Pub Date : 2020-12-30DOI: 10.26614/les-wood.2020.v69n02a05
Katarina Remic, Miran Merhar
V delu smo izvedli analizo optimizacije procesa obdelave umetniškega lesenega izdelka (okvir ogledala) na 3-osnem CNC stroju. Iz grafične slike smo najprej v programu ArtCAM izdelali 3D model, triangulirali njegovo površino in ustvarili STL datoteko. To smo naložili v program SolidWorks, kjer smo z njegovim dodatkom SolidCAM določili parametre obdelave. Grobo obdelavo smo določili z operacijami HSR (high speed roughing), fino pa s HSM (high speed machining). Posamezne operacije smo primerjali in ugotovili, da bi najkrajši čas obdelave pri najboljši kvaliteti dobili pri izbiri HSR operacij »Contour Roughing«nato »Rest Roughing« ter HSM operacije »3D Constant Step Over«, znašal pa bi 4 ure in 1 minuto. Izdelano kodo smo preverili s simulacijo izdelave ter na koncu izdelali G kodo za naš izdelek.
{"title":"Optimizacija CNC tehnologije pri izdelavi umetniškega izdelka","authors":"Katarina Remic, Miran Merhar","doi":"10.26614/les-wood.2020.v69n02a05","DOIUrl":"https://doi.org/10.26614/les-wood.2020.v69n02a05","url":null,"abstract":"V delu smo izvedli analizo optimizacije procesa obdelave umetniškega lesenega izdelka (okvir ogledala) na 3-osnem CNC stroju. Iz grafične slike smo najprej v programu ArtCAM izdelali 3D model, triangulirali njegovo površino in ustvarili STL datoteko. To smo naložili v program SolidWorks, kjer smo z njegovim dodatkom SolidCAM določili parametre obdelave. Grobo obdelavo smo določili z operacijami HSR (high speed roughing), fino pa s HSM (high speed machining). Posamezne operacije smo primerjali in ugotovili, da bi najkrajši čas obdelave pri najboljši kvaliteti dobili pri izbiri HSR operacij »Contour Roughing«nato »Rest Roughing« ter HSM operacije »3D Constant Step Over«, znašal pa bi 4 ure in 1 minuto. Izdelano kodo smo preverili s simulacijo izdelave ter na koncu izdelali G kodo za naš izdelek.","PeriodicalId":52851,"journal":{"name":"Les","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48201450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-30DOI: 10.26614/les-wood.2020.v69n02a01
Boštjan Lesar, Miha Humar
Krožno gospodarstvo in uporaba sekundarnih surovin postajata vedno polj pomembna. Uporaba odsluženega lesa za materialno izrabo je trenutno še zelo slabo izkoriščena. Večino odsluženega lesa se namreč porabi v energetske namene. Eden od potencialnih virov odsluženega lesa so tudi stara lesena okna. Večino oken se v današnjem času zamenja zaradi neustreznih energetskih karakteristik, medem ko je les večine zamenjanih oken še brez znakov razkroja. Težavo pri uporabi lesa odsluženih oken za proizvodnjo novih izdelkov predstavljajo predvsem površinski premazi. V raziskavi smo preverili vpliv starosti, tipa in površinske obdelave na delež onesnažil. Iz okenskih profilov smo najprej odstranili vse nelesne materiale, profile razžagali po debelini, ter s tem preverili, kako globoko v les so prodrla anorganska onesnažila. Les smo analizirali z rentgenskim fluorescenčnim spektrometrom (in določili deleže posameznih anorganskih onesnažil (Cr, Cu, Cl, Fe, Zn, Pb). Rezultati so pokazali, da odslužena okna vsebujejo anorganska onesnažila zgolj na površini (do 5 mm globoko), količine onesnažil močno variirajo glede na starost oken in uporabljeno površinsko zaščito. Raziskava je pokazala, da so odslužena okna lahko surovina za proizvodnjo novih izdelkov in materialov, ob pogoju, da pred uporabo odstranimo površinski sloj.
