Tehnološke lastnosti in uporabnost lesa velikega pajesena v primerjavi z lesom velikega jesena: Technological properties and usability of Chinese sumac wood | Tehnološke lastnosti in uporabnost lesa velikega pajesena v primerjavi z lesom velikega jesena: Technological properties and usability of Chinese sumac wood

English. Chinese sumac (Ailanthus altissima (Mill.) Swingle) is one of the most invasive alien species in Europe, and also in Slovenia. Due to its great renewal power the species is spreading rapidly, especially in abandoned agricultural and forest areas and along the traffic routes. It is botanically different from the European ash (Fraxinus excelsior L.), but it has similar tree habitus as well as similar structural characteristics of the wood. For this reason, we analysed the visual, anatomical and some physical and mechanical properties of both wood species. In all anatomical planes, the typical visual and colorimetric similarity of both studied woods was confirmed. Anatomically both ring porous wood species differ mainly in size and distribution of vessels, axial parenchyma and ray tissue. Wood of both species has a similar density as well, but the Chinese sumac has greater shrinkage. Some of the mechanical properties are comparable, although Chinese sumac wood has a lower modulus of elasticity and hardness and greater shear strength than ash wood. We can recommend that the wood of Chinese sumac can be used for production of pulp and paper, various panels and partly for less loaded constructions, which are not exposed to drastic climatic variability.

Slovenian. Veliki pajesen (Ailanthus altissima (Mill.) Swingle)) spada med najbolj invazivne tujerodne drevesne vrste v Evropi in pri nas. Zaradi velike obnovitvene moči se hitro širi, predvsem na golosekih, na opuščenih kmetijskih površinah ter ob prometnih poteh. Botanično se razlikuje od velikega jesena (Fraxinus excelsior L.), sicer pa nanj značilno spominja z izgledom drevesa kot tudi s strukturnimi lastnostmi lesa. Zaradi tega smo primerjalno analizirali vizualne, anatomske in nekatere fizikalne ter mehanske lastnosti obeh lesnih vrst. V vseh anatomskih ravninah smo potrdili značilno vizualno in barvnometrično podobnost obeh proučevanih lesov. Anatomsko se raziskani venčasto porozni lesni vrsti razlikujeta predvsem v velikosti in razporedu trahej ter parenhimskega tkiva. Lesova imata podobni gostoti, pajesen pa je bolj ­dimenzijsko nestabilen. Mehanske lastnosti lesa pajesena so le nekoliko slabše od tistih pri lesu velikega jesena. Določili pa smo 20 % manjšo upogibno togost ter povprečno 50 % nižjo trdoto lesa pajesena v primerjavi z lesom velikega jesena. Nasprotno pa je bila strižna trdnost pri pajesenu 30 % višja. Glede na ugotovljene lastnosti je les pajesena uporaben za predelavo v celulozo in papir, razne lesne plošče in delno za manj obremenjene konstrukcije, ki niso izpostavljene drastičnim klimatskim razmeram.