Forests Grow Even Faster: Trees Impacted by Climate

Since the 1960s, trees have been growing more quickly--even though their development phases haven't changed. Now, scientists have discovered that tree growth has sped up even more by as much as 70 percent.

About 30 years ago, there was concern about how much forest was being lost due to human activity. Yet it seems as if forests are coming back with a vengeance-faster than ever before. How and why forests have changed their growth patterns, though, has long remained a source of debate. Now, scientists may have the answers.

The researchers examined data from experimental forest plots that have been monitored since 1870, making them some of the oldest forest study sites in the world. This allowed the scientists to observe growth rates over time to see how climate and other factors might be influencing the trees.

In this case, the researchers found that for spruce and beech, there were significant accelerated rates of growth. Beech trees grew at a rate that was 77 percent faster than in 1860 while spruce grew 32 percent faster. The stand volume for beech was 30 percent and for spruce, 10 percent.

So why the faster growth rates? The scientists believe that the trees are growing faster due to rising temperatures and an extended growing season. In addition, carbon dioxide and nitrogen in the atmosphere may be helping fuel tree growth since they've rising steadily in the atmosphere over the last century.

What's interesting to note is that the altered timescale for these trees has not yet been incorporated into traditional forestry yield models, which monitor growth as a function of age. This means that current models don't show that trees are growing as fast as they actually are. In addition, this accelerated tree growth is likely having a large impact on forest ecosystems as a whole.

"The plant and animal species that will be most affected are those living in habitats which depend on special phases and structures of forest development," said Hans Pretzsch, one of the researchers, in a news release. "It is true though that only a few of our experimental areas are located in the ridges of the highland mountains where the greatest damage was observed."

The findings could help create better models of forest growth and show how climate can drastically impact these forest ecosystems.

The findings are published in the journal Nature Communications.