I was pleased to recently see some New York Times press devoted to forestry issues and while like many articles it is thin on solutions, I appreciate the effort of bringing the complicated mix of challenges (and opportunities) out into the public eye.
In the end I don't know how much a good article (including my blog!) changes ACTIONS taken on the ground, and that is the real issue. We have a long mountain to climb in the areas of forest literacy, of moving beyond appreciation and a general "forests are good" attitude into the type of deeper understanding and intervention I believe is required to support the healthiest forests possible in the face of so many uncertainties.
The full New York Times article, published
here, is well worth the read. I am going to grab a few interesting excerpts and comment on them.
First off, we know that trees and forest are important in terms of carbon storage; they lock up carbon in their wood and soil, sometimes for hundreds of years or more. In fact, as the article notes,
"Scientists have figured out — with the precise numbers deduced only
recently — that forests have been absorbing more than a quarter of the
carbon dioxide that people are putting into the air by burning fossil
fuels and other activities. It is an amount so large that trees are
effectively absorbing the emissions from all the world’s cars and
trucks."
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| A devastated forest I visited a few years back; much of the carbon storage built up was quickly releasing again. |
This comes as good news, but the challenges trail right behind as we look at trends where increased deforestation and mass disturbance from climate change and other sources. Forests that burn or are removed by humans, pests, and disease can rapidly release these carbon storages, adding to the overall total. Even if allowed, it will be some time before these forest can regrow and put that carbon back in the bank, so to speak:
“Forests take a century to grow to maturity,” said Werner A. Kurz, a
Canadian scientist who is a leading expert on forest carbon. “It takes
only a single extreme climate event, a single attack by insects, to
interrupt that hundred-year uptake of carbon.”
Another interesting point the article makes is about the potential for forests to put carbon into long term storage, which could potentially be amplified by two factors; the idea that increased C02 is causing plants to grow faster, coupled with the warming temperatures which means and longer growing season:
"Today, the re-growing forests of the Eastern United States are among the
most important carbon sponges in the world. In the Harvard Forest, the
rate of carbon storage accelerated about a decade ago. As in much of the
world, the temperature is warming there — by an average of 2.3 degrees
Fahrenheit in the last 40 years — and that has led to longer growing
seasons, benefiting this particular forest more than hurting it, at
least so far. “We’re actually seeing that the leaves are falling off the trees later in the fall,” Mr. Werden said.
Scientists say that something similar may be happening in other forests,
particularly in cold northern regions that are warming rapidly. In some
places, the higher temperatures could aid tree growth or cause forests
to expand into zones previously occupied by grasslands or tundra,
storing more carbon."
and
"One major reason is that forests, like other types of plants, appear
to be responding to the rise of carbon dioxide in the atmosphere by
growing more vigorously. The gas is, after all, the main food supply
for plants. Scientists have been surprised in recent years to learn
that this factor is causing a growth spurt even in mature forests, a
finding that overturned decades of ecological dogma."
At first this reads as good news to those of us aware of the challenges of a short growing season in the Northeast. I laugh sometimes when I hear stories of forests in the tropics that grow so fast you can almost see the trees growing. Our game here, whether it is forestry or farming, is a patient one. On some tree species a few inches of growth each season is good.
So we know that forests are good carbon sinks, so long at they are healthy, standing, and resilient to changes and disturbances. And while climate change has brought and will continue to bring more dramatic weather events, more droughts, and more floods, in the longer term picture the forests in the east MAY reap some benefit from warming temperatures (longer growing season) and more rapid growth from all the available CO2.
Maybe....let's not forget the added complications. I ran the second quote above by my friend Danica, who is doing a program in the Cornell Department of Ecology & Evolutionary Biology. She has been conducting some experiments to look at the effects of ozone on plant growth and health. Here is what she said:
There have been a lot of experiments looking at the effects of
increased carbon dioxide on plants. These experiments artificially
elevate carbon dioxide in the atmosphere surrounding the plants and
then look at how the plants respond in terms of growth, photosynthesis,
respiration, and many other variables.
Most of these find that plants
can increase their growth and photosynthesis (i.e. carbon capture)
rates up to a point, but plants do acclimate at these higher carbon
dioxide concentrations over time so the rate of increase is fleeting.
Often, this acclimation has to do with the plant balancing the
tradeoff between capturing more carbon while limiting water loss.
If
plants do not have enough water, they will close their stomatal cells
to minimize water loss, but this closure also means that they cannot
absorb carbon dioxide.
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| The brown splotches are from mass die-off from pink bark beetle in the Black Hills of SD (this picture was taken there) and across the Rocky Mountains. |
One of the issues that Danica's response gets at is the challenge if isolated experiments in labs where the only variable is CO2 concentration versus the "real world" scenario in the forest, where other gases, precipitation, latitude, species composition, soil, land use, etc all play a role in the unique story, and thus outcome of a forest.
The good news, in my mind, is that the actions we need to take are largely the same: promote healthy, resilient individual trees, stands of trees, and whole forests. Also, while in the past forestry might focus on concentrating on a particular species and encouraging that species to dominate, we might look for adding species diversity more into the mix.
This conversation gets at the first part of the title of this entry; it speaks to our practice as stewards of the forested landscape. I'll drop one more quote which hints at the next role I believe we need to play as propagators of better species, of more species, of species we may not yet find growing in our region:
"Forests are re-growing on abandoned agricultural land across vast reaches of Europe and Russia. China,
trying to slow the advance of a desert, has planted nearly 100 million
acres of trees, and those forests, too, are absorbing carbon.
But, as a strategy for managing carbon emissions, these recovering
forests have one big limitation: the planet simply does not have room
for many more of them. To expand them significantly would require taking
more farmland out of production, an unlikely prospect in a world where
food demand and prices are rising."
As a permaculture designer, my logical and first response to this quote was, "why can't we have agriculture and forests, too?" This topic, and the literature I've been obsessing over lately, will be the topic of next week's entry. Thanks for reading!
