ScienceDaily
(Feb. 2, 2010) — Speed is not a word
typically associated with trees; they can take centuries to grow. However, a
new study in the Proceedings of the
National Academy of Sciences has found evidence that forests in the
For more than
20 years forest ecologist Geoffrey Parker has tracked the growth of 55 stands
of mixed hardwood forest plots in
Parker's tree
censuses have revealed that the forest is packing on weight at a much faster
rate than expected. He and Smithsonian Tropical Research Institute postdoctoral
fellow Sean McMahon discovered that, on average, the forest is growing an
additional 2 tons per acre annually. That is the equivalent of a tree with a
diameter of 2 feet sprouting up over a year.
Forests and
their soils store the majority of the Earth's terrestrial carbon stock. Small changes
in their growth rate can have significant ramifications in weather patterns,
nutrient cycles, climate change and biodiversity. Exactly how these systems
will be affected remains to be studied.
Parker and
McMahon's paper focuses on the drivers of the accelerated tree growth. The
chief culprit appears to be climate change, more specifically, the rising
levels of atmospheric CO2, higher temperatures and longer growing seasons.
Assessing how a
forest is changing is no easy task.
By grouping the
forest stands by age, McMahon and Parker were also able to determine that the
faster growth is a recent phenomenon. If the forest stands had been growing
this quickly their entire lives, they would be much larger than they are.
Parker
estimates that among himself, his colleague Dawn Miller and a cadre of citizen scientists, they have taken a quarter of a million
measurements over the years. Parker began his tree census work Sept. 8, 1987 --
his first day on the job. He measures all trees that are 2 centimeters or more
in diameter. He also identifies the species, marks the tree's coordinates and
notes if it is dead or alive.
By knowing the
species and diameter, McMahon is able to calculate the biomass of a tree. He
specializes in the data-analysis side of forest ecology. "Walking in the
woods helps, but so does looking at the numbers," said McMahon. He
analyzed Parker's tree censuses but was hungry for more data.
It was not
enough to document the faster growth rate; Parker and McMahon wanted to know
why it might be happening. "We made a list of reasons these forests could
be growing faster and then ruled half of them out," said Parker. The ones
that remained included increased temperature, a longer growing season and
increased levels of atmospheric CO2.
During the past 22 years CO2 levels at SERC have
risen 12%, (Take this with a grain
of salt as we do not know nor can we verify these numbers in CO2 levels as
everywhere else it is measured in parts per million.) the mean temperature
has increased by nearly three-tenths of a degree and the growing season has
lengthened by 7.8 days. (This data we know is skewed from the fraud exposed in climate
data from Europe and around the world as these sellect labs were working in colussion.
For ten years now the earth’s temperature has been dropping, now in the last
two years it has been dropping faster and has become impossible to ignore –
even by those who need money and make their living off of a deceitful man-made
crisis.) The
trees now have more CO2 and an extra week to put on weight. Parker and McMahon
suggest that a combination of these three factors has caused the forest's
accelerated biomass gain.
Ecosystem
responses are one of the major uncertainties in predicting the effects of
climate change. Parker thinks there is every reason to believe his study sites
are representative of the Eastern deciduous forest, the regional ecosystem that
surrounds many of the population centers on the East Coast. He and McMahon hope
other forest ecologists will examine data from their own tree censuses to help
determine how widespread the phenomenon is.