Browsing by Subject "WOODY-PLANTS"

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  • Mencuccini, Maurizio; Salmon, Yann; Mitchell, Patrick; Hölttä, Teemu; Choat, Brendan; Meir, Patrick; O'Grady, Anthony; Tissue, David; Zweifel, Roman; Sevanto, Sanna; Pfautsch, Sebastian (2017)
    Substantial uncertainty surrounds our knowledge of tree stem growth, with some of the most basic questions, such as when stem radial growth occurs through the daily cycle, still unanswered. We employed high-resolution point dendrometers, sap flow sensors, and developed theory and statistical approaches, to devise a novel method separating irreversible radial growth from elastic tension-driven and elastic osmotically driven changes in bark water content. We tested this method using data from five case study species. Experimental manipulations, namely a field irrigation experiment on Scots pine and a stem girdling experiment on red forest gum trees, were used to validate the theory. Time courses of stem radial growth following irrigation and stem girdling were consistent with a-priori predictions. Patterns of stem radial growth varied across case studies, with growth occurring during the day and/or night, consistent with the available literature. Importantly, our approach provides a valuable alternative to existing methods, as it can be approximated by a simple empirical interpolation routine that derives irreversible radial growth using standard regression techniques. Our novel method provides an improved understanding of the relative source-sink carbon dynamics of tree stems at a sub-daily time scale.
  • Etongo, Daniel; Djenontin, Ida Nadia S.; Kanninen, Markku; Glover, Edinam K. (2017)
    Empirical ethnobotanical studies in Burkina Faso and the Sahel apply unmodified use-value methods, which often fail to capture uses of plants within and across categories. These methods mask both the relative uses and local people's 'true' knowledge of plant species. This study addresses these methodological weaknesses by assessing plant use-values within and across eight use categories for livelihood values and their potentials for environmental protection among 48 informants, selected through a stratified random technique. The research is twofold: (1) to document and identify the conservation status of plant species and (2) to assess local knowledge and perceived importance of the most easily found plant species in relation to informant's age, gender, ethnicity, and location. Seventy-three plant species belonging to 24 families were recorded on fields, fallows, and forests. The most easily found 30 species belonged to 14 families of which Combretaceae, Mimosodeae, Caesalpinioideae, and Anacardiaceae dominated. Results show that Adansonia digitata, Parkia biglobosa, Vitellaria paradoxa, and Balanites aegyptiaca were more valued for livelihood benefits, while A. digitata, Tamarindus indica, and Ficus thonningii received more value for their potentials in environmental protection. Local knowledge was unevenly distributed and showed significant differences at the 0.01 % level among gender, age, ethnicity, and study village. The relative importance of plant uses goes beyond nutrition and potentials in environmental protection and can provide valuable information for creating local markets for such goods. Three species belonging to different families were identified as vulnerable and considered priority for conservation. The design of conservation and development projects should consider creating opportunities for knowledge sharing that will not only improve knowledge but provide better understanding of local priorities based on sociocultural and economic factors.
