From useless thickets to valuable resource? – Financial performance of downy birch management on drained peatlands

1 SILVA FENNICA Sil a Fennica ol. 51 no. 3 a icle id 2017 Ca ego y: esea ch a icle h ps://doi.o g/10.14214/s .2017 h p://www.sil a ennica. i Licenced CC BY-SA 4.0 ISSN-L 0037-5330 | ISSN 2242-4075 (Online) The Finnish Socie y o Fo es Science Pen i Niemis ö1, Soili Kojola 2, Anssi Ah ikoski 3 and Raija Laiho 2 F om useless hicke s o aluable esou ce? – Financial pe o mance o downy bi ch managemen on d ained pea lands Niemis ö P., Kojola S., Ah ikoski A., Laiho R. (2017). F om useless hicke s o aluable esou ce? – Financial pe o mance o downy bi ch managemen on d ained pea lands. Sil a Fennica ol. 51 no. 3 a icle id 2017. 28 p. h ps://doi.o g/10.14214/s .2017 Highligh s • The mos p o i able managemen egimes o pulpwood and ene gy wood p oduc ion in dense downy bi ch s ands on d ained pea lands include no hinnings, bu inal cu ing a he s and age o 40–45 yea s as whole- ee ha es ing, o as in eg a ed ha es ing o pulpwood and delimbed ene gy wood s ems abou 10 yea s la e depending on applicable ha es ing me hod. • A compe i i e managemen egime is ea ly p ecomme cial hinning a 4 m dominan heigh o a densi y o 2500 s ems pe hec a e and p oduc ion o pulpwood wi h a o a ion o 55–65 yea s. Equal p o i abili y is achie ed wi h o wi hou adi ional i s hinning, which can hus be included o o he easons, o example o imp o e egene a ion o sp uce. Abs ac Downy bi ch (Be ula pubescens Eh h.) s ands on d ained pea lands a e o en conside ed useless because hey ypically do no yield good-quali y sawn imbe . Howe e , co e ing an a ea o ca. 0.5 million hec a es and wi h o al yields o up o 250 m3 ha–1, downy bi ch s ands on pea lands in Finland ha e a po en ial o pulpwood and/o ene gy wood p oduc ion. We examined he inancial pe o mance o al e na i e managemen egimes (wi h o wi hou hinnings, di e en hinning in ensi ies, se e al o a ion leng hs) combined wi h al e na i e ha es ing me hods (pulpwood, ene gy wood, o in eg a ed, ene gy wood being delimbed s ems o whole ees). We used da a om 19 expe imen al s ands, moni o ed o 20–30 yea s. Fo ha es ing emo als we conside ed bo h ac ual hinning emo als and inal-cu ing emo als wi h al e na i e imings ha we e based on he moni o ing da a. We assessed he p o i abili y as a combina ion o he ne p esen alue o he bi ch gene a ion and he ba e land alue o u u e gene a ions o No way sp uce (Picea abies (L.) Ka s .). The mos p o i able managemen was g owing wi hou hinnings un il whole- ee inal cu ing a he s and age o 40–45 yea s wi h an ad anced mul i- ee ha es ing me hod. In con as , he s anda d me hod in whole- ee inal cu ing esul ed in he lowes p o i abili y, and an in eg a ed me hod wi h he ene gy wood as delimbed s ems was he bes o he s anda d me hods. Thinnings we e unp o i able especially when aiming o p oduce ene gy wood, whe eas aiming o pulpwood, ligh p ecomme cial hinning was compe i i e. Comme cial hinning a he adi ional “pulpwood s age” had li le e ec on p o i abili y. The bes s and age o inal cu ing was 40–65 yea s – ea lie o e y dense s ands and whole- ee ene gy wood ha es ing wi h ad anced me hod, la e o p ecomme cially hinned s ands and pulpwood ha es ing. Keywo ds Be ula pubescens; ene gy wood; inal cu ing; o es managemen ; p o i abili y; pulp- wood; hinning 2 Sil a Fennica ol. 51 no. 3 a icle id 2017 · Niemis ö e al. · F om useless hicke s o aluable esou ce?… Add esses 1 Na u al Resou ces Ins i u e Finland (Luke), Managemen and P oduc ion o Renew- able Resou ces, Kampus an a 9 C, 60320 Seinäjoki, Finland; 2 Na u al Resou ces Ins i u e Fin- land (Luke), Managemen and P oduc ion o Renewable Resou ces, La oka anonkaa i 9, 00790 Helsinki, Finland; 3 Na u al Resou ces Ins i u e Finland (Luke), Managemen and P oduc ion o Renewable Resou ces, Paa o Ha aksen ie 3, 90014 Uni e si y o Oulu, Finland E-mail [email p o ec ed] Recei ed 13 Janua y 2017 Re ised 29 May 2017 Accep ed 30 May 2017 1 In oduc ion Downy bi ch (Be ula pubescens Eh h.) is one o he mos common ee species in No he n Eu ope. In Finland, i ep esen s abou 12% o he o al olume o he g owing s ock (Niemis ö and Ko honen 2008). Downy bi ch ole a es mois condi ions and hus g ows well on we soils, and as a pionee ee species e y easily o ms dense s ands on, e.g., d ained pea lands (Kel ikangas and Seppälä 1977; Sa amäki 1977; Moilanen 1985). In Finland, whe e d ainage o pea lands o imp o e o es g ow h has ema kably inc eased he a ea (ca. 5 million hec a es; Me in o 2014) and he annual ha es ing po en ial (9–12 million m3 ha–1 a–1; Nuu inen e al. 2007) o pea land o es s, downy bi ch s ands ha e a no able ole in o es y, especially egionally. Based on he Finnish Na ional Fo es In en o y da a (NFI11, measu ed in 2009–2013), he o al a ea o bi ch-domina ed s ands (p opo ion o bi ch a leas 50% o s and olume) on d ained pea lands ep esen ing “ o es land” was 572 000 ha. These s ands we e mos common in he no he n pa s o Finland, especially in No he n Os obo hnia and sou h-wes e n Lapland (Niemis ö and Ko honen 2008; Kojola e al. 2015). The e we e u he 29 000 ha o bi ch-domina ed s ands on “poo ly p oduc i e o es land”. The downy bi ch s ands g owing on d ained pea lands a e o en conside ed useless hick- e s, wi hou any easonable o es managemen pu pose. Ye , hei wood-p oduc ion po en ial is o en good. When g owing on well-p oduc i e si e ypes, he o al yield o downy bi ch s ands may each 250 m3 ha–1 (Niemis ö 2013). In he NFI11, he o al olume o he g owing s ock on bi ch-domina ed d ained pea lands was es ima ed o be close o 60 million cubic me e s. Based on Niemis ö and Ko honen (2008), app oxima ely h ee qua e s o ha can be expec ed o be bi ch wood. E en i he sawn- imbe yield may be low in bi ch-domina ed pea land o es s (Koi is o 1959; F ies 1964; B aas ad 1967; Ve kasalo 1997; Hynynen e al. 2010), he yield o pulpwood and especially biomass o ene gy can be no able. P o i able managemen o hese s ands calls o app op ia e ha es ing p ocedu es (Fe nandez-Lac uz e al. 2013; Jylhä and Be gs öm 2016), o which up- o-da e guidelines a e cu en ly lacking. Such guidelines a e u gen ly needed, since he o al a ea o young downy bi ch s ands may be expec ed o inc ease in he nea u u e. This is because p esen ly o in he nea u u e la ge a eas o pea land s ands a e in he inal-cu ing s age due o he ac i e pe iod o d ainage du ing 1960s and 1970s. In cases o ailed o o ally neglec ed o es egene a ion, insu icien ea lie ca e o sapling s ands, o os damages in sp uce saplings, downy bi ch as a pionee ee species (Hynynen e al. 2010) is likely o ake dominance o he si es. Fo ins ance, as much as 29% o he plan ed pea land sp uce s ands (age unde 20 yea s) in he Os obo hnia, Kainuu, and Lapland egions ha e su e ed om os damages (NFI11, unpublished). Un il ecen ly, he managemen o d ained pea land o es s has gene ally aimed a p oduc ion o pulpwood and sawlogs. Howe e , he cu en iew is ha some s ands may be mo e sui able o ene gy wood p oduc ion (Kojola e al. 2015). Because o he ela i ely small size and low quali y o he s ems o sawlogs o enee logs, downy bi ch s ands may be in mo e e ec i e use when managed pa ly o o ally o ene gy wood. The apidly inc eased consump ion o o es chips has inc eased he demand o wood biomass sui able o ene gy in gene al. In 2015, 7.3 million solid 3 Sil a Fennica ol. 51 no. 3 a icle id 2017 · Niemis ö e al. · F om useless hicke s o aluable esou ce?