Published by De Gruyter

Volume 74 Issue 3

Issue of Holzforschung

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Contents
Journal Overview

Publicly Available February 22, 2020

Frontmatter

Page range: i-iii

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November 8, 2019

Wood color changes and termiticidal properties of teak heartwood extract used as a wood preservative

Victor Fassina Brocco, Juarez Benigno Paes, Lais Gonçalves da Costa, Grant T. Kirker, Sérgio Brazolin

Page range: 233-245

Abstract

The aim of this study was to evaluate the change in colorimetric patterns and the termite resistance of light-colored and low durability wood when impregnated with teak ( Tectona grandis ) heartwood extractives. Hot water and ethanol extracts were obtained from 20-year-old teak heartwood and used to evaluate the influence on color change and the natural resistance of 10-year-old teak sapwood and Pinus sp. For wood impregnation, a full-cell (Bethell) treatment was conducted. To verify the influence of the teak extracts, the colorimetric patterns of wood were determined using the Munsell and CIE-L*a*b* systems. Choice and no-choice feeding tests were performed under laboratory conditions to test the efficacy of the teak extract solutions against two termite species Nasutitermes corniger and Cryptotermes brevis . All of the extract solutions promoted a significant darkening of the wood, bringing the color of the impregnated wood closer to older teak heartwood than the untreated samples of the respective species. Ethanol extracts increased the resistance and mortality against N. corniger in both choice and no-choice tests. Resistance to C. brevis was not clearly affected.

September 17, 2019

Relationship between attenuated total reflectance Fourier transform infrared spectroscopy of western juniper and natural resistance to fungal and termite attack

Shahlinney Lipeh, Laurence R. Schimleck, Mark E. Mankowski, Armando G. McDonald, Jeffrey J. Morrell

Page range: 246-259

Abstract

Wood extractives are considered the major factor determining the natural durability of wood. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy was assessed for rapid determination of western juniper ( Juniperus occidentalis Hook. var. occidentalis ) durability based on extractives in heartwood, sapwood-heartwood and sapwood regions. Durability was assessed by exposing samples to brown-rot decay fungi [ Gloeophyllum trabeum (Pers.) Murrill and Rhodonia placenta (Fr.) Niemelä, K.H. Larss. & Schigel] or eastern subterranean termite ( Reticulitermes flavipes Kollar). Durability classifications were compared to their extractive contents, along with ATR-FTIR spectra of extracted and unextracted blocks to establish relationships using hierarchical cluster analysis (HCA) and principal component analysis (PCA). Western juniper durability varied with test organisms, but the majority of samples had high fungal and termite resistance. Moderate to weak connections were observed between durability and extractive content, but HCA and PCA analysis were unable to classify durability with accuracy. The absence of non-resistant samples may have influenced the ability of the chemometric methods to accurately categorize durability.

September 7, 2019

Natural durability of four Tunisian Eucalyptus spp. and their respective compositions in extractives

Mohamed Tahar Elaieb, Sarra Ben Ayed, Stéphane Dumarçay, Bruno De Freitas Homen De Faria, Marie-France Thévenon, Philippe Gérardin, Kévin Candelier

Page range: 260-274

Abstract

Eucalyptus trees have been adapted to the Tunisian climate. Now, they need to be economically valued. Tunisian Eucalyptus have great technological properties allowing us to use them as wooden material. However, there is large variability in the natural durability between heartwood Eucalyptus spp. The wood sustainability assessment provides reliable parameters to predict the service life of wood-based products. This study aimed to evaluate the wood deterioration of four North Tunisian fast-growing Eucalyptus spp. ( Eucalyptus maidenii , Eucalyptus saligna , Eucalyptus camaldulensis and Eucalyptus gomphocephala ) exposed to basidiomycetes ( Coniophora puteana and Trametes versicolor ) and termite ( Reticulitermes flavipes ) attacks. Among the four Eucalyptus woods, Eucalyptus gomphocephala presents the highest decay and termite resistance. The four Eucalyptus wood species are classified as very durable against fungal degradation and durable against termite attacks, expect for Eucalyptus saligna which is classified as sensible against termites. The natural durability of Eucalyptus seems to be mainly caused by extractives, and a lot of compounds are involved. Antifungal and anti-termite properties of these compounds were put in perspective with the natural durability of wood. Gas chromatography-mass spectrometry (GC-MS) analyses highlighted that Eucalyptus durability is mostly governed by gallic acid, fatty acid glycerides, fatty acid esters, phenolic compounds, sitosterol, catechin and ellagic acid.

