Sequoia Fiery Tree Rings

This is good to see.  More important is the last bit about the impact of man driven fire control on reproduction.  It is clearly not good at all.

I have already posted on this subject and this is yet another great example.

Best practice for almost all forests is the introduction of timed and controlled burns.  We have plenty of data and plenty of need to implement such programs everywhere.  They are clearly necessary for forest health, to say nothing about other parts of the biome.

The huge burns that ran rampant a couple of years back was a combination of a decadal drought and a great manmade fuel build up.  The fuel must be reduced.  No one understands quite how much fuel hits a forest floor every year.  In the East it rots slowly and is blanketed with moisture holding leaves.  The Indians still burned it all out.

In the West it tends to get tinder dry.  Walking through a ponderosa pine forest in July is a bit like passing through a gas filled house.  Only a madman would light a match and the forestry department orders folks out.  It really is that obvious.

In the long run and we actually have the time, what I am saying here is been said by others and this is slowly working its way into text books and study programs.  In time proscribed burns will be done everywhere and in time stakeholders will optimize forests for maximum long term productivity.

Today we can recognize the problem and tomorrow we can implement proper changes.  Enough knowledge already exists to assure us that most new changes will be for the better.   The sequoias can wait for us to get our act together.

EARTH'S BIGGEST TREE RINGS TELL FIERY TALES

 Fifty-two giant fallen giant sequoias reveal a 3,000-year-old history of fire and drought after giant chainsaws expose their rings.

By Larry O'Hanlon | Mon Mar 29, 2010

http://news.discovery.com/earth/giant-sequoia-tree-rings.html

Using huge chainsaws and strong backs, the largest trees in the world are finally giving up their 3,000-yearrecord of fires and droughts. No trees, however, were harmed in the making of this fire history.

"We only used dead trees," emphasized tree ringresearcher Thomas Swetnam of the University of Arizona. Swetnam led the study that was reported in a recent issue of the journal Fire Ecology. "We spent multiple years collecting the wood and hauling it back to Tucson."

The giant sequoias in California's Sequoia National Park are far too thick to be cored for the extraction of the pencil-thin cores typically used by tree ring researchers. So the authors of a new report on tree ring evidence of past droughts and fires used all sorts of other tools to slice and dice 52 giant dead and fallen sequoias, lug the pieces back to roads by hand. Then they spent years piecing together the valuable history in their laboratories.

Among the things they found in the ring record was a very dry and fiery period from 800 to 1300 A.D. That corresponds to a controversial climate interval called the Medieval Warm Period.

That period was very dry," said Swetnam. "But we're not so clear how warm it was."

Modern temperatures already exceed those of the Medieval Warm Period, said Swetnam. So if heat has anything to do with fire frequency, we could expect more fires.

"What makes this work unique is that it goes so far back in time," said U.S. Geological Survey research ecologist Nathan Stephenson, who has spent a lot of years studying sequoias. Usually if you are working with pines you get centuries. With these you get multi-millennial annual resolution records."

But unlike a tree ring history that's based on just rings, this one is based cross dating rings between various trees the dating of fire scars.

These scars happen during natural fires when debris close to the tree bakes and burns the trunk, which is otherwise fire resistant. The trees can grow over a lot of these scars, but in cross sections, that can be easily spotted and dated.

"That way were able to establish a fire chronology," Swetnam told Discovery News. Of course, there have been other fire chronologies. Some are based, for instance, on charcoal layers found in mountain lakes. But nothing has quite the resolution of tree rings.

"The punch line from all of this," said Stephenson, "Is that over at least 2,000 years the most severe (sequoia) reproduction reduction has been in the last 100 years. Human land use changes have had greater effect than the preceding 2,000 years of changing fire regimes."

The problem, said Stephenson, is fire suppression. Excluding fires from the sequoia groves, makes it very difficult for sequoia seeds to germinate or have enough space for saplings to get started.