… cubic me e s o o es chips we e used in hea ing and powe plan s in Finland (Na u al Resou ces Ins i u e Finland 2016), a majo pa o he aw ma e ial o he o es chips, 3.9 million cubic me e s, being small-sized ees. Bi ch-domina ed pea land s ands would appea o make a sui able biomass ese e o his pu pose. The densi y o young s ands domina ed by downy bi ch is o en e y high, ens o hou- sands o s ems pe hec a e (Fe m and Kauppi 1990; Fe m 1993). Managemen guidelines (Hy än me sänhoidon… 2007) o pulpwood p oduc ion ha e ecommended ending young s ands o 2000–2500 s ems pe hec a e, and applying he i s comme cial hinning when s and dominan heigh has eached 13–15 me e s. A e hinning he basal a ea should be 12–13 squa e me e s o densi y 1100 s ems pe hec a e. Howe e , downy bi ch has p o ed o espond only weakly o hinning (Niemis ö 2013). Many low-diame e s ems a e also was ed in such managemen , and hus he g owing capaci y o he si e is no ully used. The e o e, s udies conce ning al e na i e ways o manage downy bi ch s ands a e needed. When compa ing di e en ha es ing me hods, he esul ing p o i abili y alues a e bound o a y wi h he me hod and machine y used in ha es ing. The common o es y p ac ice is o ha es he ene gy wood, small s ems wi h o wi hou b anches and ops, simul aneously wi h he pulpwood. This in eg a ed ha es ing gene ally educes p ocu emen cos s o small-diame e wood (Rummukainen e al. 2003; Kä hä 2011; Pe y and Kä hä 2014), and o ins ance Heikkilä e al. (2009) ound he o al s and managemen o be mo e p o i able wi h in eg a ed i s hinning han wi h whole- ee i s hinning in young pine o sp uce s ands. Whole- ee ha es ing, whe e all ees including b anches and ops a e conside ed ene gy wood, may dec ease he cos s o cu ing (no delimbing) bu , on he o he hand, inc ease he cos o o wa ding due o he dec easing load size (Lai ila e al. 2010; Lai ila and Vää äinen 2012). P elimina y s udies conce ning downy bi ch s ands on d ained pea lands ha e also shown ha whole- ee ene gy wood ha es ing, especially, may ha e poo p o i abili y (Kojola e al. 2015). In spi e o he mul i- ee me hod used, cu ing o small s ems is gene ally ime-consuming (Lai ila e al. 2016; Kä hä 2011; Pe y and Kä hä 2014). The aim o his s udy was o ind ou wha kind o managemen egimes, ha is, hinning in ensi ies and o a ion leng hs, combined wi h di e en ha es ing me hods, would be he mos p oduc i e o bi ch pulpwood and biomass, and he mos p o i able o be pu in o p ac ice. The ocus in ou examina ion was in he ime poin s, when managemen decisions o he es o he o a ion a e made. The key ques ion examined was whe he he managemen should be ocused on ene gy wood p oduc ion a he han on adi ional pulpwood p oduc ion. This s udy is a sequel o he epo s o Niemis ö (1991, 2013) analyzing he s and dynamics and managemen o pea land bi ch s ands. 2 Ma e ials and me hods 2.1 Expe imen al s ands and hei measu emen s We u ilized a se o 19 expe imen al downy bi ch s ands ea ed wi h di e en hinnings ha com- p ised a hinning expe imen implemen ed by he Finnish Fo es Resea ch Ins i u e (Me la; cu - en ly me ged in o he Na u al Resou ces Ins i u e Finland, Luke) in 1975–1990. The s ands we e loca ed in Os obo hnia and wes e n Lapland (Table 1). A de ailed desc ip ion o he expe imen al design and measu emen s has been p esen ed by Niemis ö (2013). The d ained pea land o es si e ypes we e MT2 (Vaccinium my illus ype II) o H T (He b- ich ype), M kg II and Rh kg in he Finnish nomencla u e (Laine e al. 2012; b ie ly in English in Wes man and Laiho 2003), which ep esen ela i ely high le els o wood-p oduc ion po en ial. The s ands we e pu e downy 4 Sil a Fennica ol. 51 no. 3 a icle id 2017 · Niemis ö e al. · F om useless hicke s o aluable esou ce?… Table 1. Mean cha ac e is ics o he expe imen al s ands a he onse o he expe imen and he leng h o he s udy pe iods. S and g oups: Sapling s and s age (SS; H0 < 8 m), ene gy wood hinning s age (EW; 8 m < H0 < 11 m), and pulpwood hinning s age (PW; H0 > 12 m). Exp #: Code o he s ands in Luke’s da a a chi e. 1) 2) 2) 3) 4) 5) 6) 7) 8) S and code Loca ion Temp. sum, dd No h coo dina e Eas coo dina e Si e ype H50, m Hdom, m H0, m D0, ha–1 S ems, ha–1 Volume, m3 ha–1 Age, y S udy pe iod, y Numbe o measu e- men s Repli- ca es Numbe o plo s Exp # SS1 Oulu 1125 7216691 426800 MT2 17.2 3.9 3.0 1.6 30500 11 10–30 20 5 2–3 8 8550 SS2 Yli o nio 945 7360051 384943 MT2 14.3 6.0 5.0 5.1 20600 57 20–47 27 6 2 6 981 SS3 Kola i 829 7453094 358504 MT2 13.7 7.0 5.3 4.2 39200 66 22–50 28 c) 6+1 3 12 185 SS4 Kola i 829 7450500 358400 MT2 14.2 7.2 5.5 4.6 43000 78 23–45 22 5+1 3 12 286 SS5 Kola i 829 7451825 358394 MT2 14.2 7.7 5.7 4.7 34300 80 20–49 29 7 4 19 383 SS6 Ro aniemi 905 7355142 490371 MT2 14.1 6.7 5.9 5.9 a) 6700 45 22–53 31 7 3 14 881 SS7 Yli o nio 945 7360052 385064 MT2 13.2 8.3 6.4 5.6 29800 90 27–51 24 6 4 20 188 SS8 Ro aniemi 865 7353534 487942 MT2 15.4 8.4 6.9 7.3 10000 79 23–40 17 4 2 16 189 SS9 Kola i 793 7483287 372735 H T 13.4 9.4 7.6 7.8 18100 112 29–54 25 6 2–3 9 183 EW10 Kola i 793 7483288 372737 H T 13.9 10.4 8.1 7.7 17200 127 30–57 27 6 1–2 6 481 EW11 Oulu 1125 7216329 426907 H T 16.8 10.7 8.8 6.8 7100 73 25–55 30 7 2 10 855 EW12 Liminka 1136 7192518 424218 MT2 14.7 11.2 8.9 8.6 4600 66 31–60 29 7 3 15 856 EW13 K uunupyy 1161 7063962 309881 MT2 17.7 10.1 9.0 9.0 a) 2500 54 20–52 32 6+1 2 8 6 EW14 Pyhäjä i 1060 7069128 434011 H T 16.6 11.3 9.2 10.1 3800 85 34–65 31 7 2–3 9 854 EW15 Muu ola 954 7359401 418050 H T 13.1 12.0 9.8 8.3 6000 113 41–61 15 5 1 5 882 EW16 Käl iä 1099 7076704 346710 MT2 19.5 12.1 10.8 10.7 4700 123 19–40 21 3+1 4–7 28 86 PW17 Haapa esi 1089 7107747 411534 H T 15.7 13.9 12.1 12.5 b) 2100 107 44–74 30 7 5–10 30 852 PW18 Kä sämäki 1091 7101751 447121 H T 15.1 14.8 12.4 12.7 b) 1800 96 52–83 31 7 2–4 10 853 PW19 U ajä i 1082 7185571 463722 MT2 15.2 16.5 13.8 12.7 4700 208 52–67 15 4 2 8 885 1) Cumula i e annual empe a u e sum wi h +5 °C h eshold alue, calcula ions based on he pe iod 1980–2010 2) ETRS-TM35FIN 3) D ained pea land o es si e ypes: MT2 (Vaccinium my illus ype II) and H T (He b- ich ype) (M kg II and Rh kg in Finnish nomencla u e. see Laine e al. 2012) 4) Si e index (dominan heigh a he age o 50 yea s) 5) Dominan heigh = mean heigh o 100 la ges bi ch ha–1 6) Mean heigh , weigh ed by basal a ea 7) Mean DBH, weigh ed by basal a ea 8) S and age a he onse o he expe imen and a he end o he s udy pe iod a) S em numbe was low compa ed o o he s ands in he g oup b) Tending a sapling s and s age c) +1 means ha one o he esul s has been in e pola ed due o he ex ao dina y long ime be ween measu emen s (2 × 5 y s). 