{"title":"Anorganska onesnažila v odsluženih oknih","authors":"Boštjan Lesar, Miha Humar","doi":"10.26614/les-wood.2020.v69n02a01","DOIUrl":"https://doi.org/10.26614/les-wood.2020.v69n02a01","url":null,"abstract":"Krožno gospodarstvo in uporaba sekundarnih surovin postajata vedno polj pomembna. Uporaba odsluženega lesa za materialno izrabo je trenutno še zelo slabo izkoriščena. Večino odsluženega lesa se namreč porabi v energetske namene. Eden od potencialnih virov odsluženega lesa so tudi stara lesena okna. Večino oken se v današnjem času zamenja zaradi neustreznih energetskih karakteristik, medem ko je les večine zamenjanih oken še brez znakov razkroja. Težavo pri uporabi lesa odsluženih oken za proizvodnjo novih izdelkov predstavljajo predvsem površinski premazi. V raziskavi smo preverili vpliv starosti, tipa in površinske obdelave na delež onesnažil. Iz okenskih profilov smo najprej odstranili vse nelesne materiale, profile razžagali po debelini, ter s tem preverili, kako globoko v les so prodrla anorganska onesnažila. Les smo analizirali z rentgenskim fluorescenčnim spektrometrom (in določili deleže posameznih anorganskih onesnažil (Cr, Cu, Cl, Fe, Zn, Pb). Rezultati so pokazali, da odslužena okna vsebujejo anorganska onesnažila zgolj na površini (do 5 mm globoko), količine onesnažil močno variirajo glede na starost oken in uporabljeno površinsko zaščito. Raziskava je pokazala, da so odslužena okna lahko surovina za proizvodnjo novih izdelkov in materialov, ob pogoju, da pred uporabo odstranimo površinski sloj.","PeriodicalId":52851,"journal":{"name":"Les","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49251250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-30DOI: 10.26614/les-wood.2020.v69n02a04
Toni Šauperl, Jaša Saražin, M. Šernek
V prispevku je predstavljen razvoj strižne trdnosti dveh polivinilacetatnih (PVAc) lepil: Mekol D3 in Mekol SPECIAL pri lepljenju furnirja v odvisnosti od časa stiskanja. Poleg testiranja trdnosti lepilnega spoja po vročem stiskanju smo proučevali tudi vpliv hlajenja na končno trdnost PVAc lepilnega spoja. Graditev strižne trdnosti PVAc lepilnega spoja med vročim stiskanjem smo ugotavljali s pomočjo sistema za avtomatizirano vrednotenje zlepljenosti (ABES). Temperatura stiskanja je bila konstantna in je znašala 80 °C medtem, ko smo čas stiskanja povečevali od 30 do 300 sekund s 30-sekundnimi intervali. Vpliv hlajenja na končno trdnost PVAc lepilnega spoja smo ugotavljali po 5-sekundnem in 30-sekundnem hlajenju. Na podlagi raziskave smo ugotovili, da je strižna trdnost PVAc lepilnih spojev naraščala s časom stiskanja in se je po določenem času približala konstantni vrednosti. Ugotovili smo značilne razlike v trdnosti spojev, zlepljenjih z Mekol D3 in Mekol SPECIAL ter statistično značilen vpliv hlajenja na trdnost lepilnih spojev.
{"title":"Razvoj trdnosti polivinilacetatnega lepilnega spoja pri lepljenju furnirja","authors":"Toni Šauperl, Jaša Saražin, M. Šernek","doi":"10.26614/les-wood.2020.v69n02a04","DOIUrl":"https://doi.org/10.26614/les-wood.2020.v69n02a04","url":null,"abstract":"V prispevku je predstavljen razvoj strižne trdnosti dveh polivinilacetatnih (PVAc) lepil: Mekol D3 in Mekol SPECIAL pri lepljenju furnirja v odvisnosti od časa stiskanja. Poleg testiranja trdnosti lepilnega spoja po vročem stiskanju smo proučevali tudi vpliv hlajenja na končno trdnost PVAc lepilnega spoja. Graditev strižne trdnosti PVAc lepilnega spoja med vročim stiskanjem smo ugotavljali s pomočjo sistema za avtomatizirano vrednotenje zlepljenosti (ABES). Temperatura stiskanja je bila konstantna in je znašala 80 °C medtem, ko smo čas stiskanja povečevali od 30 do 300 sekund s 30-sekundnimi intervali. Vpliv hlajenja na končno trdnost PVAc lepilnega spoja smo ugotavljali po 5-sekundnem in 30-sekundnem hlajenju. Na podlagi raziskave smo ugotovili, da je strižna trdnost PVAc lepilnih spojev naraščala s časom stiskanja in se je po določenem času približala konstantni vrednosti. Ugotovili smo značilne razlike v trdnosti spojev, zlepljenjih z Mekol D3 in Mekol SPECIAL ter statistično značilen vpliv hlajenja na trdnost lepilnih spojev.","PeriodicalId":52851,"journal":{"name":"Les","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44471612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-30DOI: 10.26614/les-wood.2020.v69n02a07
M. Merhar
V raziskavi smo primerjali vrednosti dinamičnega in statičnega modula elastičnosti 7- in 11-slojne vezane plošče z različnimi kombinacijami usmeritve tkiva posameznih slojev furnirjev. Dinamični modul smo določili iz lastnih frekvenc prvega in drugega nihajnega načina nihanja, kjer smo uporabili Bernoulli-Eulerjevo enačbo, statični modul pa s 4-točkovnim upogibnim testom. Rezultati so pokazali, da ima vezana plošča največji modul elastičnosti pri usmeritvi tkiva zunanjega sloja 0°, nato pa z naraščanjem kota modul pada. Dinamični modul je od statičnega v povprečju za 12 % večji pri 7-slojnih ploščah in za 14 % pri 11-slojnih ploščah. Dinamični modul, določen iz druge lastne frekvence, je v primerih, kjer ni vpliva striga, enak modulu iz prve lastne frekvence, ko pa se pojavi vpliv striga, se modul zniža. Iz omenjene raziskave lahko potrdimo, da sta tako statični kot tudi dinamični način določanja modula elastičnosti vzorcev vezane plošče ustrezna, vendar pa je treba pri dinamičnem načinu preveriti vpliv striga.
