Improving Economic Management Decisions in Forestry with the SorSim Assortment Model

This is a sel -a chi ed e sion o an o iginal a icle. This e sion may di e om he o iginal in pagina ion and ypog aphic de ails. Au ho (s): Ti le: Yea : Ve sion: Copy igh : Righ s: Righ s u l: Please ci e he o iginal e sion: CC BY 4.0 h ps://c ea i ecommons.o g/licenses/by/4.0/ Imp o ing Economic Managemen Decisions in Fo es y wi h he So Sim Asso men Model © 2019 by he au ho s Published e sion Lemm, Rena o; Bla e , Clemens; Holm, S e an; Bon , Leo; Thees, Oli e Lemm, R., Bla e , C., Holm, S., Bon , L., & Thees, O. (2019). Imp o ing Economic Managemen Decisions in Fo es y wi h he So Sim Asso men Model. C oa ian Jou nal o Fo es Enginee ing, 41(1). h ps://doi.o g/10.5552/c oj e.2020.586 2019 C oa . j. o . eng. 41(2020)1 71 1. In oduc ion Sus ainable imbe p oduc ion, along wi h all o h- e ecosys em se ices ha o es s p o ide o socie y, emains an impo an o es managemen objec i e (Fo es Eu ope 2015, EASAC 2017). Fu he mo e, im- be p o ision is he mos impo an sou ce o e enue o o es en e p ises: su icien p o ision gua an ees hei a ou able long- e m economic pe o mance, which in u n enables hem o p o ide a wide ange o o he impo an ecosys em se ices (Rigling and Scha e 2015, Bü gi e al. 2018). Howe e , economic e iciency p esupposes he selec ion o app op ia e, cos -e ec i e imbe ha es ing me hods and, a he same ime, he adop ion o sil icul u al s a egies ha deli e he p oduc s in demand. Consequen ly, he p ecise o ecas ing o cos s and e enues om o es managemen s pu suing di e en s a egies is a p e equisi e o op imising he mid- and long- e m planning o e icien imbe p oduc ion Imp o ing Economic Managemen Decisions in Fo es y wi h he So Sim Asso men Model Rena o Lemm, Clemens Bla e , S e an Holm, Leo Bon , Oli e Thees Abs ac The sus ainable supply o imbe is one o he mos impo an o es ecosys em se ices and a decisi e ac o de e mining he long- e m p o i abili y o o es en e p ises. I imbe p oduc ion is o be economically iable, he e mus always be a way o analyse o es s ands and ees elled o exploi a ion wi h ega d o he wood asso men s hey con ain. Only hen can he ex- pec ed imbe yields, achie ed by a ious sil icul u al s a egies o ac ions and di e en so - ing op ions, be quan i ied wi h su icien accu acy. The So Sim asso men simula o was de eloped o o es p ac i ione s and o es scien is s in Swi ze land o ealis ically simula e he so ing o indi idual ees and en i e o es s ands based on de ined speci ica ions. So Sim has a simple use in e ace and comes in a numbe o di e en language e sions (G, E, F). The so wa e is implemen ed in Ja a, making i pla o m-independen . I can be downloaded o ee a (h ps://www.wsl.ch/en/p ojec s/so imen simula o -so sim.h ml). This a icle p o- ides an o e iew o how he simula o wo ks and demons a es i s po en ial applica ions based on a p ac ical and a scien i ic example. A pa icula p ac ical ad an age is ha he composi ion o he asso men s o he planned ha es s can be es ima ed acco ding o quan i y and alue. When used in s a egic planning and especially in esea ch, So Sim p o ides a basis o ana- lysing ei he long- e m de elopmen s in yields om o es s ands o sil icul u al ea men me hods. Based on an e en-aged and a selec ion o es s and, he scien i ic example shows how s ongly he assessmen o he ad an ageousness o wo di e en sil icul u al s a egies de- pends on he ime when he calcula ion was made (using his o ical and cu en asso men e