StephenC. Sillett,Departrnent
oi B o og ca Sc ences,HurnboldtStateUniversty,Arcata,Ca fornia95521USA
afto
Thomas R. Rambo,Departmentof Botanyand PlantPathoogy OregonStateLlniversty,
Corva is Oregon9733i
USA
VerticalDistribution
of DominantEpiphytesin Douglas-Fir
Forestsof
the CentralOregonCascades
Abstract
'l'he
canopiesof okl growlh Doughs-fir foresis supporta di\.rsirl ofepiphytic lichen,iand bryophytcs.$t quuntified the lertical
dinnbulions of six doninant epiphlres throughout lhc cro$ns of l.rrge Tsuga hd{qh\lld
(16 57 n hll) trni Pseudotsugu
"t(11.i( sii \60 78 m t.rll) trees in five lbrest standsol |he centrd Oregon Cascades.Therc u crc no lnaior difl-erencesin epiph,vtc
dislribulion bclween the l\'o tfee species.but epiphltcs on Z lretelophl1d generally peakedin abundanceat heights l0 20 m
b.lo$ lhosc on P rrrx-'terii. Alectorioid lichens wcre mon abund:mtin the upper crorlns bul scarcc in lhe lowef crowns. Ihc
fruIicose gree. algal lichcr Spld.rr2r.Trus gbl.i]llu! $as evenl}' dislribuled throughout the crolvns. Thc clanolichen lrbdd.r
,/?8rrd and lhc mosr Artitriclia c rtipentluld \\ere mos!abundanlin niddle $awr,s. Loburid plmorali.r was most abundantin
Ihe lower middlc crosns. lt was scarceof absent in the uppcr crolrns. The mos\ /.rdrl..rD, nfr.r&r?i/(r_ $,ts also scarceor
abscnt in lhc upper cro\rns. It wr\ most abundant jn thc louer crowns. The vefical pattems dcscribed in this studv are not
rcprcs.nmd\e ol all ()1d-gro!v$Douglas fir forests.In \reller lbre\ts. bryophytesare dominant ftroughout rhe canopt. ln dricr
lbresls. alectorioicland other green algal lichcns erlend i-afiherdo\ln in the canop\'.and bryophytes and clanolichens ar. tc
stricted t0 the lorer canop).
Epiphytesarea conspicuousandecologicallysigoilicant componentol'lorcstsin thePacilic North
west,u'herethev have beenstudicdfor over 25
yeals.A greatdeal is known abouttheir floristics
(Pike et al. 1975),comnrunitydynamics(Silleu
1995.SillettandMcCune 1998,Sillettet al.2fi)0a),
populaLion
dynamics(RhoadesI 983),treeJcvcl
biomass(Pike et al. 1977.Sillett 1995).standlevel biomass(McCune 1993,Neitlich 1993).
distributionby functionalgroups(Lyons 1998,
Mccune 1993.McCune et al. 1997.Sillctt and
Neitlich 1996).rolesin nutrientcvcling(Canol1
1979,Denison 1913,1919.McCune and Daly
1994,Pike 1978).growth rates(Dcnison19813,
Rhoades1977.Sillett 1994,SillettandMccune
1998,Sillett et al. 2000b).dispersallinitations
(Sillettet al. 2000b),vulncrabilityto edgeeffects
(Sillett t99,+,1995),and susceptibility
to forest
managcmcntpracticesin old growth Douglas-fir
forests(Goward 1995.Peckand McCune 1997.
SillettandGoslin1999,SillettandGoward1998.
Sillett el al. 2000b). Hou,evel little quantitative
intormation on vertical distributionsof cpiphytes
on different tree speciesin these forests is currently available.The puryoscof this studyis to
dcscribethe vertical distributionsoI dominant
epiphyteson 1wotree specrcs,Tsuga
heteroph!ll.t
41
NorthwestScience.Vol. 7,1.No. 1, 2000
',rl(l00bt
thc \tdli\!nS.,enrlll.A\ocl$!r
Alligh[rcs.rv.d.
