Abies pinsapo Boiss.: a protected species in a protected area

Bocconea 7 - 1997 427 Abies pinsapo Boiss.: a p o ec ed species in a p o ec ed a ea Mon se a A is a, Ja ie He e a & Sal ado Tala e a In oduc ion Abs ac A is a; M., He e a, J. & Tala e a, S.: Abies pinsapo Boiss.: a p o ee ed speeies in a p o ee ed a ea. -Boeconea 7: 427-436. -lSSN 1120-4060. This pape p esen s he e sul s o a s udy on he ep oduc i e eyele o Abies pinsapo. The main ep odue i e aspec s which a ee he quan i y and quali y o h e seed s, such as he lo w pollen dispe sal capaei y, he subdioecious condi ion and h e combina ion g ow h o n- ee a chi ec u e a e di seussed. The equi emen s (l seed ge mina ion, seedling e e ui men and some aspec s o h e species a e analysed using ali he a a il able da a. Abies pinsapo Boiss. is one o he 46 species o i s which a e discon inuously dis ibu ed in he No he n hemisphe e (Fa jon 1990). Abies pinsapo was desc ibed o he i s ime by Clemen e in he i s decade o he 19 h cen u y. Howe e , his desc ip ion was lo s and he species wa s la e desc ibed by Edmund Boi ss ie in 1938 (Abies pinsapo Boiss., Biblio h. Uhi . Génè e, sé . 2,13: 402,406. 1839). Abies pinsapo is a coni e endemie o he sou h o Spain a nd belongs o a ci cum- Medi e anean g oup o i s which is conside ed o be a elic species. The wes e n Medi e anean species a e sepa a ed in o wo sec ions: sec ion Abies is ep esen ed by A. alba Mille (S. Eu ope) a nd A. neb odensis (Lojac.) Ma ei (Sicily), and sec ion Piceas e (Fig. I) by A. pinsapo Boiss. (S. Spain), A. ma ocana T ab. (N.W. Mo occo), A. azao ana C6za ex Hug. Villa (N.W. Mo occo), and A. numidica Ca . (N.W. Alge ia). The spec ie s in sec ion Piceas e a e mo phologically simila , ha ing igid Iea es, and b ac s smalle han he o uli e ous scale s. Due o such simila i i es, many au ho s ha e g ouped hese axa in o h ee spec ie s: A. pinsapo, A. a zao ana and A. numidica (including A. ma ocana as subspecies o A. pinsapo; Mai e 1952; F anco 1950) o in o wo specie s: A. pinsapo and A. numidica (Ceballos & Bolanos 192 8; Fa jon 1990), including A. ma ocana and A. a zao ana as a ie ies o A. pinsapo (Fa jon 1990). 428 A is a & al.: Abies pinsapo Boiss.: a p o ee ed speeies ... x A. pinsapo Ào. A. numidica • A. ma ocana • A. neb odensis o A. azao ana ~ A. alba Fig. I. Dis ibu ion a ea o he sec ion Abies acco ding o Mai e (1952) and Jalas & Suominen (1973). E en hough he speei ie limi s o he genus Abi es a e no clea , he pinsapo popula ions o sou he n Spain ha e some di e en eha ae e s om hose o N. A ica. Fo example, A. pinsapo has ema gina e, mue ona e b ae s (subula e in A. ma o ca na and A. azao ana). The b ae s o A. pinsapo a e 1 /3 -1 /4 sho e han he o uli e ous seales (e. 1/2 sho e in A. ma ocana a nd A. azao ana; pe so obse . Fig. 2). O he eha ae e s such as numbe o le a s oma a o numbe a nd di sposi ion o esin canals a y be ween ees and hey eanno be used o dis ing ui sh hese axa (Ma inez & Aisa 1995). Due o sueh mo phologieal di e enees, we eonside A. pinsapo Boiss. is an endemie species o he dolomi ic and se pen ine moun ains o sou he n Spain. The in o ma ion he e p esen ed come om h e Doc o al hesis 'Biologia del pinsapo (Abies pinsapo Boiss.)', Uni e si y o Se ille, Spain, 1993. Dis ibu ion o Abies pinsapo Cu en ly, Abies pinsapo occu s a 900-1600 m in he Sub-Be ie moun ains, occupying a o al o only 1200 ha. The mos impo an o es s a e in Sie a de G azalema (Cidiz P o ince), Sie a de las Nie es and Reales de Sie a Be meja (Malaga p o ince). Howe e , isola ed indi iduals o sma ll popula ions o se e al indi iduals can be ound a Ronda, Pa au a, Is {m, Monda, Ojén, Tolox, Yunque a, Es epona, Casa abonela and Co es Bocconea 7 - 1997 429 de la F on e a (Malaga), and a Algodonales, Zaha a de la Sie a, G azalema and Benacoaz (Cadiz). A TAZAOTANA A MAROCANA A PINSAPO I l l 2 l 3 Fig. 2. Scales anù B ac s o Abi es pinsapo (Spain: Càùiz, Sie a ùe G azalcma. 