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Steven&Kelley/BIO&1701Black/RoL&Project/Mar15,&2013& 1&
A&review&of&literature&
Is#Green(tree#retention#an#effective#alternative#to#traditional#clear(cut#logging#in#promoting#biodiversity#regeneration?#
&Steven&Kelley&
BIO&1701Ken&Black/Jacksonville&University&March&15,&2013&
&ABSTRACT:& This&paper&is&a&review&of&an&experimental&logging&technique&knows&as&
Green1tree&retention& that&sets&aside&a&portion&of&a&site& from& logging& in&such&a&way&
that&it&aids&the®eneration&of&biodiversity&and&is&being&conducted&on&in&the&Pacific&
Northwest&and&northern&Europe.&This&review&examines&eight&studies&conducted&over&
the&last&decade&and&attempts&a&response&as&to>R&success.&This&review&does&this&by&
breaking&down&the&studies&into&four&sets&of&categories&(mammals,&birds,µfauna,&
and& lichen)&with& each& test& answering& a& question& posed& by& this& author& comparing&
aggregate& versus& dispersed& retention& patterns,& GTR& effects& on& residential& versus&
migratory& species,& its& effects& on& fauna& found&on& retained& trees& versus&nearby& soil,&
and& whether& or& not& species& can& be& transplanted& onto& GTR& lands.& It& presents& no&
single&answer&and&some&explanations&are&obvious&while&others&prove&more&elusive..&
For&example,&in&the&insect&surveys:&enchytraeids&and&collembolas&are&found&in&rates&
greater&than&three×&other&branches&of& insects&and&spiders.&Trends&also&offer&a&
wide&range&of&implications.&Comparing&the&two&bird&surveys,>R&appears&to&have&a&
minimal&effect&on&populations&in&one&while&having&a&devastating&effect&in&the&other.&
Many& authors& of& the& surveys& reviewed& admit& to& inconclusive& data& and& a& need& for&
further& research.& If& this& review& demonstrates& anything& conclusive,& it's& that& GTR&
success& is&very&dependent&on& the&species&being&examined,& that&many&other& factors&
are¬&taken&into&consideration&that&could&provide&a&more&comprehensive&picture&
of>R,&and&that¬&enough&surveys&have&been&conducted&to&provide&either&positive&
or& negative& conclusions.& & It& also& defines& effectiveness& by& the& single& variable& of&
species& found& on& the& site& and& does& not& consider& the& explanations& that& a& broader&
understanding& of& species1dynamics&would& permit.& This& technique& is& in& its& infancy&
relative&to&the&history&of&logging&and&has¬&been&tested&on&a&variety&of&ecosystems&
sufficient&to&encourage&or&discourage>R's&continuation.&
Steven&Kelley/BIO&1701Black/RoL&Project/Mar15,&2013& 2&
#Introduction#
Ever&since& the&mechanization&of& the& timber& industry,& loggers&have&clear1cut&
all&trees&from&a&site&and&burned&the&refuse&to&reduce&the&risk&of&fire&and&competition&
from& undesirable& saplings& (Halpern& and& Evans,& et& al.& 1999).& However& it& was&
observed&that&such&methods&did¬&allow&the&succeeding&forest&to&resemble&how&a&
forest& would& have& regenerated& under& natural& circumstances& (ibid,& 1999).&&
Furthermore&controversies&like&that&which&surrounded&the&northern&spotted&owl&in&
1990& convinced& many& that& forestry& goals& should& be& redesigned& to& allow& for&
biodiversity& to& thrive&without& threatening& industry& goals& (Rosenvald& and&Lohmus.&
2008).& Consequently,& new&methods& are& being& experimented&with& that& "mimic& the&
processes& and& outcomes& of& natural& disturbance& …& by& retaining& structural&
characteristics&of&the&former&forest")&to&allow&a&forest&to&maintain&an&adequate&level&
of&biodiversity&(Halper&and&Evans,&et&al.&1999).&
Green1tree& retention& (GTR)& logging& is& a& form& of& harvesting& that& allows&
enough&of&a&forest&to&be&left&behind&to&allow&new&species&and&successive&stands&to&be&
re1established& naturally& (Rosenvald& and& Lohmus,& 2008)& and& has& been& attempted&
throughout&the&Pacific&Northwest&and&Scandinavia.&It&seeks&to&retain&a&percentage&of&
a&forest&designated&for&logging&such&that&(a)&threatened&species&are&permitted&what&