(Raf.) Sarg. and Pseudotsugamen2iesii(Mtb.)
Franco.We estimatedthe abundanceof six epiphytesthroughoutthe crowns of ten tall trees.
StudyArea
We sampledepiphytesin fir'e dd-growth forest
standswithin the Willamette National Forest in
the CascadeRange of westcm Oregon: three in
the H. J.Andrcws ExperimentalForest.one along
the South Santian Rivcr near House Rock ForestCamp,andonealongtheSouthFork McKenzie
Rivcr nearCougiLr
Reser,'oir(seeSillcttet a1.2000b
for more specific inforrnation).The standswcre
450 to 600 yearsof age.470 to 790 m elevarion,
0 to 120' aspect.and 60 to 85 m tall. They wcrc
dominatedby Pseldoh.,A,.r,lel,i:ie.rli
with smaller
amounts of Tsuga heterophl,lla. Thujd pli(d.l
Donla.,Tttxrs brevifolia Nutt.. Acer nacrop u,\llun
Pursh..andAlnls ruDraBong. Basalreas ranged
from 91 to 199nr2ha.r
lbr conifersand0.2 to 6..1
mrha r for hardwoods.Avcrageannualprecipitation in the standsrangedfrorn L5 to 2.,1m (Oregen Climate Service).These standshave been
utilizedin prcviousepiphytestudies(Sillettct al.
2000ab).
TABLE L DnnensionsofreD studl treesin thc Willa clrc ),ialional Forcstjn !lcslcm Orcson. l'he fi\e lbrest standsare li\ted
l i u l t r r - L r t hr u ' r r l h . A l l r ' . J r r r ( r c n l J r . n I h . . - \
Tsusuhe!etuLldLL
rfee heigbt
lree dbh
Pseuddsuld
trcc hcighr
tne .i(sii
lrcc db|
I
57.0
0.81
6.1.0
2.61
nrain lrunk snappcdat 6l m
).
52.0
0.97
60.5
1.86
ain runk snappcdat 57 m
-l
16.0
0.81
73.5
1.99
L02
66.5
l..tt)
0.97
11.4
t.ti9
.+
5
,18.5
Methods
Tree Se ection and Access
ln each stand,u,e selectedone large P. nen:iesii
and thc l:rrgcst healthy T. heteropl4 l ltt for detarLled
study.More speciticinfbrmation abouteachtree
is summarizedin Table1. Treecrownswctc accessedby shootinga monofilamentover sturdy
branchesrvith a compoundborv,hauling a nylon
cordfbllowedby aclimbingropcovcr thcbnnches,
tying one end of the rope at grcund level. and
the othcrcnd usingverticalropetech
ascending
nique.We used20 m long a$orist's rope lanyards
progressively
higherbranchcs
to access
andmove
laterally through trcc crowns. Tree heights were
mcasurcdby lowering a graduatedfiberglasstape
from the topmostlbliage to the lbrest lloor. Numbcrcclaluminum tags were then attachedto the
main truks at l0 m intervals.Thesetags wcrc
usedas benchmarksfor epiphyte sampling.
EpphyteSampng
W'evisuallycstimatedepiphyteabundances
within
each l0 n stmtum. Epiphyte abundancewas recordedon a0-6 scalc:0)abscnt.1)1 3 individual
t h a l l i . 2 )u p t o 5 % c o v e r , 3 5
) 1 0 % c o v e r , 41) 0 25% covcr 5.125 50% cover and 6) greaterthar
508 cover. We consideredonly six prominent
branch-dwelling
epiphytesthat were easilyrecognizedf'romthc climbingpathon eachtree: l)
alectorioid lichens (i.e.. mostly Alectori.l
strnre tos.t u'ith smaller anrounts ol- A.
yantrtuteretsis. Bnrrria spp..and Usrtecspp.).
2) the green algal iiuticosc llchen Sphaeropho/'//..tr,D,,\r\. ?) lh<cl attoliche
n [tbt r it ot e* u ut.
