The Year in Phenology

A Wisconsin scientist says the spring of 2012 was the earliest on record in the lower 48 states. He says he worries about some types of vegetation, if there’s another early spring next year.UW-Milwaukee geography department chair Mark Schwartz also heads an advisory committee to a national phenology network. The network looks at the impact of climate change on plants and animals. Schwartz has been studying weather records and other data from this year, and has confirmed that 2012 had the earliest start to any spring season, “Ways I measure that are when lawns green up, shrubs leaf out, lilacs bloom and the last freeze.”

Schwartz says the early growing season led to a problem when a frost zapped plants and damaged the Midwest fruit crop. He says the dry summer and fall completed a 1-2-3 punch to some plants. More than a foot of snow over much of Wisconsin last week may put a temporary chill on thoughts of an early spring in 2013, and Schwartz says there’s plenty of variation from year to year. But he says a trend toward earlier springs has him concerned, “The chances of early damage to sensitive crops like fruit trees will be a bigger risk.”

Schwartz says the federal government is projecting above normal temperatures for March, April and May, in this part of the country. But he notes a forecast that many months ahead is subject to revision.