Arboreally Speaking, the Good Old Growth Curve Is a Delusion

Discussions of the nature and definition of old growth and primary forests.

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#1)  Arboreally Speaking, the Good Old Growth Curve Is a Delusion

Postby edfrank » Wed Dec 28, 2011 8:42 pm

Arboreally Speaking, the ‘Good Old Growth Curve Is a Delusion’
by Neil Pederson | 12.27.2011 at 6:32pm

http://blogs.ei.columbia.edu/2011/12/27/arboreally-speaking-the-good-old-growth-curve-is-a-delusion/

In the previous post, I outlined the argument lighting up parts of the New Jersey legislature and the human elements of its ecological communities. Briefly, one reason some people are using to promote logging on public lands is the perception that old trees and forests are dying of old age. While there are other arguments as a part of the bill, like the fact that because forested ecosystems are maturing, species that use younger forests are declining, this “old trees are in decline” argument has led to much logging of old forests. I would argue it doesn’t have to be that way.

Image

I will spare you many of the details from the scientific literature. But there is a plethora of papers indicating old trees and forests are dying of anything but old age...  

Continued  http://blogs.ei.columbia.edu/2011/12/27 ... -delusion/


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"I love science and it pains me to think that so many are terrified of the subject or feel that choosing science means you cannot also choose compassion, or the arts, or be awe by nature. Science is not meant to cure us of mystery, but to reinvent and revigorate it." by Robert M. Sapolsky

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#2)  Re: Arboreally Speaking, the Good Old Growth Curve Is a Delu

Postby Joe » Thu Dec 29, 2011 4:28 pm

the forestry world is loaded with propaganda- I've been fighting it ever since I left forestry school in the early '70s
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#3)  Re: Arboreally Speaking, the Good Old Growth Curve Is a Delu

Postby Larry Tucei » Fri Dec 30, 2011 10:40 am

I'm no Forester but many times I have questioned the practices that the National Forest guru's seem to get away with. NF were set aside back in the 30's for the people to enjoy recreation. Not for the NF to make a qucik profit on the timber. They should have been studying the Forest instead of destroying it. They cut Hardwoods and use the timber to make pallets, what a waste. One good thing has happened i n Ms.lately the pratice of clear cutting has  been stopped.  The Forest Service is finally rethinking that planting Pines only is not good pratice. DUH!  A Forest should be deverse and not mono-cultured with superior Pines.  Due to the reckless management of most Southern Forests very little Old Growth is left here. Trees live a heck of a long time.  200-800 years would be the average trees would die from old age depending on the species and some 2000-3000.  I'm not blaming Foresters I'm blaming policy whoever makes theses dumb practices reality.  Maybe I should have been a Polititian that cares about the Forests!  Joe,  I think I would have been just like you had I been in Forestry going against the grain!  Larry
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#4)  Re: Arboreally Speaking, the Good Old Growth Curve Is a Delu

Postby Joe » Fri Dec 30, 2011 11:40 am

Forestry in America began with German foresters! Need I say more?
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#5)  Re: Arboreally Speaking, the Good Old Growth Curve Is a Delu

Postby Josh Kelly » Fri Dec 30, 2011 12:02 pm

Great blog post, Neil!  Thanks for including links to excellent literature, too.  

Many of those that abhor the death of old trees and their subsequent decomposition into the soil carbon pool operate under the false assumption that all trees in "old" forests are the same age. In reality, most of the trees in these "old" forests are quite young, even if many of the canopy trees are old - hence the famous inverse j-curve of age distribution in old-growth forest.  Most of the forest cover in the Eastern U.S. is naturally uneven aged, and I believe restorative forestry practices in the East should create uneven aged forests from degraded even-aged stands, not reduce the age class diversity and structural diversity of uneven-age "old" forests.  Of course, I'm preaching to the choir here.  