the& industry& terms& a& "lifeboat",& (b)& allow& a& structure& for& the& succeeding& forest& to&
fashion& itself& around,& and& (c)& allow& connectivity& between& disparate& forest& strands&
(ibid).&Two&styles&of>R&have&been&implemented:&aggregate1cutting&where&retained&
trees&are&clustered&together&in&an&island&and&dispersed1cutting&where&retained&trees&
are&scattered&apart&across&the&site&(Holloway&and&Smith,&et&al.&2012).&
Steven&Kelley/BIO&1701Black/RoL&Project/Mar15,&2013& 3&
But& is& GTR&working?& Is& it& effective& in&maintaining& existing& populations& and&
promoting& successive& ones?& Regional& forest& ecologists& have& been& attempting& to&
define&an&answer& to& that&question&over& the&past&decade.&This&paper& is& a& review&of&
their& findings&and&a& synthesis&of& their& results& to&develop&a& response.& It& focuses&on&
four& pairs& of& studies& around& similar& biodiversity& genre& and& uses& their& studies& to&
answer&an&original&question&posed&by&yours&truly&that&was¬&a&focus&of&the&original&
census.& The& first& examination& revolves& around& mammals& and& asks& whether&
aggregate1cutting&or&dispersed&cutting& is& the&more&effective& technique.&The&second&
concerns&birds&and&whether&residential&or&migratory&birds&respond&more&favorably&
to&retained&forests.&The&third&examines&theµfaunal&world&of&spiders&and&insects&
to&see&if&life&does&better&on&living&retained&trees&or&in&nearby&soil.&Finally,&lichens&are&
examined&to&see&if&transplanted&species&thrive&better&on&living&retained&trees&or&by&
natural&colonizers&on&stumps&and&snags&
There& are& several& handicaps& to& this& review's& conclusions.& First,& only& one&
variable& is& being& accounted& for& here:& headcounts& or& percentages& of& found& species&
published&in&the&original&study.&A&related&second&handicap&is&that&none&of&the&studies&
(except& one)& accounted& for& populations& prior& to& the& harvest,& which& denied& an&
opportunity& to& compare&populations& to& those&prior& to& logging.&Finally,&none&of& the&
studies&accounted&for&how>R&affected&the&predators&that&would&have&hunted&those&
species&examined.&&
& &
Steven&Kelley/BIO&1701Black/RoL&Project/Mar15,&2013& 4&
Discussion&&Except&where¬ed,&conclusions&about&data&are&the&opinions&of&this&author.&All&graphs&are&original&and¬&duplicated&from&the&sources.&&Which#is#a#more#effective#style#of#GTR#for#mammals:#aggregated#or#dispersed#retention?#&& In& the& late& 1990s,& the& government& of& Oregon& implemented& the& Northwest&
Forest& Plan& setting& GTR& standards& at& 15%& (Holloway,& Smith,& et& al.& 2012).& Several&
years&later&local&scientists&established&the&Demonstration&of&Ecosystem&Management&
Options& (DEMO)& to&oversee&studies&evaluating& the&standard's& influence&on&wildlife&
populations& (Gitzern,& West,& et& al.& 2007).& & Each& conducted& a& census& of& various&
populations& on& sites& with& retention& rates& of& 100,& 75,& 40,& and& 15%.& One& set& traps&
throughout& the&understory& to& count&mice,& shrew,&voles,& and&other& small&mammals&
(ibid,& 2007).& The& other& conducted& a& census& of& the& northern& flying& squirrel;& a&
keystone&species&dependent&on&old1growth& tree1height& to&maintain&effective&glides&
(Holloway,&Smith,&et&al.&2012).&&
&Graph&1:&Data&collected&from&Holloway,&Smith,&et&al.&2012&
#
0&
10&
20&
30&
40&
50&
60&
"100%"& "75%A"& "40%D"& "40%A"& "15%D"& "15%A"&
Combined#number#of#@lying#squirrels#
found#
#among#trees#of#varying#basal#area##
Percentage#of#tree#retention#from#sites#in#western#Oregon#and#Washington#D=#Dispersed#pattern#of#tree#retention#A=#Aggregate#pattern#of#tree#retention#
#
Flying#squirrels#found#among#varying#tree(retention#rates#
Steven&Kelley/BIO&1701Black/RoL&Project/Mar15,&2013& 5&
#Table#1:#Average#Number#of#species#found#over#a#four(day#count#in#sites#of#varying#GTR#rates#
&Captured)Animals)per)100)trap2nights) 100%)
75%)Agg.)
