Timberati » Mountain Home State Forest

Trees ain’t thermometers

Timberati — Mon, 21 Feb 2011 08:00:56 +0000

I used to work on Mountain Home State Forest in the southern Sierra. MHSF has about 3000 specimen-sized sequoia within its boundaries. Dendrochronolgists often visited to see the stumps from logging in the mid to late 1800s. These were often over 2000 years old when they had been cut.

The Dendrochronolgists were interested in the tree-ring patterns. Trees grow fast or slow in response to many factors and these seasonal factors (light, water, nutrients) created ring signatures or patterns. Certain years might have been favorable for growth with plentiful water, light and nutrients (each favorable year would be marked a large, wide ring) and certain years might have had poor conditions for growth–drought, late spring conditions, early winter–marked by thin (in some cases–microscopic) rings. In general, the wider the ring the more favorable the growing season, the narrower the ring the poor the growing conditions. These ring patterns can be distinctive and can be used to date archeological sites (where wood is present).

Oxford’s Tree-ring Laboratory put it this way:

The way dendrochronology works is relatively simple. As a tree grows, it puts on a new growth or tree-ring every year, just under the bark. Trees grow, and put on tree-rings, at different rates according to the weather in any given year: a wider ring in a favourable year and a narrower ring in an unfavourable year. Thus, over a long period of time (say 60 years or more) there will be a corresponding sequence of tree-rings giving a pattern of wider and narrower rings which reflect droughts, cold summers, etc. In effect, the span of years during which a tree has lived will be represented by a unique fingerprint, which can be detected in other geographically-similar tree-ring chronologies.

Using tree rings as a proxy for temperature however is fraught with caveats and pitfalls.

Mike D.‘s of the Western Institute for Study of the Environment comment (on William M. Briggs’ blog) about using tree ring data as proxies for temperature is an excellent explanation of the problems of using tree ring growth for temperature. He starts with how tree rings are laid down:

Diameter growth on any tree is theoretically a sigmoid growth function. No tree puts on constant radial growth year after year. Trees grow by adding a layer of new wood at the cambium, under the bark. Each year a larger surface area is added. If growth is constant, the rings get narrower. But growth is never constant. There is significant deviation from ideal (model) sigmoid diameter growth in individual trees regardless of the weather. Even when sigmoid growth models are used, the natural variation adds statistical error.

Two sigmoid curves. The taller is the period annual increment for cubic feet; the lower smoother S curve is for mean annual increment of cubic feet.

So as the diameter expands, the amount of material put on would need to be more if the ring’s width was to stay the same as the previous season. Think of a clay disk that you add the same amount of clay to in successive rings. The volume of clay would be the same but the thickness of each new ring would decrease. The ring growth is S-shaped (sigmoid) because initially the tree has little foliage for photosynthesis and often puts its initial years into root development for survival. Then once roots are deep enough the tree puts its growth into height and width.

He then points out that tree-to-tree competition for light, water, and nutrients also affects the ring growth:

Dense stands exhibit narrow rings on individual trees, sparser stands may have wider ring growth, yet both stands may have equivalent gross growth. That’s why only open-grown trees are supposed to be selected for ring studies. But nobody knows what the tree density surrounding an individual tree was 100, 200, 500 years ago. Competitors could have arisen and died without leaving evidence of their presence so long ago. More error.

Besides competition, disease and injury can affect growth.

Trees can sustain injuries that affect growth, such as top and branch damage, that are difficult to detect 200 years later, especially a few feet off the ground where the rings are sampled. There are very few pristine, undamaged trees. I know, having searched for such across broad acreages. Open grown trees at high elevations are always damaged. A heavy winter snow can snap off branches and the tree will exhibit reduced diameter growth for a few years, even if growing season conditions are ideal.

This makes using tree ring data as stand-ins for temperature problematic.

Ring width has all but been abandoned as a temperature proxy. Instead, the latest technique is sampling rings for O18 ratios, under the assumption that O18 varies with temperature. Regardless of the ring width, the O18 ratio is supposed to have recorded growing season temperature. But that theory is fuzzy and mushy, and O18 ratios in living trees correlate very poorly with known growing season temperatures. In other words, it calibrates with much error at best.