4.) the c.yanolichenLoburia pulnronaria.5) the
mossAntitrk:hia curtipendula, and 6) the moss
Isothecitonnrvstottides. Finally. rve visually es
timated the ayeragecrown radius within each 10
m stratumk) the nearest0.5 m.
Resultsand Discussion
All of the epiphytessanrpledin this studyhave
r i mi l . r lJ i . t r i h u t i o p
n r l e n r . o n b o r hr r c e. p e c i e . .
The few discrepanciesare attributableto differ
ences in tree stllture alone. Epiphytes on I
heterophylla,whoseaverageheight is 52 m, peak
in abundance
at heightsl0-20 m belowthoseon
P ,,nen.riesll.
whoseaverageheight is 68 m. Epi
phytesare absentabove60 m on T. heteroph,t'lla
sinlplybccausethe tallesttreeis only 57 m.
Vefticaldistributions
of thc six cpiphytcsdifler greatly (Figure l). Abundanceof alectorioid
lichens steadily increasestrom the lo$er to uppcr lree crowns. They cover over 25*, of sub
stratesabove50 m on P. tnertziesiiand above,10
n on T. heterophtlld. Old grorvth Douglas fir
lbrests can supportover 500 kg har of these lichens(Neitlich 1993,Sillett and Goslin 1999).
Sphaerophorusgk$osas is more evenly distributed than any otier epiphytein this study.cover
ing 5-107aof substrates
throughoutcrowns of
bothtreespecies.
This lichenis prevalenton trunks
l n d h r a n e h cirn t h e i n n e rc r o un . b u t i l r r s e a r e e
on branchletsandtwigs in the outercrown (Lyons
f q q 8 .S i f l e rar n LC
l o \ l i n l g a q ) .L o b . ui . t t ' t ( g q n a
is rnost abundantbctwccn40 and 60 m on P
menziesii and between 30 and 50 m on Z
r,here it coversover 257eof subhetercph)'Llq.
strates.This is the dominant epiphyte in humid
old-gro*th Douglas-firforcstswith a biomassof
900 2600 kg har. which is 60 80c/oof the total
Iichenbiomass(McCune1994.Neitlich 1993.Pike
1978).A closelyrelatedspccics.L. pulnonaria
VerticalDistributionofEpiphytes,+5
E
o
3
E
9
_8
abundance
abundanc€
F i g L r r cL V e i f . l l d i \ t l i b u t i o n o f s i x c p i p h ) l c s i n h u m i d o k l , g r \ , t hD o u g l a si i r i b r c \ l s ( ) 1t h e c e n t m l O r e g o n
Cr\crdcs. For each epiphllc. thc distribulion on Tsuqahetenphlh rs sho\Lnon the leit, and rhe
distribution on P.\r,tl.rtllrt, /r.,r.-ierll is \hor|n on the right. Abundancei\ on a 6-poinr. logarillrmic
scale(s.'c Njclhod\). \'.rluesarc me.rnsand standardcnor\ in = 5 lrce\ per ifee speciet. \ote lhal Z
l.&,tdrrJld urcs \\ere considerahl! \horter llri. P ,rdr.i?yi trees(seeTatrle I and Figurc 2).
+o
Sillettand Rambo
E
cro\rynradius (m)
Figurc I
Cro$r proiiler of Tsugahdttopl]\llu a l's.utlt)
t!&g.r rk r.i.,.iii lrces surveyedin this stud!. Innef
and oulcr boundariesrepresentone standarderror
b c l o \ ! . r n dr b o \ e t h e m e n r r d i i o f t h e l r ! e c r o $ ' n s
1 n= 5 I r c e s p e r t r e e\ p e c i e s ) .
accountsfor 3 l9q, of the total lichcn bionrass
in suchlbrcsls(McCune199.1.