5 Sil a Fennica ol. 51 no. 3 a icle id 2017 · Niemis ö e al. · F om useless hicke s o aluable esou ce?… bi ch s ands and ep esen ed he i s ee gene a ion a e he ini ial d ainage o he pea lands. The s and ages a ied om 10 o 52 yea s and om 30 o 83 yea s a he onse and a he end o he expe imen , espec i ely. Mos o he s ands we e measu ed 5–7 imes in 5-yea in e als. Based on he measu e- men s, we knew he ac ual s and de elopmen du ing he 15–30 s udy yea s o each o he 245 plo s wi hin he 19 expe imen al s ands (Table 1). Fo each single s and-measu emen e en he esul ing da a was used o es ima e he olumes o pulpwood and small diame e s em wood in solid cubic me e s ha–1 (Heinonen 1994) and he b anch biomass in Mg ha–1 (Repola 2008), all sepa a ely o : he o al ee s and, he na u al emo al, he ha es ing emo al, and he emaining s and. T ans o ma ion o b anch biomass om Mg o solid cubic me e s was made by he coe - icien 2.0 acco ding o b anch densi y epo ed by Bjö klund and Fe m (1982). We g ouped he da a based on he ini ial s age o he s ands and, consequen ly, he i s ea - men applied a he onse o he expe imen : sapling s and s age (SS s ands; mean heigh 3–8 m; 9 expe imen al s ands; p ecomme cial hinning), ene gy wood hinning s age (EW s ands; 8–11 m; 7 expe imen al s ands; ene gy wood hinning), o pulpwood hinning s age (PW s ands; 12–14 m; 3 expe imen al s ands; pulpwood hinning). Following a andomized block design, each s and included 5–30 ec angula plo s eaching om di ch o di ch, he a ea a ying be ween 800 and 1400 squa e me e s. The in ensi y o he i s ea men s on he plo s a ied, including: un hinned con ol plo s; e y ligh ; ligh ; mode a e; and hea y hinning (Niemis ö 2013). On an a e age, 40% o he basal a ea was emo ed in he hea y hinning o he PW, and 70–80% in he EW and SS s ands. A second hinning was applied on 20% o he p e iously hinned plo s (hence o h: wice- hinned s ands). A ligh p ecomme cial hinning o he densi y o 1900–2500 s ems pe hec a e had been ca ied ou be o e he ini ia ion o he expe imen in he PW s ands (see Fig. 1 in Niemis ö 2013). 2.2 De iningal e na i emanagemen  egimesand hei  emo als o downybi ch We de ined al e na i e managemen egimes as combina ions o he i s ac ual hinning ea - men s and ‘ i ual’ inal cu ings ha we e compu ed om he ee-le el moni o ing da a o each measu emen ime (i.e., he di e en measu emen imes yielded he al e na i e imings o he inal cu ings). Six di e en ha es ing me hods we e conside ed (A–F; Table 2), o which F was Table 2. The al e na i e ha es ing me hods and he s uc u e o he esul ing emo als (me chan able wood). Ha es ing me hod Remo al Pulpwood componen Ene gy wood componen A. Pulpwood ha es ing Pulpwood Pulpwood pa o he s em 1) – B. In eg a ed ha es ing Pulpwood + ene gy wood as delimbed s ems Pulpwood pa o he s em 1) Top was e 2) + small s ems 3) − ops 4) C. In eg a ed ha es ing Pulpwood + ene gy wood as whole- ee Pulpwood pa o he s em 1) Top was e 2) + small s ems 3) + b anches − b anch was e 5) D. Ene gy wood ha es ing Ene gy wood as delimbed s ems – La ge s ems + op was e 2) + small s ems 3) − ops 4) E. Ene gy wood ha es ing Ene gy wood as whole- ee – La ge s ems + small s ems 3) + b anches − b anch was e 5) F. Ad anced ene gy wood ha es ing 6) Ene gy wood as whole- ee – La ge s ems + small s ems 3) + b anches − b anch was e 5) 1) minimum op diame e o he pulpwood poles was 6.5 cm. 2) op was e = he pa o he s em which is no pulpwood size. 3) small s ems = s ems smalle han pulpwood s ems, diame e a b eas heigh (d1.3) o e 3.5 cm. 4) ops = he hinnes pa o he s ems cu away (diame e smalle han ~2 cm). 5) b anch was e = b anches ha we e d opped a he cu ing a ea (see ex o es ima ion). 6) o SS and EW s ands. Simila o me hod E, bu ha es ed by an accumula ing elling head ha is designed o be mo e e icien han egula mul i- ee elling heads in dense s ands wi h small s ems (Jylhä and Be gs öm 2016) 6 Sil a Fennica ol. 51 no. 3 a icle id 2017 · Niemis ö e al. · F om useless hicke s o aluable esou ce?… applicable only in he SS and EW s ands. As ha es ing emo als, hese included only pulpwood (A); only ene gy wood, ha es ed as ei he whole ees including b anches o delimbed s ems (D–F); o pulpwood plus ene gy wood, ha es ed as whole ees o delimbed s ems ob ained wi h in eg a ed ha es ing (B–C). In he in eg a ed ha es ing, he b anches om he pulpwood pa o he s em a e cu and d opped a he ha es ed a ea. We calcula ed he olume o his b anch was e using a sepa a e model (Lai ila e al. 2014), and excluded i om he emo als. In p ac ice, some b anches a e s ill shed in whole- ee ha es ing (Hy önen and Moilanen 2014), and we assumed he amoun shed o be hal o he b anch was e es ima ed o in eg a ed ha es ing. We also p oduced compu a ional hinning emo als o SS s ands o acili a e compa isons among he i s ea men s, bu igno ed hem when calcula ing he o al emo als and p o i abili y. Di ch ne wo k main enance was no conside ed necessa y be o e he inal cu ing in hese ela i ely dense, highly-s ocked bi ch s ands. Thus, he al e na i e managemen egimes included al oge he i e in ensi y le els o he i s ea men s, six ha es ing me hods, and 4–7 o a ion leng hs. Hence o h, he o al managemen egimes a e e e ed o as A–F, acco ding o he codes o he ha es ing me hods applied. 