40%)Disp.)
40%)Agg.)
15%)Disp.)
15%)Agg.)
Trowbridge's)Shrew) 2.6) 3.1) 2.8) 2.9) 2.4) 3.1)Western)Red2backed)Vole) 3) 1) 0.5) 1.2) 0.3) 0.4)Southern)red2backed)Vole) 1.9) 1.9) 4) 3) 2.2) 2)N.West)Deermouse) 0.9) 1.4) 1) 1) 0.8) 1)Vagrant)Shrew) 0.7) 0.75) 1) 0.9) 1) 0.8)Long2tailed)Vole) 0.02) 0.08) 0.05) 0.15) 0.14) 0.2)Common)Deermouse) 0.4) 0.8) 1) 1.5) 2.5) 2.1)Creeping)Vole) 0.5) 0.75) 0.7) 0.65) 0.75) 0.65))) ) ) ) ) ) )Data&collected&from&Gitzen,&West,&et&al.&2007&
& In& graph& one,& the& percentages& of& squirrels& fell& significantly& in& sites& below&
75%.&Populations&differed&between& aggregate& and&dispersed& sites& by& over&10%& in&
favor&of&aggregates.&For&the&ground&mammals,&5&species&were&found&on&cuts&of&40%1
in& aggregate& compared& to& 2& from&40%1in& dispersed& sites,& some& (like& the&Western&
vole)&more&significantly& than&others& (such&as&Trowbridge's& shrew).&On&sites& cut&at&
15%&retention&percentages&of& found1species&were&evenly&split&between&aggregates&
and&disperseds:&41to14.&Of&all&categories&the&fewest&percentage&of&species&were&found&
on&the&40%1dispersed&site.& &Yet& the&scores&were&more&balanced&between&40%&and&
15%&cuts&and&(with&the&exception&of&the&Southern&vole)&weren't&significantly&greater&
compared&to&fuller&sites.&
& Among& sites& compared& between& dispersed& and& aggregate& styles,& the& more&
effective&was& the&40%1aggregate&cut.&For& the& flying&squirrel& this& finding&should&be&
obvious&as&trees&spaced&closer&together&allows&for&a&shorter&glide1distance&between&
trees.& For& ground& mammals,& which& are& sources& of& food& for& avian& predators,&
aggregate&styles&allow&greater&protection&from&being&preyed&upon.&&The&insignificant&
Steven&Kelley/BIO&1701Black/RoL&Project/Mar15,&2013& 6&
difference&between&counts&at&sites&with& fuller&retention1rates&compared&to&sparser&
cuts&could&represent&a&drop&in&predators&within&lower>Rs.&
#Which#do#GTR#strategies#benefit#more:#resident#or#migratory#birds?##& One& of& the& possible& benefits& to& clear1cutting& is& that& it& allows& for& forests& to&
regenerate&on&sites&from&which&fire1suppression&might&have&been&in&effect&(Otto&and&
Roloff,&2012).&This&allows&for&succession&species&to&colonize&previously&unattainable&
territories.&In&the&mid12000s,&two&studies&were&conducted&in&Michigan&and&Sweden&
to& determine& GTR& effects& on& bird& populations& (Otto& and& Roloff.& 2012& and&
Soderstrom.& 2009& respectively).& Each& divided& their& census& into& two& categories:&
habitual&residents&of&the&site&and&migratory&successionists.&
&M=#Migratory#Species####################G=#Generalist###########################S=#Successionist#
Graph&2:&Data&collected&from&Otto&and&Roloff.&2012&& &
0&0.1&0.2&0.3&0.4&0.5&0.6&0.7&
Percentage#of#species#found#
Percentages#of#bird(species#found#in#harvested#Michigan#forests#with#3(10%#tree#retention#rate#combined#over#a#four(day#period#
Steven&Kelley/BIO&1701Black/RoL&Project/Mar15,&2013& 7&
&M#=#Migratory#Species################################R#=#Residential#Species#
Graph&3:&Data&collected&from&Soderstrom.&2009&&&
& Neither& study& compared& species& found&on>R&sites&with& rates&higher& than&
25%.& In& the&Michigan&study&5&migratory&species,&10&generalists,&and&5&residentials&
were&detected.&Of&all& the&species&only&six&were&found&at&rates&above&40%&(three&of&
them&generalists)&and&three&migratory&species&were&detected&at&rates&below&15%.&In&
the&Swedish&study,&the&total&species&were&evenly&split&91to19&between&migratory&and&
