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Abstract1. Mixed conifer-hardwood forests can be more productive than pure forests and they are increasingly considered as ecosystems that could provide adaptation strategies in the face of global change. However, the combined effects of tree-to-tree competition, rising atmospheric CO 2 concentrations and climate on such mixtures remain poorly characterized and understood.2. To fill this research gap, we reconstructed 34-year series of growth (basal area increment, BAI) and intrinsic water-use efficiency (iWUE) of Scots pine (Pinus sylvestris L.)-European beech (Fagus sylvatica L.) mixed stands at two climatically contrasting sites located in the southwestern Pyrenees. We also gathered data on tree-to-tree competition and climate variables in order to test the hypotheses that (1) radial growth will be greater when exposed to inter-than to intraspecific competition, that is, when species complementarity occurs and (2) enhanced iWUE could be linked to improved stem radial growth.3. Growth of both species was reduced when intraspecific competition increased.Species complementarity was linked to improved growth of Scots pine at the continental site, while competition overrode any complementarity advantage at the drought-prone Mediterranean site. Beech growth did not show any significant response to pine admixture likely due to shade tolerance and the highly competitive nature of this species. Increasing interspecific competition drove recent iWUE changes, which increased in Scots pine but decreased in European beech. The iWUE enhancement did not involve any growth improvement in Scots pine.However, the positive BAI-iWUE relationship found for beech suggests an enhanced beech growth in drought-prone sites due to improved water use.4. Synthesis. Complementarity may enhance growth in mixed forests. However, water scarcity can constrict light-related complementarity for shade intolerant species (Scots pine) in drought-prone sites. Basal area increment-intrinsic water-use efficiency relationships were negative for Scots pine and positive for European beech.These contrasting behaviours have got implications for coping with the expected increasing drought events in Scots pine-European beech mixtures located near the Paper previously published as Standard Paper

Management of mixedwoods is advocated as an effective adaptation strategy to increase ecosystem resiliency in the context of climate change. Although mixedwoods have been shown to have greater resource use efficiency relative to pure stands, considerable uncertainty remains with respect to the underlying ecological processes. We explored species interactions in Scots pine/ European beech mixedwoods with the process-based model FORECAST Climate. The model was calibrated for two contrasting forests in the southwestern Pyrenees (northern Spain): a wet Mediterranean site at 625 m.a.s.l. and a subalpine site at 1335 m.a.s.l. Predicted mixedwood yield was higher than that for beech stands but lower than pine stands. When simulating climate change, mixedwood yield was reduced at the Mediterranean site (−33%) but increased at the subalpine site (+11%). Interaction effects were enhanced as stands developed. Complementarity dominated the Mediterranean stand but neutral or net competition dominated the subalpine stand, which had higher stand density and water availability. Reduced water demand and consumption, increased canopy interception, and improved water-use efficiency in mixtures compared to beech stands, suggest a release of beech intraspecific competition. Beech also facilitated pine growth through better litter quality, nonsymbiotic nitrogen fixation, and aboveand belowground stratification, leading to higher foliar nitrogen content and deeper canopies in pines. In conclusion, mixtures may improve water availability and use efficiency for beech and light interception for pine, the main limiting factors for each species, respectively. Encouraging pine-beech mixtures could be an effective adaptation to climate change in drought-prone sites in the Mediterranean region.

As afforestation programs of former farmlands take hold in Taiwan to achieve a variety of ecological and socio-economic values, it is becoming necessary to define best forest management. Hence, we simulated mixed stands of Cinnamomum camphora and Fraxinus griffithii planted through a gradient of soil fertility and varying camphor/ash density ratios, but maintaining a fixed total stand density of 1500 trees ha. Total stand productivity was slightly lower in mixed stands than the combination of both monocultures in rich and poor sites. Maximum negative yield surpluses for 50-year old stands were 7 Mg ha ). However, for medium-quality sites, a small yield surplus (11 Mg ha −1 ) was estimated coinciding with a maximum stand woody biomass of 95 Mg ha −1 for a 1:1 camphor laurel/ash density ratio. From an ecological resilience point of view, rotation length was more important than stand composition. Long rotations (100 years) could improve soil conditions in poor sites. In rich sites, short rotations (50 years) should be avoided to reduce risks or fertility loss. OPEN ACCESSSustainability 2015, 7 3802

Because of the everlasting promotion of micro/nano-fabrication techniques, the measurement of the feature contour of micro/nano-fabricated structures become an important issue. Atomic force microscopy (AFM) is a high accuracy measurement instrument that has been frequently used in measuring of micro/nano-fabricated structures. However, most conventional AFM systems use a single probe with a monotonic tilting angle to scan all kinds of sample profiles. This type of AFM design easily suffers from the so-called "side wall effect", and the scanning result will induce a distortion phenomenon at the corner part. To solve this problem, a novel dual probe AFM system is proposed in this paper. A highly flexible system structure is adopted in this work to create different tilting angle of each probe. With the method developed for obtaining the appropriate tilting angle, we set up the so-called "effective tilting angles" under different scanning scenarios. In addition, a useful merging method has been developed to stitch together the scanning results from two different probes out of two different scanning units. For scanning a standard grating, the error of sidewall angle from the scan image decreases form 27.3 % to 4.5 % when our method is compared with a traditional scan. Finally, by integrating the proposed scan method with a new raster based local scan strategy, we can achieve a high-throughput precision scan. In the scan of human blood cells, we not only can remove unnecessary scan area up to 61.04 % but also can improve sidewall distortion. A comprehensive series of experiments have been conducted to validate the scanning capability of the proposed methods on our self-developed AFM system.