Publicly Available August 30, 2019

Understanding the structural changes of lignin in poplar following steam explosion pretreatment

Huimei Wang, Zhong Liu, Lanfeng Hui, Lan Ma, Xu Zheng, Jingzhi Li, Yan Zhang

Page range: 275-285

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Abstract

To understand the modifications of lignin in the steam explosion process (209°C, 7 min), lignin samples in native poplar (L P ), steam explosion solid residue (L S ) and steam explosion liquid (L L ) were separated and studied. The lignin samples (L P , L S and L L ) were characterized and analyzed by size exclusion chromatography (SEC), Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance [carbon 13 numclear magnetic resonance ( 13 C-NMR) and heteronuclear single quantum coherence or heteronuclear single quantum correlation experiment NMR (HSQC) NMR] analysis. The results revealed that the pretreatment induced reductions in amounts of β-O-4′, β-β′, and spirodienone structure, and increases in the syringyl/guaiacyl (S/G) ratio from 1.14 (L P ) to 1.70 (L S ) and 1.86 (L L ). The HSQC NMR spectra also gave more information about the predominance of G and S units, and only small amounts of p-hydroxyphenyl (H) units. Moreover, SEC demonstrated the depolymerization and repolymerization of lignin, which were the main reasons for the increase in the average molecular weight of L S and the decrease in average molecular weight of L L , respectively. In brief, after steam explosion treatment, the lignin structure changed, but the backbone structure was not noticeably modified.

August 31, 2019

Influence of long-term heat treatment of kraft black liquor on lignin precipitation and material properties

Thomas Pichler, Silvia Maitz, Marlene Kienberger

Page range: 286-292

Abstract

In the present study, the influence of long-term heat treatment of black liquor with focus on a subsequent lignin precipitation process was investigated. The well-known CO 2 approach to precipitate a certain amount of lignin from heat-treated black liquor was studied within defined thermal conditions. Several important characteristics of lignin such as molar mass and functional groups were analysed. Viscosity and buffer capacity of black liquor were also studied. Results showed a reduction in lignin yield as a result of a decrease in molar mass and lignin demethylation after the heat treatment. The acid consumption during precipitation was found to be higher after the heat treatment.

December 12, 2019

Effect of structure of technical lignin on the electrochemical performance of lignin-derived porous carbon from K₂CO₃ activation

Yuebin Xi, Dongjie Yang, Yuanyuan Wang, JinHao Huang, Mengzhen Yan, Conghua Yi, Yong Qian, Xueqing Qiu

Page range: 293-302

Abstract

Owing to its high aromaticity and carbon content, technical lignin as the by-product of chemical pulping and bio-refining industry can be converted into lignin-derived porous carbon (LPC) materials after activation, which is a promising strategy for high-value utilization. In particular, LPC with a higher surface area and graphitization will have a broad prospect as the electrode material for lithium-ion batteries (LIBs). However, the structure of technical lignin varies greatly due to its different industrial processes and botany sources, which remarkably affects the activation process and electrochemical properties of LPC. Herein, we study the effect of oxygen/carbon (O/C) ratio and molecular weight on the structure of LPC by exploring the effect of four kinds of technical lignin on K 2 CO 3 activation. High O/C ratio can promote LPC to maintain a high specific surface area (SSA). High molecular weight and low O/C ratio were beneficial to increase the graphitization degree and keep the porous structure of LPC. The electrochemical performance evaluation showed that high graphitization and stable porous structure were beneficial for lithium-ion storage. Therefore, LPC from enzymatic hydrolysis lignin (EHL) had long cycle performance (490 mAh · g −1 at a current density of 400 mA · g −1 ) and excellent rate performance compared to lignin from chemical pulping.

Open Access October 7, 2019

The effect of ionic liquid and superbase pre-treatment on the spring-back, set-recovery and Brinell hardness of surface-densified Scots pine

Benedikt Neyses, Olov Karlsson, Dick Sandberg

Page range: 303-312

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Abstract

Compressing the surface of sawn timber results in a substantial increase in hardness, and this opens up new market opportunities of using low-density timber species as the raw material for high-value wood products. Unfortunately, widespread commercialisation is hindered by the lack of an industrially viable surface densification process, the major obstacle being the set-recovery (SR) of the densified wood cells upon exposure to moisture. Our hypothesis is that partial dissolution of the crystalline cellulose during densification will largely prevent the SR of densified wood. We therefore evaluated the effect of ionic liquid (IL) or organic superbase pre-treatment on the elastic spring-back (SB), SR and Brinell hardness (HB) of surface-densified wood. Specimens of Scots pine were treated with solutions of ILs or superbases, and then densified in a hot press at temperatures between 200°C and 270°C. The SR was reduced from 90% for the control group to only about 10% for the treated materials. The treated and densified specimens exhibited a higher HB than their untreated and densified counterparts. The method presented in this study is a precursor to the development of a continuous densification process adapted for an open system. Further studies are needed to understand the underlying mechanisms of the pre-treatment.