2.3 Es ima ingincomes,cos s,and inancialpe o mance We es ima ed he cos s o all ea men s as well as he ha es ing incomes om bo h hinnings and inal cu ings ha would be applicable o each managemen egime and ha es ing me hod. Fo ha es ing incomes om he bi ch s ands we used eal oadside p ices acco ding o s a is ics (Me in o 2014; To elainen 2014). Because o he gene ally poo quali y o bi ch sawlogs om pea lands (Ve kasalo 1997), all wood wi h a diame e ≥ 6.5 cm o e ba k was conside ed pulpwood, wi h he p ice o 30 € m–3. The ene gy wood p ice was 24 € m–3 and 21 € m–3 o delimbed s ems and whole ees, espec i ely. The ha es ing cos s o each ha es ing me hod we e es ima ed using he olumes and s uc u es o he emo als, published ime-consump ion models, and uni cos s o he wo k. The ime-consump ion models we e based on ield s udies u ilizing de ined machine ies. We selec ed hose models ha we conside ed o be he mos app op ia e o each managemen egime and ha es ing me hod. We u he a emp ed o main ain he compa abili y o he models as good as possible, ha is, as a as possible we used models om he same s udy. Fo he ha es - ing me hods A–E (hence o h called “s anda d me hods”), we used he models o Lai ila e al. (2016). Since he me hod E does no i well o he younges and denses s ands conside ed, we complemen ed he selec ion wi h he me hod F (hence o h called “ad anced whole- ee ha es ing me hod”) and he co esponding ime-consump ion model by Jylhä and Be gs öm (2016). The models used in he me hods A–E we e based on he use o a medium-size 6-wheel ha es e (Koma su 901.4), equipped wi h a ha es e head capable o mul i- ee handling (Koma su 350.1). The model in he me hod F was based on a co esponding 6-wheel ha es e (Valme 911.3) wi h an accumula ing biomass elling head (B acke C16). Bo h he pulpwood and ene gy wood ha es ing me hods we e hus based on mul i- ee-handling in all egimes, bu he numbe o small s ems collec ed simul aneously in he elling head was much highe in he me hod F as compa ed o he o he s and only bunching on o he pile was needed. Fu he , in he me hod F, la ge s ems can be cu in wo phases – he uppe and lowe pa s sepa a ely. Fo he ha es ing me hod F, we selec ed o he models o Jylhä and Be gs öm (2016) he one ha was based on mean s em olume. Conside ing he ee size and he modelling da a used o he ime-consump ion model in he me hod F, his me hod could be applied in all he measu emen poin s o he SS s ands, hose up o he ou h measu emen o he EW s ands, and in none o he PW s ands. 7 Sil a Fennica ol. 51 no. 3 a icle id 2017 · Niemis ö e al. · F om useless hicke s o aluable esou ce?… In calcula ions o o wa ding cos s we used he models o Kui o e al. (1994) o he pulpwood, and Lai ila e al. (2007) o he ene gy wood, espec i ely. The models a e based on a medium-size o wa de . We speci ied he load size o 6 m3 o whole ees, and 9 m3 o s emwood (pulpwood and delimbed s ems), espec i ely (Lai ila e al. 2010; Lai ila and Vää äinen 2011). To acqui e he g oss e ec i e- ime p oduc i i y (E15), we mul iplied he e ec i e- ime p oduc i i y (E0) wi h 1.393 and 1.302 in ha es ing and o wa ding, espec i ely, as sugges ed by Lai ila and Vää äinen (2011). Fo ope a ing-hou cos s, upda ed by he cos index (S a is ics Finland 2013a), we used 95.4 € E15–1 and 68.9 € E15–1 o ha es e and o wa de , espec i ely (Lai ila and Vää äinen 2011). In he SS s ands he ime consump ion o p ecomme cial hinning using a clea ing saw was es ima ed as a unc ion o he s em numbe and he mean diame e a s ump heigh (es ima ed as 1.2 × mean DBH), based on he model o Kaila e al. (1999; 2001). A maximum ime consump ion o 60 h ha–1 was se o e y dense sapling s ands, whe e he model p oduced un ealis ic alues. We also included he cos o clea ing in he ha es ing cos s in such cases, whe e only pulpwood was ha es ed in he inal cu ing (me hod A), and a lo o small s ems would hus emain in he cu ing a ea. Consequen ly, clea ing is needed be o e soil p epa a ion and s and egene a ion. Fo he ime consump ion o clea ing, we used he model o Fe nandez-Lac uz e al. (2013). We used he uni cos o 35 € h–1 bo h o p ecomme cial hinning and clea ing. When examining he inancial pe o mance o he al e na i e managemen egimes o downy bi ch, he conside ably di e en egime-speci ic o a ion ime spans had o be made commensu a- ble. This was done by combining he ne p esen alue (NPV, Eq. 1) o he bi ch o a ion wi h he discoun ed ba e land alue (BLV, Eq. 2 and Eq. 3) o he managemen o u u e o a ions o No way sp uce (Picea abies (L.) Ka s .), assumed o be es ablished igh a e he bi ch o a ion. The cos s and incomes o he bi ch o a ion we e discoun ed o he decision poin , i.e., o he es ablishmen o he expe imen , which was he ime poin when he ac ual decision be ween al e na i e egimes was being made. In he discoun ing, we used he in e es a es 1, 2, and 3%, and co espondingly, he NPVs a e hence o h abb e ia ed as NPV1, NPV2, and NPV3. The NPV was calcula ed as: NPV=− ++− +−+ = −= ∑ ∑ (() )() () ,( ) HC VM sc ii i i TTT T kl k K l 1111 0 11 whe e: NPV = ne p esen alue a s and le el in bi ch s and, € ha–1 Hi = income om hinning a ime i, alued a oadside (i=0 deno es he decision poin ) VT = income om inal cu ing a o a ion T, alued a oadside Ci = cos o hinning a ime i MT = cos o inal cu ing a o a ion T SCkl = cos o sil icul u al ope a ion k a ime l (No e ha l=i o l≠i) = a e o in e es (he e 1%, 2%, o 3%) We chose No way sp uce managemen ins ead o downy bi ch managemen o he u u e s and gene a ions since i gene ally p o ides be e g ow h and yield as well as p o i abili y han downy bi ch (Koi is o 1959; Sa amäki 1977; Hökkä 1997). Fu he mo e, he onse o he expe imen s and, consequen ly, he decision poin s o ou s udy occu ed mo e o less in he middle o he bi ch o a ion, and he e o e, i was no possible o calcula e he BLV acco ding o he ongoing bi ch o a ion wi hou s ong (specula i e) assump ions conce ning he ea ly s ages o he s ands. The u u e o a ions o No way sp uce managemen we e based on he gene al managemen guidelines 8 Sil a Fennica ol. 51 no. 3 a icle id 2017 · Niemis ö e al. · F om useless hicke s o aluable esou ce?… (Hy än me sänhoidon… 2007), and a subs an ial mix u e o downy bi ch was assumed o occu also in he No way sp uce s ands, mainly because o summe - os damages in he No way sp uce, which concu s wi h he indings in he NFI11 o wes e n and no he n Finland (unpublished). Technically, he No way sp uce managemen was simula ed by he Mo i-simula o (Hynynen e al. 2005; Salminen e al. 2005), which includes speci ic g ow h models o d ained pea land s ands (Hökkä e al. 1997; Hynynen e al. 2002; Hökkä and Salminen 2006). In b ie , he simula ed No way sp uce managemen included one in e media e hinning and a inal cu ing a he s and age o 95 yea s, p oducing a o al yield o 295 m3 ha–1. In he inancial calcula ions we applied a e age s umpage p ices in eal e ms (a e age om 2011 o 2014, sepa a ely o i s and la e hinnings and inal cu ings; Me in o 2014, hen nominal p ices de la ed by he cos -o -li ing index, S a is- ics Finland…2013b) and sil icul u al cos s in eal e ms o No he n Os obo hnia and Sou he n Lapland (Me in o 2014). The No way sp uce managemen included he ollowing sil icul u al measu es: plan ing (500 € ha–1), ending o he sapling s and (350 € ha–1), o p ecomme cial hin- ning (350 € ha–1) and a di ch ne wo k main enance combined wi h mounding (300 € ha–1). In he calcula ions o he BLV (Chang and Gadow 2010; Chang 2014), we applied he Faus mann o a ion model (Faus mann 1849). The BLV was calcula ed as: BLV= −+ −+ == − − ∑∑ ()*( ) () ,( ) Rc i i s ik k mi s 01 1 11 2 whe e: BLV = ba e land alue o a