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Articles by Tapio Laakso

Category: Research article

article id 301, category Research article
Sanni Raiskila, Minna Pulkkinen, Tapio Laakso, Kurt Fagerstedt, Mia Löija, Riitta Mahlberg, Leena Paajanen, Anne-Christine Ritschkoff, Pekka Saranpää. (2007). FTIR spectroscopic prediction of Klason and acid soluble lignin variation in Norway spruce cutting clones. Silva Fennica vol. 41 no. 2 article id 301. https://doi.org/10.14214/sf.301
Our purpose was to develop a FTIR spectroscopic method to be used to determine the lignin content in a large number of samples and to apply this method studying variation in sapwood and heartwood lignin content between three fast-growing cutting clones grown in three sites. Models were estimated with 18 samples and tested with 6 samples for which the Klason lignin + acid soluble lignin content had been determined. Altogether 272 candidate models were built with all-subset regressions from the principal components estimated from differently treated transmission spectra of the samples; the spectra were recorded on KBr pellets of sieved and unsieved unextracted wood powder and subjected to four different preprocessings and two different wavenumber selection schemes. The final model showed an adequate fit in the estimation data (R2 = 0.74) as well as a good prediction performance in the test data (R2P = 0.90). This model was based on the wavenumber range of 1850–500 cm–1 of the line-subtraction-normalised spectra recorded from sieved samples. The model was used to predict lignin content in 64 samples of the same material. One of the clones had a slightly lower sapwood lignin content than the two other clones. The fertile growing site with fast growing trees showed slightly higher sapwood lignin content compared with the other two sites. The model was also used to predict the lignin content in the earlywood of 45 individual annual rings. Variation between individual stems and between annual rings was found to be large. No correlation was found between the lignin content and density of earlywood.
  • Raiskila, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Pulkkinen, Department of Forest Ecology, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Laakso, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Fagerstedt, Department of Biological and Environmental Sciences, Plant Biology, P.O. Box 65, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Löija, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland ORCID ID:E-mail:
  • Mahlberg, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland ORCID ID:E-mail:
  • Paajanen, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland ORCID ID:E-mail:
  • Ritschkoff, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland ORCID ID:E-mail:
  • Saranpää, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: pekka.saranpaa@metla.fi (email)
article id 341, category Research article
Sanni Raiskila, Pekka Saranpää, Kurt Fagerstedt, Tapio Laakso, Mia Löija, Riitta Mahlberg, Leena Paajanen, Anne-Christine Ritschkoff. (2006). Growth rate and wood properties of Norway spruce cutting clones on different sites. Silva Fennica vol. 40 no. 2 article id 341. https://doi.org/10.14214/sf.341
The effect of growth rate on weight density and strength properties of three Norway spruce cutting clones growing on three different sites in different geographic locations was studied. The purpose was to follow variation in wood physical and mechanical properties and in quality between fast-growing clones grown in environments differing in nutritional and soil properties and climate within the boreal zone. The cloned trees had been selected on grounds of good growth, health and quality. The cuttings were collected from three-year-old seedlings and rooted. The rooted cuttings were planted in the 1970’s and they were on average 26 years old at a time of felling. The variation of weight density was studied within the annual ring and within the stem between the juvenile and mature wood from the pith to the bark with an X-ray densitometric method. The average annual ring width (and latewood proportion, %) varied between the clones from 2.92±1.36 mm (15.34%) to 3.30±1.25 mm (11.80%) and between the sites from 2.76±1.07 mm (14.71%) to 3.70±1.22 mm (13.29%). The mean weight density was 0.461±0.077 g cm–3 and latewood density 0.750±0.125 g cm–3 in this material. The mean modulus of elasticity was 9.88±1.43 GPa, modulus of rupture 67.51±11.50 MPa and weight density of the test samples (ρ12) 414±44 kg m–3 in mature wood. The parameters studied showed clearly that the environment had a large effect while the three clones differed from each other similarly in the different sites, e.g. the fastest growing clone was fastest on all sites.
  • Raiskila, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Saranpää, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: pekka.saranpaa@metla.fi (email)
  • Fagerstedt, Department of Biological and Environmental Sciences, Plant Biology, P.O. Box 65, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Laakso, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Löija, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland ORCID ID:E-mail:
  • Mahlberg, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland ORCID ID:E-mail:
  • Paajanen, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland ORCID ID:E-mail:
  • Ritschkoff, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland ORCID ID:E-mail:

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