1200 m. 12 Oc 1992, M. A is a, S. Tala e a & J. He e a 139392, SEV), Abies ma ocana (Mo occo: Jbel Talamsen ane, 1800 m. 8 Feb 1993, F. Ojeda /39393. SEV) and Abies azao ana (Mo occo: Jbel Tassao , 1700 m, IO Feb 1993, F. Oj eda J 39394 , SEV). l, en al side o he o uli e ous scales; 2, do sal si de o he o uli e ous scales; 3, do sal side o he b ac s. I and 2 ba scales 10mm. 3 ba scale 8 mm. Abo e I 100 m o ele a ion Ahies pinsapo o ms pu e o es s, bu below I 100 m i o ms mixed communi ies. In he ee layc o dolomi ic soils Ahies pinsapo o ms a mixed oak- i o es wi h species such as Que cus o undi olia and Que cus aginea, hei p opo ions a ying ' wi h al i ude (Fig. 3). The sh ub laye , much mo e di e se, is composed o species such as Daphne lau eola subsp. la i olia, Hede a helix, Ruscus aculea us, I is oe idissima and Ruhia pe eg ina in he closed o es and o C a aegus monogyna subsp. h e ispina, P unus spinosa, P ilo ichum spinosum, Bupleu um spinosum, Thymus x a undanus, Vlex hae icus, E inacea an hyllis, Bupleu um gih al a icum and Cis us alhidus in he. gaps (A is a 1995). In he ee laye o se pen ine soils and only occasionally on calca eous soils, Ahies pinsapo occu s wi h Que cus suhe and wi h o he coni e s such as Pinus pinas e and Pinus halepensis. The sh ub laye in 430 A is a & al.: Abies pinsapo Boiss.: a p o ec ed species ... se pen ine soils is composed o E ica e minalis, Genis a lanuginosa, G. iacan hos, Cis us populi olius subsp. majo , Bunium alpinum subsp. macuca, Ce as ium gib al a icum and Alyssum se pylli olium subsp. malaci anum. San C is òbal 1400 1300 ~~ 1: 1200 Z '~' . o ~ HO ~ w 'i .. ~B ..... w 1000 900 8 6 o: N- Llanos del Re és Fig. 3. P opo ion o seedlings (do ed) and ep oduc i e indi iduals (black) 01' Abies pinsapo pe plo o 50 m2 along he al i udinal g adien o Sie a de G azalema (Cidiz). Rep oduc i e cycIe o Abies pinsapo Boiss. Abies pinsapo belongs o a e y s able genus (2n = 24), and has a ep oduc i e cycle o one yea (A is a & Tala e a 1994a) e y simila o hose desc ibed in o he species o genus Abies (Miyake 1903, Hu chinson 1915, Eis 1970, Powell 1970, Owens & Molde 1977, Singh & Owens 1981, 1982). The di e en ia ion o he ep oduc i e buds occu s in la e July; b ac s o mic ospo ophylls a e ini ia ed h ough Augus and in o Sep embe , and he di e en ia ion is comple ed a he end o he summe . Male buds a e ini ia ed on he abaxial su ace o he elonga ing shoo s o he lowe b anches, and a he end o he summe , hese buds en e a es ing phase. The do mancy is b oken a he end o Feb ua y and meiosis akes pIace. Ma u e pollen g ains a e shed in he i e-celled s age be ween he end o Ap iI and mid-May. The emale buds a e also ini ia ed in mid-July and a e si ua ed on he uppe b anches, on h e adaxial su ace o he elonga ing shoo . In mid-Ap il bud bu s akes pIace, and hen meiosis occu s coinciding wi h pollina ion. Du ing pollen shedding, he scales o he emale cones sepa a e o p o ide a space h ough which ai bo ne pollen g ains en e . The e o e, seed cone ecep i i y is synch onised wi h pollen shedding wi hin a ee. In an indi iduaI ee lowe ing las ed o six days (A is a & Tala e a 1994b), bu in he popula ion he lowe ing pe iod las ed one mon