enues and imbe ha es ing cos s). In pa icula , he combina ion o So Sim wi h imbe ha es p oduc i i y models enables di e en ia ed o es economic insigh s. Va ious app oach- es o alue-based op imisa ion in he so ing o indi idual ees and o he op imal alloca ion o ha es ing ac i i ies o de ined cus ome demands a e cu en ly being examined as u he So Sim de elopmen s. Keywo ds: decision suppo , o es economics, o es managemen planning, ne p esen alue, imbe e enues Open access O iginal scien i ic pape DOI: h ps://doi.o g/10.5552/c oj e.2020.586 R. Lemm e al. Imp o ing Economic Managemen Decisions in Fo es y wi h he So Sim Asso men Model (71–83) 72 C oa . j. o . eng. 41(2020)1 (Möh ing 2010, Hanewinkel e al. 2014a, Hä l e al. 2016, Bla e e al. 2017). The e a e a ious economic me hods in o es y o assessing he long- e m eco- nomic iabili y o di e en sil icul u al ea men s a egies and imbe ha es ing measu es. Many o hese me hods a e de i ed om he ield o in es - men planning (Klempe e 1996, Na a o 2003), such as he ne p esen alue (NPV) me hod (Fü s enau e al. 2007, Seidl e al. 2007, Pukkala 2016), he land expec a ion alue (LEV) me hod o Faus mann o - mula (Hanewinkel e al. 2010, Hanewinkel e al. 2013, Nöl e e al. 2018), and he annui y me hod (Möh ing and Rüping 2008, Hanewinkel e al. 2014a, Bla e e al. 2018). Howe e , he economic iabili y o any ha es ing ac i i y also has o be accu a ely calcula ed wi hin he amewo k o sho - e m planning. Such a p elimina y calcula ion also p o ides a solid basis o o es owne s’ nego ia ions wi h imbe ha es ing se ice p o ide s and imbe buye s, as well as o con olling imbe anspo . In bo h long- e m and sho - e m o es manage- men planning, he cos s o imbe ha es ing and he e enues om ma ke able p oduc s need o be quan i- ied using models. This p e-cos ing co e s h ee a eas: Þ es ima ing he quan i y o imbe ha es ed pe ee species and imbe asso men Þ de e mining imbe e enues o he expec ed p oduc s and quan i ies Þ de i ing imbe ha es ing cos s o he unde - lying condi ions (i.e. opog aphy, ha es ing egime). In Swi ze land, he e a e compu e based models o calcula ing imbe ha es ing cos s (poin 3), in- cluding he imbe ha es ing p oduc i i y model HeP oMo1 (F u ig e al. 2009). The ma ke able p od- uc s can be de e mined by es ima ing he po en ial asso men s (poin 2) in indi idual ees. Pa icula ly sui able o his pu pose a e IT-suppo ed models which, based on jus a small amoun o in o ma ion, such as ee species, diame e a b eas heigh (DBH) and age (o heigh ), simula e he s em o ms o indi- idual ees, ma ch ees wi h gi en asso men s and de e mine hei olumes. In Ge many, ins umen s al eady exis o his pu pose and a e implemen ed wi h he models Holze n e 8.1 (FVA 2013) and Wald- Plane (Hansen and Nagel 2014). In addi ion, he So - Sim 2.0 asso men simula o is now a ailable in Swi - ze land o his pu pose. So Sim is a so wa e o 1 www.wsl.ch/en/se ices-and-p oduc s/so wa e-websi es-and-apps/hep omo.h ml (May 2018) p ac i ione s and can be used in o he applica ions o calcula e eely de inable asso men s o di e en ee species and he expec ed imbe e enues. The so - wa e was de eloped a he Swiss Fede al Ins i u e o Fo es , Snow and Landscape Resea ch (WSL). A i s p o o ype o he So Sim asso men simula o was de- signed and implemen ed by Lemm and E ni (2009). In 2012 i was eimplemen ed in Ja a as e sion 2.0 (Holm e al. 2012). So Sim now suppo s he display languages Ge man, F ench and English. The use manual p o ides a de ailed