{"title":"Določanje statičnega in dinamičnega modula elastičnosti bukove vezane plošče","authors":"M. Merhar","doi":"10.26614/les-wood.2020.v69n02a07","DOIUrl":"https://doi.org/10.26614/les-wood.2020.v69n02a07","url":null,"abstract":"V raziskavi smo primerjali vrednosti dinamičnega in statičnega modula elastičnosti 7- in 11-slojne vezane plošče z različnimi kombinacijami usmeritve tkiva posameznih slojev furnirjev. Dinamični modul smo določili iz lastnih frekvenc prvega in drugega nihajnega načina nihanja, kjer smo uporabili Bernoulli-Eulerjevo enačbo, statični modul pa s 4-točkovnim upogibnim testom. Rezultati so pokazali, da ima vezana plošča največji modul elastičnosti pri usmeritvi tkiva zunanjega sloja 0°, nato pa z naraščanjem kota modul pada. Dinamični modul je od statičnega v povprečju za 12 % večji pri 7-slojnih ploščah in za 14 % pri 11-slojnih ploščah. Dinamični modul, določen iz druge lastne frekvence, je v primerih, kjer ni vpliva striga, enak modulu iz prve lastne frekvence, ko pa se pojavi vpliv striga, se modul zniža. Iz omenjene raziskave lahko potrdimo, da sta tako statični kot tudi dinamični način določanja modula elastičnosti vzorcev vezane plošče ustrezna, vendar pa je treba pri dinamičnem načinu preveriti vpliv striga.","PeriodicalId":52851,"journal":{"name":"Les","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43627177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-30DOI: 10.26614/les-wood.2020.v69n02a03
S. Dahle, J. Žigon, M. Petrić, M. Kariž
The effects of dielectric barrier discharge (DBD) plasma treatment on the dielectric properties of Norway spruce wood (Picea abies (L.) Karst.) were investigated using dielectric analysis. Dielectric constant (i.e. permittivity) and loss coefficient were determined at various frequencies. The resulting changes on lamellae specimens of different thicknesses were compared with the change in mass and moisture content. A significant influence of the plasma was found, leading to an increase of the dielectric constant by about 2%, and a decrease of sample mass directly after the plasma treatment by approx. 14%, whereas a reduction in moisture content by only about 0.6% and a corresponding change in loss coefficient were detected. Overall, the mechanisms of the observed changes remain unclear and seem mainly uncorrelated with the hitherto known chemical changes in wood surfaces caused by similar plasma discharges.
