SPRUCE-FIR FORESTS A Summa r y of Pe rt inent Inf o r ma t io n fo r the G re at Smoky Moun t a in s National Pa rk Prepared a s part o f The Up l a nd s Fiel d Res e arch L ab orat ory Volunt eer— in-Pa rks Int erp re tation of S cienc e Proj ec t Funded the G reat Smoky Mount ains Natural His t ory As s oc iation 1 1 83 May . 9 TABL E OF CONTENTS SIGNIFI CANCE OF THE BAL SAM WOOLLY ADELGID IN THE SOUTHERN APPALACHIANS THE SOUTHERN APPALACHIAN SPRUCE-FIR FOREST Phys ic al D es crip t ion D is t ribution - Human Impact t o the Spruc e Fir Fores t s THREATS TO THE SPRUCE— FIR FOREST Human D is turb anc es Ac id Ra in HI STORY AND D I STRIBUTION OF THE BAL SAM WOOLLY ADELGID BAL SAM WOOLLY ADELGID LIFE HI STORY Life Cycle Reproduct ion BAL SAM WOOLLY ADELGID EFFECT ON FIR TREES Types o f At t acks Phys ic al Change s in Infe s t ed Trees Feed ing and Mic ros copic Change s Fac t ors Af fec t ing Ho s t Suit ab il ity REGENERATION OF INFESTED STAND S BAL SAM W' OOLLY ADELGID CONTROL METHOD S Manipulat ion o f Fras er Fir Communit ies and Es t abl is hment o f S e ed Orchards Biol ogic al Control Chemic al Cont rol CONTROL AND POLI CY IN THE GREAT SMOKY MOUNTAINS NATIONAL PARK REFERENCES CITED FIGURES Dis t ribution of Ab ies s pp . and the bal sam wo ol ly adelgid in North Americ a Spruce— f ir dis t ribut ion in the S outhern Appal achians Dis t ribution of s pruce- f ir in the G reat Smoky Mount ains National Park Schematic c ro s s s ec t ion of a Fras e r f ir s t em showing the princ ipal s t ruc tures and bal sam wo olly adelgid feeding s it e Cl oseup of b als am wo ol ly adelgid feed ing s it e SIGNIFI CANCE OF THE BAL SAM WOOLLY ADELGID IN THE SOUTHERN APPALACHIANS The b al s am woolly adelgid (Adelge s p i c e ae ) is an exo t ic ins ec t that at t acks mo st s pec ies o f t rue f ir in North Ame rica . I t was int roduc ed from Europ e at the turn of the century , and s inc e then it has bec ome e st abl ished by a s ep arate introduct ion in New England and e ast e rn Canada , in the S outhe rn App al achi ans , and in the Pacif ic Northwes t . In the S outhern Appalachians , it has caused ext ensive mort al ity among Frase r fi r ( Ab ies frase ri ) . s h as Fras er Fi r i the only f ir endemic t o this reg ion , and damage been such that the very exis t enc e of this sp ec ies i s threat ened . It rep res ents an i rreplac eab le gene tic entity and is an int egral part v- of one of the more unique eco syst ems found in this r e g io n the - S outhern Appalachian s pruce f ir fores t . Thes e fo res t s are famous fo r thei r disj unc t nature and end emism of pl ant sp ec ies cont ained in them . The dis appearanc e of Fras e r f ir would f o r e s e e ab ly affec t the whol e sys t em in unknown way s . In addit ion t o b e ing an invaluabl e s cientif ic res ourc e , this fo res t provide s recreat ion opportunit ies and enj oyment fo r mil l ions of v is it ors every ye ar , as wel l as ec onomic revenue t o al l tho s e in the are a who provide good s and se rvic es for them . The presently avail ab le b al s am wo ol ly adel gid ( fo rme rly c al led the bal sam wo olly aphid ) cont rol me thod s are no t suit abl e fo r large i s s cale appl ication , and it c onc eivabl e that the c urrent trend of des t ruc t ion c ould cont inue t o the point of to t al ext inct ion of Fras e r fir . In the following page s , effo