desc ip ion o all i s unc- ions and he unde lying calcula ion me hods (Holm e al. 2012). This a icle has wo aims. The i s is o desc ibe he undamen als and he me hodological concep o So - Sim. This includes he desc ip ion o he equi ed in- pu da a, me hods o modelling he s em o m, c i e- ia and equi emen s o di iding he s em and eco ding i s quali y and e enues, and algo i hms o classi ying he s em in o asso men s. The second aim is o demons a e how So Sim can be applied in bo h p ac ice and esea ch. The p ac ical example shows how a lis o ees can be so ed and analysed o de e - mine he asso men s o each indi idual ee. The e- sea ch example uses wo expe imen al plo s (an e en- aged s and and a selec ion s and) o analyse how s ongly an assessmen o he ad an ages and disad- an ages o wo di e en sil icul u al s a egies de- pends on he ime a which he e alua ion is made. Based on his o ical and cu en cos app oaches, im- be p ices and ha es ing p oduc i i y, he p o i abil- i y o an e en-aged s and is compa ed wi h ha o a selec ion s and. 2. Ma e ial and Me hods 2.1 How Does he Asso men Simula o Wo k? 2.1.1 Basic Me hod Wi h he So Sim asso men simula o , a lis o ees can be so ed in o ma ke able asso men s ac- co ding o a ange o speci ica ions. A g oss imbe e enue can hus be calcula ed on he basis o quali y pe cen ages and imbe p ices. The classi ica ion o a gi en ee in o asso men s akes place a he s em base, s a ing wi h a a iable s ump heigh (de aul = 30 cm). The algo i hn hen checks whe he an asso men has he equi ed mid- o op-diame e speci ica ions. Asso men s a e as- signed in he o de se ou in he selec ed so ing s a - egy, usually aking he s onges and mos aluable asso men s i s . Consequen ly, So Sim does no ye op imise he alue o an en i e o es s and. Once a Imp o ing Economic Managemen Decisions in Fo es y wi h he So Sim Asso men Model (71–83) R. Lemm e al. C oa . j. o . eng. 41(2020)1 73 sui able posi ion o an asso men is ound, he ol- ume o he piece is de e mined. Inc emen al a emp s a e made (e.g. in 50 cm s eps) o leng hen he asso - men as much as possible wi hin he limi s o i s de- ined dimensions. Nex , he esul ing asso men is p ocessed and, aking in o accoun any addi ional leng h, a new posi ion on he s em is ma ked o he nex asso men . So Sim cu en ly designa es all pa s o he ee unsui able o use as s em wood (e.g. ee c own). Ow- ing o hei expansi e c owns, deciduous ees a e only di ided in o saw wood up o he base o he c own. The c own base o he di e en ee species is calcula ed acco ding o Döbbele (2002). The olume de e mina ion o he ee s em is based on he o a- ional body o he s em o m a ound i s e ical axis. A cubic spline in e pola ion can be used o model he s em o m based on he solid empi ical da abase o almos 40,000 indi idual ees measu ed in he Swiss Na ional Fo es In en o y (NFI) (B assel and Lischke 2001). The inpu a iables a e ee heigh , ee species, diame e a b eas heigh (DBH) and diame e a a heigh o 7 m (d7m). I measu ed alues a e no a ail- able, d7m can al e na i ely be calcula ed based on he o m quo ien d7m/DBH de i ed om NFI su eys. This e y p ecise spline unc ion was used in he ol- lowing examples. Ano he op ion would be o use he s em o m unc ion desc ibed by Lemm (1991). This unc ion models he s em o m o ees using species and DBH as he only a ibu es, acco ding o G undne and Schwappach (1952). Ba k unc ions a e based on in es iga ions by he Fo es Resea ch Ins i u e o Baden-Wü embe g (FVA) (Al he 1974). The