Wood biology
   
We present investigations of wood formation which started in 1999.
   
Samples for investigations are taken from living trees.
   
Processes of wood formation are affected by different factors like temperature and precipitation.
   
We use light microscopy to study cell wall formation in the wood. Double staining enables us to distinguish between differentiating cells (red and blue color) and completely differentiated cells (red color).
   
Transmission Electron Microscope (TEM) enables observation of cell wall layers and degree pf their lignification. Mature tracheids in conifers have following cell-wall layers: M, P, S1, S2, S3, and W. Darker areas contain more lignin.
   

Tracheids in process of differentiation containing following cell wall layers: M, P, S1 and S2. The layers S3 and W are not yet formed. S2 is not entirely lignified.

Transmission electron microscopy was done in cooperation with Dr. Jasna Štrus and her team from the Laboratory for Histology and Electron Microscopy, Department of Biology, Biotechnical Faculty, Ljubljana and Dr. Uwe Schmitt and his team from the Federal Research Centre for Forestry and Forest Products and University of Hamburg, Germany.
   
Degree of lignification in cell wall as determined by UV-microspectrophotometry (UMSP). Picture from Schmitt et al. 2003.
   
   
References (please write us if you are interested to receive a reprint):

GRIČAR, Jožica, GRÜNWALD, Claudia, SCHMITT, Uwe, ČUFAR, Katarina. Lignification of latewood tracheids in silver fir - a comparison of healty and declining trees. V: BUČAR, Bojan (ur.). Proceedings of the Fifth International Conference on the Development of Wood Science, Wood Technology and Forestry, ICWSF 2001, 5th - 7th September 2001, Ljubljana, Slovenia. Ljubljana: Biotechnical Faculty, Department of Wood Science and Technology, 2001, str. 341-346.

SCHMITT, Uwe, GRÜNWALD, Claudia, GRIČAR, Jožica, KOCH, Gerald, ČUFAR, Katarina. Wall structure of terminal latewood tracheids of healty and declining silver fir trees in the dinaric region, Slovenia. IAWA j., 2003, vol. 24, no. 1, str. 41-51.

GRIČAR, Jožica, ČUFAR, Katarina, SCHMITT, Uwe. Diferenciacija terminalnih traheid kasnega lesa pri navadni jelki v dormantnem obdobju = Differentiation of terminal latewood tracheids in silver fir during dormant period. Les (Ljublj.), 2003, let. 55, št. 12, str. 412-415.

GRIĆAR, Jožica, STRAŽE, Aleš, ČUFAR, Katarina. Differentiation of last formed tracheids in wood of silver firs (Abies alba) having various cambial productivity = Diferenciacija zadnjih nastalih traheid v lesu jelk (Abies alba) z razlicno produktivnim kambijem. Zb. gozd. lesar., 2003, št. 70, str. 87-100.

   
Investigations of silver fir Abies alba  
   
Investigations of silver fir (Abies alba) started in 1980s when a strong decline of this species was observed all over Slovenia.
   
Reduced cambium productivity was observed in most trees. In trees with severely damaged crowns the tree-ring widths were reduced. In some cases the annual rings in the wood were missing.
   
The amount of wood produced by the cambium of a fir with healthy crown was approx. 6 times greater than the amount of wood produced by the cambium of a declining tree.
   
Extremely narrow (only two cells wide) tree rings and an incomplete ring in a tree with damaged crown (arrows).
   
Differentiating tracheids near the cambium in firs with variously productive cambium. The tree with the most productive cambium had the lowest cambium electrical resistance (CER=7.6).
   
   
Selected references (please write us if you are interested to receive a reprint):

TORELLI, Niko, ČUFAR, Katarina, ROBIČ, Dušan. Nekateri ksilotomski, fiziološki in gozdno gojitveni vidiki umiranja jelke v Sloveniji = Some xylotomical, physiological and silvicultural aspects of Silver fir dieback in Slovenia = Einige xylotomische, physiologische und waldbauliche Aspekte des Tannensterbens in Slowenien. Les (Ljublj.), 1986, let. 38, št. 11/12, str. 297-301.

