During the last Pleistocene Ice Age advance ice covered much of the North American Continent, as well as the mountainous areas of the West.  Depending on who you consult the ice retreated sometime between 15,000 years to 12,000 years before present. A minor expansion of ice occurred during the Little Ice Age sometime between 1300 and 1850 AD.

Since that time, the ice has melted back from many areas which were once cloaked in ice.

My question is how much Ice is normal? And should we manage the Planet to create a new Ice Age?

Of course, my question is rhetorical. Most people would acknowledge that the “right amount” of ice is whatever exists. Major ice sheets 20,000 years ago were “normal” given the climate creating them.

Yet I find that most people involved in natural resource issues, particularly, the collaboratives that have sprung up around the West think they know the “right amount” of wildfire, beetles or disease is proper to the forests. And if this “right amount” is not occurring, than we have to “fix” the situation.

We hear all the time there is too much wildfire, too many hot, severe fires or beetles are killing too many trees and so forth.  As if those making such pronouncements know exactly what is the “right amount” of these processes are the “proper” amount.

The general impression of most collaborative members is that we have forests that are too dense variously ascribed to fire suppression, and/or in some cases past logging practices.  And that we are seeing some large wildfires, expansion of juniper, or expansion of bark beetle populations in some forest types, as reasons for logging and thinning. The presumption is that what we see today is not “normal” and of course, those prescribing logging as the solution are so smart they “know” the right amount of trees that should be found on various landscapes.

This gets back to my rhetorical question. How much ice is the “right amount” during an Ice Age or interglacial period?  Would those professing to know the “right amount” of fires or beetle, be smart enough to suggest the “right amount” of ice?

In my mind the right amount of trees, wildfire, juniper, bark beetles, is whatever exists. All of these are controlled by climate, just like the amount of ice that covered the continents and mountains was dictated by climate. Climate will decide what density of trees can grow on any particular site.

Forests do not need to be “fixed” or “restored” as they are perfectly capable of “restoring” themselves, if indeed, one even agrees that they “need” restoration—an assumption I would question in most instances.

The fact is that ecological processes are shaping the forests continuously. These processes like wildfire and/or bark beetles, are shaping the forest composition, species, and numbers. All without human interferences. And I might add without costing taxpayers a cent.
How a tree dies is ecologically important. For instance, bark beetles by puncturing the outer bark of trees allows other agents like fungi to enter the tree. A fire, by creating charcoal, can reduce entry of some fungi and insects. Thus anything that alters these natural pathways, can change the entire future trajectory of the forest.


One of the assumptions of many collaboratives, agencies like the Forest Service, and of course the timber industry is that logging emulates natural processes. There is a very small amount of truth in that logging as well as wildfire, beetles and other natural agents do kill trees. However, that is like suggesting that someone shot to death by a gun is analogous to dying from old age because in both cases, the person is dead. The sad truth is that most so-called “restoration” is degrading our forest ecosystems.

There is no evolutionary equal to logging in our forest ecosystems. Logging removes biomass and nutrients from the ecosystem. It reduces carbon storage. It alters fire regimes. It alters mortality.

Other impacts associated with logging includes the spread of weeds and disease, sedimentation of waterways from logging roads, disturbance of wildlife, changes in age and sometimes species structure of the forest ecosystem, loss of scenic values, and other collateral damage.

By contrast, forest ecosystems have been influenced by wildfires, bark beetles, and so forth for hundreds of millions of years. Over this evolutionary time scale, forest ecosystems have adapted measures to permit their persistence in the face of the natural processes. For instance, lodgepole pine that have serontinous cones that open upon heating in a wildfire or the think bark on a mature sequoia tree that protects the sensitive inner bark layers from heat and fire.


Natural agents like wildfire and bark beetles create an abundance of dead wood and snags which has been shown to be critical to the survival of many other species. Some wildlife, and many plants, are only found in burnt forests and/or on dead trees. Once the trees fall to the ground, an entirely new set of species depend on their existence. If a dead snags falls into water it create habitat for aquatic insects and fish. A burnt tree with a charred bark that is buried, stores carbon for hundreds, if not thousands of years.

Asserting that logging is the same as natural agents like wildfire is like suggesting that hunters emulate natural predators like wolves. Many studies show that wolves select different animals in an elk population than hunters. Hunters tend to take the prime age and reproductive animals, while wolves, by and large, take the young, old, and infirmed. Natural agents like bark beetles and wildfire exert a different evolutionary pressure on forest ecosystems than human logging.


Next time you comment on a forest service logging proposal or go on a field trip, ask those advocating more logging how much ice is the right amount. See what they have to say. If they are honest, they will admit they don’t know what the right amount of ice is. At that point ask them how they think they know the right amount of fire, beetles, or juniper.

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About The Author

George Wuerthner

George Wuerthner is an ecologist and former hunting guide with a degree in wildlife biology

4 Responses to How Much Ice is Right? Collaboratives and forest ecosystems

  1. avatar monty says:

    Some would say “the right amount” is enough to feed our pathological consumption habits.

    The Willamette N.F.(1.7 million acres) stores the greatest tonnage of carbon in the lower 48. The annual harvest is about 75 million board feet(B.F) on 1.1 million acres with a net annual growth of something in excess of 500 million B.F. Coastal forests growth rates far exceed Cascade mountain rates. The 1.1 million acres are gross in that during timber sale planning many acres are discarded never to be logged. The remaining 600 thousand acres are wilderness, riparian zones and special set asides. Given that humans use wood, forest management, as practiced on the Willamette NF is as close to being reasonable given our industrial war on nature.

    P.S, About 30 percent of acreage is Old Growth and is left to grow and die. Logging technology and forest standards are the highest required on this planet.

    • avatar rork says:

      Not too shabby of an answer, though I do agree our author had a point.
      I worry it got a little Gottfried Leibniz in there too. There’s some pretty rationalized arguments out there that many things humans do to the landscape are natural. The 1491 book comes to mind.

  2. avatar monty says:

    rork: What is the 1491 book and who is Gottfried Leibniz? I left a lot out about the incredible productivity of these northwest forests. If my memory is intact, I believe that the net annual growth on the Willamette NF is closer to 800 million BF. Most folks when viewing a 60 year old DF planted forest think it is native.One thing I failed to mention is that 90 percent of the logging roads were built in the 60’s thru the 80’s so no new major logging roads are being built. And many roads are put to bed post logging.

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January 2016
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‎"At some point we must draw a line across the ground of our home and our being, drive a spear into the land and say to the bulldozers, earthmovers, government and corporations, “thus far and no further.” If we do not, we shall later feel, instead of pride, the regret of Thoreau, that good but overly-bookish man, who wrote, near the end of his life, “If I repent of anything it is likely to be my good behaviour."

~ Edward Abbey

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