unc- ions desc ibed by (Badoux 1979) a e inally used o deduce he olume o ba k. The asso men speci ica ions used o classi y ees a e cu en ly based on he Swiss asso men guide- lines o aw imbe (Table 1) (Waldwi scha Schweiz 2010). These classes can be modi ied in he asso men speci ica ion ile. Fu he mo e, he maximum op di- ame e up o which ound imbe is so ed can be se , as well as he minimum diame e below which s em sec ions a e o be designa ed as class ze o ( o ene gy- ela ed o ma e ial use). Howe e , alongside he as- so men speci ica ions o Swi ze land, i is also a simple ma e o implemen o he coun y-speci ic as- so men guidelines o aw imbe . The asso men p ices and quali y p opo ions pe asso men speci ied in he model can also be amend- ed as equi ed. The speci ied asso men p ices cu - en ly se as de aul alues a e based on p ices ecom- mended in Swi ze land in he o es yea 2017/2018. Quali y p opo ions a e based on empi ical alues om he WSL esea ch o es a Wagen ain (in he can- on o Aa gau) (Rosse e al. 2009). Timbe e enues om each ee a e calcula ed based on each asso men quan i y, p ice and quali y p opo ion. 2.1.2 Use In e ace On he main sc een o So Sim, he »Fi asso men in ee lis « sub-applica ion consis s o he panels »T ee lis «, »Timbe asso men speci ica ion«, »Exp ession o esul s« and »Summa y o he esul s« (Fig. 1). Based on he equi ed inpu a iables, he s em o ms o a se o ees a e modelled and di ided in o a se o asso - men s. In he »T ee lis « panel, a lis o ees is en e ed as inpu om a CSV ile. This is whe e indi idual ees a e lis ed, along wi h hei DBH and, i known, heigh and d7m. In he »Timbe asso men speci ica ion« panel, he classi ica ion c i e ia a e de ined in an ex e - nal CSV ile, in line wi h coun y-speci ic equi emen s. The main c i e ia used o dimension so ing a e s em leng h and mid- and op-diame e . The asso men lis is c ea ed in he »Exp ession o esul s« submenu (Fig. 1). By icking he »W i e gene a ed asso men lis o he ollowing ou pu ile« check box, asso men s can be expo ed in CSV o ma o a eely chosen ou pu ile. A summa y o he asso men s is displayed in he ex box in he »Summa y o he esul s« panel. Fu he de- ails can be ound in he use manual (Holm e al. 2012). Table 1 Asso men speci ica ions implemen ed in So Sim cu - en ly conside he Swiss asso men guidelines o aw imbe (Waldwi scha Schweiz 2010). The imbe is mainly ca ego ised acco ding o i s dimensions, based on he mid-diame e o he cu ees. T ee leng hs a e classi ied in o: sho imbe L1 (3.0–6.0 m), medium-long imbe L2 (6.5–14.5 m) o long imbe L3 (15.0–22.0 m). Deciduous wood is only classi ied as sho imbe L1 Classes Mid-diame e Minimum op diame e , only o L3 6≥60 cm 22 cm 550–59 cm 22 cm 440–49 cm 22 cm 3b 35–39 cm 18 cm 3a 30–34 cm 18 cm 2b 25–29 cm 18 cm 2a 20–24 cm 18 cm 1b 15–19 cm 14 cm 1a 10–14 cm – 0<10 cm – R. Lemm e al. Imp o ing Economic Managemen Decisions in Fo es y wi h he So Sim Asso men Model (71–83) 74 C oa . j. o . eng. 41(2020)1 2.2 Typical Applica ions and Da abase The ollowing wo examples o applica ions om o es p ac ice (Sec ion 2.2.1) and esea ch (Sec ion 2.2.2) demons a e possible use cases o So Sim. 2.2.1 Example 1 – T ee-Lis -Pased So ing In his i s example o a So Sim use case, asso - men s and hei co esponding e enues we e calcu- la ed based on he ee lis o a scheduled ha es ing ope a ion. A ques ion equen ly a ising in p ac ice is: Which asso men s and g oss ha es ing e enues can be expec ed i a gi en s and o No way sp uce (Picea abies L.), sil e i (Abies alba M.), Eu opean beech (Fagus syl a ica L.) and Eu opean ash (F axinus excelsio L.) ees a e ha es ed? The inpu da a equi ed by So Sim was a lis o he s and o be ha es ed in which he ees o be elled we e eco ded, speci ying hei species and DBH. In he »Fi asso men in ee lis « sub-applica ion, So Sim expec s a lis o ees o be di ided in o asso - men s (Fig. 1). Such a ee lis is a cs ile wi h a spe- ci ic s uc u e (Fig. 2). Commen lines always s a wi h a »#« and a e igno ed by he applica ion. Each ee o be assigned o an asso men is de ined in a sepa a e line. The ile can con ain an a bi a y numbe o commen lines and ee de ini ions. 2.2.2 Example 2 – Compa ison o Selec ion S ands and E en-Aged S ands The second example was a scien i ic analysis o s a egic planning o wo di e en ly ea ed sil icul- u al s ands. The op imal use o esou ces is a claim o he economic p inciple (Möh ing 2010) and hus a ques ion o which science can p o ide use ul assis- ance in answe ing. The ques ion in his example was: How does an a ea o selec ion o es di e om an a ea o e en-aged o es in e ms o asso men yield and ne e enue as a unc ion o dis inc cos and e - enue si ua ions? The e is cu en ly no uni o m pic u e o he condi ions unde which a selec ion s and can p o e inancially mo e success ul han an e en-aged high o es (Knoke 2009). Ou esea ch example can- no close his knowledge gap di ec ly, bu he esul s Fig. 1 Sc eensho o he So Sim asso men simula o (sub applica ion: »Fi asso men in ee lis «) Imp o ing Economic Managemen Decisions in Fo es y wi h he So Sim Asso men Model (71–83) R. Lemm e al. C oa . j. o . eng. 41(2020)1 75 in his example do highligh how e enue-based and cos -based app oaches in luence he ad an age o an e en-aged s and compa ed o a selec ion o es . The esea ch example was based on an ex ensi e se ies o measu emen s aken a wo expe imen al o - es yield es si es in Swi ze land: an e en-aged s and and a selec ion s and. Table 2 displays he basic cha - ac e is ics o bo h s ands and o he in o ma ion ele- an o hei managemen . The e en-aged s and wi h an a e age olume in- c ease o 18.5 m3 a-1 ha-1 was si ua ed on a mo e e ile si e han he selec ion s and wi h an a e age olume inc ease o 9.7 m3 a-1 ha-1 due o he sea le el. The selec- ion s and was i s in en o ied in 1928, he e en-aged s and in 1888. In hese wo in en o ies, he DBH and ee heigh o he s and o be elled and o he emain- ing s and we e eco ded. So Sim used cubic spline in e pola ion o calcula e he s em o m o each ee, wi h and wi hou ba k, om he DBH, d7m and ee heigh (B assel and Lischke 2001). The ees we e di- ided in o asso men s as sho imbe (L1), in line wi h he Swiss imbe asso men guidelines (Wald- wi scha Schweiz 2010). In each case, he asso men s and e enues o each s em we e calcula ed o di e en ee species and a di e en in en o y imes. The ha es ne e enues o he s and o be elled and o he emaining s and we e asce ained based on he o al yields o all ees and he imbe ha es ing cos s incu ed, which we e cal- cula ed wi h HeP oMo. This p oduced accu a e o e - iews o e 70 o 90 yea s o he s ands exis ence and hei managemen (e en-aged o selec ion), based on measu emen s o single s ems. Once he e enue and cos si ua ions o he s ands a e calcula ed, hey can be compa ed in e ms o hei economic e iciency, and he s a egies o ea ing hem can hen be assessed. Niede e and Bill (2015) showed ha nominal imbe p ices in 2015 we e only hal as high as hey had been in 