September 9, 2019

Microwave-assisted direct transformation of lignocellulose into methyl glycopyranoside in ionic liquid

Takao Kishimoto, Mafuyu Saito, Satoshi Suzuki, Masahiro Hamada, Noriyuki Nakajima, Daisuke Urabe

Page range: 313-320

Abstract

Recently, conversion of lignocellulose into useful substances has attracted increasing attention. In our previous investigations, microcrystalline cellulose was successfully converted to methyl glucopyranosides (MeGlc) by the combined use of ionic liquid (IL) and microwave irradiation under moderate reaction conditions. In this study, lignocelluloses, including softwood, hardwood, and rice straw, were directly converted to methyl glycopyranosides (MG), including MeGlc, methyl mannopyranosides (MeMan), and methyl xylopyranosides (MeXyl) using acid-catalyzed methanolysis under microwave irradiation in ILs. Lignocellulose ball-milling was quite effective as a crucial process of increasing the yield of MG. Under the optimized reaction conditions, the molar yield of MeGlc reached 40% from softwood, which was a comparable yield from microcrystalline cellulose. MeXyl was also obtained in a 48% yield. These results showed that the combination of the dissolution of ball-milled lignocellulose in IL and the microwave-assisted methanolysis was an effective method of converting lignocellulose into a high-value-added substance.

September 10, 2019

Uncovering the ultrastructure of ramiform pits in the parenchyma cells of bamboo [Phyllostachys edulis (Carr.) J. Houz.]

Caiping Lian, Shuqin Zhang, Xianmiao Liu, Junji Luo, Feng Yang, Rong Liu, Benhua Fei

Page range: 321-331

Abstract

Pits are the main transverse channels of intercellular liquid transport in bamboo. Ramiform pits are a special type of simple pit with two or more branches. However, little is known about the morphology and physiological functions of ramiform pits. The anatomy of plants can provide important evidence for the role of cells. To better understand the ultrastructure and the structure-function relationship of ramiform pits, their characteristics need to be investigated. In this study, both qualitative and quantitative features of ramiform pits were studied using field-emission environmental scanning electron microscopy (FE-ESEM). The samples included the native structures and the replica structures obtained by resin castings. The results show that the ramiform pits have a diverse morphology that can be divided into main categories: type I (the primary branches) and type II (the secondary branches). The distribution of ramiform pits is different in ground parenchyma cells (GPCs) and vascular parenchyma cells (VPCs). The number, the pit aperture diameter and the pit canal length of ramiform pits in the VPCs were, respectively, greater (3-fold), larger (2–3-fold) and shorter (1.3-fold) than those in the GPCs.

About this journal

Objective
Holzforschung (HF) is an international scholarly journal that publishes cutting-edge research on the biology, chemistry, physics and technology of wood and wood components. High quality papers about biotechnology and tree genetics are also welcome. Rated year after year as one of the top scientific journals in the category of Pulp and Paper (ISI Journal Citation Index), Holzforschung represents innovative, high quality basic and applied research. The German title reflects the journal's origins in a long scientific tradition, but all articles are published in English to stimulate and promote cooperation between experts all over the world. Ahead-of-print publishing ensures fastest possible knowledge transfer.

Topics

Biology, chemistry, physics and technology of wood and wood components
Biotechnology and tree genetics

Article formats
Original articles, Reviews, Short notes

> Information on submission process

Volume 74 Issue 3

Issue of Holzforschung

Frontmatter

Wood color changes and termiticidal properties of teak heartwood extract used as a wood preservative

Abstract

Relationship between attenuated total reflectance Fourier transform infrared spectroscopy of western juniper and natural resistance to fungal and termite attack

Abstract

Natural durability of four Tunisian Eucalyptus spp. and their respective compositions in extractives

Abstract

Understanding the structural changes of lignin in poplar following steam explosion pretreatment

Abstract

Influence of long-term heat treatment of kraft black liquor on lignin precipitation and material properties

Abstract

Effect of structure of technical lignin on the electrochemical performance of lignin-derived porous carbon from K2CO3 activation

Abstract

The effect of ionic liquid and superbase pre-treatment on the spring-back, set-recovery and Brinell hardness of surface-densified Scots pine

Abstract

Microwave-assisted direct transformation of lignocellulose into methyl glycopyranoside in ionic liquid

Abstract

Uncovering the ultrastructure of ramiform pits in the parenchyma cells of bamboo [Phyllostachys edulis (Carr.) J. Houz.]

Abstract

Effect of structure of technical lignin on the electrochemical performance of lignin-derived porous carbon from K₂CO₃ activation