5 March 2022 | New Scientist | 27Views
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INCE the 13th century,
forests have been managed
as sources of trees that can
be processed into timber. More
recently, with mounting concerns
over climate change, they are
often studied as potential carbon
sinks because trees are capable
of sequestering greenhouse gas
emissions. But what remains
largely unknown is the true
relationship between a forest
and the trees that make it up.
While there is an international
commitment to protecting
biodiversity, a lack of knowledge
about forests poses a huge
obstacle to making effective
conservation decisions.
With global attention drawn
to increasing the number of
trees as a means of climate
change mitigation, highly
publicised strategies such as the
Million Tree Initiative, the Plant
a Billion Trees scheme and the
Trillion Tree Campaign have
emerged. Overshadowed by
these commendable feats is the
degradation and deforestation
of 10 million hectares of forests
worldwide each year.
Many of the trees we are losing
are in primary forests – a type of
pristine ecosystem that offers
irreplaceable ecological and
socio-economic benefits, such
as harbouring threatened flora
and fauna, as well as underpinning
the unique cultures and customs
of Indigenous communities.
Some have survived earthquakes,
hurricanes, fires and other natural
MIdisasters over thousands of years,
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but have been wiped off the face of
the Earth in a short space of time
due to adverse human impacts.
Perhaps we can plant millions,
billions or even trillions of trees,
but those we are putting in the
ground today can hardly make up
for the forests we are losing, and
very few of these trees will ever
grow into a primary forest.
When a forest is regarded
as simply a collection of trees,
we miss the holistic value of
its biodiversity. From uniform
alpine and circumpolar forests
to tropical rainforests that host
a plethora of species, they are the
most important global repositoryof terrestrial biodiversity. When
a forest is cut down, we also lose
other living organisms from
which we can draw new materials,
processes, designs and inspiration
to confront environmental,
medical and engineering
challenges in a world full of crises.
For instance, in 2019, scientists
discovered a new antibiotic in a
Mexican tropical forest; hundreds
of other potential pharmaceuticals
are still waiting to be found.
To address the lack of knowledge
about tree populations, my
colleagues and I compiled a
unique, ground-sourced forest
database through the GlobalForest Biodiversity Initiative.
Underpinned by complete tree-
level survey records from more
than 1 million sample plots across
110 countries and territories, it is a
snapshot of forest ecosystems and
allows us to estimate important
attributes of forest biodiversity
at a global level. One such attribute
is the total number of tree species
worldwide. According to our
estimate, there are approximately
73,000 tree species on Earth, and
more than 12 per cent of them
haven’t been documented yet.
These findings remind us how little
we understand our own planet.
What is still unknown is the
number of tree species at a local
level and how evenly trees are
distributed among these species.
Mapping them across the global
forest range is vital for prioritising
global conservation and detecting,
monitoring and assessing the rate
of extinction, as well as its impact
on ecosystem functionality and
human well-being.
To effectively protect forests,
international communities
must work together to address
the disproportionate share of
responsibilities between richer and
poorer countries, since more than
90 per cent of the most diverse
forests are in low-income nations.
Together, we can truly begin to
see the forest for the trees. ❚The trees of life
Forest ecosystems are under threat and replanting isn’t enough.
We need to understand them to save them, says Jingjing LiangJingjing Liang is
a co-founder of
the Global Forest
Biodiversity Initiative