The Harris Center for Conservation Education, the Monadnock Conservancy, and the Keene State College Film Society will host a screening of our film Lost Forests of New England on
Thursday, January 30, 2020, in Keene, NH. The event will be held in the Putnam Theater, at the Redfern Arts Center of Keene State College at 7pm, and is free and open to the public.
After the film, old-growth forest expert Bob Leverett of the Native Tree Society, ecologist Tom Wessels, botanist Jared Lockwood, and filmmaker Ray Asselin will conduct a Q&A session to further help attendees understand the complexities and importance of the remnant old growth forests of the region.
More info here .
Tuesday, January 28, 2020
Monday, January 20, 2020
The Value of Large Trees in Carbon Sequestration
The topic of climate change is a hot-button issue today. Carbon sequestration has been identified as the tool of choice to reverse the negative effects of a warming climate. The following article by old-growth forest expert and author Bob Leverett, and Ray Asselin, discusses the best tool in the toolbox.
What is Carbon Sequestration, and Why Do We Need It?
Earth's
atmosphere contains gases, primarily oxygen and nitrogen. But
there are small amounts of other
gases, including carbon dioxide (CO2),
which is designated as a “greenhouse” gas. Why “greenhouse”?
Because it acts like the glass of a greenhouse, in that it allows
solar radiation to penetrate through the atmosphere to heat Earth,
but does not allow heat to radiate back into space. This causes a
rise in surface temperatures on the planet, resulting in climate
change.
The gradual rise in temperatures causes a cascade of
ecological and environmental problems, such as polar ice cap and
glacial melting (and therefore rising sea levels), desiccation of
forests, changing forest species composition and distribution, etc.
With the rise of industrialization and burning of fossil fuels,
carbon dioxide concentrations have increased substantially in the
atmosphere.
We
must find ways to reduce the level of CO2
in
the atmosphere in order to reverse negative climate change effects.
That's what “carbon sequestration” is all about. The carbon in
carbon dioxide must be recaptured, or sequestered, from the
atmosphere and stored long-term on Earth. How on earth (pardon the
pun) can this be done?
Trees Sequester Carbon
Carbon
is a major constituent of plants on land and in the oceans, because
their process of photosynthesis uses carbon dioxide, water, and solar
radiation to grow their tissues. In particular, woody plants such as
trees contain relatively large amounts of carbon.
So, if we grow more
trees, and let trees grow larger, they will sequester greater amounts
of carbon in their wood, drawing CO2
out
of the atmosphere. In theory, it's a very simple solution, and
requires virtually no effort or great cost... just let more forests
grow, and grow to old age! In reality though, we regularly harvest
trees to satisfy our demand for wood and paper products. As long as
wood products remain intact, the carbon they contain is still stored,
although there is a significant loss of carbon in the harvesting process.
But as they decompose (or are burned), their carbon re-enters the
atmosphere. To reduce atmospheric CO2,
we have to sequester much more carbon (principally, in the form of
trees) than we allow to enter the atmosphere. There is no method more
effective, less expensive, and quicker than letting trees already
growing get progressively larger. Planting lots more trees is also
helpful, but not nearly as effective in the short-term. It
is becoming clear that large trees play the major role in sequestering
carbon; here, we will look at carbon storage in large trees by
focusing on big
eastern
white
pines (Pinus
strobus). But
first, it is worthwhile to briefly pay a visit to New England past.
Primeval Eastern White Pines
Our New England woodlands are not associated with exceptionally large trees like
those in California and the Pacific Northwest. But it wasn’t always
this way. In the 1600s and 1700s, chroniclers described a landscape
that featured giant eastern white pines, some claimed to be well over
200 feet in height, and up to seven or more feet in diameter.
Romantic accounts exist of pines in Maine and New Hampshire reaching
astounding sizes and achieving great ages, and of course, the species
was famous as a resource for British ship masts.
The
great whites became the replacement for the exhausted European Riga
Fir (actually Scots Pine, Pinus
sylvestris L.)
used by the King’s Navy to hold up the sails of its warships. Trees
of a certain size and shape were reserved exclusively for the Royal
Navy. They were often marked by three slashes with an ax, called the
broad arrow mark. In fact, the white pine was the foremost symbol
of the region’s original virgin wilderness, but the time of those
legendary pines came and went.
The intense lumbering of the region,
especially in the 1700s and 1800s, depleted the rich old growth
forests. By the early to mid-1900s, New England’s recovering
woodlands consisted of younger trees, and it is safe to conclude
that, based on what they saw, people’s perception of what the white
pine (or any species for that matter) could achieve in size was
greatly scaled down.