1969, whe eas he labou cos s o imbe ha es ing had doubled. Na u ally, his has consequences o as- sessing he p o i abili y o a sil icul u al s a egy. The analysis in his example also included an examina ion o how he assessmen o he wo s a egies had changed be ween his o ical and mode n-day consid- e a ions. In he example, he egene a ion cos s o he e en- aged s and in he i s 15 yea s we e assumed o be 4800 CHF ha-1 in 1969 and 24,000 CHF ha-1 in 2018, conside ing he cos s o plan ing and ending. Due o he con inuous na u al egene a ion, no plan ing cos s we e aken in o accoun o he selec ion s and (Table 2). The nominal imbe p ices we e de ined pe asso - men o he yea 2018 and he p ice and quali y sha es we e based on he expe ience o a Swiss o es en e - p ise (Table 3). Fo he yea 1969, he nominal imbe p ices we e aken om he pe iod 1919 o 2014 o Swi ze land (a e age o sho imbe ) (Niede e and Bill 2015). The alloca ion o imbe p ices by asso - men in 1969 was based on a p opo ionali y ac o ha was de i ed om he nominal imbe p ice o 2018. The nominal ull cos s o 1969 we e aken om a ime se ies (1966 o 2017) o a Swiss o es en e p ise (Anon. 2018) and a e compa eable o hose o Niede e and Bill 2015. The cos o imbe ha es ing in 1969 was calcu- la ed using he olde HeP oMo models o »mo o - manual elling and p ocessing« and »skidding« (F u ig e al. 2009). These models a e based on da a om he 1970s. By con as , 2018 ha es ing cos s we e calcu- la ed using upda ed HeP oMo models based on da a om 2014–2016. Ha es ing o he e en-aged s and would p obably be ully mechanised in 2018, and hus he imbe ha es ing cos s we e also simula ed using he HeP oMo ha es e and o wa de models. The Fig. 2 Example o a lis wi h ees ha will be alloca ed in o ma ke able p oduc s using he asso men simula o So Sim R. Lemm e al. Imp o ing Economic Managemen Decisions in Fo es y wi h he So Sim Asso men Model (71–83) 76 C oa . j. o . eng. 41(2020)1 inpu a iables o HeP oMo we e he p opo ions o ee species, mean ee olume, skidding dis ances and cos s pe hou o pe sonnel and machine y. The Ne P esen Value (NPV) was used o compa e he syl icula u al s a egies unde he dis inc i e p ice and cos si ua ions (Klempe e 1996). The NPV de- pends on he selec ed discoun a e, which assumes a empo al p e e ence o cash lows and gi es less im- po ance o u u e e en s. Fo his example, he NPV was calcula ed o he discoun a es o 1% and 3%. The s a ing poin o he cacula ions was he ime o s and es ablishmen o he e en-aged and he i s in en o y o he selec ion s and (Table 1). Fo each s and, he NPV was calcula ed along he in en o y ime s eps. NPVP RC i LV i =- +- - () ++ () = å n n n 1 11 (1) Whe e: NPV ne p esen alue P cos o plan ing and ending R imbe e enue a in en o y ime s ep, C ha es ing cos a in en o y ime s ep, LV liquida ion alue o s and a end o in en o y, n i discoun a e, 1%, 3% 3. Resul s and Discussion 3.1 Example 1: T ee-Lis -Based So ing The aim o he i s example was o compu e as- so emen s and hei co esponding e enues o a scheduled ha es ing ope a ion. Based on he cs ile, which consis s o a lis o ees o be so ed, use s can c ea e hei own g aphics. Fig. 3a shows he diame e dis ibu ion o he ee lis ha was di ided in o as- Table 2 Desc ip ion o he wo long- e m expe imen al plo s in es iga ed in he scien i ic applica ion example. In bo h plo s, he ha es ed and he emaining s ands we e measu ed in each in en o y Cha ac e is ic E en-aged s and Selec ion o es (Plen e wald) Pe manen obse a ion a ea