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

Abstract

Advancing climate change is affecting the health and vitality of forests in many parts of the world. Europe is currently facing spruce bark beetle outbreaks, which are most often caused by wind disturbances, hot summers, or lack of rainfall and are having a massive economic impact on the forestry sector. The aim of this research article was to summarize current scientific knowledge about the structure and physical and mechanical properties of wood from bark beetle-attacked trees. Spruce stands are attacked by a number of beetles, of which Ips typographus is the most common and widespread in Central Europe. When attacking a tree, bark beetles introduce ophiostomatoid fungi into the tree, which then have a greater effect on the properties of the wood than the beetles themselves. Fungal hyphae grow through the lumina of wood cells and spread between individual cells through pits. Both white rot and brown rot fungi are associated with enzymatic degradation of lignin or holocellulose, which is subsequently reflected in the change of the physical and mechanical properties of wood. Wood-decay fungi that colonize wood after infestation of a tree with bark beetles can cause significant changes in the structure and properties of the wood, and these changes are predominantly negative, in the form of reducing modulus of rupture, modulus of elasticity, discolouration, or, over time, weight loss. In certain specific examples, a reduction in energy consumption for the production of wood particles from beetle-attacked trees, or an increase in surface free energy due to wood infestation by staining fungi in order to achieve better adhesion of paints or glues, can be evaluated positively.

Re-inventories at two study sites in the Oberpfalz (Bavaria, Germany): Increase in RWA nests, herb biodiversity and dead wood in sustainably managed forests

“…This result confirms the results of the WEVF [32] and contrasts with the results of [68], suggesting that bark beetle infestations alter the physical and mechanical properties of lignin and wood. Degradation of lignin or holocellulose is hypothesized to have negative effects on plant-sucking insects (Aphidae, Coccidae, Psyllidae) living in trophobiosis with RWA [69,70]. To control bark beetle infestations, rapid salvage clearing of the infested tree is used that reduce the survival of RWA nests [62].…”

X-ray Imaging and Computed Tomography for the Identification of Geometry and Construction Elements in the Structure of Old Violins

“…Taking into account the way the violin plates were assembled, where the young wood is found in the joint area, we assume that the holes observed at CT were produced by Anobium pertinax or Anobium punctatum, which laid eggs under the rhytidome, and the larvae bear irregular galleries of maximum 3 mm and filled them with sawdust. The wood can be attacked inside without being noticed on the outside [32,33]. Similarly, the other violins were analyzed, obtaining the dimensions of the violins in different sections, the thickness of the plates and the radius of curvature.…”

Insight into the genomes of dominant yeast symbionts of European spruce bark beetle, Ips typographus

“…They are sources of nutrients, i.e., sterols, vitamins, essential amino acids, and other nitrogenous compounds ( Ayres et al, 2000 ; Bentz and Six, 2006 ; Veselská et al, 2019 ; Ibarra-Juarez et al, 2020 ), facilitate plant tissue colonization by detoxification of tree defense compounds (e.g., Zhao et al, 2019 ) or necrotize healthy plant tissue by which they also can cause tree mortality ( Hofstetter et al, 2015 ; Li et al, 2022 ). It is assumed that microorganisms introduced by beetles under the bark of a tree have a greater effect on the wood modifications than beetle themselves ( Hýsek et al, 2021 ).…”