Today’s
forest historians largely relegate chronicler accounts of giant pines
to the pages of history.
This is evidenced by descriptions of the species in popular 20th
century field guides, which
often listed the white pine as a tree capable of surpassing 100 feet
in height, but commonly
reaching only 75 to 100. More descriptive authors like Donald Culross Peattie
reminded us of the historic
heights, but most of these authors made it clear that such giants no
longer grow. In fact, the
stature of the species had been so diminished in the public eye that
one hiking guide to trails
in New Hampshire described a white pine, stated to be 125 feet tall,
as exceptional. The guide
was written in the mid-1980s, even though many pines then were
already above that
height, with specimens reaching to 150 feet and more in iconic places
like Cook Forest and Hearts
Content in western Pennsylvania, Hartwick Pines in Michigan, Pack
Forest in the Adirondacks,
and the Cathedral Pines in Cornwall, CT.
Further
diminishing the growth potential of the species in our eyes today,
forest managers keep woodlands
artificially young, largely for short-term economic reasons. Yet
despite this reigning management
paradigm, the eastern white pine is re-emerging to reclaim some of
its former glory
as our tallest eastern species.
The Return of Large White Pines in the Landscape
In
some Massachusetts conservation areas, parks, state forests, and
private lands, white pines are starting to once again reach
impressive stature (often on recovering old fields). As of 2019, Mohawk Trail State Forest is home
to at least 146 white pines reaching to over 150 feet in height as
confirmed by the Native Tree Society; 25 of these surpass 160 feet,
and two of those exceed 170.
Saheda (center) |
One
of the most impressive pines is a 180- to 200-year-old tree growing
in western Massachusetts. It is presently 172.4 feet tall and has a
circumference (at breast height) of 12.2 feet. It is an example of a
class of emerging modern-day super pines that offers us an
opportunity to better understand the long-term carbon storage
capacity of very big trees and their rates of sequestration from
youth to maturity and beyond. Our huge pine, which we named “Saheda”,
is neither a young tree nor what we would classify as old growth.
Based on the longevity of the species, it may have another 100 years
or more of life.
How
does a pine in Saheda’s size and age class perform in terms of its
rate of carbon sequestration from youth until the present? Many may
think that the growth performance of trees like Saheda is well
understood, but white pines of its age and stature are rare today,
since the species is typically harvested (at least in the Northeast)
at 60 years or less. The prevailing belief in forest management has
been that trees much over 100 years in age have plateaued in their
annual growth, and are stagnant or senescent. This belief has led to
a gap in our understanding of the growth performance of large
dominant trees in the Northeast.
The
calculated trunk volume of Saheda is 864
cubic
feet (ft3).
Its limbs add approximately 15.4% of the trunk’s volume, giving a
trunk and limb total of 997
ft3
(the
15.4% is from a US Forest Service biomass model that we use). In
today’s management paradigm, pines one third to one half this size
are considered large. In fact, pines with diameters over 18 inches
typically fall into the large category. By contrast, Saheda’s
diameter is 46.6 inches, making it a super-pine.
Beyond
the simple dimensions of diameter and height, there is volume.
Determining the trunk, limb, and root volume of a tree is important
because, from it, we can calculate the amount of carbon sequestered
in the tree (and from that, the equivalent amount of CO2
removed
from the atmosphere).
Those who favor using forests as the climate solution are divided on
strategy. Some advocate concentrating on young forests, believing
that they grow fastest and can sequester the most carbon in the near
future. Many in this camp also believe that forests hit growth
plateaus at 70 or 80 years. This faction is prone to making
statements like: younger forests have a higher rate of carbon
sequestration than older ones do. They seldom specify the dividing
point between young and old.
A second group believes that older forests should be left to grow. Some
believe this primarily because of the great carbon stores the old
forests presently hold. Releasing large amounts of carbon by
harvesting would work against the sequestration objective. Some of
the second group believe that annual growth in the older forests
exceeds that of their younger counterparts. With due respect to both
groups, the truth lies somewhere in the middle, but favors the
arguments of the older-forest champions over those of
young-forest advocates, and substantially so (if "young" forests are
those in the age range of 0 to 50 years, a not untypical age for
stand rotation).
What
follows is a discussion of the role large dominant eastern white
pines can play in productively sequestering carbon for beyond a
century and a half.
