Are vines taking over the planet?

Welcome to the 'Planet of the Vines'.  It's a world where proliferating vines strangle trees, suppress forests, and diminish forest carbon storage -- increasing greenhouse-gas emissions and making Earth a hotter place for us all.

  Are vines running amok?  (photo by William Laurance)

Are vines running amok? (photo by William Laurance)

That's the implication of two recent studies in the leading journal Ecology

In the first, ALERT director Bill Laurance and colleagues showed that woody vines (known as 'lianas') in undisturbed forests of the Amazon have increased markedly in abundance, by about 1% per year over at least the last couple of decades.

Why?  Nobody knows for sure, but Laurance and colleagues think it might be a response to rising carbon dioxide levels in the atmosphere.  This stimulates plant growth, and fast-growing species such as vines seem especially adept at taking advantage of it.

In the second study, researcher Stefan Schnitzer and colleagues experimentally removed woody vines from forests in Panama, by cutting them off of infested trees.  They found that growth rates of the trees nearly tripled, and that forest-carbon storage increased by a fifth.

This illustrates just how dramatically vines can affect forests.  Vine-infested trees grow more slowly, reproduce less, and die more often.  When they die, the carbon that's stored in their wood and leaves is released into the atmosphere, as carbon dioxide.

  Some woody vines are hefty...  (photo by William Laurance)

Some woody vines are hefty... (photo by William Laurance)

This kind of scenario sends shivers up the spines of ecologists, because it can turn into a positive feedback -- a situation that can quickly snowball out of control. 

In other words: humans spew carbon dioxide into the atmosphere, leading to more vines, which then kill and suppress trees, which in turn emit more carbon dioxide...  And on and on it goes...

In the 1970s a margarine commercial on TV resonated with the punchline, "It's not nice to fool Mother Nature". 

Clearly we haven't learned that lesson. 

It seems increasingly likely that Mother Nature might now be fooling around with us.