A1 Journal article (refereed)
Behaviour of Extractives in Norway Spruce (Picea abies) Bark during Pile Storage (2022)

Halmemies, E. S., Alén, R., Hellström, J., Läspä, O., Nurmi, J., Hujala, M., & Brännström, H. E. (2022). Behaviour of Extractives in Norway Spruce (Picea abies) Bark during Pile Storage. Molecules, 27(4), Article 1186. https://doi.org/10.3390/molecules27041186

JYU authors or editors

Publication details

All authors or editorsHalmemies, Eelis S.; Alén, Raimo; Hellström, Jarkko; Läspä, Otto; Nurmi, Juha; Hujala, Maija; Brännström, Hanna E.

Journal or seriesMolecules


Publication year2022

Publication date10/02/2022


Issue number4

Article number1186

PublisherMDPI AG

Publication countrySwitzerland

Publication languageEnglish


Publication open accessOpenly available

Publication channel open accessOpen Access channel

Publication is parallel published (JYX)https://jyx.jyu.fi/handle/123456789/80217


The current practices regarding the procurement chain of forest industry sidestreams, such as conifer bark, do not always lead to optimal conditions for preserving individual chemical compounds. This study investigates the standard way of storing bark in large piles in an open area. We mainly focus on the degradation of the most essential hydrophilic and hydrophobic extractives and carbohydrates. First, two large 450 m3 piles of bark from Norway spruce (Picea abies) were formed, one of which was covered with snow. The degradation of the bark extractives was monitored for 24 weeks. Samples were taken from the middle, side and top of the pile. Each sample was extracted at 120 °C with both n-hexane and water, and the extracts produced were then analysed chromatographically using gas chromatography with flame ionisation or mass selective detection and high-performance liquid chromatography. The carbohydrates were next analysed using acidic hydrolysis and acidic methanolysis, followed by chromatographic separation of the monosaccharides formed and their derivatives. The results showed that the most intensive degradation occurred during the first 4 weeks of storage. The levels of hydrophilic extractives were also found to decrease drastically (69% in normal pile and 73% in snow-covered pile) during storage, whereas the decrease in hydrophobic extractives was relatively stable (15% in normal pile and 8% in snow-covered pile). The top of the piles exhibited the most significant decrease in the total level of extractives (73% in normal and snow-covered pile), whereas the bark in the middle of the pile retained the highest amount of extractives (decreased by 51% in normal pile and 47% in snow-covered pile) after 24-week storage.

KeywordsbarkNorway sprucestoragedegradationextractstanninsstilbenesgas chromatographyhigh pressure liquid chromatography

Free keywordspile storage; wood extractives; condensed tannins; stilbenes; gas chromatography with mass selective detection (GC-MS); high-performance liquid chromatography (HPLC)

Contributing organizations

Ministry reportingYes

Reporting Year2022

JUFO rating1

Last updated on 2024-03-04 at 19:05