TORELLI, Niko, KRIŽAJ, Bojana, OVEN, Primož, ZUPANČIČ, Martin, ČUFAR, Katarina. Schleimzellen in der Rinde und traumatische Harzkanale sterbender Tannen. Holz Roh- Werkst.. [Print ed.], 1992, 50, 6, str. 252.

ROBIČ, Dušan, ČUFAR, Katarina, KERMAVNAR, Andrej, TORELLI, Niko. Reprodukcijska rast pri jelki (Abies alba Mill.) v odvisnosti od stopnje prizadetosti dreves = Reproductive growth in silver fir (Abies alba Mill.) related to state of tree health. Gozd. vestn., 1993, 51, no. 2, str. 74-79.

ČUFAR, Katarina, ROBIČ, Dušan, TORELLI, Niko, KERMAVNAR, Andrej. Blütenbildung unterschiedlich geschädigter Weisstannen in Slowenien. Forst Holz (1988), 1994, jg. 49, nr. 2, str. 34-36

ČUFAR, Katarina, ROBIČ, Dušan, TORELLI, Niko, KERMAVNAR, Andrej. Phenology, occurrence of epicormic branches and reproductive growth on air-polluted silver firs. Acta pharm. (Zagreb), 1995, 45, no. 2, suppl. 1, str. 379-381. KRIŽAJ, Bojana, ČUFAR, Katarina, ZUPANČIČ, Martin. Characteristics of "barrier zone" and wood formed after wounding in silver fir(Abies alba Mill.). Acta pharm. (Zagreb), 1995, 45, no. 2, suppl. 1, str. 383-385. [COBISS.SI-ID 19849]

LEVANIČ, Tom, ČUFAR, Katarina. Three local silver fir (Abies alba Mill.) chronologies from the Dinaric phytogeographic region of Slovenia. Dendrochronologia (Verona), 1995, vol. 13, str. 127-134.

LEVANIČ, Tom, ČUFAR, Katarina. Primerjava standardnih kronologij jelke (Abies alba Mill.) v dinarski fitogeografski regiji Slovenije = Comparision of standard chronologies of silver fir (Abies alba Mill.) in Dinaric phytogeografical region in Slovenia. Zb. gozd. lesar., 1995, št. 46, str. 131-144.

TORELLI, Niko, ČUFAR, Katarina, OVEN, Primož. Bioelectrical characterization of tree conditions and slime cells in the bark as possible symptoms of silver fir decline. Phyton (Horn), 1996, vol. 36, no. 3, str. 35-38.

ČUFAR, Katarina, ROBIČ, Dušan, TORELLI, Niko, KERMAVNAR, Andrej. Die Phänologie von unterschiedlich geschädigten Weisstannen (Abies alba Mill.) in Slowenien. Schweiz. Z. Forstwes., 1996, 147, nr. 2, str. 99-108.

ČUFAR, Katarina. Umiranja jelke (Abies alba Mill.) v Sloveniji : pregled raziskav katedre za tehnologijo lesa = Silver fir (Abies alba Mill.) decline in Slovenia : a review of the investigations carried out by the chair of wood science. V: ROBEK, Robert (ur.). Proučevanje propadanja gozdov v Sloveniji v obdobju 1985-1995, (Zbornik gozdarstva in lesarstva, Tematska številka, 52). Ljubljana: Gozdarski inštitut: Biotehniška fakulteta, Oddelek za gozdarstvo: Biotehniška fakulteta, Oddelek za lesarstvo, 1997, str. 165-186.

LEVANIČ, Tom, ČUFAR, Katarina. The chronology of the silver fir (Abies alba Mill.) from Pohorje, Slovenia = Kronologija jelke (Abies alba Mill.) za obmocje Pohorja. Zb. gozd. lesar., 1998, 55, str. 135-149.

TORELLI, Niko, SHORTLE, W.C., ČUFAR, Katarina, FERLIN, Franc, SMITH, K.T. Detecting changes in tree health and productivity of silver fir in Slovenia. Eur. j. for. pathol., 1999, vol. 29, no. 3, str. 189-197, graf. prikazi, pregl., fotogr.

SMITH, Kevin T., ČUFAR, Katarina, LEVANIČ, Tom. Temporal stability and dendroclimatology in silver fir and red spruce. Phyton (Horn), 1999, vol. 39, fasc. 3, str. 117-122.