Sanni Raiskila,
Minna Pulkkinen,
Tapio Laakso,
Kurt Fagerstedt,
Mia Löija,
Riitta Mahlberg,
Leena Paajanen,
Anne-Christine Ritschkoff,
Pekka Saranpää 
FTIR spectroscopic prediction of Klason and acid soluble lignin variation in Norway spruce cutting clones
Raiskila S., Pulkkinen M., Laakso T., Fagerstedt K., Löija M., Mahlberg R., Paajanen L., Ritschkoff A.-C., Saranpää P. (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
Abstract
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.
Keywords
Norway spruce;
FTIR;
lignin;
PCR;
principal component regression
- Raiskila, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail sr@nn.fi
- Pulkkinen, Department of Forest Ecology, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail mp@nn.fi
- Laakso, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail tl@nn.fi
- Fagerstedt, Department of Biological and Environmental Sciences, Plant Biology, P.O. Box 65, FI-00014 University of Helsinki, Finland E-mail kf@nn.fi
- Löija, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland E-mail ml@nn.fi
- Mahlberg, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland E-mail rm@nn.fi
- Paajanen, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland E-mail lp@nn.fi
- Ritschkoff, VTT Building and Transport, P.O. Box 1806, FI-02044 VTT, Finland E-mail acr@nn.fi
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Saranpää,
Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland
E-mail
pekka.saranpaa@metla.fi
Received 26 June 2006 Accepted 13 March 2007 Published 31 December 2007
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