numbe 21,019,000 1,041,000 Loca ion, ele a ion (m a.s.l.) Ol en, 445 Rougemon Les A ses, 1294 Size, ha 0.25 1.50 Es ablishmen o s and, yea 1867 Con inuously since 1928 Fi s in en o y, yea 1888 1928 Las in en o y, yea 1963 2013 Ini ial g owing s ock ( i s in en o y), m3/ha 188 367 P opo ions o ee species, % 100 sp uce (Picea abies) i s in en o y: 60 sp uce (Picea abies), 40 i (Abies alba) las in en o y: 40 sp uce, 60 i Numbe o in en o ies, n 14 14 Time be ween wo in en o ies, yea s 4–14 4–10 Plan ing and ea men cos s du ing i s 15 yea s, CHF/ha 4800 24,000 none Table 3 Sou ces and assump ions o imbe p ices and ha es ing cos s Yea 1969 2018 Sou ce o imbe e enue His o ic imbe p ice se ies om 1919 o 2014 (Niede e and Bill 2015) Recommenda ions o oundwood sales 2017/2018 (www.waldaa gau.ch, May 2018) De ined ha es ing egimes o HeP oMo, ( imbe ha es da a on which he model was de i ed) ‘Mo o -manual elling’ and ‘skidding wi h skidde ’, da a basis 1970s ‘Mo o -manual elling’ and ‘skidding wi h skidde ’, da a basis 2014–2016 ‘Felling wi h ha es e ’ and ‘skidding wi h o wa de ’, da a basis 2014–2016 Sou ce o ha es ing cos s S a 9 CHF/ha, chainsaw 7 CHF/ha, skidde 40 CHF/ha (Niede e and Bill 2015, Anonymous 2018) S a 70 CHF/ha, chainsaw 14 CHF/ha, skidde 100 CHF/ha (www. us-e s.ch, May 2018) S a 70 CHF/ha, ha es e 240 CHF/ha, o wa de 120 CHF/ha (www. us-e s.ch, May 2018) Imp o ing Economic Managemen Decisions in Fo es y wi h he So Sim Asso men Model (71–83) R. Lemm e al. C oa . j. o . eng. 41(2020)1 77 so men s in he i s example. As displayed in Fig. 3b, asso men s we e alloca ed as saw wood up o ca ego- y 4 o beech and ash, and up o ca ego y 2 o so - wood. The emainde was so ed as esidual imbe (ca ego y 0), used o ene gy wood. Fo deciduous species, s em wood was only so ed up o he c own base. Thus, o beech a conside able amoun o imbe ends up as ene gy wood. Only a ew cubic me es o ound imbe ell in o ca ego y 4 o 5. Roughly he same p opo ion o imbe om ash ees ell in o ca - ego y 4. Mos sp uce imbe ell in o ca ego y 3 o 4, and mos i ell in o ca ego y 2 o 3. The calcula ed e enues indica e ha coni e spe- cies can be expec ed o make a la ge con ibu ion o he inancial esul (Fig. 3c). The asso men simula o gi es o es p ac i ione s a way o designa e asso men s Fig. 3 (a) Diame e dis ibu ion o he ee lis used as cs -inpu o So Sim. (b) Simula ed asso men olumes (m3, wi hou ba k) o he class L1 wi h a leng h o 3–6 m. (c) Simula ed economic alue (CHF) o asso men s based on cu en asso men p ices pe m3 (see Table 1) R. Lemm e al. Imp o ing Economic Managemen Decisions in Fo es y wi h he So Sim Asso men Model (71–83) 78 C oa . j. o . eng. 41(2020)1 acco ding o hei chosen so ing s a egy, compa e a ian s and imp o e he economic e iciency o imbe use. The ins umen e icien ly de e mines his speci ic in o ma ion. Apa om he p ac ical example desc ibed he e, So Sim was also es ed wi h h ee o es en e p ises using speci ic ha es ing ac i i ies. In mos cases, hese es s we e si ua ed in sp uce-domina ed o es s ands. Howe e , he es s also included s ands o i , la ch, beech and o he ha dwood species. The expec ed as- so men s we e calcula ed based on ee lis s. A e elling, he esul s o he imbe in en o y we e com- pa ed wi h he calcula ions. Compa ison o he inal p ocessed asso men s wi h p elimina y calcula ions om So Sim showed good co ela ion, hough occa- sional de ia ions occu ed o all ee species. In mos ins ances, hese cases could be explained by he his- o y o he espec i e o es s and and i s associa ed s uc u al and quali a i e consequences. 