h. In ecen yea s, lowe ing in ensi y and p oduc ion o cones we e simila in he h ee mai n o es s o Abies pinsapo. The mean pollen cone p oduc ion pe ee anged om 800 o 39 200 and he emale p oduc ion anged om 62 cones pe ee o 198. Bocconea 7 - 1997 431 Pollen e ili y in Abies pinsapo is e y high, nea ly 100 %, and in i o, he pollen needs only dis illed wa e and a empe a u e om 20 o 24°C o ge mina ion. Pollen dispe sal capaci y in Abies pinsapo was s udied in Sie a de G azalema a di e en s and densi ies. Ai pollen densi y (measu ed using pollen aps) o pinsapo in open o es was ma kedly lowe han ha in closed o es (A is a & Tala e a 1994b). This e lec s a poo suspension o pinsapo pollen in he ai , and in consequence a sho -dis ance pollen dispe sal. Al hough he pollen g ains ha e wo wings, hei la ge size and he high humidi y o he a ea could be impo an ac o s in educing suspension. Al hough Abies pinsapo is a monoecious species, in ali he popula ions a p edominance o emale plan s ( ees ha de elop only emale cones) was obse ed, wi h a ew male and monoecious indi iduaI s, hus indica ing a unc ionally subdioecious b eeding sys em (A is a & Tala e a 1996b). Va ia ion in gende exp ession is obse ed be ween di e en densi ies, and could be explained as a consequence o ee a chi ec u e ( emale and male cone posi ion) in combina ion wi h he g ow h o mo A low densi y, ees a e sho -b oad wi h b anches om g ound le el, and end o exp ess hemsel es sexually by p oducing male cones (Fig. 4). In con as , ees g owing a high densi y a e ali wi h b anches limi ed o he op hal o he ee, and end o emaleness. A simila si ua ion has been ound in o he coni e s such as Picea (Ca on & al. 1990) o Pinus (Smi h & al. 1988). A e pollina ion, he o uli e ous scales enla ge and o e g ow he b ac s, and he megaspo e begins ee nuclea di isions. A he end o lune a chegonium o ma ion occu s ·and e ilisa ion akes pIace ( wo mon hs a e pollina ion). The emale cones achie e hei maximum size in ea ly lune, and a he beginning o Sep embe , he emb yo is appa en ly ully de eloped. Seeds begin o shed om Oc obe o No embe . Seeds eaching he so il en e do mancy un il Feb ua y o he ollowing yea , when ge mina ion begins. Seeds ha ail o ge mina e his yea die, so ha a pe sis en seed bank is no o med. Abies pinsapo indi iduals lowe in al e na e yea s and occasionally in wo consecu i e yea s. In he las ou een yea s, A. pinsapo popula ions lowe ed in 1982, 1983, 1985, 1987, 1989, 1991, 1992 and 1994 (A is a & Ta1a e a 1995). Cone c op cycles o wo o h ee yea s a e common in o he i species (Singh & Owens 1981, Shea 1989a, 1989b, Houle & Paye e 1991). Synch onisa ion o he ees in lowe ing is p obably due o an ° endogenous hy hm o he species con olled by in ins ic ac o s bu ha could be modi ied by ex insic condi ions (Powell 1977). Cone p oduc ion and ui ~e om 1990 o 1993 in Abies pinsapo o es s o Sie a de G azalema, Sie a de las Nie es and Sie a Be meja we e e y di e en . The ui se was always highe among pinsapo ees o he Sie a de las Nie es and Sie a Be meja ela i e o Sie a de G azalema ees. This si ua ion e lec s he clima e suppo ed by he eas e n- mos popula ions o A. pinsapo. In hese popula ions ain all du ing he lowe ing pe i od is hal ha o he Sie a de G azalema. This could in ol e a lowe pollina ion index in Sie a de G azalema ees, and hus a lowe ui se (A is a & Tala e a 1995). Va ia ion in ui se was also ound be ween di e en densi ies (A is a & Tala e a 1 996a). Low densi y A. pinsapo popula ions had ma kedly highe cone c op p oduc ion and ui -se pe plan han hose a