Effect of xylanase pretreatment on the kraft pulping of poplar

This study aimed to determine the influence of prehydrolysis of wood chips on the kraft pulping of Populus x euramericana. Optimum cooking conditions were determined by evaluating different alkali concentrations and cooking periods. Xylanase was used to hydrolyze chips before cooking. Prehydrolysis process increased the yield and viscosity of pulp. Consequently, the mechanical properties of paper changed remarkably. In contrast, the optical properties of the unbleached kraft pulp declined due to lignin content.

Susceptibility of Populus x euramericana ‘I-214’ of Spanish origin to xylophagous attacks: durability tests for its possible inclusion in European standard

Aim of study: to assess the natural durability of Populus x euramericana ‘I-214’ against xylophagous fungi and termites, and to carry out a macro-microscopic analysis of the alterations caused by each xylophagous agent in order to get the necessary information for its possible inclusion in existing European standards.Area of study: A 20-years-old commercial plantation Populus x euramericana‘I-214’ located in Quintanilla de Sollamas (42° 36′ 00″N - 05° 49′ 00″ W), Spanish community of Castile-LeonMaterial and methods: material sampling and selection was carried out following EN 350:2017 for commercial sawn timber. Poplar resistance to xylophagous basidiomycete, soft rot fungi and subterranean termites was determined according to CEN/TS 15083-1:2005, CEN/TS 15083-2:2005 and EN 117:2012, respectively. The durability and use classes were estimated according to EN 350:2016 and EN 335:2013, respectively. The anatomical studies were carried out with Optical and Scanning Electron Microscope. Material characterization was carried out by reference to Anagnost (1998) and Schwarze (2007).Main results: ‘I-214’ poplar wood proved to be “Not-durable” to the action of basidiomycetes, soft rot fungi and termites, use classes 1-2, and showed macro-microscopic evidence of these types of decay.Research highlights: the information obtained in this study would allow the inclusion of clone I-214 in the standard EN 350 and its explicit classification within it.Keywords: wood-decay fungi; termites; EN 350.Abbreviations used: TM: test material; RM: reference material; RH: relative humidity; ML: mass loss; mi: initial dry mass; mf: final dry mass; DC: durability class; OM: Optical Microscope; SEM: Scanning Electron Microscope; TS: transverse section samples; LS: longitudinal section samples; CI: robust confidence intervals; F: fibre; V: vessel; h: hole; t: erosion trough; R: radial parenchyma cell; ep: erosion pitting; Fc: fungal colonization; fr: fracture; c: cavity; b: bore hole; m: mycelium.

An overview and evaluation of Hungarian publications required for material science examinations of poplar wood species

<p class="p1">A Nyugat-magyarországi Egyetem „Alacsony sűrűségű faanyag fiziko-mechanikai és felületfizikai tulajdonságainak komplex elemzése” címmel (azonosító: K116-216), Országos Tudományos Kutatási Alapprogram pályázatot nyert, melynek keretein belül a hazai nyárfa és különös tekintettel a Pannónia nyár (<em>Populus x euramericana cv. Pannónia</em>) állományok felmérésére és sokrétű vizsgálatára kerül sor. A pályázat fő célja a hazai, különböző termőhelyekről származó, ültetvényes nyár faanyag szerkezeti felhasználásának előkészítésére elvégzett anatómiai, mechanikai és felületfizikai vizsgálatok elvégzése. A pályázat első fél évében a hazai releváns irodalmak feltárására koncentráltunk annak érdekében, hogy a terepi munkák megkezdéséhez szükséges információkkal rendelkezzünk. A publikációk feltárásakor a hazai releváns publikációk megismerése volt a cél, amely során a szaporítóanyag aktuális helyzete, az erdősültségi szempontok, a nyártermesztés, valamint az anatómiai és szerkezeti tulajdonságok tekintetében közölt publikációk, felmérések, kutatási eredmények feldolgozását végeztük el.</p>

Cas de suie de l'érable et de chancre du peuplier dans le canton de Genève

A case of sooty bark disease and Cytospora poplar canker in the Canton of Geneva In summer 2014, a case of sooty bark disease caused by Cryptostroma corticale on an individual field maple (Acer campestre) and two cases of poplar canker due to Cytospora chrysosperma on Populus x euramericana were identified genetically for the first time on the territory of the Canton of Geneva. In both cases, the trees presented signs of very advanced dieback, accompanied by specific symptoms such as bark peeling and sooty plaques for the maple, and loose twisted bark layers and black colouring of the wood in structural branches of the poplars. Sampling was carried out in the symptomatic areas and components of the fungal flora were isolated in pure cultures in order to identify any pathogenic fungi. The molecular analysis of the rDNA internal transcribed spacer (ITS) sequences made it possible to identify precisely all pure isolates obtained. The results showed a majority presence of C. corticale in the maple tree, and of C. chrysosperma in the two poplars. Both these fungi are little known in Switzerland and Europe, and their presence is maybe associated with changes in the climate.

Investment appraisal of a poplar plantation aged 42 years

Commercial profitability of poplar cultivation was analyzed in an artificial poplar plantation in Serbia. The aim of this study was to validate the invested financial means in the artificial poplar plantation, on the basis of the analysis of costs and receipts during a 42-year rotation, on alluvial semigley, at a discount rate of 12%. Methods of dynamic investment calculation (net present value - NPV, internal rate of return - IRR, benefit-cost method - B/C and payback period - PBP) were used. The investigated plantations were established from Populus x euramericana cl. I-214, with a planting spacing of 6 x 3 m. At the calculation discount rate of 12%, the project for the production cycle of 42 years was not cost-effective from the economic aspect. The discount rate of 6% can be accepted in the studied plot because of the better site (alluvial semigley), but the oldness of the stand is unfavourable. For the studied sample plot, IRR was 5.51 %. B/C at r=12% in the study compartment was 0.24. The analysis shows that PBP is practically unacceptable for the investor at the discount rate of 6%. In practice, it is necessary to improve the position of producers in getting financial means for investment in poplar cultivation, so as to stimulate the establishment of artificial poplar plantations, especially in the private sector (on private land).

The Impact of Root Temperature on Photosynthesis and Isoprene Emission in Three Different Plant Species

Most of the perennial plant species, particularly trees, emit volatile organic compounds (BVOCs) such as isoprene and monoterpenes, which in several cases have been demonstrated to protect against thermal shock and more generally against oxidative stress. In this paper, we show the response of three strong isoprene emitter species, namely,Phragmites australis, Populus x euramericana, andSalix phylicifoliaexposed to artificial or natural warming of the root system in different conditions. This aspect has not been investigated so far while it is well known that warming the air around a plant stimulates considerably isoprene emission, as also shown in this paper. In the green house experiments where the warming corresponded with high stress conditions, as confirmed by higher activities of the main antioxidant enzymes, we found that isoprene uncoupled from photosynthesis at a certain stage of the warming treatment and that even when photosynthesis approached to zero isoprene emission was still ongoing. In the field experiment, in a typical cold-limited environment, warming did not affect isoprene emission whereas it increased significantly CO2assimilation. Our findings suggest that the increase of isoprene could be a good marker of heat stress, whereas the decrease of isoprene a good marker of accelerated foliar senescence, two hypotheses that should be better investigated in the future.