Neitlich 1993.Sillett
1995).It is most abundantbetween30 and,10m
on P nten:iesiiand betweenl0 and 30 m on I
heterophylla.whcrc it coversover l07c of sub
strates.Unlike L. oregtma.which can tderate
cxposedsitesin the uppercaoopy(Sillett 1995).
L. pulmowcia is tirlually abscntabove60 m on
P nenziesii and rbove 50 m on T. heteropl4 u.
The mossArlilri.rlirr crrrlTr,rdrila is most abundant between 30 and 60 m on P rreir:idsli and
betwccn 20 and 50 nr on I lrctercphr.lla.wherc
i t c o r e r . o r e r l 5 i r ' f . u h : . t r r t . . l t l . ' r n r 'e r t e n sive nratsup to 10 cm thick on largebranchcs.
and individual trces can suppoft up to 7 kg dry
$cight of this species(Sillett 1995.).
The noss
Isotltet:itnt mrostuttidr:sis most abundantbelou,
30 m. whereit covers25 50Q,of substrates
on P
nten:.iesiiand over 507c of substratesot I
heteroplullu.UnlikeA. ootrpendirlrr.it is sparselv
distributedin the uppercanopyandabsentabovc
60 m on P nen.-iesii and above 50 m on 7l
heterophtl[u. We did not record any epiphytes
below l0 m becausethe study trces hilve no
branchcsbelo$'thisheight(Figure2). However,
I. nrosuroides isprcvalcnt on the lo$'er branches
of smaller I heteropl\ lla lrees alswcll ;tson un(Lyons199E.Pikeer al. 1975).
derstorlr'egetation
The \,erticaldistributionol an epiphytespe
cics gcncrallyretlectsits sensitivitlto dcsiccation ald abilitv to altainpositivenet photosyn
thesistrl low wlter contents(Hosokawaet al. 196.1,
Tobiessen
eI al. 19'77).ln1a11
Douglas-tlrtr€es.
somcspccies(e.g.,aJectorioid
lichensand othcr
greenalgal lichcns)pret'erexposedsitesin thc
upper.outer crowns.whilc others(e.g..se\,eral
cyanolichens
prclcr sheland man)'br)'ophytes)
teredsitesin thelowcr'.innercrou'ns(Sillett l995).
Such preterences
are probablythe rcsull of an
interpla.vbetrveendesiccalitltltolerancesandcotn
pctitivcrbilities.For example.a desiccatron-scnsitivemossmay not be ableto surr,ivein the xcric envilonmenlof thc uppcr canopy.while a
desiccation-tolerant
lichen may not bc able to
c o r n p e l $e i t h r p i r u . . i ! c n l . I - l i ' r r n i n m
g o . s e si n
the mesicenvironmentof tl'relower canop).Based
or the verticaldistributionsdocunrented
in this
stud],.the epiph)tesmay be tentali\cly ranked
from highcst10lowestdesiccationtoleranceor
ti-omiou,estto highestconrpetitive
ability asfol
lorvs: 1) alectorioidlichens,2) Sphueroltltorus
globosus.3) Lobarid oregatru,4) Antitrithia
L'trrtipettdulcr.
51 Lolutria puhnonaria, and 6)
Isothe(iu l nnrtsuroide.s.
Ecophysiological
and
lransplantexperimentsale neededto tcst this
h)'pothesis.
The pattcnrsdocumented
in this studyshould
Dotbe consideredreprcscntative
of all old-growth
Douglas-firlbrests,becausethereis high landscapelevel variabilitl,in epiphytedistribution
dcpcndingon moistureregime(McCunc 1993).
Ar intemediate moislurc rcgimelavors a canopv
cpiphytecommunitywith high cyanolichendiversily,rvhcrelsforestson the wetteror dricr cncls
of the moisturegladicnt are nroredorninatedby
bryophytesor greenalgal lichcns.respectivelv.