sp uce s and, € ha–1 Ri = ha es ing income in yea i alued a s umpage, € ha–1 Cik = sil icul u al cos k (k = 1, …, m) in yea i s = o a ion leng h o sp uce s and, yea s = a e o in e es (he e 1%, 2%, o 3%) Because he examined ime pe iods om he onse o he expe imen s o he inal cu ings o he ongoing bi ch o a ion a ied, he BLV o he sp uce gene a ions had o be discoun ed o he deci- sion poin . This was done acco ding o: BLV×+ −− () ,( ) () 1 3 Tb whe e: T = o a ion o he downy bi ch s and, in yea s b = age o he downy bi ch s and a he onse o expe imen , in yea s Finally, we combined he NPV o he ongoing bi ch o a ion and he discoun ed BLV o he u u e sp uce gene a ions by summing up he ou comes o Eq. 1 and Eq. 3 o each case. Hence o h, hese combined alues a e e e ed o as CoV1, CoV2 and CoV3, he numbe s indica ing he discoun a es 1%, 2% and 3%, espec i ely. 2.4 Compa isons be ween managemen egimes and ha es ing me hods We analysed he di e ences in ha es ing emo als and p o i abili y among managemen egimes h ough co a iance analysis. We es ed he e ec s o hinning in ensi ies, wi h di e en ha es ing me hods, o a ion leng hs, and in e es a es by a mixed model (Eq. 4), sepa a ely o he s and 9 Sil a Fennica ol. 51 no. 3 a icle id 2017 · Niemis ö e al. · F om useless hicke s o aluable esou ce?… g oups SS, EW and PW. The s and was included as a andom block e ec . We used he s and dominan heigh a he onse o he expe imen as a co a ia e, because o he a ia ion in ee heigh (de elopmen s age) wi hin he s and g oups. We adjus ed he es ima ed emo als and p o i abili ies on he basis o he o e all means ac oss he s and g oups: Hdom: 7.45 m, 11.35 m, and 14.5 m in SS, EW and PW s ands, espec i ely, o make he esul s compa able wi hin s and g oups. Because o he small a ia ion in s and age wi hin each s and g oup, we used he mean age o s ands a each o a ion leng h, no he exac age o he indi idual s ands. The model was: YHue sp T dom ssp =+ +++ µδ β 14 ,( ) whe e: Ysp = emo al o p o i abili y µ = o e all mean in he s and g oup (SS, EW, o PW) δT = ec o o ea men e ec s ( hinning in ensi y, ha es ing me hod, o a ion leng h, in e es a e) β = coe icien o he co a ia e Hdom1 = s and dominan heigh a he onse o he expe imen us = andom e m o expe imen al s and s esp = esidual e m (s and and plo ) To simpli y he p esen a ion o ou esul s ha spanned o e di e en ime in e als, we calcula ed he means and a ia ion o he pa ame e s o one speci ic ime poin , 20 yea s a e i s hinning, i.e., a he ime o he 4 h (me hod F) o he 5 h (o he me hods) measu emen . We selec ed his ime poin , because he e ec s o he i s hinning could hus be ollowed o as long as possible using da a om all s ands. Because he inancial pe o mance was de e mined o he ime poin cons i u ing he onse o he expe imen , we inally modelled he e ec o de elopmen s age (Hdom a he onse o he expe imen ) and si e index (Hdom a he s and age o 50 yea s) on he CoVs using he ha es ing me hod A. This allows o a gene al examina ion on how s and cha ac e is ics a ec he inancial pe o mance. In his model (Eq. 5) we used all da a ac oss 20 yea s om he i s hinning om all s and g oups (SS, EW and PW) oge he : CoV ea men ea men =+×+×+×+×+ ××+× ab cH dH eH Hg dom dom dom 50 2 ea men ×+++Huue dom ddsdsp 25 ,( ) whe e: CoV = CoV1, CoV2, o CoV3 a 20 yea s a e he onse o he expe imen ea men = hinning in ensi y: un hinned, e y ligh , ligh , mode a e, hea y, wice hinned H50 = si e index, s and dominan heigh a he age o 50 yea s Hdom = s and dominan heigh a he onse o he expe imen ud, uds = andom e ms o s and g oup d, and expe imen al s and s edsp = esidual e m Res ic ed maximum likelihood (REML) es ima ion in he “Mixed linea ” p ocedu e o hie a chi- cally s uc u ed da a was used in hese analyses (SPSS 16.0, PASW S a is ics). Pai wise compa isons we e pe o med h ough compu ing o gene alised leas -squa e means o he ea men e ec s. 16 Sil a Fennica ol. 51 no. 3 a icle id 2017 · Niemis ö e al. · F om useless hicke s o aluable esou ce?… Fig. 6. P o i abili y, exp essed as combined alues (CoV, € ha–1) o ne p esen alue o he ongoing bi ch o a ion and discoun ed ba e land alue o u u e sp uce o a ions, as a unc ion o s and age (y s) o ene gy wood hinning s age (EW) s ands. Lines desc ibe he di e en hinning in ensi ies and di e en panels show he ha es ing me hods A ( op), B (middle), and C (bo om) (me hod desc ip ions a e in Table 2). Discoun ing was done o he onse o he expe imen wi h in e es a es 2% (CoV2, le ) and 3% (CoV3, igh ). Thinning in ensi ies ma ked wi h he same le e we e no signi ican ly di e en wi hin he ha es ing me hod and in e es a e (p > 0.05). 17 Sil a Fennica ol. 51 no. 3 a icle id 2017 · Niemis ö e al. · F om useless hicke s o aluable esou ce?… s ill inc easing a he s and age o 46–50 yea s. In he un hinned o e y ligh ly hinned SS s ands he in eg a ed me hods we e no compe i i e un il he inal-cu ing ages o 42–46 yea s, when hey eached he o e all CoV le els o he o he hinning in ensi ies. In he EW s ands, he anking o he hinning in ensi ies was he same o all ha es ing me hods and in e es a es (Fig. 6). The CoV was as i s highes in he un hinned s ands, and he lowe he hea ie he hinning was. The highes CoVs we e achie ed wi h he pulpwood me hod A and he in eg a ed me hod B a he s and age o 46 yea s, being 1800 and 1300 € ha–1 wi h CoV2 and CoV3, espec i ely (Fig. 6abcd). Fo he me hod C he maximum was 110–130 € ha–1 lowe . In he un hinned EW s ands he p o i abili y did no inc ease a e he s and age o 46 yea s, bu in hinned ones i con inued inc easing un il he end o s udy pe iod a he age o 58 yea s (Fig. 6). The di e ences in CoV caused by hinning in ensi y we e almos equal wi h he in e es a es o 2% and 3%, and by he me hods A and B. By he me hods A and B he CoV in he hinned s ands was 700, 900, 1050, and 1550 € ha–1 below he maximum in he e y ligh , ligh , mode a e and hea y i s hinnings, espec i ely. Fo he me hod C he CoV in un hinned s ands was lowe bu in hinned s ands almos equal o he me hods A and B. In he EW s ands he ad anced whole- ee ha es ing me hod F was also applicable un il s and age o 40 yea s, when he s ems had g own oo hick o he ene gy-wood ha es e used. In he un hinned EW s ands CoV2 and CoV3 we e posi i e om he onse o he s udy a he s and age o 26 yea s. A he age o 40 yea s, hese alues we e ou s anding in he un hinned EW s ands, being 1660 and 1250 € ha–1 o CoV2 and CoV3, espec i ely. Tha is, he CoVs o he me hod F a he s and age o 40 yea s we e close o he maxima eached wi h he me hods A and B se e al yea s la e . In he PW s ands, he CoVs we e posi i e o all me hods and hinning in ensi ies (Fig. 7). The CoVs we e equal o he pulpwood me hod A and he in eg a ed me hod B, excep ha in wice- hinned s ands he me hod A ou pe o med