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#6)  Re: Arboreally Speaking, the Good Old Growth Curve Is a Delu

Postby Joe » Fri Dec 30, 2011 12:12 pm

The only reason foresters whine about "overmature" forests is that they want to cut them- pure and simple. They'll make all sorts of lame arguments. Then they pitch how wonderful the new baby forests will be-  how the wildlife love them, unlike those old, decadent forests.

Of course there will never again be as much wildlife as there was before the first pale face showed up.

I always prefer uneven age mgt.: http://www.maforests.org/rulethum.pdf
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#7)  Re: Arboreally Speaking, the Good Old Growth Curve Is a Delu

Postby Lee Frelich » Sat Jan 07, 2012 12:39 pm

Neil et al.:

Here is a trip through the universe of temporal and spatial scales in forest ecology, which gives some perspective to the above discussion.

Its true that many old trees continue to grow at a high rate (especially of you calculate basal area or volume increment, which one of Craig Lorimer's graduate students did for sugar maple in the Porcupine Mountains and discovered that they just kept going up as trees go to 150, 200, 250 years old).  Some of this has to do with stand dynamics, and the fact that certain old trees get better and better canopy growing space as they age, and its also partly CO2 fertilization, and partly longer growing seasons, and in certain areas, more rainfall or more positive rainfall/evaporation balance, although these latter effects may abruptly reverse in the near future as the climate continues to change and evaporation overtakes the effect of additional rainfall, and the CO2 fertilization begins to reach its asymptote.

Returning to the issue of increasing carbon storage in older forests, inevitably, if old forests continue to accumulate C, especially in the soil, it will lead to a high C:N ratio and other effects that will stall increased production, and without rejuvenating disturbance, in many cases to ecosystem retrogression. This might take hundreds of years (especially in northern hardwoods), so for now, many forests will continue to increase carbon, an important 'transient' dynamic (I put transient in quotes because in this case transient is a few centuries, rather than the few years usually referred to), since the increasing carbon storage is very important over the next couple of centuries for the future of the climate.

In other forest types, this increasing C storage will lead to retrogression in a relatively short time. For example, boreal forest in northern Minnesota, in the absence of fire, becomes a half dead pile of crap (i.e. balsam fir with budworm) on top of a moss blanket in just two hundred years (that's a quote of myself from the news media this past September). Productivity in the tree layer goes backwards at this stage, and the moss carpet increases very, very slowly, on its way to the world-wide retrogressed climax by Sphagnum mentioned in my other post yesterday.  Some forest types have to have a major high severity disturbance to maintain productivity. Most ENTS are used to and biased by northern hardwoods where that is not the case, at least on time scales of several centuries.

On a longer time scale 1000s of years, all ecosystems retrogress to less productive states (See Peltzer et al 2010, Understanding Ecosystem Retrogression, Ecological Monographs 80: 509-529, which I reviewed last year for Faculty of 1000). This is due to loss of P over time in areas that are not either heavily burned or glaciated periodically. This occurs in ecosystems across the world in many different climates.

Most ENTS are lucky to live in a forest ecosystem where, at least on the scale of a few centuries, carbon would tend to keep accumulating, due to the young age of the soils and/or the mineral content of the underlying weathering bedrock. However, at this point its unlikely that this carbon accumulation will continue, because in a few decades this will all reverse due to a warming climate, and the initial increased productivity from a warmer climate will turn to forest dieback, with a time-lag of several centuries before the ecosystem processes and species composition catches up to the new climate (assuming the climate stops changing in a few centuries). That's not a problem for the ecosystem. For example, a white pine tree does not care if it lives in NY or in Canada, nor whether it lives in a stable ecosystem, nor whether it lives in a productive ecosystem, nor an ecosystem that is increasing its carbon storage. Its only a problem for people who are wedded to the idea of a stable, productive old growth white pine forest existing in a certain location.

