Some trees are growing like crazy

[Xnn]

This is basically a good news story. Aspen trees (I call them populars) are doing just about
everything they can to soak up as much CO2 as a tree can. While CO2 levels
have risen about 19% over the last 50 years, Aspen trees have accelerated their growth
rate even more so; 53%! That is astounding as it is more than proportional. Aspens already
grown fairly fast and since global warming is also predicted to result in elevated precipitation
levels, Aspens have been shown to grow like crazy. This has not been observed in Pine or
Oak and I can't speculate on why that may be.

Anyhow, it seems a good reason to quit mowing the lawn and plant some trees instead.

http://www3.interscience.wiley.com/journal/122659631/abstract

As atmospheric CO2 levels rise, temperate and boreal forests in the Northern
Hemisphere are gaining importance as carbon sinks. Quantification of that role, however, has
been difficult due to the confounding effects of climate change. Recent large-scale
experiments with quaking aspen (Populus tremuloides), a dominant species in many northern
forest ecosystems, indicate that elevated CO2 levels can enhance net primary production.
Field studies also reveal that droughts contribute to extensive aspen mortality. To
complement this work, we analyzed how the growth of wild aspen clones in Wisconsin has
responded to historical shifts in CO2 and climate, accounting for age, genotype
(microsatellite heterozygosity), and other factors. Aspen growth has increased an average of
53% over the past five decades, primarily in response to the 19.2% rise in ambient CO2
levels. CO2-induced growth is particularly enhanced during periods of high moisture
availability. The analysis accounts for the highly nonlinear changes in growth rate with age,
and is unaffected by sex or location sampled. Growth also increases with individual
heterozygosity, but this heterozygote advantage has not changed with rising levels of CO2
or moisture. Thus, increases in future growth predicted from previous large-scale, common
garden work are already evident in this abundant and ecologically important tree species.
Owing to aspen's role as a foundation species in many North American forest ecosystems,
CO2-stimulated growth is likely to have repercussions for numerous associated species and
ecosystem processes.

http://www.eurekalert.org/pub_releases/2009-12/uow-ggc120109.php

The rising level of atmospheric carbon dioxide may be fueling more than climate
change. It could also be making some trees grow like crazy.

That is the finding of a new study of natural stands of quaking aspen, one of North America's
most important and widespread deciduous trees. The study, by scientists from the University
of Wisconsin-Madison and the University of Minnesota at Morris (UMM) and published today
(Dec. 4) in the journal Global Change Biology, shows that elevated levels of atmospheric
carbon dioxide during the past 50 years have boosted aspen growth rates by an astonishing
50 percent.

"Trees are already responding to a relatively nominal increase in atmospheric carbon dioxide
over the past 50 years," says Rick Lindroth, a UW-Madison professor of ecology and an
expert on plant responses to climate change. Lindroth, UW-Madison colleague Don Waller,
and professors Christopher Cole and Jon Anderson of UMM conducted the new study.

The study's findings are important as the world's forests, which cover about 30 percent of
the Earth's land surface, play an important role in regulating climate and sequestering
greenhouses gases. The forests of the Northern Hemisphere, in particular, act as sinks for
carbon dioxide, helping to offset the increase in levels of the greenhouse gas, widely viewed
as a threat to global climate stability.

What's more, according to the study's authors, the accelerated growth rates of aspen could
have widespread unknown ecological consequences. Aspen is a dominant tree in mountainous
and northern forested regions of North America, including 42 million acres of Canadian forest
and up to 6.5 million acres in Wisconsin and Minnesota. Aspen and their poplar cousins are
considered "foundation species," meaning they exert a strong influence on the plant and
animal communities and dynamics of the forest ecosystems where they reside.

 

[Integral]

Very interesting

Seems we need to start planting lots of Aspen!

The problem is that we dare not burn the resulting wood. It should be buried, how good a form of sequestration is this?.

This is the type of response discussed in the Gaia Hypothesis. Essentially, it is Earth's lifeforms that not only control the composition of the atmosphere, they determine it.

 

[Blenton]

Or at least the timber be used to make some nice furniture that will be used for a large period of time.