me hod B (Fig. 7). Fo he in eg a ed me hod C, CoV was only 30–50 € ha–1 lowe han o me hods A and B. The bes p o i abili y was eached in he un hinned s ands (=ea ly ended con ol) a he s and age o 65 yea s, being 2170 (CoV2) and 1600 € ha–1 (CoV3). Fo he o he hinning in ensi ies, CoV was 250–200 € ha–1 lowe . Howe e , he di e ences be ween hinning in ensi ies we e no s a is ically signi ican . Ye , a u he a gu- men in a o o managemen wi hou hinning was ha al hough he un hinned PW plo s showed less p o i able immedia e inal cu ing han he hinned plo s, i.e., by chance hey had less aluable emo als, a e 20 yea s he inal cu ing esul ed in highe CoVs in he un hinned plo s. Rega d- less o he hinning in ensi y and ha es ing me hod, he mos p o i able inal-cu ing age was 65 yea s o he PW s ands, on a e age. A e ha age, he p o i abili y dec eased. Fo he PW s ands, an immedia e clea cu ing was mo e p o i able han applying hinning and g owing he s ands o 5 yea s (Fig. 7). The s ands had o be g own o a leas 10–15 yea s a e hinning, depending on hinning in ensi y, be o e he p o i abili y su passed ha o an immedia e clea cu . Howe e , g owing o PW s ands abou 20 yea s wi hou hinning was a p o i able al e na i e. 3.2.3E ec so s andde elopmen s ageandsi eindexon hep o i abili y The expec ed CoVs calcula ed o he di e en de elopmen s ages (de ined by s and dominan heigh , Hdom) o un hinned downy bi ch s ands by Eq. 5 (Table 3) indica ed a as alue inc ease un il a Hdom o 10 me e s bu wi h a slowe inc ease a e wa ds (Fig. 8). On a e age, one me e inc ease in Hdom om 6 o 7 me e s inc eased he CoV2 o un hinned s and by 519 € ha–1 and om 10 o 11 me e s by 195 € ha–1 (Fig. 8). In he un hinned s ands a one-uni change in si e index (Hdom a he s and age o 50 yea s) co esponded o a change o 133 and 113 € ha–1 in CoV2 and CoV3, espec i ely (no shown). 18 Sil a Fennica ol. 51 no. 3 a icle id 2017 · Niemis ö e al. · F om useless hicke s o aluable esou ce?… Fig. 7. P o i abili y, exp essed as combined alues (CoV, € ha–1) o ne p esen alue o he ongoing bi ch o a ion and discoun ed ba e land alue o u u e sp uce o a ions, as a unc ion o s and age (y s) o pulpwood hinning s age (PW) s ands. Lines desc ibe he di e en hinning in ensi ies and di e en panels show he ha es ing me hods A ( op), B (middle), and C (bo om) (me hod desc ip ions a e in Table 2). Discoun ing was done o he onse o he expe imen wi h in e es a es 2% (CoV2, le ) and 3% (CoV3, igh ). Thinning in ensi ies ma ked wi h he same le e we e no signi ican ly di e en wi hin he ha es ing me hod and in e es a e (p > 0.05). 19 Sil a Fennica ol. 51 no. 3 a icle id 2017 · Niemis ö e al. · F om useless hicke s o aluable esou ce?… Fig. 8. Expec ed combined alues (CoV2 and CoV3, € ha–1) a 20 yea s om he onse o he expe imen s ob ained wi h ha es ing me hod A (see Table 2) o s ands ep esen ing di e en dominan heigh s (Hdom, m, a he onse o he expe imen s) and o e all mean si e index (H50 = 15.5) (Eq. 5). Lines desc ibe di e en hinning in ensi ies. Table 3. Mixed model (Eq. 5) pa ame e s conce ning he whole da a. Independen a iables CoV2 and CoV3 when g owing s ands 20 yea s a e he i s hinning. CoV2: coe . CoV2: sig. CoV3: coe . CoV3: sig. In e cep (a) –6728.3 < 0.01 –6180.2 0.00 Twice hinned (b5) 79.8 0.98 –717.9 0.83 Hea y (b4) 4543.2 < 0.01 4436.9 < 0.01 Mode a e (b3) 1850.9 0.06 1776.2 0.06 Ligh (b2) 1426.9 0.15 1467.9 0.11 Ve y ligh (b1) 1995.7 0.11 1858.2 0.11 Un hinned (b0) 0.0 0.0 Co a ia es: H50 (c) 133.3 < 0.01 113.0 < 0.01 Hdom (d) 1044.0 < 0.01 944.8 < 0.01 Hdom2 (e) –40.4 < 0.01 –37.3 < 0.01 In e ac ions: Twice * Hdom ( 5) –365.0 0.53 –245.4 0.65 Hea y * Hdom ( 4) –1121.6 < 0.01 –1108.6 < 0.01 Mode a e * Hdom ( 3) –492.6 0.02 –489.1 0.02 Ligh * Hdom ( 2) –387.7 0.07 –407.9 0.04 Ve y ligh * Hdom ( 1) –556.4 0.06 –520.9 0.06 Un hinned * Hdom( 0) 0.0 0.0 Twice * Hdom2 (g5) 22.8 0.34 18.7 0.40 Hea y * Hdom2 (g4) 52.9 < 0.01 52.9 < 0.01 Mode a e * Hdom2 (g3) 21.8 0.06 22.3 0.04 Ligh * Hdom2 (g2) 17.6 0.11 19.1 0.06 Ve y ligh * Hdom2 (g1) 29.2 0.08 27.0 0.09 Un hinned * Hdom2 (g0) 0.0 0.0 20 Sil a Fennica ol. 51 no. 3 a icle id 2017 · Niemis ö e al. · F om useless hicke s o aluable esou ce?… 4 Discussion The o al a ea o bi ch-domina ed s ands on d ained pea lands, ca. 0.5 million hec a es (Kojola e al. 2015), is a signi ican ese e o bo h pulpwood and ene gy wood in Finland. The s uc u e, olume, and g ow h po en ial o he si es (Sa amäki 1977; Kel ikangas and Seppälä 1977; Niemis ö 2013) enable applica ion o di e en ha es ing me hods and managemen egimes so ha he bes possible gain may be eached. 4.1 Choosing he bes managemen egime Based on ou esul s, he o emos h ee hings o conside when deciding how o manage a downy bi ch s and a e 1) managemen his o y, 2) p oduc ion ocus (whe he pulpwood o ene gy wood p oduc ion is emphasized), and 3) he ha es ing machine y a ailable. I he s and has no been managed ea lie , he e a e no speci ic easons o aim a pulpwood p oduc ion, and i an e ec i e mul i- ee ha es e o ad anced whole- ee ha es ing is a ailable, he mos p o i able op ion clea ly is o g ow he s and un ea ed un il inal cu ing as whole- ee ene gy wood a he s and age o 40–45 yea s. I such a machine y is no a ailable, i is be e o op o in eg a ed ha es ing o bo h pulpwood and ene gy-wood poles a abou en yea s la e . P oducing only ene gy wood hus seems o be p o i able only wi h a speci ic me hod (like me hod F in ou s udy). I he aim is o speci ically p oduce pulpwood, applying a ligh p ecomme cial hinning a 4–5 me e dominan heigh o he densi y o 2000–2500 s ems pe hec a e is a compe i i e al e na- i e. I p ecomme cial hinning o ea ly ligh hinning has al eady been done, he inal cu ing should be delayed un il he s and age o 50–65 yea s, when pulpwood ha es ing is he mos p o i able op ion. In ha case, comme cial hinning is no necessa y bu i is possible wi hou any signi ican economic e ec . Tending be o e 4 me e s heigh is eached would be a cheape ope a ion, bu , due o coppicing, may lead o he s and becoming e en dense , wi h sp ou s almos equal in size o he ees in un hinned sapling s ands (Niemis ö 2013). In pulpwood p oduc ion, o a ion leng hs sho e han 40–50 yea s, wi h o wi hou hin- nings, we e economically in e io o longe o a ions, due o he low emo al and high ha es ing cos s o small s ems. In un hinned s ands he p o i able inal-cu ing age seemed o be ea lie han in ligh ly hinned s ands. In spi e o he inc easing na u al mo ali y, qui e a long ma u ing pe iod was compe i i e o he un hinned s ands, because sel - hinning was mos ly selec ing he smalles s ems ha a e he mos expensi e o cu . These choices a e based on he es ima ed p o i abili y only, bu he e may be o he easons also o hinning: egene a ion h ough u