In wet foresls,brvophytescan dominatethc cntirc vefticrl profile.Forexample,bryoph)tesale
superabundantin thc rain tbrestsof Olynpic and
Mount RainierNationalParks.Washington(pers.
obs.).whcrc nrossesnormallyfound on thc forest floor also flourish as epiph)tes(Sillett and
N e i t l i Lh l 0 0 6' . T h e . e| r i n i ' r . . r tr . r n , , f i e \ | e \ o
nossy thal cpiphyticlichens.includingclanolichens.are muchlessabundantthan in the cen
(SillettandGorvard19981.
tral OregonCascadcs
In clryfbrests,verticalrangesol alcclorioidand
othergrccnalgallichensextendlafiher down in
the canop)'(Sillett 1995),while bryophvtesand
cyanolichens
becomereslictcd to thclowercanopy
V c r l i cIcD i . t r i h u l i , ' n ,L' lp i p h ) t e .
+7
(Gou ard l995).Suchdricrtbrestssuppona smaller
biomassof bryophytesand cyanolichcns.but
alectorioidand gleenalgallichensare abundant
(Ho\\'e1978.Sillettunpubl.).Eventheold-growth
Douglas-1irfolestat theWind RiverCanopyCrane
sitc in the southernWashington
Cascadcs.
which
expedenccsslightlv drier sununerconditionsthan
the lbrests in this study. supponsrelatively few
cpiphyticbn/ophytesandcvanolichens,especially
above30 m (McCuneet al. 1997).Old-growth
associated
cyanolichens.
includingl. orz3ana.
Pseudoo pheIktria rai ni erensis. Ltld Sti( ta \, eigel i i.
appcarto reachtheirgreatestaccunrulations
and
widestverticaldistributionsin the humid Douglas-fir forcsts of thc ccntral Oregon Cascadcs
(pers.0bs.).
LiteratureCited
\eitlich. P ),,1.I99-l.I-ichcn abundancernd biodiversir! along
a chronoscqucncefioln voung managedstandslo un
c i e n t f o r e s t . N { . S .T h c s i s . U n i \ e r s i t y o f V e r m o n t .
Burlington.
Peck.J. E.. rnd B. I,lccunc. 1997.Rclnmnt tree\ and can(rpy
lichcn comnunities in [estem Oregoni a rcfospect i \ e a p p r o . r c hE.c ol o g i c a A
l p p l i c . r t i o n7s: 1 1 8 1 - 1 1 8 7 .
P i k e .L . H . l 9 7 8 . T h ci m p o r t . r n coef e p i p h !t i c l i c h e n si n m i n
c r a l c , , - c l i r : .B r l o L o g i s 8
t l: l17 251.
Pikc. L. H.. \\'. C. Denison. D. iV. Trac,"-.\L A. Sherwood.
andF. N{. Rhoadcr.1975.Floristic sune) ofepiph}lic
lichcns xrd br) ophytesgrowing on old gro\ith conifef\ in u'esternOrcgon. Br1-okrgist78: 389 102.
P i k c . 1 - .H . . R . A . R y d e l l r n d $ ' . C l .l ) $ i s o n . 1 9 7 7 .A : 1 0 0 ve.rFold I)ougla! fir ircc and its epiphlres: bio rass.
suriacc arc.r.rnd dreir disrributions.Canadirn Jour,
n x l 0 i F o r e s lR e \ e a r c hl : 6 E 0 6 9 9 .
Rho.rde\, F. M. I917. Crowlh ntes of the lichen l,rdri.l
or?.(ard as dct.rnined fiom sequentialpholographs.
C a n a d i a nJ o u f n a lo f t s o t a n t5 5 i : 2 2 6 2 2 3 3 .
. 1 9 8 3 . I ) i s l r i b u r i o no l t h a l l i i n a p o t u l a t i o no i | h e
epiphltic lichenbrdfi.r irre3ararndamodel ofpopulatron dvnamics and production.Br_-\'ologist
86i 309
131.
