Mencuccini M, Martínez-Vilalta J, Hölttä T (2012) Structural limitations of water and sugar transport in trees during drought: Model characterization of the relative importance of xylem embolism, carbon starvation, and lack of phloem transport. ESA Annual Meeting 2012, Portland, OR, United States of America, 5-10 August 2012. (Comunicació oral convidada).
Poyatos R, Gornall J, Mencuccini M, Huntley B, Baxter R (2012) Seasonal controls on net branch CO2 assimilation in sub-Arctic Mountain Birch (Betula pubescens ssp. czerepanovii (Orlova) Hamet-Ahti). Agricultural and Forest Meteorology 158: 90-100.
Sterck F.J., Martínez-Vilalta J., Mencuccini M., Cochard H., Gerrits P., Zweifel R., Herrero A., Korhonen J.F., Llorens P., Nikinmaa E., Nolè A., Poyatos R., Ripullone F., Sass-Klaassen U. (2012) Understanding trait interactions and their impacts on growth in Scots pine branches across Europe. Functional Ecology. 26: 541-549.EnllaçDoi: 10.1111/j.1365-2435.2012.01963.x
Plants exhibit a wide variety in traits at different organizational levels. Intraspecific and interspecific studies have potential to demonstrate functional relationships and trade-offs amongst traits, with potential consequences for growth. However, the distinction between the correlative and functional nature of trait covariation presents a challenge because traits interact in complex ways. We present an intraspecific study on Scots pine branches and use functional multi-trait concepts to organize and understand trait interactions and their impacts on growth. Branch-level traits were assessed for 97 branches from 12 Scots pine sites across Europe. To test alternative hypotheses on cause-effect relationships between anatomical traits, hydraulic traits and branch growth, we measured for each branch: the tracheid hydraulic diameter, double cell wall thickness, cell lumen span area, wood density, cavitation vulnerability, wood-specific hydraulic conductivity, the leaf area to sapwood area ratio and branch growth. We used mixed linear effect models and path models to show how anatomical traits determine hydraulic traits and, in turn, how those traits influence growth. Tracheid hydraulic diameter was the best predictor of cavitation vulnerability (R 2=0·09 explained by path model) and specific conductivity (R 2=0·19) amongst anatomical traits. Leaf area to sapwood area ratio had the strongest direct effect on branch growth (R 2=0·19) and was positively associated with the tracheid hydraulic diameter (R 2=0·22). A number of bivariate correlations between traits could be explained by these functional relationships amongst traits. The plasticity in tracheid hydraulic diameter (10.0-15.1μm) and leaf area to sapwood area ratio (600-6051cm 2cm -2) and the maintenance of a minimum leaf water potential (between -2 and -2·5MPa) appear to drive the anatomical and hydraulic traits of Scots pine across Europe. These properties are major drivers of the functional trait network underlying the growth variation amongst pine branches and thus possibly contribute to the ecological success of pines at a local and continental scale. © 2012 The Authors. Functional Ecology © 2012 British Ecological Society.
Mencuccini M, Hölttä T, Martinez-Vilalta J. (2011) Design Criteria for Models of the Hydraulic Systems of Tall Trees. 2011. In: FC Meinzer, T Dawson and B Lachenbruch. Size- and Age-Related Changes in Tree Structure and Function. Springer-Verlag.
Martínez-Vilalta J., Mencuccini M., Vayreda J., Retana J. (2010) Interspecific variation in functional traits, not climatic differences among species ranges, determines demographic rates across 44 temperate and Mediterranean tree species. Journal of Ecology. 98: 1462-1475.EnllaçDoi: 10.1111/j.1365-2745.2010.01718.x
Surprisingly little is known about the relationship between functional traits and demographic rates of tree species under field conditions, particularly for non-tropical species. We studied the interspecific relationship between key functional traits (wood density (WD), maximum tree height, specific leaf area, nitrogen (N) content of leaves, leaf size and seed mass), demographic rates (relative growth rate (RGR) and mortality rate (MR)) and climatic niche for the 44 most abundant tree species in Spain. Demographic data were derived from the Spanish Forest Inventory, a repeated-measures scheme including c. 90 000 permanent plots spread over a territory of c. 500 000 km[TD-SUP-OPEN]2. Functional traits data came primarily from a more detailed forest inventory carried out in Catalonia, NE Spain. Our study region covers a wide range of climatic conditions and, not surprisingly, the studied species differed markedly in their climatic niche. Despite that fact, our results showed that the variability in demographic rates across species was much more related to differences in functional traits than to differences in the average climate among species. Maximum tree height and, particularly, WD, emerged as key functional traits, and were the best predictors of demographic rates in our study. These two variables also mediated the marginally significant relationship between RGR and MR, suggestive of a weak trade-off between growth and survival. The main aspects of our results were not altered by the explicit incorporation of phylogenetic effects, suggesting that the observed relationships are not due to divergences between a few major clades. Synthesis. Our study gives support to the notion that variation in functional traits across species allows them to perform largely independently of climatic conditions along environmental gradients. © 2010 The Authors. Journal compilation © 2010 British Ecological Society.
