Embed Size (px)
DESCRIPTION
fens, information
Citation preview
Wha
t is
a Fe
n?
A fe
n is
a p
eat*
form
ing
wet
land
that
rec
eive
s its
nut
rien
ts fr
om s
ourc
es
othe
r th
an p
reci
pita
ion,
suc
h as
a n
atur
al s
prin
g. F
en’s
are
less
aci
dic
and
have
hig
her
nutr
ient
leve
ls an
d co
ntai
n la
rger
am
ount
s of
cal
cium
and
m
agne
sium
than
bog
s an
d ot
her
wet
land
s, th
eref
ore
can
supp
ort a
div
erse
an
imal
and
pla
nt c
omm
unity
.
*Pea
t is
an a
ccum
ulat
ion
of p
artia
lly d
ecay
ed v
eget
atio
n th
at c
an’t
fully
de
com
pose
bec
ause
of
anae
robi
c co
nditi
ons
(lack
of
oxyg
en)
Why
are
Fen
s so
Im
port
ant?
A w
ater
shed
is a
n ar
ea w
here
all
wat
er u
nder
neat
h an
are
a of
land
or
the
wat
er th
at d
rain
s of
f it
go to
the
sam
e pl
ace,
and
fens
pro
vide
impo
rtan
t be
nefit
s to
this
type
of
area
. Fen
s re
duce
the
risk
of
flood
s, im
prov
e th
e w
a-te
r qu
ality
and
pro
vide
uni
que
plan
t and
ani
mal
com
mun
ities
.
Fens
com
mun
ities
are
bec
omin
g in
crea
sing
ly r
are
and
expe
rian
ces
a de
-cl
ine
in a
reag
e of
8%
from
195
0 to
197
0 du
e to
min
ing
and
drai
ning
of
crop
land
for
fuel
and
fert
ilize
r. A
fen
take
s ab
out 1
0,00
0 to
form
nat
ural
ly.
How
do
Fens
App
ear?
Fens
form
whe
re a
gro
undw
ater
sou
rce
rich
in m
iner
als
is e
xpos
ed to
the
surf
ace
and
is la
id d
urin
g th
e gl
acia
l per
iod.
The
re a
re tw
o m
ain
way
s th
at a
fen
is fo
rmed
.1.
Gro
undw
ater
sou
rce
is b
urie
d un
der
a sa
nd a
nd g
rave
l dep
osit
from
the
debr
is
of a
gla
cier
. O
ver
time
eros
ion
expo
ses
port
ions
of
the
sand
and
gra
vel r
esul
ting
in
a se
ep a
rea
(a p
lace
whe
re g
roun
dwat
er is
nea
r th
e su
rfac
e). P
eat i
s a
com
mon
sid
e af
fect
of
this
form
and
this
form
is th
e m
ost c
omm
on.
2. T
he g
roun
dwat
er s
ourc
e is
in th
e sa
nd a
nd g
rave
l tha
t was
dep
osite
d on
the
sur-
face
by
flow
ing
wat
er fr
om m
eltin
g gl
acie
rs.
Thi
s ty
pe o
f fe
n is
eas
ily c
onta
min
ated
by
pol
luta
nts.
Also
, the
zon
ing
of p
lant
s is
an
unus
ual p
heno
men
on fo
und
in fe
n co
mm
uniti
es.
The
re a
re 3
mai
n zo
nes,
the
disc
harg
e zo
ne (l
ocat
ed a
roun
d gr
ound
wat
er s
ourc
e), a
se
dge
mat
zon
e an
d a
bord
er z
one.
Mai
ntai
ning
a F
en
Car
eful
bur
ning
eve
ry fo
ur o
r five
yea
rs is
nec
essa
ry fo
r con
trolli
ng in
vad-
ing
woo
dy v
eget
atio
n. B
urni
ng c
an o
nly
be d
one
durin
g w
et se
ason
s to
avoi
d st
artin
g th
e pe
at o
n fir
e. F
ire is
a n
orm
al p
art o
f for
est o
r gra
ssla
nd
ecol
ogy
so th
e co
ntro
lled
or p
ersc
ribed
bur
ning
is a
way
to re
new
pla
nt
com
mun
ity. I
t als
o ca
n st
imul
ate
germ
inat
ion
in so
me
plan
ts a
nd in
som
e ca
ses fi
re is
nee
ded
to b
reak
dow
n a
seed
coa
ting.
Bur
ning
is o
ne o
f the
m
ore
natu
ral w
ays o
f con
trolli
ng a
fen’
s gro
wth
but
her
bici
des a
nd m
ow-
ing
are
also
som
etim
es n
eces
sary
.
The
Ret
zer N
atur
e C
ente
r
The
Ret
zer N
atur
e C
ente
r is h
ome
to m
any
type
s of p
lant
com
mun
ities
incl
udin
g a
fen,
whi
ch is
w
here
all
of th
e im
ages
for t
his b
ook
cam
e fr
om.
This
fen
is a
form
er c
attle
pas
ture
whi
ch m
akes
it a
wet
seep
min
eral
site
. By
1976
it w
as a
moi
st
old
field
and
con
tain
ed a
shal
low,
wea
k sp
ring
and
by 1
977
natu
ralis
t Jim
Rei
mer
had
beg
un a
pl
antin
g pr
ojec
t on
the
site
by
plan
ting
it w
ith fe
n sp
ecie
s. Si
nce
then
it h
as re
ceiv
ed tr
ansp
lant
a-tio
n fr
om o
ther
site
s and
has
had
nat
ural
ly in
vadi
ng sp
ecie
s. Fe
ns th
at h
ave
rece
ntly
retir
ed fr
om
farm
ing
ofte
n ge
t wet
ter w
ith ti
me
due
to p
rogr
essi
vely
bet
ter r
ainf
all i
nfiltr
atio
n up
slop
e, a
nd th
e m
anag
emen
t of t
his f
en is
cha
lleng
ing.
Thi
s par
ticul
ar fe
n is
har
d to
bur
n be
caus
e of
the
cons
tant
w
et fu
el a
nd th
e in
vasi
vene
ss o
f the
shru
bs su
rrou
ndin
g it.
Fen
s als
o ha
ve v
ery
idea
l co
nditi
ons f
or v
ery
inva
sive
spec
ies.