ilizing a No way sp uce unde s o y ha o en appea s in his kind o si es, p oducing saw logs o plywood in e y high quali y and e ile downy bi ch s ands, o es he ic easons only. 4.2 To hin o no o hin Among he combina ions o he i e in ensi y le els o he i s ea men s, six ha es ing me hods, and se e al o a ion leng hs, he mos p o i able managemen in young and dense downy bi ch s ands was g owing wi hou any hinnings o inal cu ing as whole- ee ene gy wood a he s and age o 40–45 yea s. The bes p o i abili y equi ed, howe e , ha i was possible o use an ad anced whole- ee ha es ing me hod speci ically designed o small s ems in he inal cu ing (Jylhä and Be gs öm 2016), whe eas wi h he s anda d, non-speci ic, whole- ee me hod he p o i abili y d opped d as ically. As expec ed, he dense a bi ch-s and was g own, he highe was he p oduc- ion o small-diame e poles and b anch biomass. A sligh ly unexpec ed esul , in con as , was ha 21 Sil a Fennica ol. 51 no. 3 a icle id 2017 · Niemis ö e al. · F om useless hicke s o aluable esou ce?… he pulpwood emo al also was he highes in e y dense s ands, as Niemis ö (2013) has al eady epo ed. Gene ally, opposi e esul s, lowe pulpwood yields in dense s ands, ha e been obse ed (Sco s pine: Ruha and Va mola 1997; Huuskonen and Hynynen 2006; sil e bi ch: Niemis ö 1995). The commonly held idea is ha ligh hinning enables a maximal amoun o s ems o each he size equi emen o pulpwood, while in dense s ands mos s ems emain oo small. This seems no o be he case wi h downy bi ch, howe e , which hus seems o ole a e compe i ion be e han mos species a he ea ly s ages o de elopmen . Dis inc i ely, applying ene gy wood hinning in dense downy bi ch s ands wi h a mean heigh o 8–11 me e s esul ed in low o e all p o i abili y. The s em size in such hinnings is modes and he hinning emo al ends o be low, esul ing in an unp o i able ope a ion. Ge ing la ge emo als by inc easing hinning in ensi y causes g ow h losses (Niemis ö 2013) ha lead o dec easing o al p o i abili y o he inal cu ing, he mo e he hea ie he hinning. In he SS and EW s age s ands, hese nega i e impac s will u he inc ease wi h ime. Rega dless o he iming o me hod o inal cu ing he o al p o i abili y was he highes in he un hinned s ands. In he absence o hinning, na u al mo ali y akes ca e o emo ing he smalles s ems o ee, and hus, hese will no lowe he p o i abili y o he inal cu ing. Applying a second hinning 10–15 yea s a e he ligh i s hinning, did no inc ease he p o i abili y, ei he . P ecomme cial hinning as well as ene gy wood hinning seemed o be unnecessa y and expensi e ea men s. Thinning did no inc ease he alue o he inal-cu ing emo al. Mo eo e , i did no signi ican ly dec ease he ha es ing cos s pe cubic me e o he inal cu ing, ei he , because na u al mo ali y had emo ed he smalles ees du ing he o a ion, wi hou any cos . In all he s udied o a ion leng hs and hinning ea men s he o al emo als we e lowe in he SS and PW s ands han in he EW s ands. This was due o he p ecomme cial hinning o he SS and PW s ands which does no esul in a me chan able emo al, and he g ow h loss caused by ea ly uncomme cial hinning. This conclusion was p o ed in he un hinned SS s ands, whe e he p o- duc ion o small diame e poles and b anch biomass eached he same le el as in he EW s ands a he s and age o 55 yea s. The cos s o la e p ecomme cial hinning o ene gy wood hinning we e e y high in dense bi ch s ands and he e o e he p o i abili y o hinned sapling s ands (SS) we e highe han hose o olde EW s ands, e en i he o a ion leng h was 55 yea s. E en hough hinnings we e gene ally useless, applying a ligh p ecomme cial hinning o he densi y o 2500–3500 s ems pe hec a e was a compe i i e op ion when he aim o he s and managemen was o p oduce pulpwood (wi h o wi hou ene gy wood). Tha was shown in he esul s o bo h young s ands (SS) and mo e ma u e s ands (PW). The adi ional comme cial hinning a he PW s age had a e y small e ec on o al p o i abili y. Due o his, he decision be ween o hin o no o hin may be based on o he goals o o es managemen . Fo he sapling s ands (SS), ou s udy pe iod was no long enough o p oduce inal e idence o conclude, which o he wo hin- ning in ensi ies, un hinned o ligh , and wo ha es ing ypes, pulpwood o in eg a ed, would be he mos p o i able. Ob iously in pulpwood p oduc ion he di e ence be ween he un hinned and ligh ly- hinned s ands was small, whe eas wi h in eg a ed ha es ing me hods he ligh - hinning al e na i e was sligh ly be e . In any case, inal cu ing o pulpwood was a p ope me hod o he p ecomme cially hinned mo e ma u e s ands. As o o es managemen in gene al, he hinnings a e mo e p o i able (o a leas less unp o - i able) when highe in e es a es a e used, due o he ea lie incomes (Hyy iäinen and Tah onen 2002; Ah ikoski e al. 2004). In he s ands examined he e, his was ue only in ea ly ended bi ch s ands a he con en ional i s - hinning s age (PW), al hough he di e ence be ween hinned and un hinned s ands e en hen was e y small. The opposi e e ec o in e es a e in dense downy bi ch s ands s ems om a combina ion o p ecomme cial hinning causing cos s and ene gy wood ha es ing also o en causing ne cos s o he ne income being low wi hou any subsidies. The 22 Sil a Fennica ol. 51 no. 3 a icle id 2017 · Niemis ö e al. · F om useless hicke s o aluable esou ce?… highe in e es a e was used, he mo e compe i i e he un hinned managemen egimes we e. Because o he low alue inc emen and low hinning esponse o downy bi ch (Niemis ö 2013), he compensa ion o he cos s o p ecomme cial hinning o ea ly hinning akes place e y slowly, i a all. In addi ion, in a p ac ical scale, he yield o aluable imbe is nonexis en because o he low quali y and small size o he s ems. Al hough ou esul s showed low bene i s o hinnings, he goals o he han economic gain may be ele an easons o hem, such as egene a ion o sp uce ia unde g ow h (Niemis ö and Pou iainen 2004; Niemis ö e al. 2012) o landscaping o mul iple use aspec s. On he mos nu ien - ich si es wi h a high p oduc ion po en ial, when he quali y o he downy bi ch s ands is excep ionally high i may also be possible o p oduce saw o enee imbe besides pulpwood and ene gy wood. In such cases, di e en kinds o managemen egimes han hose discussed in his s udy should mos likely be applied. 