  • Thomas, H. J. D.; Bjorkman, A. D.; Myers-Smith, I. H.; Elmendorf, S. C.; Kattge, J.; Diaz, S.; Vellend, M.; Blok, D.; Cornelissen, J. H. C.; Forbes, B. C.; Henry, G. H. R.; Hollister, R. D.; Normand, S.; Prevéy, J. S.; Rixen, C.; Schaepman-Strub, G.; Wilmking, M.; Wipf, S.; Cornwell, W. K.; Beck, P. S. A.; Georges, D.; Goetz, S. J.; Guay, K. C.; Rüger, N.; Soudzilovskaia, N. A.; Spasojevic, M. J.; Alatalo, J. M.; Alexander, H. D.; Anadon-Rosell, A.; Angers-Blondin, S.; te Beest, M.; Berner, L. T.; Björk, R. G.; Buchwal, A.; Buras, A.; Carbognani, M.; Christie, K. S.; Collier, L. S.; Cooper, E. J.; Elberling, B.; Eskelinen, A.; Frei, E. R.; Grau, O.; Grogan, P.; Hallinger, M.; Heijmans, M. M. P. D.; Hermanutz, L.; Hudson, J. M. G.; Johnstone, J. F.; Hülber, K.; Iturrate-Garcia, M.; Iversen, C. M.; Jaroszynska, F.; Kaarlejarvi, E.; Kulonen, A.; Lamarque, L. J.; Lantz, T. C.; Lévesque, E.; Little, C. J.; Michelsen, A.; Milbau, A.; Nabe-Nielsen, J.; Nielsen, S. S.; Ninot, J. M.; Oberbauer, S. F.; Olofsson, J.; Onipchenko, V. G.; Petraglia, A.; Rumpf, S. B.; Shetti, R.; Speed, J. D. M.; Suding, K. N.; Tape, K. D.; Tomaselli, M.; Trant, A. J.; Treier, U. A.; Tremblay, M.; Venn, S. E.; Vowles, T.; Weijers, S.; Wookey, P. A.; Zamin, T. J.; Bahn, M.; Blonder, B.; van Bodegom, P. M.; Bond-Lamberty, B.; Campetella, G.; Cerabolini, B. E. L.; Chapin, F. S.; Craine, J. M.; Dainese, M.; Green, W. A.; Jansen, S.; Kleyer, M.; Manning, P.; Niinemets, Ü.; Onoda, Y.; Ozinga, W. A.; Peñuelas, J.; Poschlod, P.; Reich, P. B.; Sandel, B.; Schamp, B. S.; Sheremetiev, S. N.; de Vries, F. T. (2020)
    The majority of variation in six traits critical to the growth, survival and reproduction of plant species is thought to be organised along just two dimensions, corresponding to strategies of plant size and resource acquisition. However, it is unknown whether global plant trait relationships extend to climatic extremes, and if these interspecific relationships are confounded by trait variation within species. We test whether trait relationships extend to the cold extremes of life on Earth using the largest database of tundra plant traits yet compiled. We show that tundra plants demonstrate remarkably similar resource economic traits, but not size traits, compared to global distributions, and exhibit the same two dimensions of trait variation. Three quarters of trait variation occurs among species, mirroring global estimates of interspecific trait variation. Plant trait relationships are thus generalizable to the edge of global trait-space, informing prediction of plant community change in a warming world.
  • Wu, Dongxia; Palonen, Pauliina; Lettojärvi, Iiris Annemari; Finni, Sanna; Haikonen, Tuuli; Luoranen, Jaana; Repo, Tapani (2020)
    The rates of dehardening and rehardening in response to rapid temperature changes in winter are important traits that affect the survival, growth and productivity of the European pear (Pyrus communis [L.]) cultivars in northern countries. The frost hardiness (FH) of shoots of three pear cultivars were studied by a series of freezing tests, after sampling in natural conditions, after dehardening in a growth chamber at 5 degrees C for 3-4 days (D1) and 16 days (D2), and then after rehardening at -7 degrees C for 5-7 days (R1 and R2). The FH was assessed by a differential thermal analysis (DTA) to measure the low temperature exotherm (LTE) of shoots, by relative electrolyte leakage (REL) of shoots and by visual damage scoring (VD) of shoots and buds. According to the DTA, the FH of the cultivars varied between -38 degrees C ('Conference' in D2) and -41 degrees C ('Pepi' in R2). The shoots of the cultivar 'Pepi' and 'Conference' had the highest and the lowest FH, respectively, in all conditions and methods. All the cultivars had the lowest shoot FH after dehardening in either D1 (between -26 degrees C and -30 degrees C by REL and between -28 degrees C and -30 degrees C by VD) or D2 (between -38 degrees C and -40 degrees C by DTA), and the highest FH after rehardening (R1) preceded by D1 (between -30 degrees C and -34 degrees C by REL, and between -29 degrees C and -32 degrees C by VD). After the dehardening in D1, the buds did not reharden but continued to deharden (the average FH by VD - 24.5 degrees C). In the forcing conditions, bud growth was resumed most rapidly in 'Conference', indicating a shallower dormancy in this cultivar than in 'Pepi' or 'Clara Frijs'. We conclude that the pear cultivars responded to temperature changes in mid-winter, but less than expected, and the responses were similar in all cultivars.