Trees are not thermometers, but even thermometers have some serious measurement error problems.

Tree ring studies are a fad akin to phrenology and other discredited pseudosciences that has not dissipated as it should have decades ago.

Weekend Postcard from Mountain Home State Forest

Timberati — Sun, 09 May 2010 07:07:54 +0000

I was the Assistant Forest Manager at Mountain Home State Forest in the early 1980′s.

Mountain Home Demonstration State Forest is a 4,800 acre tract of forest land in Tulare County managed by the California Department of Forestry and Fire Protection. The State Forest lies within the Tule River watershed some 22 air miles northeast of Porterville. Elevations range from 4,500 feet to 7,500 feet. Vegetation on the forest is dominated by a mixed-conifer forest with over 5,000 individual old-growth giant sequoia trees.

For more information on MHSF read Management of Giant Sequoia on Mountain Home Demonstration State Forest written by forest manager, David Dulitz.

Here’s a picture of a kid standing in one of the area’s so-called “Indian Bathtubs.”

For more on these rock basins read Rock Basins in Mt. Home State Forest and Immediate Vicinity.

Green, Inc.

Timberati — Tue, 30 Jun 2009 08:01:03 +0000

Fear motivates.

Fear was the reason I got into forestry. When I was in college (I grew up in the 1960s and graduated high school in 1969), Martin Litton’s iconinc picture of a boy looking out over a large clearcut of redwoods caused a number of us to take action.

The Photos Were a Snapshot in Time.

For most, their complete environmental education was that photo.

While Martin LItton hasn’t changed his views, I have. My forestry major allayed my fear of deforestation through timber cutting for lumber. Coast redwood (where Litton photographed) sprouts from the stump. The place the boy looked at should be covered with redwood 40-60 feet tall. Photos tell a story of a moment in time, not of all time.

Now concern revolves around deforestation and old growth. In April of 2000, President Clinton used the Antiquities Act of 1906 to create the 327,769-acre Giant Sequoia National Monument (GSNM). That nearly, 330,000 acres presumably protects less than 20,000 acres of sierra redwood (giant sequoia).

Removing 500 Square Miles of Second-Growth Forest From Further Harvests Hurts Untouched Rainforest.

According to The Illusion of Preservation (Harvard Press), for every twenty acres of previously harvested forest placed off-limits to logging, one acre of primary forest–virgin forest–somewhere else is logged. That totals:

Primary Forest Lost Due to the GSNM set aside – 16,400 ac

We get no free lunches, someone pays and the someone in this case, is the wildlife and unique flora in previously untouched wilderness. Once roads are placed in this 16,400 acres of primary forest, it is usually converted to agriculture; the wildlife is open to extirpation.

Green, Inc. Slogans Masquerading as Scientific Fact

Tom Knudson wrote in his 2001 series, Environment, Inc.:

[T]oday [environmental] groups prosper while the land does not. Competition for money and members is keen. Litigation is a blood sport. Crisis, real or not, is a commodity. And slogans and sound bites masquerade as scientific fact.

What are you going to believe, slogans or your lying eyes?

As the management of Mountain Home Demonstration State Forest proves, harvesting is not the end of the world. Yet, Green, Inc. is interested in zero timber cut from public lands, so they support moving the GSNM from the Forest Service to the Park Service, this is not only unnecessary, it is counter-productive to GSNM’s articulated goals.

Sequoia needs disturbance to regenerate. Such disturbance has historically come from fire. But the past 100 years of aggressive fire suppression, shade-tolerant white fir has seeded under the old-growth giant sequoia groves. And now fire is a problematic tool due to Clean Air Laws. Logging provides the needed bare mineral soil sequoia seedlings require. And logging can be done around giant sequoia without adverse affects. Mountain Home Demonstration State Forest (MHDSF) manages its land consistent with the recommendations in the GSNM’s management plan. One irony of the GSNM: most visitors don’t see any giant sequoia until they reach the State Forest’s boundary. MHDSF has incorporated logging its management since 1946.

Not allowing harvesting in GSNM will eventually require a name change to the White Fir National Monument.

