Fossils
f om
Wyomi g
a e
eveali g
how
fo ests
espo ded
whe
Ea th
expe ie ced
o e
of
its
most
i te se
episodes
of
global
wa mi g
a ou d
56
millio
yea s
ago.
A
ew
study,
published
i
the
jou al
Scie ce
o
August
13,
2026,
eco st ucts
the
st uctu e
of
fo ests
du i g
the
Paleoce e-Eoce e
The mal
Maximum,
o
PETM,
a d
fi ds
that
thei
ca opies
became
d amatically
mo e
ope
as
tempe atu es
ose
a d
moistu e
became
less
available.
The
esea che s
estimate
that
fo est
ca opy
cove
decli ed
by
about
60%
a d
emai ed
substa tially
educed
fo
mo e
tha
100,000
yea s
befo e
ecove i g.
The
fi di g
offe s
a
st iki g
example
of
how
climate-d ive
st ess
ca
alte
e ti e
ecosystems
fo
ext ao di a ily
lo g
pe iods.
Scie tists
cautio
that
the
PETM
is
ot
a
exact
p eview
of
mode
climate
cha ge,
but
its
fossil
eco d
p ovides
a
impo ta t
wa i g
about
what
ca
happe
whe
wa mi g
pushes
vegetatio
beyo d
its
e vi o me tal
limits.
Wyomi g
fossils
eveal
what
happe ed
to
a cie t
fo ests
du i g
global
wa mi g
The
ew
esea ch
is
titled
“Fo est
ca opy
decli e
u de
elevated
CO2
du i g
the
Paleoce e-Eoce e
The mal
Maximum”
a d
was
published
i
Scie ce
by
Rega
E.
Du
a d
colleagues.
The
team
exami ed
fossil
mate ial
f om
Wyomi g
to
eco st uct
ot
o ly
which
pla ts
lived
the e
but
also
the
physical
st uctu e
of
the
fo est
above
them.
The
PETM
bega
a ou d
56
millio
yea s
ago
afte
a
majo
i jectio
of
ca bo
i to
the
atmosphe e
a d
ocea ,
p oduci g
global
wa mi g
ge e ally
estimated
at
a ou d
5
to
6°C,
with
some
eco st uctio s
placi g
the
i c ease
as
high
as
8°C.
The
wa mi g
t a sfo med
vegetatio
ac oss
ma y
egio s,
a d
Wyomi g
p ovides
a
u usually
detailed
te est ial
eco d
because
sedime ts
f om
the
pe iod
p ese ve
leaves,
polle
a d
othe
pla t
emai s.
Ea lie
wo k
i
the
Bigho
Basi
showed
that
the
egio ‘s
fo ests
u de we t
a
majo
tu ove
du i g
the
eve t.
Elle
Cu a o,
a
U ive sity
of
Wyomi g
palaeobota ist
who
has
studied
these
fo ests
fo
yea s,
p eviously
desc ibed
the
cha ge
as
a
“ ea ly
complete
tu ove
of
pla ts”.
Fossil
leaves
evealed
the
de sity
of
the
a cie t
ca opy
The
esea che s
developed
thei
eco st uctio
usi g
mic oscopic
details
p ese ved
i
fossilised
leaf
cuticles,
the
thi
waxy
laye
cove i g
leaves.
The
shape
of
epide mal
cells
cha ges
depe di g
o
how
much
su light
eaches
a
developi g
leaf.
Leaves
g owi g
u de
de se
shade
te d
to
develop
mo e
elo gated
cells,
while
those
exposed
to
st o ge
su light
develop
sho te
a d
mo e
ou ded
cells.
By
calib ati g
this
elatio ship
agai st
mode
fo ests,
scie tists
ca
use
fossil
cuticles
to
estimate
the
leaf
a ea
i dex,
o
LAI,
which
measu es
the
amou t
of
foliage
elative
to
the
g ou d
a ea
be eath
it.
A
highe
LAI
i dicates
a
de se ,
multilaye ed
ca opy,
while
a
lowe
value
i dicates
a
mo e
ope
fo est.
The
esea ch
the efo e
p ovides
a
way
to
eco st uct
a
aspect
of
a
56-millio -yea -old
fo est
that
ca ot
be
obse ved
di ectly.
P evious
wo k
by
the
team
had
al eady
established
this
method
i
Wyomi g,
while
the
ew
Scie ce
study
applies
it
to
show
how
ca opy
st uctu e
shifted
th ough
the
PETM.