residential&species&but&didn't&distinguish&a&third&category&for&generalists.&However:&
of&the&18&species&detected,&only&8&species&were&found&in&numbers&of&50&or&more.&&
& There& is& a& contradiction& in& the& findings& of& the& studies& that& prohibits& a&
response& in& favor& of& either& bird1type.& In& the& first,&more& generalists&were& found& in&
greater&percentages&but&enough&residents&were& found&to&complicate&a& trend& in& the&
generalists&favor.&&In&the&second,&the&number&of&species&of&each&bird1type&was&equal&
but& generalists& weren't& considered.& However,& in& the& Swedish& study& only& seven&
0&50&100&150&200&250&300&350&400&
Total#Num
ber#of#Select#Birds#
#
#Total#pairs#of#select#birds#found#on#54#Swedish#forests#harvested#at#retention#rates#between#1%(25%#eight#years#
after#harvest#
Steven&Kelley/BIO&1701Black/RoL&Project/Mar15,&2013& 8&
species& were& found& in& significant& quantities& while& the& majority& was& found& in&
extremely&low&numbers.&Any&suggestion&could&be&drawn&from&the&findings&without&
knowing&more&about&the&nature&of&the&individual&species.&For&example:&were&those&
birds&found&in&low&numbers&reduced&by&logging&or&a&rare&species&to&begin&with?&The&
conclusion&from&this&author&thus&is&that&the&data&is&inconclusive&and&further&studies&
are&needed&to&resolve&the&issue.&
#
Do#microfauna#fare#better#on#standing#trees#or#soil#following#GTR?#
& GTR1felled&forests&present&a&dilemma&for&insects&and&spiders&that&previously&
existed&on&a&fully1developed&forest:&do&they&succeed&better&on&the&trees&that&remain&
or&in&the&cleared&soil&left&behind?&From&199611998&scientists&collected&soil&samples&
from& sites& in& Norway& to& determine& populations& of& insects& (Siira1Pietikainen& and&
Haimi.2009)& from& tree1retention& sites.& In& Oregon& as& part& of& the& DEMO& studies,&
scientists&surveyed&arthropods&collected&in&traps&to&determine&success&rates&on&sites&
of&varying&tree1retention&(Halag,&Halpern,&et&al.&2009).&
Steven&Kelley/BIO&1701Black/RoL&Project/Mar15,&2013& 9&
&&Graph&4:&Data&collected&from&Pietkainene&and&Haimi.&2009&&&&
Arthropod)taxa) 100%)40%)Agg)
40%)Disp)
15%)Agg)
15%)Disp) Greatest)Category)
) ) ) ) ) ) )Collembola) 14351) 14609) 19826) 15730) 17173) 40%)Disp.)Coleoptera) 637) 886) 1232) 1335) 1976) 15%)Disp)Hemiptera) 1123) 880) 1276) 728) 1228) 40%)Disp.)Diptera) 235) 373) 458) 558) 1169) 15%)Disp)
Hymenoptera) 100) 181) 266) 262) 531) 15%)Disp)Diplopoda) 178) 60) 122) 214) 874) 15%)Disp)Formicidae) 230) 339) 669) 231) 2110) 15%)Disp)Orthoptera) 75) 196) 226) 293) 682) 15%Disp)Lepidoptera) 5) 9) 31) 33) 154) 15%)Disp)Psocoptera) 66) 9) 280) 67) 64) 40%)Disp)
Microcoryphia) 89) 85) 22) 120) 33) 15%)Agg)Homoptera) 104) 59) 104) 55) 53) 100%/40%)Disp)
Non2arachnids) 15) 16) 5) 5) 11) 40%)Agg)Neuroptera) 7) 10) 9) 17) 10) 15%)Agg)
&Table&2:&Data&collected&from&Halaj,&Halpern,&et&al.&2009&
0&10000&20000&30000&40000&50000&60000&70000&
Enchytraeids&10%
&&50%&w/out&site&prep&
50%&with&site&prep&
"0%"&
"70%
"&"100%"&
Collembolans&10%
&50%&w/out&site&prep&
50%&with&site&prep&
"0%"&
"70%
"&"100%"&
Herbivores&10%
&50%&w/out&site&prep&
50%&with&site&prep&
"0%"&
"70%
"&"100%"&
Microbivores&10%
&50%&w/out&site&prep&
50%&with&site&prep&
"0%"&
"70%
"&"100%"&
Predators&10%
&50%&w/out&site&prep&
50%&with&site&prep&
"0%"&
"70%
"&"100%"&
Num
ber#of#species#found#
#
Species#type#found#in#10%,#50%#without#and#50%#with#site#preparation,#0%,#70%,#and#100%#tree(retention#
