Sweden’s Growing Wood Basket

Since 1997, subarctic forests are thicker and taller than ever before
By Luke Geiver | July 03, 2012

Sweden’s subarctic forest range is setting records. A research team consisting of six Swedish scientists has found that over roughly the past 15 years, forest density and the average tree-line height in the region has increased by 19 percent. In addition, a new survey of shrub, tree and vegetation data on 549 plots in 61 forest clusters originally collected and analyzed in 1997 was performed by the team using in-field testing and remote sensing, revealing that over the past 43 years, “tree biomass has doubled.”

According to the team, “tree basal area and biomass increased by 19 percent between 1997 and 2010 with the main increase occurring in established birch forest.” The results concur with the results of other studies that suggest that there has been a general increase in cover and biomass of trees and shrubs in subarctic and Arctic areas. Those studies were performed in 2001, 2006, 2007, two in 2010 and another in 2011.

So what does all this mean? According the research team, in spite of increased browsing pressure from a growing reindeer population and the occasional outburst from moths that eat away at birch trees located in the study region, there is simply more tree growth and biomass availability in the region now than before. The group calls the situation a “welcome phenomenon,” and says that, “increased nutrient availability associated with higher soil temperatures and a longer growing season,” could continue the expansion of the forest.

For biomass developers and biomass users in Sweden, the obvious impact of a growing woody biomass resource could mean anything from cheaper feedstock for biomass-based power, or an expansion of more bioenergy use in the region. However, for the Center for the Study of Carbon Dioxide and Global Change, a group that also took notice of the study, the work of the Swedish research team might help explain a theme supported by the center. In its quest to provide their version of non-emotionally charged, unbiased information regarding the rise of carbon dioxide in the atmosphere, the center believes that a warming earth will benefit plants, not cause their extinction. Right or wrong, six Swedish scientists who’ve shown a 19 percent increase in biomass density and tree line height that is linked to warmer soil and a longer growing season might help their argument.

—Luke Geiver