Detection, description, and technological properties of colour aberration in wood of standards and shoots from a chestnut (Castanea sativa Mill.) coppice stand

Sweet chestnut forests occupy an important role in Italy and Europe, its resilience is often affected by aggressive pathogen attack. In the last times some chestnut wood colour aberrations have attracted attention suggesting intercorrelation with biotic attacks. The present study analyses chestnut wood from a coppice-with-standards stand in Central Italy aiming to understand the reasons for discolorations in respect to a possible effect on wood physical and mechanical character. Wood specimens with different chromatic aberrations were analysed by mechanical tests, microscopic techniques (SEM), specific density measurements, and ATR-FTIR spectroscopy. Standing trees and logs were investigated by IML-RESI. Results by SEM show as all stained wood zones correspond to mycelium presence and abnormal cell wall morphologies. No real trend was found between specific density, or compressive strength, with coloured samples, infact some test samples with colour aberrations had the highest value for specific gravity. Comparing sound wood with stained wood, the semiquantitative analysis by ATR-FTIR spectroscopy allowed to detect a change in the ratio lignin/cellulose which might be due to a white rot fungus. IML-Resi has showed wood decay symptoms at root collar in coppice standards with a decrease in amplitude at least of 30%. The results find an agreement with similar studies carried out in Spanish chestnut suggesting to indeep the analysis to investigated the geographical distribution and the impact of the damage.