high densi ies. Densi y e en a ec ed he cone size and he numbe o seeds pe cone: cones om he high densi y zone we e signi ican ly la ge and had a highe numbe o seeds han hose om low densi y zone. In he ully de eloped cone, all he o ules each he ull size al hough some o hem ha e no emb yo. 432 A is a & al.: Abies pinsapo Boiss.: a p o ec ed species ... I ~~ Il I ~---_. - HIGH DENSITY lOW DENSITY Fig. 4. Mo phology o Abi es pinsapo ees li ing in high and low densi y. The blaek zone indiea es he ema le eo ne posi ion and he s iped he male eone posi ion. Bocconea 7 - 1997 433 Seed c ap iabili y be ween densi ies is ma kedly di e en , e.g. in 1992, a e age seed iabili y in he low-densi y zone was 21 %, bu some ees had only 3 % o iable seeds. In he high densi y popula ions seed c ap iabili y a e aged 82 % wi h a ange o 54 %- 93.3 % (A is a & Tala e a 1996). Di e ences in seed iabili y a e also ound in esponse o gende exp ession o he ees in low and high densi y popula ions. A high densi y, ees ha p oduced only emale cones du ing he 10we ing pe iod had g ea e seed c ap iabili y han hose wi h male and emale cones (a e ages o 80 % and 63.3 % espec i ely). In con as , low densi y zone ees wi h only emale cones a 10we ing had lowe seed c ap iabili y (a e age 8.3) han hose wi h bo h male and emale cones (a e age 31 .8). This e lec s di e ences in quan i y and quali y o he a ailable pollen du ing he pollina ion pe iodo Ge mina ion o Abies pinsapo seeds akes pIace in Feb ua y. In he labo a o y, ge mina ion o seeds exceeding 60 mg ( hose ha ha e an emb yo, A is a & al. 1992) is nea 100 %. In he ield, seed ge mina ion depends on he pIace in which he seeds allo Inside he o es , he gaps a e he bes places o ge mina ion, anging om 26.6 % o 63.3 % (A is a 1993b). Unde he o es canopy, ge mina ion is e y low, nea 0%. The highes mo ali y o seedlings occu s in he i s yea o li e, a e which mo ali y is p ac ically ze o. Howe e , su i al depends on he pIace in he o es a which ge mina ion occu s. In o es gaps, su i al is e y high e en in he i s yea , wi h only 18 % · o mo ali y. In con as , in he in e io o es mo ali y in he i s yea o seedling li e is 52 %. Thus, mo ali y unde he o es canopy is always highe han in gaps. One-mon h-old seedlings om seeds collec ed am ees a low densi y ha e a g ea e igou ha~ hose om he high densi y zone. This si ua ion oge he wi h he di e en seed iabili y in ees o high and low densi y popula ions, could ha e impo an consequences. The lowe ed seed iabili y ound in monoecious ees s. emale ees in high densi y s ands sugges s a possible inb eeding dep ession in he endogamous emb yos o A. pinsapo, and consequen ly, he selec i e abo ion o some o hem. The heo y ha he e is inb ecding dep ession in A. pinsapo is suppo ed i s ly by di e ences in seed c ap iabili y and secondly by he highe igou o seedlings om high dcnsi y popula ions (A is a & Tala e a 1 996a). The esul s o his s udy a e impo an because hey ha e se e al implica ions o he collec ion and p aduc ion o A. pinsapo seeds o ea o es a ion plans. They p a ide addi ional. e idence agains he disc edi ed p ac ice o collec ing cones om open-g own semi-isola ed indi iduals. Al hough hese ees o en p oduce abundan , easily-collec ed cones, a signi ican p opo ion o seeds a e no iable, due o high a es o sel - e ilisa ion. Whe e he seeds a e iable a subsequen lack o igou in he seedlings esul s om sel ing. The si ua ion desc ibed he e sugges s ha he na u al egene a ion o low densi y popula ions o Abi es pinsapo is di icul . Conse a ion A p esen , mos o he pinsapo· o