{"title":"Plasma treatment of spruce wood changes its dielectric properties","authors":"S. Dahle, J. Žigon, M. Petrić, M. Kariž","doi":"10.26614/les-wood.2020.v69n02a03","DOIUrl":"https://doi.org/10.26614/les-wood.2020.v69n02a03","url":null,"abstract":"The effects of dielectric barrier discharge (DBD) plasma treatment on the dielectric properties of Norway spruce wood (Picea abies (L.) Karst.) were investigated using dielectric analysis. Dielectric constant (i.e. permittivity) and loss coefficient were determined at various frequencies. The resulting changes on lamellae specimens of different thicknesses were compared with the change in mass and moisture content. A significant influence of the plasma was found, leading to an increase of the dielectric constant by about 2%, and a decrease of sample mass directly after the plasma treatment by approx. 14%, whereas a reduction in moisture content by only about 0.6% and a corresponding change in loss coefficient were detected. Overall, the mechanisms of the observed changes remain unclear and seem mainly uncorrelated with the hitherto known chemical changes in wood surfaces caused by similar plasma discharges.","PeriodicalId":52851,"journal":{"name":"Les","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42942011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-30DOI: 10.26614/les-wood.2020.v69n02a02
A. Balzano, K. Čufar, Luka Krže, M. Merela
Wood identification of barbecue charcoal from commercial packages of three retailers (B1, B2, B3) in Slovenia and Croatia was performed with help of Confocal Laser Scanning Microscopy (CLSM). CLSM enabled us to image key identification features of charcoal wood that were compared with light micrographs of wood from the reference collection. Product B1 contained charcoal made exclusively of beech wood (Fagus sylvatica) and the declaration indicated the address of the producer, in Serbia which allowed traceability of the wood. The selection of wood species in product B2, consisted of red oak (Quercus cerris or Q. rubra), black locust (Robinia pseudoacacia), and cherry (Prunus avium), which could originate from Serbia, and it did not contain tropical wood as stated on the package. Product B3 contained wood from at least four (sub)topical species which could not be exactly identified to species/genus level. The declaration on the product did not allow traceability of wood. As the risks of illegal logging are high for wood of (sub)tropical origin, our results support the initiative that the monitoring of the charcoal trade should be covered by the EUTR - European Timber Regulations.
{"title":"Wood identification of charcoal with Confocal Laser Scanning Microscopy","authors":"A. Balzano, K. Čufar, Luka Krže, M. Merela","doi":"10.26614/les-wood.2020.v69n02a02","DOIUrl":"https://doi.org/10.26614/les-wood.2020.v69n02a02","url":null,"abstract":"Wood identification of barbecue charcoal from commercial packages of three retailers (B1, B2, B3) in Slovenia and Croatia was performed with help of Confocal Laser Scanning Microscopy (CLSM). CLSM enabled us to image key identification features of charcoal wood that were compared with light micrographs of wood from the reference collection. Product B1 contained charcoal made exclusively of beech wood (Fagus sylvatica) and the declaration indicated the address of the producer, in Serbia which allowed traceability of the wood. The selection of wood species in product B2, consisted of red oak (Quercus cerris or Q. rubra), black locust (Robinia pseudoacacia), and cherry (Prunus avium), which could originate from Serbia, and it did not contain tropical wood as stated on the package. Product B3 contained wood from at least four (sub)topical species which could not be exactly identified to species/genus level. The declaration on the product did not allow traceability of wood. As the risks of illegal logging are high for wood of (sub)tropical origin, our results support the initiative that the monitoring of the charcoal trade should be covered by the EUTR - European Timber Regulations.","PeriodicalId":52851,"journal":{"name":"Les","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41530258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-30DOI: 10.26614/les-wood.2020.v69n02a06
Monika Horvat, Jernej Iskra, Matjaž Pavlič, Jure Žigon, Maks Merela
Cilj raziskave je bil pripraviti različne tipe premazov na osnovi naravnih barvil, pridobljenih iz invazivnih tujerodnih rastlin ter iz ostankov proizvodnje papirja. Kot vir barvil smo uporabili ekstrakte iz octovca, japonskega dresnika, žlezave nedotike ter kanadske in orjaške zlate rozge. Podlaga za premaze sta bila les velikega pajesena in les navadnega divjega kostanja. Premaze smo opazovali vizualno, hidrofobnost premazanih površin pa ugotavljali z metodo merjenja stičnih kotov kapljic vode. Poleg prozornih in rjavo obarvanih premazov smo dosegli tudi intenzivna obarvanja, od rdeče, rumene, zelene, rjave do vijolične barve. S kombinacijo različnih komponent so se spreminjale hidrofobne lastnosti premazanih površin. Uspelo nam je pridobiti premaz z izrazito hidrofobnostjo, in sicer iz kombinacije ekstrakta iz cvetov orjaške zlate rozge in 3-(trietoksisilil)propil izocianata. V okviru raziskave je bil razvit postopek za pripravo barvnih ter transparentnih hidrofobnih premazov. S prisotnimi različnimi silanskimi molekulami in z aplikacijo premazov na površine lesov smo tako spremenili njihov izgled in izboljšali njihovo hidrofobnost.