The Efficiency of Large Trees in Sequestering and Storing Carbon
A
stand of white pines on a good growing site will gain carbon most
rapidly between 40 and 80 years. However, growth from 80 to 120 years
will outpace growth from 0 to 40 years. Growth from 120 to 140 years
will outpace growth from 0 to 20. Beyond 160 years, annual
sequestration in the living pines drops more quickly, partly due to
continued self-thinning of the stand. However, other species
progressively fill the gaps left by dying larger pines. Additionally,
after logging, the soil releases carbon from the root systems for 10
to 30 years, partially offsetting gains from new growth.
Consequently, for between 140 and 160 years, annual sequestration
likely outpaces that of the first 40 years. So, how does this
information impact the arguments given for young versus old forests?
Young White Pine Stand |
One
reason the older forest group’s position has gained ground among
the scientific community is the high performance of the dominant
trees. They continue to add carbon at accelerated rates for decades
longer than commonly realized. Ordinary stand rotations of 50 years
or less do not allow managers to assess the performance of really big
trees.
It
is often stated that young, vigorously growing forests are the most
effective at sequestering carbon. That seems intuitive, doesn't it?
One can rather easily witness the rapid growth taking place in a
sapling from year to year. Young trees seem like they’re on
steroids. Surely, they can outperform an old, hulking, grandfather of
a tree. Or can they? An 8-foot tall pine sapling might put on another
foot of height in the next year; as a percentage, that's an
impressive 12.5% growth in height. But in terms of actual volume,
that doesn't amount to very much wood. The growth looks
impressively fast, but there's still not a lot of wood in a 9-foot
tall pine sapling. A larger tree can add much more volume of wood in
a year (and therefore sequester more carbon), but we don't tend to
notice it because most of the growth is occurring aloft, and is
spread over a large trunk diameter. A 1/8-inch increase in the radius
of a 3-foot diameter tree represents far more wood than a 1/8-inch
increase in the radius of a 1-inch diameter sapling.
So,
just how effective is a huge pine like Saheda
(mentioned above)
in
sequestering carbon compared to younger/smaller pines? We have
performed considerable, accurate measurements of white pines, and
careful calculations of their trunk volumes. Here, we will offer
generalized results for the class of largest pines.
Imagine
the space on the ground under Saheda's crown. If we were to replace
Saheda with 20-year-old pines, approximately 27 would fit in the same
space; but it would require about 402 of those young pines to equal
Saheda's volume and carbon content! This would require ground space
equal to 73% of an acre. It is apparent that large trees are
efficient utilizers of ground space, since most of their bulk is aloft. In addition, young trees can
grow beneath their crowns. That is a win-win situation.
Grand White Pines |
A
tree does not add a fixed volume of wood to its trunk and limbs each
year. As it grows larger, its greater foliage area carries on more
photosynthesis, thereby creating a greater volume of new wood. So,
for a period of many years, as it grows larger, it increases its
volume faster, and consequently outperforms young trees in
sequestering carbon. Eventually, an older tree's growth will slow
down. But its total carbon content is still there, stored in its
trunk, limbs, and roots. What's more, when that huge tree comes
crashing down in the wind and is lying on the forest floor, its
large carcass will take much longer to decompose than a small log
would, so its carbon remains stored longer, not released to the
atmosphere.
So,
how might a Saheda-sized pine gain trunk volume across a span of 180
years? A new stand development model we are employing gives the
following cubic-foot gains at 20-year periods for this largest size
class pine. Between 20 and 40 years, the largest class pines gain
56.5 ft3
of trunk volume on the model. Between 140 and 160 years, the amount
is 97.9 ft3.
Trunk growth stays above the first 35 to 40 years up to an age of
180. It is abundantly clear that most of the fast volume growth for
this size class pine occurs after 40 years. If that were not the
case, the tree would not have achieved such a huge size.
What's the Lesson Here?
There
is great concern about climate change these days. Increased
atmospheric CO2
has been identified as one of the main culprits, so we must take
steps to reduce it. Harvesting trees on short rotations (e.g. 50
years) is counterproductive for climate change resolution. Managing
for large tree size is an excellent strategy, as is retaining as much carbon
on the forest floor as possible. Removing all downed coarse woody
material from the forest floor during harvest operations, or chipping
it up on site, releases stored carbon more rapidly. It also invites drying of the forest floor and introduction of non-native invasive plants, and
compromises wildlife habitat.
Carbon-rich Coarse Woody Debris |
And, certainly, burning trees as a
biomass fuel is counterproductive, by not only removing still-growing
carbon-storing plants, but putting their carbon directly back into
the air. Some argue that those removed trees will be replaced by vigorous young trees that will quickly store carbon... yes, they will; but it has now been shown that those vigorous young trees can't come close to matching the carbon content of the large trees they're replacing, at least for many, many decades. And in the meantime, the carbon of the burned trees is making the problem worse.
