First vs. second rotation of a poplar short rotation coppice: leaf area development, light interception and radiation use efficiency

Abstract: Given the high expectations for lignocellulosic biomass as one of the potential solutions for energy security and climate change mitigation, commercial scale studies over several rotations are crucial to assess the potential and the sustainability of short rotation coppice (SRC) cultures for bioenergy. The first and the second rotation of the SRC poplar (Populus) plantation of the present study differed significantly in biomass yield and in productivity determinants and their relationships. Coppicing enhanced leaf area development, radiation interception and woody biomass productivity. High total leaf area and radiation use efficiency (RUE) equally contributed to the high biomass yield during the establishment rotation, while RUE became the most important determinant of biomass yield after coppice. The study confirmed the significant genotypic variation in biomass productivity and its underlying determinants, also among more recently selected poplar genotypes. The absence of a correlation between intercepted radiation and RUE suggests the potential of selecting for genotypes combining high total leaf area and photosynthetic carbon uptake in future breeding programs for yield maximization towards sustainable bioenergy cultivation

Carbon isotope compositions (δ13C) of leaf, wood and holocellulose differ among genotypes of poplar and between previous land uses in a short-rotation biomass plantation

The efficiency of water use to produce biomass is a key trait in designing sustainable bioenergy-devoted systems. We characterized variations in the carbon isotope composition (C-13) of leaves, current year wood and holocellulose (as proxies for water use efficiency, WUE) among six poplar genotypes in a short-rotation plantation. Values of C-13(wood) and C-13(holocellulose) were tightly and positively correlated, but the offset varied significantly among genotypes (0.79-1.01). Leaf phenology was strongly correlated with C-13, and genotypes with a longer growing season showed a higher WUE. In contrast, traits related to growth and carbon uptake were poorly linked to C-13. Trees growing on former pasture with higher N-availability displayed higher C-13 as compared with trees growing on former cropland. The positive relationships between C-13(leaf) and leaf N suggested that spatial variations in WUE over the plantation were mainly driven by an N-related effect on photosynthetic capacities. The very coherent genotype ranking obtained with C-13 in the different tree compartments has some practical outreach. Because WUE remains largely uncoupled from growth in poplar plantations, there is potential to identify genotypes with satisfactory growth and higher WUE. The carbon isotope composition ((13) C) is often used as a proxy for water use efficiency (WUE). For six poplar (Populus) genotypes in a short-rotation (bio-energy) plantation the values of C-13(wood) and C-13(holocellulose) were tightly and positively correlated, but the offset varied significantly among genotypes. The positive relationships between (13) C-leaf and leaf N suggested that spatial variations in WUE over the plantation were mainly driven by an N-related effect on photosynthetic capacities. As WUE remained largely uncoupled from growth, there is potential to identify poplar genotypes with satisfactory growth and higher WUE

Comparative study of biomass determinants of 12 poplar (Populus) genotypes in a high-density short-rotation culture

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A comparative study of four approaches to assess phenology of Populus in a short-rotation coppice culture

Abstract: We compared four approaches to assess phenology in a short-rotation coppice culture with 12 poplar (Populus) genotypes. The four approaches quantified phenology at different spatial scales and with different temporal resolutions: (i) visual observations of bud phenology; (ii) measurements of leaf area index; (iii) webcam images; and (iv) satellite images. For validation purposes we applied the four approaches during two years: the year preceding a coppice event and the year following the coppice event. The delayed spring greenup and the faster canopy development in the year after coppicing (as compared to the year before coppicing) were similarly quantified by the four approaches. The four approaches detected very similar seasonal changes in phenology, although they had different spatial scales and a different temporal resolution. The onset of autumn senescence after coppicing remained the same as in the year before coppicing according to the bud set observations, but it started earlier according to the webcam images, and later according to the MODIS images. In comparison to the year before coppicing, the growing season-in terms of leaf area duration-was shorter in the year after coppicing, while the leaf area index was higher

Production of selected short-rotation wood crop species and quality of obtained biomass

Abstract View references (68) Short-rotation coppice (SRC) represents an important source of wood biomass. Many uncertainties create barriers to farmers establishing SRC plantations, especially under Mediterranean climate conditions. In this study, five species and respective genotypes were analyzed. The five species were Fraxinus angustifolia, Robinia pseudoacacia, Salix alba, Populus nigra (Limatola), and Populus × euroamericana, with the genotypes of the latter being Grimminge, Vesten, Hoogvorst, Muur. For the plantations studied, two different harvesting systems were replicated: the single machine pass, or cut-and-chip (CC); and the double machine pass, for which the tree are cut first, then chipped later (chip of stored trees CS). In the CC, fresh trees were harvested and chipped by Claas Jaguar 880. In the CS, dry trees were chipped by Farmi Forest CH 260. Within the same site, in climatic conditions and low-input management, the best result in terms of biomass yield was obtained from the black poplar Limatola. Both wood typologies and harvesting systems affected the chip quality. The disk chipper, when working on dried biomass, produced lower quality chips than the other chipping device in terms of particle size. In the chips obtained, there was an increase in the number of chips classified as being “larger size” and “oversized”, and a decrease in the percentage of those classified as “accept” (45–3 mm fraction). The chips obtained from dried trees were of better energy quality compared with the same biomass obtained from the fresh trees in terms of heating value and ash content. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature