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Disappearing Sierra Meadows

Grab your bear can or camp chair, kick your feet up and chew the fat about anything Sierra Nevada related that doesn't quite fit in any of the other forums. Within reason, (and the HST rules and guidelines) this is also an anything goes forum. Tell stories, discuss wilderness issues, music, or whatever else the High Sierra stirs up in your mind.

Re: Disappearing Sierra Meadows

Postby Tom_H » Thu Nov 30, 2017 6:39 pm

I wandered away, geographically, from the Sierra in my comments. There is much evidence re. Native Americans' use of fire to intentionally modify the environment, in CA particularly in the coast ranges.

http://citeseerx.ist.psu.edu/viewdoc/do ... 1&type=pdf

http://www.californiachaparral.org/enat ... icans.html

http://www.wildlandfire.com/docs/biblio_indianfire.htm



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Re: Disappearing Sierra Meadows

Postby Harlen » Thu Nov 30, 2017 6:50 pm

Thanks for the interesting piece concerning Sierra meadows. I found the write-up below in an eastern ecology review, and thought it might add to the points made on eutrophication and the evolution of lakes, also termed "lake aging."

This "Disappearing Sierra Meadows" piece is an interesting twist on the more common ecological point we've all heard before- that we are lucky to be exploring the High Sierra at this point in time when it is so full of lakes. And that those glacially-carved lake's days are numbered due to the inexorable erosional processes, which are turning lakes into meadows.... and now it's the meadows turning into forests.

Was it Heraclitus who said: "The only constant... is change."
________________________________________________________________________
Lake Eutrophication

What is lake aging?
Lake aging is the natural process by which a lake fills in over geologic time with erosional
materials carried in by tributary streams, with materials deposited directly from the atmosphere,
and with materials produced within the lake itself. From the time a lake is created through glacial
action, the aging or filling in process begins. Although New Hampshire’s lakes have the same
chronological age, they age (fill in) at different rates due to differences in runoff and watershed
characteristics. The natural succession is from lake to pond, pond to marsh, marsh to meadow,
and meadow to dry land. Examples of each can be seen today including areas of dry land where
past lake basins can still be identified.

What is eutrophication?
Eutrophication is the process of increased productivity of a lake as it ages. Often this process is
greatly accelerated by human influence and is termed cultural eutrophication. The increase in
nutrient supply from human activities usually results in an increase in the biological production
that occurs in the lake. Although the increased production may increase the rate of lake filling, it
is incorrect to define eutrophication as lake aging. A lake does not die with it reaches a state of
high productivity, but when it no longer exists (is filled in). Lake filling results both from
production that occurs in the lake, which may increase with eutrophication, and from organic and
inorganic material deposited from outside the lake, which has no relationship with lake
eutrophication.
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Re: Disappearing Sierra Meadows

Postby dave54 » Fri Dec 01, 2017 9:14 pm

Several researchers have estimated up to one half of Sierra west slope was non-forested prior to European influence, but that half includes not only wet and dry meadows, but also savannah, brushfields, and barren.

Related to meadow preservation: Several years ago the Forest Service initiated a project to identify, map, and protect fens. Previously fens were lumped in with wet meadows and marshes when they really have different characteristics and ecology. Some of those found where I worked were only a few square meters in size and previously not known. Others were several to tens of acres. All are now protected.