 

[vanesch]

There's another way of looking at this: one has always emphasised the catastrophic side of increased CO2 levels. Maybe this is one of the advantages. If this works out for crops too, that would simply be fantastic.

 

[Bored Wombat]

It should be buried, how good a form of sequestration is this?

My guess would be risky.

Buried in a peat swamp might lead to long term sequestration of most of it. But you'd run out of peat swamps fairly smartly.

Just sticking it in a hole would lend itself to breaking down anaerobically, which would eventually release methane, which would be worse that the CO2 that you started with in the small number of centuries time-scale.

As far as I can see the only reliable geosequestration would be to leave the coal and oil underground in the first place. I call it presequestration. It's yet to catch on at ExxonMobil.

 

[Bored Wombat]

Or at least the timber be used to make some nice furniture that will be used for a large period of time.

There's probably a limit to how many tables we can use.

If we have released 329 billion tonnes of carbon into the atmosphere, and wood is about 50% carbon by weight, and there's 6.8 billion of us, we need about 100 tonnes of wood furniture each, to bring us to pre-industrial levels.

Or, if we are prepared to accept 350ppm, and there are 380 ppm, and the oceans would resupply about 1:1 then we need to use about 60ppm by volume in the atmosphere. Which is about 90ppm by weight. If the atmosphere weighs about 5.2 quadrillion tonnes, that's about 468 billion tonnes of CO2, or about 127 billion tonnes of carbon or about 254 billion tonnes of wood.

Which is only about 36.7 tonnes each. Of course last year we released about 8.6 billion tonnes of carbon more, so at current rates (which look to be conservative) we'd have to add about 2 tonnes of wooden furniture each year each from now on ... less natural sequestration. Probably around 1700 kilograms. Give or take a couple of hundred.

Many people in Ethiopia can't afford their share of the furniture so we might have to buy it for them and ship it over. (Perhaps in heavy wooden boats).

Or look at lower fossil fuel use.

 

[Xezlec]

There's another way of looking at this: one has always emphasised the catastrophic side of increased CO2 levels. Maybe this is one of the advantages. If this works out for crops too, that would simply be fantastic.

Yeah, I thought carbon fertilization was one of the biggest things people talked about on the "it's not really a problem" side of the issue. Remember that book, "The Greening of Earth" or something like that? But I thought that was pretty much debunked, and it had been determined that relatively few species are as overjoyed by the climate changes as this kind of tree, and therefore the overall positive effect was tiny compared to other effects being discussed. Disclaimer: I have no citation for this and am probably somewhat of a moron. :tongue2:

 

[Bored Wombat]

Yeah, I thought carbon fertilization was one of the biggest things people talked about on the "it's not really a problem" side of the issue. Remember that book, "The Greening of Earth" or something like that? But I thought that was pretty much debunked, and it had been determined that relatively few species are as overjoyed by the climate changes as this kind of tree, and therefore the overall positive effect was tiny compared to other effects being discussed. Disclaimer: I have no citation for this and am probably somewhat of a moron. :tongue2:

I think that that's right.

There are parts of the world where primary production is limited by CO2, but there are also ground nutrients, sunlight and water limiting growth.

There is a missing Carbon sink that is fairly significant. (See the right hand column in http://lgmacweb.env.uea.ac.uk/lequere/co2/carbon_budget.htm"). And I personally attribute this to increased primary production in the terrestrial biosphere of phytoplankton.

But increased primary production is not always a good thing:

• Parasitic vines tend to show more increased growth than woody species under increased CO2 concentrations. This suggests more risks for biodiversity. (And other unforeseeable consequences like http://www.msnbc.msn.com/id/13046200/").
  
• Many plants respond to the increased CO2 with reduced stomata, either in number or size or both. This increases the plants resistance to drought, but is expected to have a devastating effect on the climate of the west Amazon basin where nearly all the rainfall is from repeated transpiration. (The weather systems move generally from west to east, and the Andes mean that most moisture falls as orographical rainfall.) This contributes to the modeled collapse of the Amazon rainforest after about 3 degrees of warming.
  
• Plants that have increased production under CO2 fertilisation often have reduced nutritional value. This is bad for grazing plants and insects, but also for humans and transport costs.