If you’d like to use my petition to keep the GSNM in the Forest Service’s jurisdiction and not tie land managers’ hands, it’s here.

Green Giant Politics

Timberati — Fri, 01 May 2009 07:00:04 +0000

Sequoiadendron giganteum occurs naturally in scattered groves only in the western Sierra. The 327,769-acre GSNP is at the southern boundary of its distribution. (Nat'l Park Service image)

My wife and I are members of the Sierra Club. She, because she supported their agenda. Me, because I want to know what the arguments are going to be about. The other day, we found a mailer from the Sierra Club imploring us to write the President, the Speaker of the House, and the Senate Majority Leader to urge them to use their “power to finally bring real protection to the Giant Sequoia National Monument by transferring management from the United States Forest Service to the National Park Service.”

That’s what I like about the Sierra Club, they are for science except when they’re not. The Forest Service has a plan based upon the appointed science advisers. But, anything involving commercial harvesting scares some people. Harvesting especially scares those who want no timber cut commercially in the United States. Zero-cut is a bad idea for all the reasons I’ve already listed here.

Now, in these United States, petitioning the government for redress of wrongs is one of our rights as American citizens. I just don’t believe that the USDA Forest Service is the wrong place for the Giant Sequoia National Monument (GSNM). I was the assistant forest manager at Mountain Home State Forest, the GSNM’s neighbor. I bring this up, because MHSF has harvested timber for over 60 years and people looking for the GSNM think they’ve found it when they reached the border of the State Forest. So harvesting and old growth sequoia can exist together and even thrive. The two are not antithetical and may be more sympathetic than the Sierra Club and the Zero-Cut supporters and their ilk would have you believe.

Here’s what my petition says:

Dear ___________________________

I urge you to use your influence to keep the Giant Sequoia National Monument (GSNM) within the USDA Forest Service’s jurisdiction.

Groups interested in zero timber cut from public lands, including the Sierra Club, want your support to move the GSNM from the Forest Service to the Park Service, this is not only unnecessary it is counter-productive to GSNM’s articulated goals.

As you know, the Proclamation speaks of “restoring natural forest resilience” in the Monument. This goal requires tools: adaptive management. To meet this goal, GSNM’s vegetation mix has to be brought to a place where the vegetation has the ability to resist stressors (stability) and to recover from stresses once they occur (resilience), while best maintaining native biodiversity.

You are no doubt also aware that the shade-tolerant white fir has seeded under the old-growth giant sequoia groves during the past 100 years of aggressive fire suppression. Sequoia needs disturbance to regenerate and fire is a problematic tool due to Clean Air Laws. This leaves logging as the efficacious treatment to provide the needed bare mineral soil sequoia seedling require.

Logging around giant sequoia can be done without the adverse affects the Sierra Club claims. Mountain Home Demonstration State Forest (MHDSF) manages its land consistent with the recommendations in the GSNM’s management plan. This highlights the irony of the GSNM: most visitors don’t see any giant sequoia until they reach the State Forest’s boundary. MHDSF has incorporated logging its management since 1946.

Not allowing harvesting in GSNM will eventually require a name change to the White Fir National Monument.

________________________________
Signed

I will admit the White Fir Nat’l Monument comment is a little snarky, but it is true.

If you’d like to use my petition, it’s here.

The Sierra Club’s full text and online petition may be found here.

For technical peer-reviewed information:

An Ecological Basis for Managing Giant Sequoia Ecosystems, Dr. Douglas Piirto (with Robert R. Rogers), Environmental Management (2002)
The Giant Sequoia National Monument Management Plan

Life imitates art

Timberati — Fri, 19 Sep 2008 17:12:00 +0000

This BBC story, Survey turns hill into a mountain, about Mynydd Graig Goch in Snowdonia in Wales sounds like the movie that starred Hugh Grant, The Englishman Who Went Up a Hill But Came Down a Mountain.

Maggie Mountain in the Sierra Nevada

I’ve worked in the Sierra Nevada at Mountain Home State Forest. I could see Mount Whitney. I now live near the Mayacamas Mountains. The thing is just a big hill.