#
Species#of#soil#fauna#found#in#various#tree(retention#rates#in#Finnish#sites#10#years#after#harvest#2005#
Steven&Kelley/BIO&1701Black/RoL&Project/Mar15,&2013& 10&
& In& the& first& study& enchytraeids& (potworms)& and& collembolas& (springtails)&
were&significantly&more&successful& than&other&genre&succeeding&on&sites&even&with&
0%& retention.&Of& herbivores& andµbivores,& populations&were& found& in& greater&
numbers&as&retention&increased.&Predators&were&found&in&significantly&low&numbers&
regardless& of& the& amount& of& retention.& In& the& second& study& significantly& more&
arthropods&(including&beetles&and&spiders)&were&found&on&15%1dispersed&sites.&The&
greatest& number& of& any& species& was& the& collembolas& and& the& fewest& were& the&
neuropteras&&(lacewings&and&kin).&
& Regardless& of& the& amount& of& tree1retention,& collembolas& maintain& their&
populations& successfully&with& herbivores& and& predators&more& sensitive& to& change.&
Pietikainen& suggests& that& the& two& most& populous& orders& succeeded& due& to& their&
nature& of& living& close& to& the& surface& naturally& (Pietikainen& and& Haimi.& 2009);& the&
"thick& humus& layer& can& offer& a& refugium& for& decomposers& and& protect& them& from&
harvesting& induced& environmental& changes"& (ibid,& p.& 336).& It's& also& possible& that&
even&with&logging&these&ratios&are&traditional&to&predators,&prey,&and&decomposers;&
the& numbers&more& pronounced& due& to& harvesting.& Thus& neither& trees& nor& soil& are&
necessarily&better&predictors&of&success&forµfauna&in>R&lands&but&rather&the&
ability&to&live&in&both&environments.&
&
Do#transplanted#lichen#survive#better#on#GTR#lands#than#those#colonizers?#&# In&1999&scientists&transplanted&lichen&Lobaria&pulmonaria&onto&trees&in>R&
sites& in& Swedish& forests& (Hazell& and& Gustafsson.& 1999)& to& compare& their& vitality&
among& stands& with& varying& retention& rates.& In& Estonia,& a& similar& census& was&
Steven&Kelley/BIO&1701Black/RoL&Project/Mar15,&2013& 11&
conducted& on& lichen& colonizing& stumps& and& snags& to& determine& their& success&
(Rosenvald&and&Lohmus.&2013)&within&various&tree&species.& &A&comparison&of&their&
findings&can&determine&if&human1induced&colonization&would&be&successful.&
&Graph&5:&Data&collected&from&Hazell&and&Gustafsson.&1999&&
&Graph&6:&Data&collected&from&Rosenvald&and&Lohmus.&2013&& &
0%&10%&20%&30%&40%&50%&60%&70%&80%&
100%&tree&loss& X>50%&tree&loss& 10150%&tree&loss&
x<10%&tree&loss&
Survival#rates#of##Lobaria#pulmonaria#
Categories#of#forests#harvested#at#various#tree(retention#rates##
Survival#rates#of#transplanted#lichen#to#Swedish#forests#harvested#at#various#rates#of#tree(retention#
#
Aggregate&Retention&
Dispersed&Retention&
0&5&10&15&20&25&30&
Birch&Trunks&415&
Birch&Trunks&617&
Birch&Trunks&819&
Birch&Snags&113&
Birch&Snags&415&
Birch&Snags&617&
Birch&Snags&819&
Aspen&Trunks&
Aspen&Trunks&
Aspen&Trunks&
Aspen&Trunks&
Aspen&Snags&113&
Aspen&Snags&415&
Aspen&Snags&617&
Aspen&Snags&819&
Pine&Trunks&113&
Pine&Trunks&415&
Pine&Trunks&617&
Pine&Trunks&819&
Pine&Snags&113&
Pine&Snags&415&
Pine&Snags&617&
Pine&Snags&819&
Num
ber#of#different#lichen#species#
found#
#
Trees#surveyed#at#sites#with#varying#retention#rates#of#trunks#and#snags##
Populations#of#lichen#found#on#dead#wood#at#tree(retention#sites#in#Estonia##
Surveyed&in&2010&
Surveyed&in&2011&
Steven&Kelley/BIO&1701Black/RoL&Project/Mar15,&2013& 12&
& The&first&graphs&shows&that&the&transplanted&lichen&did¬&fare&well&at&all&on&
