If
you want to talk about a forest that is larger than the Amazon jungle, then you
will probably talk about the Taiga, the Boreal Forest or the snow forest. They
are all one thing, with different names used in different parts of the world.
Some say it is one huge forest, stretching from Iceland through the Scandinavian
countries, Russia, Mongolia, Alaska and Canada. It is a coniferous forest
consisting mostly of pipes, spruces and larches. It covers 6.6 million square
miles or 11.5% of the Earth’s land area.
The
boreal forest has a subarctic climate, with a very large temperature range
between seasons. Summers last 1-3 months, always less than 4 months, and any
given 24 hour period during the summer will average 50 °F or less. In Siberia,
the average temperature of the coldest winter month is between 21 and -58 °F.
The ground being frozen for much of the year, or even permanently frozen, can
restrict the growth of deep roots, thereby favoring shallow-rooted trees like
the Siberian larch.
Despite
these harsh condition, the plants in the boreal forest have a lower threshold
to trigger growth, and thus they ‘wake up’ a little earlier than one would
expect. Even so, the soil tends to be poor in nutrients. Fallen leaves and moss
tend to sit on the soil for a long time in the cold climate, so their organic
components are very slow to be added to the soil. Also, acids from the
evergreen needles leach the soil, making it even less ‘appetizing’ for anything
but lichens and some mosses. On the other hand, diversity of soil organisms is
high, comparable to a tropical rainforest.
It
seems surprising to me that in a world that is frozen most of the time, fire is
one of the most important factors that shape the composition and development of
boreal forest. Some members of the boreal forest won’t release their seeds until
the pods have been exposed to fire, and I get that, but how does something
covered in snow most of the time suddenly burst into flames? Obviously, there
is something about the process that I don’t understand.
Most
boreal forest fires are either high-intensity crown fires or severe surface
fires. These are large, often more than 10,000 hectares (a hectare is 100
acres) and sometimes more than 400,000 hectares. Different areas of the boreal
forest burn at different lengths of time; drier areas might burn every 50
years, while wetter areas only burn every 200 to 300 years. And when an area
burns, it could take decades, even a couple centuries to get back to ‘normal’.
So all that carbon dioxide (a greenhouse gas) that is released into the air
when those trees burn takes those same decades or centuries to be absorbed into
the growing forest again.
This
is particularly important now, when so much of the boreal forest is burning.
Even Greenland - which doesn’t have any boreal forest, but does grow grasses
and scrub brushes when enough ice melts to expose ground to seeds being blown
around by winds - is on fire. Alaska and Canada are experiencing horrendous
fires in their boreal forestland. In northern Siberia, one fire covered 7.9
million acres (over 3 million hectares), and that’s only one fire of 11 (or
more) burning in Russia.
It’s
been estimated that these fires dumped over 50 million tons of carbon into the
atmosphere in June (2019), and they are still at it. 16 million adult trees
burn in a day in Russia’s boreal forest fires. The Earth is not ready to absorb
that much carbon. If we planted more trees - billions of them - it would help, but possibly not before the
climate changes even more in response to that much carbon and carbon dioxide
having been freed to begin with.
We
really can’t sit around and wait any longer. We have to start facing this
problem, and we have to do it NOW. The sky is falling, and doomsday is just
around the corner.
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