California’s Forests: Where Have All the Big Trees Gone?

“The number of trees larger than two feet in diameter has declined by 50 percent on more than 46,000 square miles of California forests, the new study finds.”

“But in comparing a census of California forests done in the 1920s and 1930s with another survey between 2001 and 2010, McIntyre and his colleagues documented a widespread demise of big trees that was evident even in wildlands protected from logging or development.  The loss of big trees was greatest in areas where trees had suffered the greatest water deficit.”

If nothing else, this supports a policy of not killing the survivors.


  1. I’m not sure what you mean by “If nothing else, this supports a policy of not killing the survivors.” If you mean that we need to save the biggest & the best of the trees I can generally agree with that. The trees I see dying in our forests are either the oldest/largest or those suppressed in the understory of the canopy. One end of the spectrum dies because they cannot effectively compete for the available water with the vigorously growing younger trees that surround them. The other because they lack sufficient sunlight and cannot compete with the overtopping trees. And by their sheer density, the canopy in these stands intercepts a significant volume of the very water needed in the soil, in the root zone, exacerbating the localized drought.

    • One fact that cannot be ignored is that the existing old growth had plenty of space and water, during Indian times, never needing to develop a very deep root system, even for ponderosa pine. So now, the understory trees directly compete with the old growth for the water near the surface. Another problem is that those understory trees serve as ladder fuels, to kill even the largest of trees. When seed sources are eliminated, that tends to skew the large-tree data. *smirk* Changed species compositions also seem to play a big role, with an understory of flammable firs and cedars. (BTW, green cedar boughs burn quite well!)

  2. Of course, those old growth pines were, and continue to be, a testimony to Indian forest management. Wherever there are big ponderosa pines, especially associated with bearclover, there was intensive Indian burning. Both plants thrive under those conditions but, not so much in “The White Man’s World”. Of course, ALL of the losses of large trees (to logging) on Forest Service lands, in the Sierra Nevada, happened before 1993 (which the article doesn’t mention!). The article also doesn’t mention that there is a current ban on cutting trees over 19.9″ in diameter. Even with a 30″ diameter limit, canopy cover was never reduced below threshold by cutting trees between 20-29.9″ in diameter. It does take a keen eye to be able to pluck as many “excess” 20-something inchers as we can. Those trees help carry the sale, especially when other non-commercial tasks are required, on such projects.

    It is all-too-easy to blame forest problems on “climate change”, while throwing up your hands in frustration, choosing to do nothing in mitigation. Meanwhile, there are 5 successful bug patches within a quarter mile of my house. It certainly hasn’t been cold enough, or rainy enough to offset their exploding populations.

    Welcome to the new reality, folks. We can plan for drought, bark beetles and catastrophic wildfires….. or not

    (It seems the choice has already been made, in the courts, for the Sierra Nevada).

  3. The land’s carrying capacity is finite which means the amount of life the land can support is also finite.

    Until they were removed from the land, California’s forests were once managed by the Indian; in other words, their use of fire left the landscape. Add to that the fact that we’ve been putting out fires for a very long time now. This absence of fire has allowd all sorts of vegetation to grow that would not have been their during the Indian’s burning regime. All this extra vegetation is probably in excess of the land’s carrying capacity which means the vegetation is prone to drought-caused stress. In other words, today, we have an awful lot of so-called “ancient” forest that does not even remotely resemble the forest encountered by the first white settlers. (Muir would not recognize the ancient sequoia forests!)

    Given its carrying capacity (i.e., its finite resources), if 100 trees of 10 inch average diameter is all an acre can support, then that same acre can only support 25 trees if they grow to average 20 inches diameter. Grown to 40 inches average diameter, the land can support only about 6 trees per acre. Think about that when there is a call to keep all the big trees and let them grow larger when people cry out in horror if someone suggests cutting those 75 trees. Either nature removes those trees (via fire, drought, insects, etc.) or people must remove them if the forest is to stay healthy; i.e.,within its carrying capacity.

  4. What about harvesting the ones that didn’t survive? Is it true that the diameter limit applies to dead trees also? I would guess that since 1993 fire has killed more big trees than any other cause.

    • Although many eco-groups would like to see a rigid nationwide diameter limit for snags, that isn’t yet a reality. I have seen salvage guidelines that mandate leaving the tallest, largest and straightest snags for wildlife. I still think that the success of a salvage project should be gauged by how much of the small diameter trees are turned into products. And yes, here in the Sierra Nevada, bark beetles and wildfires have killed the most large trees since 1993. Sure, if the Forest Service was still clearcutting owl territories, the loss of large trees would be a problem. Eco-groups like to point at “industrial logging” as a destroyer of public forests but, that 80’s style of logging does not exist in Sierra Nevada National Forests. Both the Rim and King Fires shows how vulnerable to wildfires “protected” landscapes are.

  5. It is interesting to see the reference to how the Indians used fire and the positive impacts it had on the abundance of large trees. I support the fact that fire is a legitimate tool and has a place in management strategies. Fire, like any other tool must be applied to the individual forest communities so as to maximize diversity. Silvaculture treatments are also nothing more than tools. We must recognize the use of fire today is considerably different than when the Native Americans were the only occupants. There is a big difference between having less than one million people on this continent and currently having 350 million! Yes times have changed, but the importance of trees to our human environment has not decreased, only expanded. The most important consideration today is to focus on health and diversity of our remaining forests. This can only be accomplished by recognizing and treating the unique individual communities that make up the forest mosaic. Applying the tools of the trade to large areas is simply unacceptable. Just because a farmer has a 160 acre, square field does not mean every acre has the same characteristics. Modern day farming equipment applies the required applications to each individual acre. Science needs to manage our remaining forests following the same principles.

    • Less than ONE MILLION on the continent?
      No, no, no, no, Brian, read your history. There were tens of millions of Indians in North America and tens millions more in SOUTH and Central America, all farming and hunting and gathering and warring. When the smallpox hit, around 85 to 90 percent of Indians with no resistance or genetic exposure ever, died.
      The disease preceded white settlement for a substantial period, at least 50 and often 100 years between first contact and trade to white incursion. That left a large time gap where the land did what it wanted, FROM AN ANTHROPOLOGIAL basis.
      So fire really was a tool, systematically applied by humans who hadn’t gotten around to steel axes and Stihls quite yet.
      And all the comments here on basal area against the water budget are perfectly true. Go look at the edge of a regenerating clearcut next to a “virgin” stand of big wood and you can see the curve of growth as the draw circles of the big wood suck the little neighbors dry.
      As for water deficits, well, when do fires burn best? When the hour-rated fuels become fuels. Only has to be for a couple of days or weeks, but floompf! happens.

    • Early estimates of the human population of the western hemisphere was around a million people. That has been debunked and more recent estimates were around 115 million! A very large number were in the Pacific Northwest; think abundant fish.

      What does “remaining forests” mean? A forest is a forest regardless of tree species, age, etc. That it has been harvested and reforested does not mean it is no longer a forest.

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