{"title":"Barvila za les iz tujerodnih invazivnih rastlin","authors":"Monika Horvat, Jernej Iskra, Matjaž Pavlič, Jure Žigon, Maks Merela","doi":"10.26614/les-wood.2020.v69n02a06","DOIUrl":"https://doi.org/10.26614/les-wood.2020.v69n02a06","url":null,"abstract":"Cilj raziskave je bil pripraviti različne tipe premazov na osnovi naravnih barvil, pridobljenih iz invazivnih tujerodnih rastlin ter iz ostankov proizvodnje papirja. Kot vir barvil smo uporabili ekstrakte iz octovca, japonskega dresnika, žlezave nedotike ter kanadske in orjaške zlate rozge. Podlaga za premaze sta bila les velikega pajesena in les navadnega divjega kostanja. Premaze smo opazovali vizualno, hidrofobnost premazanih površin pa ugotavljali z metodo merjenja stičnih kotov kapljic vode. Poleg prozornih in rjavo obarvanih premazov smo dosegli tudi intenzivna obarvanja, od rdeče, rumene, zelene, rjave do vijolične barve. S kombinacijo različnih komponent so se spreminjale hidrofobne lastnosti premazanih površin. Uspelo nam je pridobiti premaz z izrazito hidrofobnostjo, in sicer iz kombinacije ekstrakta iz cvetov orjaške zlate rozge in 3-(trietoksisilil)propil izocianata. \u0000V okviru raziskave je bil razvit postopek za pripravo barvnih ter transparentnih hidrofobnih premazov. S prisotnimi različnimi silanskimi molekulami in z aplikacijo premazov na površine lesov smo tako spremenili njihov izgled in izboljšali njihovo hidrofobnost.","PeriodicalId":52851,"journal":{"name":"Les","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69038635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-30DOI: 10.26614/les-wood.2020.v69n02a09
Nina Škrk, A. Balzano, Z. Črepinšek, K. Čufar
Temporal variability of leaf senescence (autumn phenology) was observed in 2020 in 11 European beech (Fagus sylvatica) trees in Tivoli, Rožnik and Šišenski hrib Landscape Park in Ljubljana, Slovenia, and also observed for spring phenology in the same year. General leaf colouring, BBCH94, occurred between 19 and 24 October 2020, with lower inter-individual variability than that of leaf unfolding, BBCH11. The trees had active leaves (time between leaf unfolding and leaf colouring) between 177 and 199 days. In only three trees total leaf fall, BBCH97, occurred before 19 November 2020. Leaf colouring of the tree included in the long-term monitoring program of the Slovenian Environment Agency ARSO occurred on 24 October 2020. This is 7 days later than the 65-year average of the same tree/location and is ascribed to weather conditions. Investigation of tree tissues showed that the width of the last formed tree-ring in the wood varied between 0.39 and 9.61 mm and in the phloem between 0.09 and 0.26 mm, and that the tissues reflect the health condition of the trees.
{"title":"Inter-tree variability of autumn leaf phenology of European beech (Fagus sylvatica) on a site in Ljubljana, Slovenia","authors":"Nina Škrk, A. Balzano, Z. Črepinšek, K. Čufar","doi":"10.26614/les-wood.2020.v69n02a09","DOIUrl":"https://doi.org/10.26614/les-wood.2020.v69n02a09","url":null,"abstract":"Temporal variability of leaf senescence (autumn phenology) was observed in 2020 in 11 European beech (Fagus sylvatica) trees in Tivoli, Rožnik and Šišenski hrib Landscape Park in Ljubljana, Slovenia, and also observed for spring phenology in the same year. General leaf colouring, BBCH94, occurred between 19 and 24 October 2020, with lower inter-individual variability than that of leaf unfolding, BBCH11. The trees had active leaves (time between leaf unfolding and leaf colouring) between 177 and 199 days. In only three trees total leaf fall, BBCH97, occurred before 19 November 2020. Leaf colouring of the tree included in the long-term monitoring program of the Slovenian Environment Agency ARSO occurred on 24 October 2020. This is 7 days later than the 65-year average of the same tree/location and is ascribed to weather conditions. Investigation of tree tissues showed that the width of the last formed tree-ring in the wood varied between 0.39 and 9.61 mm and in the phloem between 0.09 and 0.26 mm, and that the tissues reflect the health condition of the trees.","PeriodicalId":52851,"journal":{"name":"Les","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42800008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Vers des transports par voie navigable durables et compétitifs en Europe: Prochaines étapes et recommandations","authors":"","doi":"10.18356/781cf808-fr","DOIUrl":"https://doi.org/10.18356/781cf808-fr","url":null,"abstract":"","PeriodicalId":52851,"journal":{"name":"Les","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80403252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Cadres institutionnel et réglementaire de la navigation intérieure en Europe","authors":"","doi":"10.18356/7880d3dc-fr","DOIUrl":"https://doi.org/10.18356/7880d3dc-fr","url":null,"abstract":"","PeriodicalId":52851,"journal":{"name":"Les","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84208157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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