Future grim for 'biggest and most magnificent' trees

Dec 07, 2012

Across the world, big old trees face a dire future globally from agriculture, logging, habitat fragmentation, exotic invaders, and the effects of climate change, warn leading scientists in an article published this week in Science magazine.

Professor William Laurance, an ecologist at James Cook University in Cairns, Australia, reveals a dramatic decline among the world's "biggest and most magnificent" and details the range of threats they face.

"Their demise will have substantial impacts on biodiversity and , while worsening climate change," he said.

"To persist, big trees need a safe place to live and long periods of stability but time and stability are becoming very rare commodities in our modern world."

Giant trees offer critical shelter and food for innumerable species of mammals, birds and insects, while emitting massive amounts of water through their leaves, contributing to local rainfall.

Old trees also lock up large amounts of carbon and thereby help to slow global warming.

But their ability to store carbon and provide other vital services is threatened by human activities, according to Professor Laurance and his coauthors Professor David Lindenmayer at ANU in Canberra, Australia and Professor Jerry Franklin at the University of Washington in Seattle, USA.

Some of the world's largest trees are particularly targeted by loggers. The oldest trees are among the most valuable and therefore the first to be cut in "virgin" forest areas.

Big trees are also sensitive to , which exposes them to stronger winds and drier conditions.

Professor Laurance's research in the has shown substantial die-off of canopy giants in small forest fragments. Their susceptibility seems counter-intuitive given big trees' life histories, which invariably include periods of drought and other stress.

"All around the tropics, big trees are succumbing to strong droughts," Professor Laurance said. "That's been a surprise to me and many other ecologists, because big, ancient trees would have had to survive many droughts in the past."

He said that forest giants may suffer disproportionately from climate change.

"According to one popular theory, trees get a double-whammy when the thermometer rises.

"During the day, their photosynthesis shuts down when it gets too warm, and at night they use more energy because their metabolic rate increases, much as a reptile's would do when it gets warmer."

With less energy being produced in warmer years and more being consumed just to survive, there is less energy available for growth.

"This hypothesis, if correct, means tropical forests could shrink over time," Professor Laurance said.

"The largest, oldest trees would progressively die off and tend not to be replaced. Alarmingly, this might trigger a positive feedback that could destabilize the climate: as older trees die, forests would release some of their stored carbon into the atmosphere, prompting a vicious circle of further warming, forest shrinkage and carbon emissions."

Professor Laurance noted that was having less direct impacts on forests, including creating conditions for exotic pathogens to thrive. For example, pathogens such as Dutch Elm Disease, introduced by trade or happenstance, have devastated trees in many parts of the world.

All told, the outlook for big trees is not good, Professor Laurance and his coauthors said.

"The decline of foretells a different world where ancient behemoths are replaced by short-lived pioneers and generalists that can grow anywhere, where forests store less carbon and sustain fewer dependent animals," Professor Laurance said.

"It's a place where giant cathedral-like crowns could become a thing of the past."

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More information: Lindenmayer, David B., William F. Laurance, and Jerry F. Franklin. 2012. Global decline in large old trees. Science 338:1305-1306.

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User comments : 6

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Roland
5 / 5 (2) Dec 07, 2012
Check the price for a 2x12 at your local building supply store. You will understand why most floors these days are made of trusses made from 2x4s. You will also understand why loggers salivate at the prospect of cutting old growth. It's simple greed.
ScooterG
1.6 / 5 (7) Dec 07, 2012
Check the price for a 2x12 at your local building supply store. You will understand why most floors these days are made of trusses made from 2x4s. You will also understand why loggers salivate at the prospect of cutting old growth. It's simple greed.


A quick check of my local Home Depot website puts a 20-foot 2x12 at $.56 per board foot and a 10-foot 2x4 at $.62 per board foot.

It may be true that loggers would prefer harvesting larger trees as opposed to smaller trees, but to call loggers greedy is unwarranted. There's much more factoring into lumber prices than most of us know.

Floor trusses are more desirable than solid lumber for many reasons. They are lighter, stronger, and can span longer distances. They accommodate other trades better, such as electrical, plumbing, and HVAC. They are far more stable (stay straighter and less problematic) than solid lumber.
ScooterG
1.7 / 5 (6) Dec 07, 2012
But getting back to the crux of the article...trees are a renewable resource and as such need intensive and proper management - proper being the key word.

It would not be difficult to identify and mark the trees that we do not want cut versus the trees we want removed. I'm guessing the USDA does that now in the US, as logging is highly regulated.

If you wish to make the environment more suitable for old growth timber, proper thinning is mandatory. The only place that happens is on private land - go figure!

To continuously blame man (via AGW) for every forest malady is a shameless cop-out.
Lurker2358
5 / 5 (2) Dec 08, 2012
Logging is highly regulated because if it wasn't the companies would have driven everything extinct.

Just look what happened to the Sequoia and the Louisiana Cypress. If not for the government stopping it, they'd be totally extinct, and they may well be headed that way anyway.

The first thing man does when he finds a new type of tree is cut it down.
Jadxia
5 / 5 (2) Dec 08, 2012
Industry vs. Forest is like that adage about facing a horde of assassins. You have to be lucky or win every day, they only have to get lucky once.

Likewise, the eco-minded have to win every battle, every day to preserve a tree, but a big agro-business only has to win one legal battle to have it cut down and it is gone forever.

I rented a townhouse apartment by an area of woods that was always supposed to be woods as it was technically wetland. When they ran out of development room they changed the legislation so that wetlands could now be drained in that county to put up a poorly built subdivision. Even if you could change the law back, the damage is done. No more woods, no more streams, no more wetland.
Howhot
not rated yet Dec 09, 2012
When they ran out of development room they changed the legislation so that wetlands could now be drained in that county to put up a poorly built subdivision. Even if you could change the law back, the damage is done. No more woods, no more streams, no more wetland.


I've seen this so many times it's just saddening. Time and time again the developer wins and the environment suffers. If some land isn't under some sort of Federal protection, rarely will it be left un-attacked.

Without protection, the only way to influence the developers is to fight back with a people movement. Employ the Sierra Club, Historical clubs etc. Go all Greenpeace on the mofos. I've seen it work on occasion with enough out cry.

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