4.3 Ha es ing me hod Ou esul s showed ha i was possible o signi ican ly inc ease he p oduc i i y o inal cu ing in dense bi ch s ands wi h small s ems by using an ad anced whole- ee ha es ing me hod, which is mo e sui able o mul i- ee ha es ing o small s ems han he s anda d whole- ee me hod. The gain o he ad anced me hod used in ou s udy ( ia p oduc i i y models) may be especially high in downy bi ch ha es ing, whe e o en ben and c ooked s ems a e ill-sui ed o egula mul i- ee ha es ing, which uses eeding and delimbing ha es e heads (Lai ila e al. 2016). Fu he , he ad anced me hod is capable o wo-phase cu ing o s ems, which enables s anda d o wa ding o up o e en 15-m all ees. Gene ally, imp o ing he p oduc i i y o o es o wa ding also should be a ge ed o be e p o i abili y. Ye , he small size o whole- ee loads (6 m3 a a ime) used in his s udy as model inpu may be an unde es ima e e en o up- o-da e o wa de s in inal cu ings o ma u e bi ch s ands wi h a conside able amoun o long s emwood logs. In Finland, whole- ee ha es ing solu ions ha e hus a been mainly conside ed om hin- ning ope a ions poin s o iew. Elsewhe e, whole- ee ha es ing is used in inal cu ings, bu he a ge is usually single la ge , sawn- imbe sized ees. Mul i- ee ea men o smalle -sized ees in inal cu ings is s ill a no el and a e app oach, and he me hodologies ha e been li le de eloped o s udied. Because o new bio- e ine ies and an inc easing use o o es ene gy i seems ha he need and, consequen ly, de elopmen o his kind o machine y will inc ease in he u u e. 4.4 Me hodological conside a ions The esul s o his s udy we e based on 19 expe imen al s ands ha included a wide ange o hinning in ensi ies and a weal h o g ow h da a om sapling s ands o ma u e s ands. These s ands co e ed well he a ia ion exis ing in he mos common pea land si e ypes o downy bi ch domina ed s ands, as well as hei equency in wes e n and no he n Finland. Acco ding o NFI11 46%, 39%, and 18% o he downy bi ch domina ed s ands we e si ua ed a H T, MT2, and MT1 si es (He b- ich ype and V. my illus ype II and I; see Wes man and Laiho 2003), and mo e han hal o he o al a ea was ound in he egions whe e ou expe imen al s ands we e loca ed (Kojola e al. 2015). The long- ime ial wi h se e al s ands and ca e ully planned expe imen al design allowed us o s udy a wide ange o ea men s, s and densi ies and o a ion pe iods. All he s and da a ha e ea lie been c oss-checked and analyzed by Niemis ö (2013), gi ing a eliable s a ing poin o his s udy. Thanks o he accu a e measu emen da a we we e able o augmen he da a u he o ex a asso men s, like small ene gy wood s ems and b anch biomass. 23 Sil a Fennica ol. 51 no. 3 a icle id 2017 · Niemis ö e al. · F om useless hicke s o aluable esou ce?… Wi h models, we we e able o compa e many ypes o ha es ing me hods simul aneously. O cou se, such calcula ions a e based on se e al assump ions ha we e made al eady a he de el- opmen phase o he models. The ha es ing models o Lai ila e al. (2016) ha e been de eloped o be applicable on simila ypes o pea land bi ch s ands as used in his s udy and o ha es ing o delimbed s ems. Fu he mo e, he models dis inguish be ween hinning and clea cu ing, hus esul ing in mo e accu a e es ima es in di e en cases. The e o e, hose models we e easily adap ed o he ci cums ances o ou s udy s ands o ha es ing o pulpwood o delimbed s ems. Howe e , e en o whole- ee ha es ing, he olume o delimbed s ems is used as an inpu o he model, which may cause a small o e es ima ion in ha es ing cos . The me hod and model o Jylhä and Be gs öm (2016) ga e us he ad anced whole- ee ha es ing al e na i e. To ensu e he unc ion- ing o he model in ou s ands, i s use was ca e ully es ic ed only o da a ma ching he modelling da a. The model o Kui o e al. (1994) o o wa ding cos s was o pulpwood. The e o e we also used he models o Lai ila e al. (2007) o he delimbed s ems and whole- ee, o ge mo e exac esul s. Howe e , he load size may s ill be deba able. Compa ing he esul s ob ained wi h p oduc i i y models om di e en s udies, which in ol e di e en ope a o s, whose impac on p oduc i i y may be g ea (Lai ila e al. 2016), in ol es some isk. He e, he me hod F was de i ed om a di e en s udy han he o he s. Howe e , we did no conside he di e ences ha we go be ween he whole- ee me hods E and F, whe e he me hod o mul i- ee handling bu also he ope a o changed, o be o e ly dependen on he la e . Since he me hod F in ol es a e y di e en app oach o he whole ope a ion han me hod E, he expe ience o he ope a o wi h he me hod in ques ion may be o mo e impo ance han u ilizing a “s anda d” ope a o . Also, he di e ence ob ained o hese wo me hods in downy bi ch s ands, especially, is qui e logical, as poin ed ou in he p e ious sec ion. Uni p ices and cos s a e impo an a iables when p o i abili y is discussed. We se he le els acco ding o s a is ics. Howe e , especially he p ice o ene gy wood is di icul o speci y since i luc ua es in he ma ke . In ou s udy he ene gy wood p ice conside ed was a subsidized p ice, esul ing in a ela i ely high alue when compa ed o ha o pulpwood. In he cu en o es y con ex , i was no easonable o assume ha se e al downy bi ch gene a ions would be epea edly managed. Ins ead, we assumed ha he main species would be changed o No way sp uce a e he ongoing bi ch o a ion, al hough a leas some bi ch will hen appea as mix u e. The sp uce gene a ion was used as a ep esen a i e managemen egime o assessing he ba e land alue, BLV, enabling us o compa e he di e en inal-cu ing imes o bi ch. Due o he g ea a ia ion in inal-cu ing imes o bi ch, he discoun ed BLV o he u u e sp uce gene a ions needed o be included in he inancial analyses in o de o commensu a e he al e na i e managemen egimes o he ongoing bi ch o a ion in a heo e ically solid manne (Amache e al. 2009). In gene al, he s ands o his s udy we e loca ed on such si e ypes and cli- ma ic condi ions whe e o es y on pea lands can be conside ed p o i able also in he u u e based on hei BLV (Hy än me sänhoidon… 2007), i he equi ed a e o e u n and he egene a ion cos s emain mode a e. On he o he hand, Niemis ö (2013) has shown ha he p oduc i i y o he downy bi ch may be e y high in he si es in ques ion. Because o he di icul ies ela ed o he es ablishmen o sp uce s ands, like os damages, i may be ques ioned i he egene a ion o sp uce is always he bes al e na i e. This s udy ocused on pu e downy bi ch s ands in cen al and no he n Finland ha we e assumed o be egene a ed o sp uce a e inal cu ing. Fu he esea ch is s ill needed conce ning he managemen o downy bi ch-domina ed mixed o es s and wo-s o ied bi ch-sp uce s ands. Also, while he challenges and isks ela ed o egene a ion o he highly p oduc i e pea lands a e well known (Hånell 1993; Moilanen e al. 2011), he e is insu icien scien i ic in o ma ion o sup- po he alua ion o he al e na i e egene a ion me hods. In sou he n Finland, downy bi ch s ands 24 Sil a Fennica ol. 51 no. 3 a icle id 2017 · Niemis ö e al. · F om useless hicke s o aluable esou ce?… may yield aluable logwood on bo h pea land and mine al-soil si es o high p oduc ion po en ial, which should be conside ed when making decisions on hei managemen . 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