Impact of the European bark beetle Ips typographus on biochemical and growth properties of wood and needles in Siberian spruce Picea obovata

Abstract

European spruce bark beetle Ips typographus is an important driver of ecological processes in spruce stands, with severe effects on forestry economies. To prevent bark beetle outbreaks, early detection of infestations is a crucial step in forest management. It is expected that bark beetle infestation modifies biochemical composition of wood and needles, alters physiological responses in the early stage of infestation, which results in the reduction of tree growth and ultimately a tree death. Therefore, we studied the differences in biochemical composition of wood, content of photosynthesis-related pigments, shoot morphology, and growth between the healthy Siberian spruce trees (Picea obovata) and trees which were infested by I. typographus. The study was performed in five experimental plots established in the south of the Udmurt Republic in the European part of the Russian Federation. Three infested and three non-infested trees were chosen on each plot. Our results showed no significant effect of bark beetle infestation on the content of main structural components of wood – holocellulose (cellulose and hemicellulose) and lignin. On the other hand, we found differences in the content of extractive substances in the wood. Specifically, we found a higher tannin content in the non-infested trees. The content of photosynthesis-related pigments differed between the non-infested and infested trees as well. Unexpectedly, bark beetle infestation caused the overproduction of both pigment types rather than their degradation. Moreover, we observed that a higher amount of total extractive substances positively affected the incremental growth, whereas tannins supported the growth of shoots and needles.

What Happens to Wood after a Tree Is Attacked by a Bark Beetle?

“…However, research on Siberian spruce (Picea obovata) infested with European bark beetle I. typographus showed that infested spruce wood had a lower tannin content. No effect of attack on resin formation was observed in this study [23]. Hood et al [24] noted, however, that many coniferous trees increase the amount of resin produced and change their composition after infestation with bark beetle [24,37,38].…”

“…It is obvious that in the region where certain tree species are most affected by bark beetles, the properties of the wood of these tree species are investigated, and in other regions where bark beetles attack other tree species, the properties of those other tree species are investigated. For these reasons, research in Central and Eastern Europe deals mainly with spruce (Picea abies, Picea obovata Ledeb) [21][22][23] and in North America mainly pine (Pinus ponderosa Douglas ex C.Lawson, Pinus taeda L.) [24][25][26][27].…”

Novel coupled permafrost–forest model (LAVESI–CryoGrid v1.0) revealing the interplay between permafrost, vegetation, and climate across eastern Siberia

“…3). For each species, the SLA was extracted from literature values: SLA LAGM = 120 cm 2 g −1 (Xian- Kui et al, 2015), which was also used for the closely related sister species LACA, SLA PIOB = 50 cm 2 g −1 (Konôpková et al, 2020), and SLA PISY = 50 cm 2 g −1 (extracted from the most recent source Błasiak et al, 2021, although other values are reported; 34 cm 2 g −1 in Reich et al, 1998, 40 cm 2 g −1 in Mencuccini and Bonosi, 2001). For PISI no source for SLA values was found and we assume it is similar to PISY: LA Tree i, Species j = BM dry needle SLA Species j /100,…”