Several studies have illustrated various responses to this climate forcing, i.e., the recorded changes in temperature and precipitation concurrent with the increase in atmospheric CO2 concentration, increases in density of tree populations, declines in tree populations, treeline displacement or lack thereof, lengthening of the growing season, and enhanced tree growth. It is critical that we identify the tools needed to estimate potential consequences of climate change on forest ecosystems and develop management practices and policies adapted to projected drifts in the geographic distribution of ecosystems.