3.2 Example 2: Compa ison o a Selec ion S and and an E en-Aged S and The a ge o example wo was an economic analy- sis o di e en ly ea ed s ands. When in e p e ing he esul s o his example, i should be no ed ha he alue o he e en-aged s and has acc ued o e a pe- iod o 96 yea s, as opposed o a pe iod o jus 85 yea s o he selec ion s and. Figs. 4a and 4b show he e ec s o syl ical u al s a egies and he dis inc i e e enues and cos si ua- ions and he NPV. Þ In he yea 1969, he NPV was clea ly highe in he selec ion s and han in he e en-aged s and, unde bo h a discoun a e o 1% and 3%. A a discoun a e o 1%, he selec ion s and eached a alue o 84,560 CHF ha-1 a e 85 yea s. The co esponding alue in he e en-aged s and was 43,249 CHF ha–1 a e 96 yea s. The selec ion s and u he showed a con inous inc ease igh om he beginning, whe eas he NPV o he e en-aged s and emained almos cons an un il yea 40. Þ A a discoun a e o 3%, he NPV eached a alue o 34,896 CHF ha–1 a e 85 yea s in he selec ion s and and a alue o 3002 CHF ha–1 in he e en-aged s and. Þ Calcula ed wi h ha es ing cos s and e enues om 2018 (Fig. 4b), he selec ion s and showed again highe NPVs. I eacheed a alue o 23,460 CHF ha–1 a a discoun a e o 1% a e 85 yea s, whe eas he e en-aged s and ecie ed a alue o –29,984 CHF ha–1. Þ A a discoun a e o 3%, he selec ion s and showed a alue o 9153 CHF ha–1 a e 85 yea s and he e en-aged s and eached a alue o –28,649 CHF ha–1. Þ When compa ing he 1% s he 3% discoun ing a es o he e en aged s and 2018, we can see he ollowing: In he i s yea s, he NPV wi h 1% discoun ing a e was much lowe han ha wi h 3%. Howe e , in he second hal o he pe- iod hey app oached and eached abou he same le el a e 96 yea s. This can be explained by he ac ha he a o es a ion was expensi e and he i s hinnings we e no p o i able. These de ici s became less nega i e h ough highe discoun a es. Towa ds he end o he pe iod, howe e , he ha es ne e enues om hin- ning and inal cu became posi i e: hese posi- i e alues we e smalle wi h 3% discoun ing han wi h 1%. All in all, hese e ec s canceled each o he ou . Þ Nowadays, e en-aged s ands a e ha es ed us- ing highly mechanised and cos -e ec i e me h- ods whene e possible. The ha es ing cos s o ha es e s and o wa de s could be easily cal- cula ed hanks o HeP oMo. Unde he mecha- nised scena io, he NPV o he e en-aged s and achie ed a alue o –10,564 CHF ha–1 a a 1% and a alue o –24,026 CHF ha–1 a a 3% discoun a e a e 96 yea s. The mode n a ionalized ha es - ing me hods he e o e conside ably imp o ed he economic si ua ion om –27,125 CHF ha–1 o –10,564 CHF ha–1 a 1% and om –28,649 CHF ha–1 o –24,026 CHF ha–1 a 3% discoun ing. Þ While in he selec ion s and he mean s em ol- ume pe exploi a ion was 1–3 m3, in he e en- aged s and i was less han 1 m3 e en in olde s ands. This o cou se had a signi ican e ec on he cos s and e enues o imbe ha es . Þ The ne alue a he end o he obse a ion pe- iod showed s iking di e ences (Table 4). The asse s in he e en-aged s and we e concen a ed in he inal s ock, which ep esen s a high isk. In he case o he selc ion s and, on he o he hand, he inc ease in alue was con inuously ha es ed. The alue o he s and was he e o e ela i ely low. O e all, i is ema kable ha he selec ion s and, al hough g owing on a hal as e ile si e as he e en- aged s and, s ill pe o med much be e . The judge- men , which s and is in ad an age, has no changed