lands& cut& lower& than& 50%.& In& the& first& three& categories& neither& dispersed& nor&
aggregate& sites& proved& successful& for&more& than& 22%&of& the& transplanted& species.&
Only&on&lands&cut&with&less&than&10%&loss&did&the&pulmonaria&thrive&with&more&than&
75%&on&aggregate&sites.&For&the&natural&colonists&at&the&Estonia&sites,&only&eight&of&
the&22&sites&yielded&more&than&10&species&of&lichen.&Aspen&trunks&provided&the&best&
homes.&Ten&of&the&18&sites&had&less&than&five&species&and&all&of&them&were&surveyed&
on& snags& but& that& could& be& due& less& to& suitability& than& the& geometry& of& snags&
compared&to&trunks.&
& The&data&would&suggest&that&natural&colonies&thrive&better&than&transplanted.&
However&the&surveys&are&too&different&in&nature&to&reach&credible&conclusions.&The&
author& of& the& L.& pulmonaria& survey& admitted& that& it& was& likely& that& the& lichen's&
failure&to&survive&was&due&more&to&the&transplanting&process&than&from&the&site&itself&
(Hazell& and& Gustafsson.& 1999).& Also& handicapping& the& comparison& is& that&
transplanting&was&only&tried&for&a&single&species;&a&wider&sample&variety&could&have&
yielded&different&results.&Also:&the&second&study&surveyed&different&tree&species&and&
different& types&of&deadwood.&The&only&conclusion& that&can&reasonably&be&drawn& is&
that&there&is&a&lack&of&significant&data&and&that&further&studies&are&needed.&
& &
Steven&Kelley/BIO&1701Black/RoL&Project/Mar15,&2013& 13&
Conclusions#
& Is&Green1tree&retention&an&effective&alternative&to&traditional&clear1cut&logging&
in& promoting& biodiversity& regeneration?& The& answer& appears& conditional& to& the&
species&being&examined.&Small&mammals&seem&to&vary&in&their&vitality&on>R&sites&
among& species&but& clearly& the&more& trees& retained& the&greater& their& viability.&Bird&
viability&on>R&lands&appears&balanced&between&residential&and&migratory&species&
but&fared&well&in&Michigan&and&poorly&in&Sweden.&Microfauna&exhibited&the&greatest&
disparities& in& vitality& rates& with& some& thriving& extremely& well& while& others& fared&
dismally.& & A& further& understanding& of& insect& and& spider& dynamics& is& needed& to&
explain& such& results.& & Lichen& fared& better& on& trunks& than& snags& and& on& sites&with&
greater&retention;&which&should&be&obvious&as&the&more&wood&exists&on&a&stand&the&
greater&surface&area&the&lichen&have&to&colonize&on.&
& There&are&many&handicaps& to& the& responses&given& in& this& review.&The&most&
influential& handicap& is& the& limited& scope& that& GTR& has& been& attempted& on.& Only& a&
handful&of&states&and&European&countries&have&implemented>R&methods&limiting&
the&scope&of&ecosystems&that&can&be&examined&for&its&effectiveness.&The&second&is&the&
dearth& of& studies& that& have& been& conducted& on& its& effectiveness& and& the& nature& of&
those& surveys.&Most& of& the& authors& of& the& studies& admitted& that& their& conclusions&
were& to&be& taken& in&context&with& the& lack&of&data&needed& for&more&comprehensive&
responses.&Also:&in&only&one&study&was&the&population&of&the&targeted&species&prior&
to& cutting& considered& (Gitzen,& Maquire,& et& al& 2007).& Another& handicap& is& that&
unstudied&species'&effect&on&those&studied&was¬&taken&into&consideration.&Effects&
of>R&on&predatory&species&and&their&subsequent&influence&on&the&species&studied&
Steven&Kelley/BIO&1701Black/RoL&Project/Mar15,&2013& 14&
would&provide&a&richer&determinant&of>R's&potential.&Finally&there&is&this&review's&
