Though in most circumstances a copious body of research shows that deforestation contributes to global warming, a new paper published in Nature shows that in northern latitudes clearing trees has actually had a net cooling effect on the local environment.
The research from the the Yale University School of Forestry & Environment, shows that "if you cut trees in the boreal region, north of 45° latitude, you have a net cooling effect. You release carbon into the atmosphere by cutting down trees, but you increase the albedo effect, the reflection of sunlight."The study found that north of Minnesota the temperature has decreased on average 1.5°F because of deforestation; while south of 35° latitude, the level of North Carolina, deforestation has led to increased warming. In between these latitudes, the effect on deforestation on warming has been "statistically insignificant."
Here's the original research: Observed increase in local cooling effect of deforestation at higher latitudes