Evaluation of Low-Grade Yellow-Poplar (Liriodendron tulipifera) as Raw Material for Cross-Laminated Timber Panel Production

Utilization of low-grade yellow-poplar (Liriodendron tulipifera) lumber would provide for alternative structural lumber sources and promote the growth of cross-laminated timber (CLT) manufacturing facilities within the Appalachian Region. A significant amount of low-grade yellow-poplar lumber (i.e., National Hardwood Lumber Association [NHLA] No. 2A and Below Grade) is utilized for wood pallets. In practice, this material is not graded for structural purposes. Additionally, research on yellow-poplar for structural use has focused on grading lumber from a small population of selected logs, not by regrading NHLA lumber from manufacturing facilities. Therefore, the research's objective was to investigate the structural grades of a typical population of NHLA graded No. 2 and lower lumber and evaluate their potential to meet structural grades necessary for CLT panels. NHLA graded lumber was regraded and assigned to visual structural grades following Northeastern Lumber Manufacturers Association rules and evaluated for flatwise bending modulus of elasticity (MOEb) by nondestructive proof loading. The results of the study indicated that 54.6 percent of the boards possessed a minimal structural visual grade required for CLT panels according to American National Standards Institutes/The Engineered Wood Association (ANSI/APA) PRG 320-2019 (2020). Splits were the most common limiting defect that downgraded boards to nonstructural grades. Also, 96.6 percent of the boards evaluated had a MOEb above the required minimal board value of 1.2 ×106 psi (8,274 MPa) listed in ANSI/APA PRG 320-2019 (2020). The results of the study indicated that a majority of NHLA low-grade yellow-poplar, when regraded for structural purposes, meets or exceeds minimum lumber grade values necessary for use in CLT panel production.

Study on the influence of stimulants on the rooting of the paulownia (paulownia) and tulip (liriodendron tulipifera) trees during the propagation by cuttings

This article describes the effect of a growth stimulant on the rooting of Paulownia and tulip tree saplings in the conditions of the Tashkent region. In addition, the article discusses the method of propagation of sapling from lignified and annual green cuttings, the influence of the preparation of the substrate 3: 3: 1 from sand, klinec (crushed stone), vermicompost on the development of saplings. In this case, the usual water (control), root SP, basfoliar Kel-SL and heteroauxin stimulants were used.

American tulipwood (Liriodendron tulipifera L.) as an innovative material in CLT technology

American tulipwood (Liriodendron tulipifera L.) as an innovative material in CLT technology. CLT (cross laminated timber, X-Lam) is one type of engineered wood products. The first idea of CLT was presented in the seventies of the last century. It is manufactured with timber boards placed side by side commonly with 3, 5 and 7 layers glued at 90 degrees to adjacent layer. The CLT production technology was developed for softwood. The main species in CLT production is Norway spruce (Picea abies L.) and less often White fir (Abies alba Mill.). Hardwood is also used more and more for production of CLT, most often, the wood of Silver birch (Betula pendula Roth.), Ash (Fraxinus excelsior L.), poplars (Populus spp.), Locust tree (Robinia pseudoacacia L.). This paper describes the suitability of cheap tulipwood (Liriodendron tulipifera L.) as a raw material for the production of CLT. Examples of the use of this type of panels in construction are also presented. The tulipwood has similar physical characteristics to softwood, for which CLT production technologies were previously developed. This makes it possible to use the technology previously for softwood CLT was developed. In addition, the tulipwood is characterized by aesthetic visual quality (wood surface similar to marble). Thanks to this, CLT boards to make exposed surfaces can be used.

Resolving host and species boundaries for perithecia-producing nectriaceous fungi across the central Appalachian Mountains

The Nectriaceae contains numerous canker pathogens. Due to scarcity of ascomata on many hosts, comprehensive surveys are lacking. Here we characterize the diversity of perithecia-producing nectriaceous fungi across the central Appalachians. Ten species from twelve hosts were recovered including a novel Corinectria sp. from Picea rubens. Neonectria ditissima and N. faginata were most abundant and associated with Fagus grandifolia with beech bark disease (BBD). N. ditissima was also recovered from additional cankered hardwoods, including previously unreported Acer spicatum, Ilex mucronata, and Sorbus americana. Cross-pathogenicity inoculations of N. ditissima confirmed susceptibility of Acer and Betula spp. Neonectria magnoliae was recovered from cankered Liriodendron tulipifera and Magnolia fraseri and pathogenicity on L. tulipifera was confirmed. Fusarium babinda was consistently recovered from beech with BBD, although its role remains unclear. This survey provides a contemporary snapshot of Nectriaceae diversity across the Appalachian Mountains. The following nomenclatural changes are proposed: Neonectria magnoliae comb. nov.