For many of you, the title of this blog got your attention. Why? It's a hot-button issue. Climate change. Global warming. Call it what you will, the subject raises the ire of many folks. Some believe climate change does not exist, others are convinced it does. This blog is not about deciding this issue, because for most of you any argument I could raise would not change your mind.
Instead I am writing about nature on the move. As a bird watcher, I think it is interesting that the range of birds are changing. And as somebody who enjoys hiking in the woods, findings that show tree species migrating north have caught my interest.
A few years ago the U.S. Forest Service (USFS) found through research that some tree species may be migrating north at an average of 62 miles in the past 100 years. The journal Forest Ecology and Management contained the USFS study which documented the progression north of 40 major tree species in more than 30 states. USFS ground-based data was used to measure the movement of the trees based on latitude.
Fifteen northern tree species, 15 southern tree species, and 10 tree species found in both regions were studied. Young trees (seedlings) were compared to the position of their older siblings. Eleven of the 15 northern species shifted more than 12 miles compared to their average ranges. The species included northern white cedar, American basswood, sugar maple, black ash, bigtooth aspen, and yellow birch.
The approximate shift north of overwintering goldfinch in the past 40 years, about 250 miles, is equivalent to the distance from southern to northern Missouri.
When it comes to the birds, as I mentioned in my previous blog, research has shown at least 60 species are now wintering 100 miles or more farther north compared to the 1960s. The American Goldfinch, for example, a common bird at our backyard feeders (a photo of the male goldfinch is at the top of this blog), is estimated to be wintering about 250 miles farther north compared to 40 years ago. That is about the distance from southern to northern Missouri.
Between 1966 and 2005, it is estimated that the lower 48 United States has warmed about 5° Fahrenheit in January , making it easier for birds to overwinter in more northern latitudes.