es s a e included in he so-cali ed 'Ne wo k o P o ec ed A eas in Andalusia': Sie a de G azalema Na u al Pa k (1984), Sie a de las Nie es Na u al Pa k (1989) and Los Reales de Sie a Be meja Na u e A ea (1989). Bo h Sie a de G azalema and Sie a de las Nie es Na u al Pa ks ha e been decla ed as Biosphe e Rese es by UNESCO, in 1977 and 1995 espec i ely. A Eu opean le el, he 434 A is a & al.: Abies pinsapo Boiss.: a p o ec ed species ... pinsapo o es s ha e been included in he Rabi a s Di ec i e 92/43 and he species IS p o ec ed by Dec e o 104/94 in he 'Andalusian Ca alogue o Th ea ened Wild Plan s'. In he pinsapo o es o Sie a de G azalema, he e seems o be no p oblem o na u al egene a ion. Abies pinsapo does no seem o be a long-li ed species. The oldes pinsapo o es is a Canada de los Cue os, in he Sie a de las Nie es, Miilaga p o ince. In his o es , he oldes ees a e unde 200 yea s old. In Sie a de G azalema he e a e no ees app oaching his age ( he oldes i was abou 123 yea s old), p obably because i egene a ed a he beginning o he cen u y a e an in ense i e. The Abies pinsapo o es o Sie a de G azalema has a balanced mul i-age condi ion in which ec ui men and mo ali y a es end o be cons an . The p opo ion o seedlings in Sie a de G aza1ema is e y high (o 69%) and hey ha e p ac icaIly no signs o he bi o e damage (1e ss han 5% o he seedlings a e consumed by he bi o es). Size s uc u e is e y di e en in he o he wo impo an o es s o A. pinsapo. In Sie a de las Nie es, he p opo ion o young indi idua ls is e y small (only 4%), indica ing a low a e o ec ui men . This si ua ion e lec s i s ly, he s ong he bi o e damage caused by bo h wild and domes ic li es ock and secondly, he s ong p uning on he lowe b anches o he ees which dec eases he male eone c op p oduc ion and in consequence, seed iabili y due o lack o pollina ion, and hi dly he ma kedly low le el o he e ozygosi y o his popula ion (Pascual & al. 1993), which p obably a ce s seed igou . In Sie a Be meja, diame e dis ibu ion esembled a no mal dis ibu ion, wi h ees o 40 cm DBR as h e mos equen . This could e lec he selec i e choice o which he ees g ea e han 60 cm DBR had been submi ed. In his popula ion he seedlings also su e he bi o e damage, bu a lowe le els han in Sie a de las Nie es. The e is a signi ican nega i e co ela ion be ween ee densi y (a measu emen o canopy co e ) and numbe o pinsapo seedlings, indica ing ha A. pinsapo es ablishmen a es a e highe in he ligh gaps (A is a 1995). The small numbe o seedlings which su i ed unde o es canopy su e s supp ession. Abies pinsapo is a mode a ely shade- ole an species, which can su i e un il i is 40 yea s old unde o es canopy. Du ing hi s ime, i cons i u es a seedling bank, which p obably eoccupies he a ailable space when a gap is o med. The mai n pa hogen agen s o he pinsapo o es a e he coleop e an C yphalus numidicus, he lepidop e an Dio ic ia aulloi and he ungi A milla ia meliea (Vahl. F .) Kumm and He e obasidium annosum B es. (Cobos 1994). Li le is known abou he incidence o such o es pes s; bu he e a e some da a on p eda ion pe cen age o seed cones by Dio yc ia al/lioi (A is a & Tala e a 1995) in Sie a de G azalema, bu i seems ha he highcs pa hogen impac occu s in he Sie a de la Nie es popula ion. This is being s udied a p esen . In conclusion, na u al e gene a ion in he Sie a dc G azalema pinsapo o es is gua an eed due o bo h he good seed quali y and hc absence o he bi o es (allowing seedling ec ui men ). Ou side he c10sed o es , e gene a ion is mo e di icul . and a po en ial gene ic imp o emen would be