The premature bud development you have noted sometimes occurs during mild winters or extended warm spells. Early blooming plants such as magnolias are most likely to be affected. Buds that have begun to expand prematurely may be lost depending upon weather conditions later this winter and early spring. So far as we know nothing can be done to prevent this.

Following are comments from Extension Specialist Jeff Gillman published during the unprecedented winter warmth of 2012.

Should We Worry Trees are Budding?
http://minnesota.cbslocal.com/2012/01/09/good-question-should-we-be-worried-that-trees-are-budding-in-winter/