Often associated with meadows are Aspen groves. No secret to anyone here, aspen groves in the sierra were endangered. Conifers were overshadowing the aspen (aspen is very shade intolerant) and as a result the existing trees were doing poorly and there was no reproduction. Solution: logging! Remove the conifer overstory, much of which is commercially valuable. Sold as a timber sale the proceeds paid for additional aspen and meadow enhancement. The logging activity itself was beneficial. Aspen regenerates from its roots. The roots send up shoots that will grow into trees. Disturbing the ground surface with heavy equipment and skidders dragging the log out of the aspen stand stimulates aspen regeneration. Win-win at little to no cost to the taxpayers.
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Log off and get outdoors!
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Re: Disappearing Sierra Meadows

Postby gdurkee » Thu Dec 07, 2017 8:27 pm

For Sierra meadows above ~8,000 feet, the classic image of lake to meadow is not true. Sierra meadows have been relatively stable since the Pleistocene retreat of the ice. That is, they aren't former lakes that fill in with debris to swamp to meadow to forest. Nor do present day lakes show any sign of that happening through eutophication. Somewhere or other, I have a great paper on that and will try to dig it up and post a reference.(Connie Millar of USFS has authored a number of excellent and more recent papers).

The Lodgepole invasion is a real thing but I do have questions and reservations. There's some good papers out there indicating discrete surges in some years since about 1900 or so. That coincides with the end of the Little Ice Age. Millar and others believes that to be climate change related though I have trouble believing that stock grazing is not somehow related. The meadows I've seen with LP invasion have all had significant stock grazing since the late 1800s (cattle, sheep, horses). This has compacted the meadow sod, sheared off stream banks and, generally, caused meadows to drain more quickly and compacted the soil such that they don't hold as much water.

Still, I believe Millar attributes it mostly to climate. That said, it seems to be extremely slow. When I was first stationed an McClure in 1979, there were small lodgepole at the edge of the existing mature forest coming into the meadow. About 15 years before, NPS Soil and Moisture crews had build check dams on the small side streams (to restore the stream banks and raise the water table) and cut out hundreds of encroaching trees. By the time I was there, trees were back in the exact same place but no farther. I did cut some of the trees and counted tree rings. Trees only about 4 feet high were 30+ years old. Returning again in the 90s and 2008 or so, nothing much had changed. I did, though, measure the perimeter of the mature forest (which itself looked like in came in in the early 1900s) and the smaller trees. The reduction in meadow between the two was about 20% by actual mapping.

In the early 70s, I participated in an attempt to start prescribed fire in Tuolumne Meadows. The theory was that it was lack of fire that was a factor in allowing the invasion there. We couldn't get the fuel going to carry a hot enough fire. Not sure that's even a theory anymore but, at that elevation, a fire started in the meadow seems unlikel. Though not impossible a catastrophic fire in LP would remove enough trees to raise the water table to slow encroachment. It's a hugely interesting topic and I'll try to find some references.
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Re: Disappearing Sierra Meadows

Postby rlown » Fri Dec 08, 2017 1:13 pm

This Connie Millar? https://www.fs.fed.us/psw/programs/efh/staff/millar/

Look at the publications section..
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Re: Disappearing Sierra Meadows

Postby gdurkee » Fri Dec 08, 2017 1:25 pm

Yep. She's been doing great work in the Sierra for decades. While I'm here, the first paper I was thinking of is Holocene stratigraphy and chronology of mountain meadows,
Sierra Nevada, California.
Wood, S. H. 1975
U.S. Department of Agriculture Forest Service Monograph 4: 180

Trouble is, I probably have one of the few copies in the universe. If anyone PM's me, I'll send it. Old, but I think it still holds up. I'll try to find the paper Connie wrote on LP encroachment. I thought I had it but hadn't yet gone through her list of papers.
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Re: Disappearing Sierra Meadows

Postby gdurkee » Fri Dec 08, 2017 1:39 pm

OK. This is the one I was thinking of for LP invasion:
https://www.fs.usda.gov/treesearch/pubs/31786
Response of Subalpine Conifers in the Sierra Nevada, California, U.S.A., to 20th-Century Warming and Decadal Climate Variability

But this one's very good too:
Sierra Nevada Forests:
Where Did They Come From?
Where Are They Going? What Does It Mean?
Constance I. Millar USDA Forest Service Albany, California

Wallace B. Woolfenden
USDA Forest Service
Lee Vining, California
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