Chemical composition and natural durability of juvenile and mature heartwood of Robinia pseudoacacia L.

Abstract

The aim of this study was to characterize the properties of juvenile and mature heartwood of Robinia pseudoacacia L. (black locust). The content, the composition, and subcellular localization of heartwood extractives were studied in 14 old-grown trees from forest sites in Germany and Hungary, as well as in 16 younger trees of four clone types. Heartwood extractives (methanol and acetone extraction) were analysed by HPLC-chromatography. UV microspectrophotometry was used to localize the extractives in the wood cell walls. The natural durability of juvenile and mature heartwood was analysed according to the European standard EN 350-1. Growth analyses, as well as the chemical analyses, showed that in Robinia the formation of juvenile wood is restricted to the first 10-15 years of cambial growth. In the heartwood high contents of phenolic compounds and flavonoids were present, which were in high concentrations in the cell walls of the axial parenchyma and of the vessels. In the juvenile heartwood, the content of these extractives is significantly lower than in the mature heartwood. In agree, the juvenile heartwood had a lower resistance to decay by Coniophora puteana (brown rot fungus) and Coriolus versicolor (white rot fungus) compared to the mature.

The Effects of Wood Storage on the Chemical Composition and Indigenous Microflora of Eucalyptus species Used in the Pulping Industry

“…Low concentrations of extractives in wood have previously been associated with low resistance to decay, as extractives may function as a fungicide (Haupt et al 2003;Latorraca et al 2011;Severo et al 2016). The increase in microbial populations and diversity may have been facilitated by the lower extractives content observed in the tested samples.…”

Gram-Scale Purification of Dihydrorobinetin from Robinia pseudoacacia L. Wood by Centrifugal Partition Chromatography

“…Dihydrorobinetin (DHRob) and robinetin (Rob) have been described as the main characteristic compounds found in R. pseudoacacia wood extracts [20,21]. Standard molecules (DHRob and Rob) injected in the HPLC device were eluted at 14.1 min and 20.8 min respectively.…”

“…Two flavonoids dihydrorobinetin (3,3 ,4 ,5 ,7-pentahydroxyflavanone, DHRob) and robinetin (3,3 ,4 ,5 ,7-pentahydroxyflavone, Rob) are the major phenolic compounds that have been extracted from R. pseudoacacia heartwood [18][19][20]. They are present in higher contents in mature heartwood compared to juvenile wood, and have thus been related to the higher decay resistance observed in mature heartwood [16,21,22].…”

Decay resistance of four fast-growing Eucalypts wood exposed to three types of fields

“…According to Latorraca et al 2011, regardless of the variation in the constitution and the content of wood extractives of different species, mature wood is more durable due to the presence of phenolic compounds and flavonoids in the cell wall.…”

“…Many factors influence the degree of degradation of wood in contact with soil, for instance, chemical composition (Latorraca et al 2011), moisture content of wood (Thybring 2013), soil characteristics: pH, salinity, organic matter and nutrient content (Brischke et al 2014), climatic conditions: relative humidity and temperature (Raberg et al 2005). Thus, microbial activity in field tests vary between and within the exposure sites (Brischke et al 2014).…”