S i l l e t t .S . C . 1 9 9 . 1C. l r o ! r l hr a l c so l t r o e p i p h ) r i cc v a n o l i c h c n
spccic\ al lhe edge and in the interior of a 100 year,
old Douglas-fir fofest in the *'cncnr CrscadesofOfe g o n .B r y o l o g i s l 9 7 :l 2 l 1 2 , 1 .
. 1995.Branch epiphrte assemblngcsin fie lbrest
interior rnd on thc clcarcul eLlgeof .r 700-fear old
lbrcst cxnopt ir \re\tefn Oregon. Uryologisl 98: l0l ll2.
S i l l e l t ,S . C . a n d N L \ . G o s l i n . 1 9 9 9 .D i s r r i b u l i o no l e p i ,
I l r ] r . m r . r ' ' l r c h i I .i r r " i r . { r r . ' . r n r ' " . r, r e e ,i l
multiple-ageDouglas fir loresr. C:nadian Joumal of
F o r e s tR c s e a r c 2
h 9 : 1 1 0 ' 11- 2 1 5 .
S i l l c r . S . C . a n d T . G o n r r d . 1 9 9 8 .F l c o l o g ,a" n- d c o n s e r v a rio|l of Pretklu)flt?ILarn,.1irL,r..r!r. a Pacific \orh
$ e s t e n d e m i cl i c h e n .P a g e s3 7 7 3 8 81 r \ { . c . G l e n n .
R . C . l l a r r i \ . R . D i r i g . a n d N , l .S . C o l e ( c d i t o r s )
LichenogruphirThomsoniana.\'hcolaxon Ltd . Ithaca.
Ne$ Yofk. tisr\.
S i l l e t t .S . C . . a n d B . N l c c u n e .1 9 9 8 .S u r v i \ a l a n dg r o $ t h o l
c)anolicbenll'nDsplants
in Douglas firiirc\t canopies.
B r " " ' o l o g i s1i 0 1 :2 0 - l L
S i l l e t t .S . C . . a n d P N . N c i l l i c h . 1 9 9 6 .E n r e € i n g d r c m c ! i n
epiph)1ere\eafchin wcstsidclbrestswith \pecialref
ercnccloclanolichens. Nofihlve\t Sciencc70:5,1 60.
C a l T o l lG
. . C . l 9 ? 9 . F o r e s tc r n o p i c \ :c o m p l e r a n d r n d e p e n d c n l s u b s ! s t e m sP. a g e s8 7 l 0 l / n R I I . W a i n g ( e d i ,
tor) Fbrc( s: FreshPerspeciilesfr1nnEcoslstcmAnal)
\ i s . O f e g o nS l a l c U n i \ c r s i t yP r e s sC
, or!.rllis.
I)cnisonW
. C . 1 9 7 3 .L i f e i n t a l l t r c c s .S c i c n r i i c A m e r i c a n
228i7.t 80.
. 1919. Loharitt artgunu. r nilrogcr lixing lichen
i n o l d g r o $ l h D o u g l a s1 i r t b f e \ t s P a g e s1 6 6 2 1 5 / ,
J . C . C o r d o n .C . T . W h e e l e f .a n d I ) . A . P c n ) ( e d i
ior, Svinbioric \irrogen Fi\ation in the Nlanagerncnt
of Temperate Fore\Is. Forcst Rcscrfch L:rboflrt(n],.
Orcgon St:rteUni\ ersit] Corvallis.
. n l . t ( u t r L r r r t r <t r - h .n . / . , , r , - . . , , 3 , , r ,J, n J
L. pul nhdrh oi i\|ot] nronoiilrmcrt. trlr-cologia80
ll1t 8 t,1.
(-u$ 'l.l T oo5 \,[]',, \,,. . ',tLLJl l . I'-ir'tir'. .i
o f l i c h c n d i \ c r s i t , " -i n B f i t i s h C o l u m b i a . l v i i t l .
Eidgenos\. FoAch. ann. Wald Schncc Landsch. l0l
9l l0l.