rt has be en made t o exp res s the c ompl exity of this is sue in simpl e t erms , ye t without omitt ing any de tails rel evant t o the unde rs t anding of the whol e is sue . SOUTHERN APPALACHIAN SPRUCE-FIR FOREST Phys ic al D es cript ion The cl imat e of the S outhern Appalachian s pruce— f ir fo res t is u charact e riz ed by high winds , co ol s mme rs and c ol d wint ers . Prec ipit ation and humidity are high throughout the ye ar . The g rowing se as on ( the time in a year be tween the l as t fros t and the firs t one ) is short and the s oil s are thin and ac idic (Mc cracken e t a l . 1 96 2 ; St ephens Al l thes e fact ors c omb ine t o al l ow only — the presenc e of c ert ain species well suit ed fo r this environment . The Southern Appalachian sp ruc e— fi r forest s are dominat ed by red spruc e ( Pic e a rub ens ) and Fras e r f ir . As soc iat ed canopy s pec ies include yellow b i rch (Betula lut ea) , f ire cherry ( Prunus - pensylvanic a) , and Ame rican mount ain ash ( Sorbus americ ana) . Frase r f ir is the only t rue f ir oc curring in this region and it is al s o limit ed t o this region alone . In the S outhern Appal achians , Fras e r f ir density increas es with el evat ion s o that mos t mount ain top s ab ove 62 0 0 feet in this region are c overed exclusively by Fras e r f ir (Whit t ake r In mixed s t ands at ab out 5 80 0 , Frase r f i r s eedl ings are ab out f ive times more numerous than red spruce s eedlings ( Oo st ing and B il ling s There are als o other dif fe renc e s be twe en the two s pec ies . Red sp ruc e att ains a great e r s iz e (maximum height 1 20 fee t , maximum diamet er 40 inches vs . maximum height of Fras e r f ir 7 5 fee t , maximum diamete r 3 0 inches ) . Red sp ruc e grow sl owe r but live l onge r (up t o 40 0 years a s oppo sed t o Fras e r f ir has a higher s e edl ing— t o - mature tre e rat io and is a very prolif ic s eed produce r . Both red spruc e and Fras er f ir are quit e shade t ol erant and res pond wel l t o releas e . The roo t s o f Frase r fi r are deepe r and grow more rapidly , enabl ing it t o survive in s oils where the uppe r inch or s o has b e en dried by sun and wind . Cons equently , Frase r f i r is imp ort ant as a — p ionee r spec ies rep roducing fast and oc cupying openings . S ome typical pl ant s of b ore al fores ts throughout North America find their s outhern l imit in the S outhern Appalachian mount ains ( Pe t er Whit e , pe rs onal c ommunicat ion) Prunus pensylvanic a Fi re cherry So rbus americ ana Americ an mount ain- ash Ac e r s pic atum Mount ain mapl e Sambucus pubens Red-berried elde r Viburnum alnifol ium Hobbl eb ush Rubus c anadens is Smoo th bl ackbe rry Circ ae a alpina Smalle r enchant er ' s-night shad e Cl in t o na b oreal is Bluebe ad l ily Oxal is mont ana Wood s orrel l Othe r specie s are f ound in S p ruce- f ir forest s in northe rn regions and in the S outhern Appalachians but are mis s ing in the int ermediat e s n regions . Oo ti g and B illings ( 1 95 1 ) rep ort ed an unusual ly high proport ion of sp ec ies c ommon t o bo th sp ruc e-f ir fores t s of the S outhern Appalachians and of the Whit e Mount ains in New Hamp shire . 1 96 4 3 6 7 8 L ikewis e , Hof fman ( ) report ed that famil ies of plant s , genera , and 1 09 species and varieties we re common t o the bo real A forest s of Canada , l aska .