limited& focus&only&on&numbers&of& found&species&being&considered&as& the&arbiter&of&
GTR& success.& Further& knowledge& of& species& dynamics& would& allow& this& author& to&
form&more&credible&conclusions.&
& Also&to&be&considered&are&the&potential&benefits&that&traditional&clear1cutting&
can& have& on& an& ecosystem.& As& previously& noted,& clear1cutting& and& its& subsequent&
incineration&of&litter&reintroduce&fire&into&systems&for&which&suppression&permitted&
over1growth& to& detrimentally& influence& regeneration& (Otto& and&Roloff.& 2012).& Also&
studies&on&Canadian&clear1cut&lands&have&found&successes&for&many&species&like&the&
snowshoe&hare&(Forsey&and&Baggs.&2012)&possibly&due&to&its&effect&on&its&predators.&
There&is&also&the&potential&for&removing&invasive&plant&species&expediently&through&
clear1cuts&(this&author's&opinion;&no&citation&necessary).&If&the&logging&industry&can&
be&convinced&to&manage&clear1cut&sites&in&a&sustainable&fashion,&then&clear1cuts&can&
remain&a&suitable&technique&for&utilizing&and&managing&forests.&
& &
Steven&Kelley/BIO&1701Black/RoL&Project/Mar15,&2013& 15&
References:&&Halpern&CB,&Evans&SA,&Nelson&CR,&McKenzie&D,&Liguori&DA,&Hibbs&DE,&Haleg&MJ.&1999.&Response& of& Forest& Vegetation& to& Varying& Levels& and& Patterns& of& Green1tree&Retention:&An&Overview&of&a&Long1term&Experiment.&NW&Science.&73(Special&Issue):&27144.&&Holloway& GL,& Smith& WP,& Halpern& CB,& Gitzen& RA,& Macguire& CC,& West& SD& 2012.&Influence& of& forest& structure& and& experimental& green1tree& retention& on& northern&flying1squirrel.&Forest&Ecology&and&Management.&285&(1):&1871194.&&Silra1Pietikainen& A,& Haimi& J.& 2009.& Changes& in& soil& fauna& 10& years& after& forest&harvestings:& Comparison& between& clear& felling& and& green1tree& retention&methods.&Forest&Ecology&and&Management.&258&(3):&3321338.&&Halaj& J,& Halpern& CB.& 2009.& Effects& of& green1tree& retention& on& abundance& and& guild&composition& of& corticolous& arthropods.& Forest& Ecology& and&Management.& 258& (5):&8501859.&&Gitzen&RA,&West&SD,&Maguire&CC,&Manning&T,&Halpern&C.&2007.&Response&of&terrestrial&small&mammals& to&varying&amounts&and&patterns&of&green1tree&retention& in&Pacific&Northwest&forests.&Forest&Ecology&and&Management.&251&(3):&1421156.&&Forsey& ES,& Baggs& EM.& 2001.& Winter& activity& of& mammals& in& riparian& zones& and&adjacent&forests&prior&to&and&following&clear1cutting&at&Copper&Lake,&Newfoundland,&Canada.&Forest&Ecology&and&Management.&145&(3):&1631171.&&Otto&CR,&Roloff&GJ.&2012&Songbird&response&to&green1tree&retention&prescriptions&in&clear1cut&forests.&Forest&Ecology&and&Management.&284&(15):&2411250.&&Soderstrom&B.&2009.&Effects&of&different& levels&of&green&and&dead1tree&retention&on&hemi1boreal& forest&bird& communities& in&Sweden.&Forest&Ecology&and&Management.&257(1):&2151222.&&Rosenvald&R,& Lohmus&A.&2008.&For&what,&when,& and&where& is& green1tree& retention&better& than&clear1cutting?&A&review&of& the&biodiversity&aspects.&Forest&Ecology&and&Management.&255&(2008):&1115.&&Hazell& P,& Gustafsson& L.& 1999.& Retention& of& trees& at& final& harvest1evaluation& of& a&conservation&technique&using&epiphytic&bryophyte&and&lichen&transplants.&Biological&Conservation&90&(2):&1331142.&&Runnel&K,&Rosenvald&R,&Lohmus&A.&2013.&The&dying& legacy&of&green1tree&retention:&different& habitat& values& for& polypores& and& wood1inhabiting& lichens.& Biological&Conservation.&159:&1871196.&&&