Hosoka\ a. T.. \. Odari. and IL T.rg.r$.r.196,t.Caus.rlitf of
rhe distributkm ofconirolous spccicsin lbrcsl\ \\,ith
spccial rcierence lo dre phvsio-ecologicalrpprcach.
B r y o l o e i s t6 l : 3 9 6 , l l l .
l l o s c . K . D . 1 9 7 8 .D i s t r i b u t i o na n da b u n d i n c co l l c n e n r i d
and arborealliche.s i. thc old grorth conifefousforcsl\ ol lhe westernCascrcle\ofOregon. x jIh spccial
refefencero rhe nirogcn ilxing species.NLS. Thesis.
U n i \ e r s i t ) 'o f O f e g o n ,E r g e n e .
Lrons. ts. 199EC
. r o s n s t u c t u r el l l l d r p . r t i r ld i s t d h u r i o no f
epifh)1eson wcslcm hcmlock. Wind Ri\er WA. M.S.
T h < . i . .t \ ( r . ' r e e r \ r r ^ l e ! . . O \ - . p r . r
M c c u n e . B . 1 9 9 3 C r a d i e r l si n e p i p h ) t eb i o m a \ s i n r h r c c
P , ' , . 1' t , , e - l ' , , ! , , " . r . , d ' ( r . , r , ! < . . n , . i \ r em Oregon and \!shingr|)n. Bf","ologist96: .105-.ll l.
. 199.1.trsing epiphyte liuer to cnirnatc cpidrlre
b r o m a s sU
. r y o l o g i s9l 7 : 3 9 6 , 1 0 1 .
\{cCune. B.. rnd \\'. J. Dali. | 99,1.Consumplion .rnddeL-rnnp o s i l i o n o 1 l i c h e n l i t t e r i n a t e m p e r a t cc o n r l c r o u s
f a i n f o r e s tl.- i c h c n o l o s i s1t 6 : 6 7 , 7 1 .
\ l c c u n e . B . , K . A . A m s b e n i . F l . l C a n l a c h oS
. . C l e r y .C .
C o l c . C . E m c r \ o n .G . F e l d e f .P F f e n c h .D . G r e c n c .
R . H a r f i s .N f . H u l t e n .B . I - a r s o n .\ ' 1 .L e s k o .S . N , l a Jors. T. N{ark{cll. C C. Ptllter. K. Pendergfas\,E.
B . P e r e r s o nE
. . T . P e t e r s o n . . l .P l a t ! .J . P r o c l o r .T .
Rambo.A. Ros\o. D. Sha$. R. Tumer and\f. Wid'ner
1997.\'eftical profile of cpiph)tcs ll1a Pacilic Nolth$ c n o l d g r o \ \ t h f b r e s t .N o r l h $ e s t S c j c n c c7 l : l - 1 5
l5t.
lll
Sillettrnd RrLmbtr
S i l l e t l .S . C . . B . M c c u n e . J . E . P e c k .T . R . R a b o . 2 0 0 0 a .
Four ,vearsof cpiph)!. colonizrtion ir Douglas-fir
l b r c s l c a n o p i e sB. r v o l o g i s t i,n r e ! i e \ r .
S i l l e t t .S . C . . B . M c c u n e , J . E . P e c k . l . l t . I t a f f h o . i n d A .
Ruchr) 2000b. Dispersal li riurjon\ ofcpiphyric li
che.s rclult in spccicsdependenton old-gro$th for( . r . . t . . ' 1 ,e i f . | \ t t | r . . , r , . , . . , - n , . . .
T o b i e s s e nP, L . , K . A . N f o i t .a n d \ . C . S l a c k .1 9 7 7 A
. coDr,
paratllc study ol photo\,,-rlhesis,re\pirarion and \la
lcr relirlions in lbuf speciesof epiphydc molsc\ rn
relarion to their \'eltical dirrribution. Brtophlrorun
B i b l i o t h e c al 3 : 2 5 - l : 1 7 .
Reteivedl7 August1999
Actepted20 Decenther1999
Vertical Distribution of Epiphytes
19