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#8)  Re: Arboreally Speaking, the Good Old Growth Curve Is a Delu

Postby KoutaR » Sun Jan 08, 2012 12:43 pm

... boreal forest in northern Minnesota, in the absence of fire, becomes a half dead pile of crap (i.e. balsam fir with budworm) on top of a moss blanket in just two hundred years (that's a quote of myself from the news media this past September). Productivity in the tree layer goes backwards at this stage, and the moss carpet increases very, very slowly, on its way to the world-wide retrogressed climax by Sphagnum...


That's interesting as in Finland this is not the case. Actually, this was an old belief in Finland, too, influenced by forestry sponsored research of 50's. Natural spruce forest was called "suicide spruce forest", because it collapses/deteriorates without fires or clearcutting. This was then extensively used by forest industry as the ecological basis for clearcutting ("clearcutting mimics forest fires"). However, newer research has shown, in north Finland there are spruce stands thousands of years old which have not collapsed/deteriorated and are able to regenerate without fires. Of course, the productivity of a pioneer stand is still higher. (The spruces there are Picea abies, Picea obovata and their hybrids.) Reference: Keto-Tokoi, P. & Kuuluvainen, T. (2010): Suomalainen aarniometsä. Maahenki.

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#9)  Re: Arboreally Speaking, the Good Old Growth Curve Is a Delu

Postby Neil » Sun Jan 08, 2012 9:49 pm

thanks Lee,

I keep forgetting about ecosystem regression for the long time periods required for it to occur.

So, would the application of the information on ecosystem regression to forest management go something like: ecological justification for logging forest to 'save its health', prevent ecosystem regression, is on the order of every 100-150 years or less in the absence of fire in boreal systems and on the order several hundred to thousands of years for other temperate forest types?

And, what about all the pine beetle and other insects re-setting succession? How long do you think regression takes in those systems?

thanks,

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#10)  Re: Arboreally Speaking, the Good Old Growth Curve Is a Delu

Postby Lee Frelich » Mon Jan 09, 2012 10:37 am

Kouta and Neil:

I think the forests in Finland are quite different--they don't have balsam fir which is susceptible to the native (and poorly named, since it mainly infests fir and not spruce) insect spruce budworm. So, the time for retrogression is uniquely short in boreal forests of central North America, on the order of 200-300 years. Central North America has an extraordinary frequency of severe disturbance, even in the absence of humans--the droughts and fires, the tornadoes, and the derechos, that are often followed by fire. The forests never had a chance to develop some sort of non-disturbance dependent ecosystem where productivity was maximized, so it has this half dead balsam fir.

In other places, as Neil suggests, rejuvenating disturbance is necessary at much longer intervals to prevent retrogression. However, I am not sure that logging would be a good agent to prevent retrogression. Fire is much better at preventing retrogression, because it releases cations bound up in organic materials, which on sites with some P in the bedrock, could prevent retrogression essentially forever (I know I should not use the word forever, I used it once in a manuscript and a reviewer informed me that only diamonds are forever). Even better at preventing retrogression, is a round of glaciation, being covered with volcanic ash, or some other such geological disturbance, every million years, with fires every 1000 years or so in between.

Most ENTS live in a recently glaciated landscape with young soils that still have a lot of P in them (and therefore N is the limiting nutrient in most cases). Additional N can come from atmospheric deposition, N fixation by various microbes, and sometimes by weathering of bedrock. Its not as hard to replace over long time scales as P. Also, a lot of ENTS live in areas, especially New England, where a lot of the landscape supported uneven-aged northern hardwoods and hemlock prior to European settlement, and this forest type does not need rejuvenation from logging or other disturbance on time scales relevant to the people living there at this time.

Regarding pine beetle and other insects, I don't think they play a very important role in long-term rejuvenation of ecosystems, unless they have a relationship with fire whereby they increase the chance of fire. If they aren't related to fire, I don't think they reset succession, but rather they are important in regulating the fluctuations among dominant tree species over time (I am not talking about exotic insects and diseases that wipe out tree species).

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