possible wi h supplemen a y pollina ion managemen as has been sugges ed in o he coni e o es s (F anklin 1981 , Askew 1992) o wi h a i icial seed ain using igo ous seeds. Regene a ion in Sie a de las Nie es a nd Sie a Be meja o es s equi es mainly seedling p o ec ion om he bi o es. The si ua ions desc ibed ha e been ound in he absence o majo e en s such as i e. Abies pinsapo is a mode a ely shade- ole an species, which could domina e whe e he e is Bocconea 7 - 1997 435 no exogenous dis u bance, bu less ole an species (such as Q. o undi olia and Q. aginea) a e capable o pe sis ing as mino componen in he canopy o o es cap u ing space when majo e en s occu (Ba den 1979, 1981). In addi ion, Abies pinsapo seeds nei he ge mina e a e i e no esp ou bu Que cus spp. do bo h. The e o e, i e, a ecu en dis u bance in Medi e anean ecosys ems, could be an impo an ac o in de e mining species composi ion and dynamics, and is p obably he mos impo an dange in A. pinsapo o es s. Re e ences A is a, M. 1993: Supe i encia de las pllin ulas de Abies pinsapo Bois s. en su habi a na u al. - Anales Ja din Bo . Mad id 51: 193-198. 1993: Ge minaci6n de la s se millas y supe i encia de las plan ulas de Abies pinsapo Boiss. -Ac a Bo . Malaci ana 18: 173-178. 1995 The s uc u e and dynamics o an Abiespinsapo o es in sou hem Spain. -Fo es Ecol. Manag. 74: 81-89. & Tala e a, S. I 994a. Phenology and ana omy o he ep oduc i e phase o Abies pinsapo Boiss. (Pinaceae), -Bo . J. Linn. Soc. 116: 223-234. & -I 994b: Pollen dispe sal capaci y and pollen iabili y o Abies pinsapo Boiss. -Sil ae Gene ica 43: 155- 15 8. & - 1995: P oducci6n de pi ias y ciclos de cosechas en Abies pinsapo Bois s. - An ales del Ja din Bo . Mad id 53: 5-12. & - 1996a: Densi y e ec on he ui -se , seed c op iabili y and seedling igou o Abies pinsapo. -Annals o Bo . 77: 187-192. &- 1996b: Gende exp ession in Abies pinsapo Boiss., a Medi e anean i . -Annals 01' Bo . ( in p ess). - & He e a, J. 1992: Viabilidad y ge minaci6n de las semillas de Abies pinsapo Boiss. - Ac a Bo . Malaci ana 17: 223-228. Askew, G. R. 1992: Po en i al gene ic imp o emen due o supplemen al mass pollina ion managemen in coni e se ed o cha d. -Fo e s Eco!. Manag. 47: 135-147. Ba den, L. S. 1979: T ee el"l acemen in small canopy gaps 01' a Tsuga canadiensis o es in he sou hem Appalachian, Tenessee. -Oecologia 44: 141-142. 1981: Fo es de elopmen in canopy gaps o a di e se ha dwood o es o he sou hem Moun ains. -Oikos 37: 205-209 Ca on, J. E., Wang, B. S. P. & Schooley, H. O. 1990: E ec o ee spacing, cone s o age and p echilling on ge mina ion o Picea glauca seed. -Fo es Ch on. 66: 388-392. Ceballos, L. F. C. & Bola ios, M. M. 1928: Flo a y mapa o es al. El pinsapo y el abe o de Ma uecos.~ Ins i u o Nacional Expe . Ag on. Fo es a l, Mad id 1: I-57. Cobos, J. M. 1994: Es ado i osani a io de los pinsapa es andaluces. - In : Ges i6n y conse aci6n de los pinsapa es Andaluces. -Asociaci6n Fo es al Ahdaluza. Jun a de Andalucia. Eis, S. 1970: Rep oduc ion and ep oduc i e i egula i ies o Abies lasioca pa and Abies g andis. -Canadian J. Bo . 48: 141 - 143 . Fa jon, A. 1990: Pinaceae. -Koel z Scien i ic Books, Koenigs ein. F anco, J. 1950: Abe os. -Anais Ins i u o Supe io Ag onomia 17. F anklin, E. C. 1981: Pollen managemen handbook. -USDA Fo . Se o Ag ic. Handbook 587, 98 pp. Houle, G. & Paye e, S. 1991: Seed dynamics ol' Abi es balsamea and Ac e saccha um in a deciduous o es 01' No heas em No h Ame ica. -Ame ican J. Bo . 78: 895-905. Hu chinson, A. H. 1915: Fe ilisa ion in Abies balsamea. -Bo . Gaz. 60: 457-472.