Mencuccini M., Martinez-Vilalta J., Piñol J., Loepfe L., Mireia B., Alvarez X., Camacho J., Gil D. (2010) A quantitative and statistically robust method for the determination of xylem conduit spatial distribution. American Journal of Botany. 97: 1247-1259.EnllaçDoi: 10.3732/ajb.0900289
Premise of the study: Because of their limited length, xylem conduits need to connect to each other to maintain water transport from roots to leaves. Conduit spatial distribution in a cross section plays an important role in aiding this connectivity. While indices of conduit spatial distribution already exist, they are not well defi ned statistically. Methods: We used point pattern analysis to derive new spatial indices. One hundred and fi ve cross-sectional images from different species were transformed into binary images. The resulting point patterns, based on the locations of the conduit centersof-area, were analyzed to determine whether they departed from randomness. Conduit distribution was then modeled using a spatially explicit stochastic model. Key results: The presence of conduit randomness, uniformity, or aggregation depended on the spatial scale of the analysis. The large majority of the images showed patterns signifi cantly different from randomness at least at one spatial scale. A strong phylogenetic signal was detected in the spatial variables. Conclusions: Conduit spatial arrangement has been largely conserved during evolution, especially at small spatial scales. Species in which conduits were aggregated in clusters had a lower conduit density compared to those with uniform distribution. Statistically sound spatial indices must be employed as an aid in the characterization of distributional patterns across species and in models of xylem water transport. Point pattern analysis is a very useful tool in identifying spatial patterns. © 2010 Botanical Society of America.
Poyatos R, Martínez-Vilalta J, Poyatos R, Martínez-Vilalta J, Curiel J, Barba J, ,Aguadé D, Mencuccini M,Lloret F (2010) Canvis recents en els fluxos d’aigua i carboni a les pinedes de pi roig del bosc de Poblet: implicacions en un escenari de canvi climàtic. III Jornades sobre el bosc de Poblet i les muntanyes de Prades (en prensa).
Curiel J, Janssens I, Bahn M, Longdoz B, Baldocchi DD, Misson L, Davidson EA, Luyssaert S, Peñuelas J, Mencuccini M, Acosta M, Arrigan N, Aubinet JM, Carrara A, Gimeno C, Gruenwald T, Inglima I, Ma S, Montagnani L, Moyano F, Pavelka M et al. (2009) Influence of plant productivity over variability of soil respiration: a multi-scale approach. Geophys. Res. Abstr. 11, EGU2009-10349.
Martínez-Vilalta J., Cochard H., Mencuccini M., Sterck F., Herrero A., Korhonen J.F.J., Llorens P., Nikinmaa E., Nolè A., Poyatos R., Ripullone F., Sass-Klaassen U., Zweifel R. (2009) Hydraulic adjustment of Scots pine across Europe. New Phytologist. 184: 353-364.EnllaçDoi: 10.1111/j.1469-8137.2009.02954.x
Summary The variability of branch-level hydraulic properties was assessed across 12 Scots pine populations covering a wide range of environmental conditions, including some of the southernmost populations of the species. The aims were to relate this variability to differences in climate, and to study the potential tradeoffs between traits. Traits measured included wood density, radial growth, xylem anatomy, sapwood- and leaf-specific hydraulic conductivity (KS and KL), vulnerability to embolism, leaf-to-sapwood area ratio (AL : AS), needle carbon isotope discrimination (Δ13C) and nitrogen content, and specific leaf area. Between-population variability was high for most of the hydraulic traits studied, but it was directly associated with climate dryness (defined as a combination of atmospheric moisture demand and availability) only for A L : AS, KL and Δ13C. Shoot radial growth and AL : AS declined with stand development, which is consistent with a strategy to avoid exceedingly low water potentials as tree size increases. In addition, we did not find evidence at the intraspecific level of some associations between hydraulic traits that have been commonly reported across species. The adjustment of Scots pine's hydraulic system to local climatic conditions occurred primarily through modifications of AL : AS and direct stomatal control, whereas intraspecific variation in vulnerability to embolism and leaf physiology appears to be limited. © 2009 New Phytologist.
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