Since
we don’t have much time to make headway in getting CO2
emissions under control, the most straightforward and easiest
solution, especially in our public forests, is allowing the trees to
grow to their maximum sizes. Nothing else will be as effective, less
costly, more ecologically beneficial, or easier. One approach to
doing this is explained in the concept of “Proforestation”, which
basically advocates letting as many of our forests as practicable
grow without interference.
More
information can be found at https://bit.ly/2L434Ln
Friday, January 17, 2020
Eastern White Pine Film Now Available
We're pleased to announce that our newest documentary film, Eastern White Pine- The Tree Rooted in American History, is now available for viewing on our Youtube channel.
The one-hour documentary uses archival and new footage, and aerial views to tell the story of the eastern white pine: what pre-settlement pines looked like in the primeval forest; the central role white pines played in America's founding and history; and the pine's current status and ecological significance. You may be surprised to learn how prominent a role the tree played in this country's formation.
Further, the white pine's importance to wildlife and people is related by three experts in their respective fields: famed Minnesota wildlife biologist Lynn Rogers; Trinity College neuroscientist Professor Susan Masino; and nationally known old-growth forest expert Bob Leverett.
Local screenings have been held in Massachusetts and Connecticut; if your organization would like to schedule a showing of the film (followed by a Q&A session) in the central New England area, contact us (see Contact page).
The one-hour documentary uses archival and new footage, and aerial views to tell the story of the eastern white pine: what pre-settlement pines looked like in the primeval forest; the central role white pines played in America's founding and history; and the pine's current status and ecological significance. You may be surprised to learn how prominent a role the tree played in this country's formation.
Further, the white pine's importance to wildlife and people is related by three experts in their respective fields: famed Minnesota wildlife biologist Lynn Rogers; Trinity College neuroscientist Professor Susan Masino; and nationally known old-growth forest expert Bob Leverett.
Local screenings have been held in Massachusetts and Connecticut; if your organization would like to schedule a showing of the film (followed by a Q&A session) in the central New England area, contact us (see Contact page).
Bob Leverett, Among White Pines |
You can view the film on our Youtube channel, or in the player window below.
Thursday, January 16, 2020
Simsbury, CT, Hosts White Pine Film Screening
The Simsbury (CT) Land Trust, Simsbury Grange, and Keep the Woods will host a screening of "Eastern White Pine- the Tree Rooted in American History," on Monday, January 27, 2020, at the Simsbury Public Library. The program is free, and open to the public.
The film contains a segment with scenes from Simsbury’s own Belden Forest, the first Connecticut forest to be dedicated into the national Old Growth Forest Network.
The one-hour documentary uses vintage images, new footage, and aerial views to tell the 4-century story of the eastern white pine's critical contribution to America's founding and history. You may be surprised to learn how significant a role the tree played in this country's formation. And the white pine's importance to wildlife and people is related by three experts in their respective fields: famed Minnesota wildlife biologist Lynn Rogers; Trinity College neuroscientist Professor Susan Masino; and nationally known old-growth forest expert Bob Leverett.
Following the film there will be a Q&A session with old-growth forest expert and author Bob Leverett, neuroscientist and forest advocate Susan Masino, botanist and big-tree hunter Jared Lockwood, and filmmaker Ray Asselin.
The film will be shown at 6:30pm, after a reception and light supper at 6:00pm.
This special event will be a multi-sensory experience featuring pine needle tea, pine-enhanced snacks, and white pine forest fragrance. You can register at the library website. We hope to see you there.
Belden Forest |
The film contains a segment with scenes from Simsbury’s own Belden Forest, the first Connecticut forest to be dedicated into the national Old Growth Forest Network.
Belden Pines |
The one-hour documentary uses vintage images, new footage, and aerial views to tell the 4-century story of the eastern white pine's critical contribution to America's founding and history. You may be surprised to learn how significant a role the tree played in this country's formation. And the white pine's importance to wildlife and people is related by three experts in their respective fields: famed Minnesota wildlife biologist Lynn Rogers; Trinity College neuroscientist Professor Susan Masino; and nationally known old-growth forest expert Bob Leverett.
Following the film there will be a Q&A session with old-growth forest expert and author Bob Leverett, neuroscientist and forest advocate Susan Masino, botanist and big-tree hunter Jared Lockwood, and filmmaker Ray Asselin.
The film will be shown at 6:30pm, after a reception and light supper at 6:00pm.
This special event will be a multi-sensory experience featuring pine needle tea, pine-enhanced snacks, and white pine forest fragrance. You can register at the library website. We hope to see you there.
Belden's Massive White Pines |