Short article from last month on fir waves, with a clear and concise description:
https://www.nhpr.org/show/something...on-and-other-challenges-in-nh-white-mountains
Something Wild: The fir wave phenomenon and other challenges in NH's White Mountains
By Dave Anderson, Chris Martin, Jessica Hunt
Published January 26, 2024 at 6:00 AM EST
...
At high altitude, soil is usually just a thin veneer of organic matter – leaves and needles decaying slowly in cold conditions to form humus stretched over and in between exposed granite.
When trees growing on this thin soil rock back and forth in the wind, they break their fine feeder roots. As they grow taller, their canopy area exceeds the roots that anchor them.
This factor leads to the “fir wave” phenomenon. That’s the dieback of spruce and fir trees on the upper slopes that occurs over years. As the trees exposed to prevailing winds die, they then expose the trees behind them.
Fir waves have been found to occur only in the northern Appalachians and in the mountains of northern Japan. These slow motion waves include dieback of canopy trees plus new seedlings that regenerate in their wake.
Waves of death and regeneration move an average of three -10 feet per year. They crest and break when they reach the ridgeline above. And the process repeats.
Ecologist Peter Marchand says in his book, North Woods, that fir waves rejuvenate the crowded aging forest by releasing nutrients and admitting sunlight to areas too moist for fires and too cold for insects.
...
https://www.nhpr.org/show/something...on-and-other-challenges-in-nh-white-mountains
Something Wild: The fir wave phenomenon and other challenges in NH's White Mountains
By Dave Anderson, Chris Martin, Jessica Hunt
Published January 26, 2024 at 6:00 AM EST
...
At high altitude, soil is usually just a thin veneer of organic matter – leaves and needles decaying slowly in cold conditions to form humus stretched over and in between exposed granite.
When trees growing on this thin soil rock back and forth in the wind, they break their fine feeder roots. As they grow taller, their canopy area exceeds the roots that anchor them.
This factor leads to the “fir wave” phenomenon. That’s the dieback of spruce and fir trees on the upper slopes that occurs over years. As the trees exposed to prevailing winds die, they then expose the trees behind them.
Fir waves have been found to occur only in the northern Appalachians and in the mountains of northern Japan. These slow motion waves include dieback of canopy trees plus new seedlings that regenerate in their wake.
Waves of death and regeneration move an average of three -10 feet per year. They crest and break when they reach the ridgeline above. And the process repeats.
Ecologist Peter Marchand says in his book, North Woods, that fir waves rejuvenate the crowded aging forest by releasing nutrients and admitting sunlight to areas too moist for fires and too cold for insects.
...
