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Dead wood provides a huge terrestrial carbon stock and a habitat to wide-ranging organisms during its decay. Our brief review highlights that, in order to understand environmental change impacts on these functions, we need to quantify the contributions of different interacting biotic and abiotic drivers to wood decomposition. LOGLIFE is a new long-term 'common-garden' experiment to disentangle the effects of species' wood traits and siterelated environmental drivers on wood decomposition dynamics and its associated diversity of microbial and invertebrate communities. This experiment is firmly rooted in pioneering experiments under the directorship of Terry Callaghan at Abisko Research Station, Sweden. LOGLIFE features two contrasting forest sites in the Netherlands, each hosting a similar set of coarse logs and branches of 10 tree species. LOGLIFE welcomes other researchers to test further questions concerning coarse wood decay that will also help to optimise forest management in view of carbon sequestration and biodiversity conservation. Copyright © Royal Swedish Academy of Sciences 2012.

Under drought conditions, arbuscular mycorrhizal (AM) fungi alter water relationships of plants and improve their resistance to drought. In a factorial greenhouse experiment, we tested the effects of the AM symbiosis and precipitation regime on the performance (growth, gas exchange, nutrient status and mycorrhizal responsiveness) of Boswellia papyrifera seedlings. A continuous precipitation regime was imitated by continuous watering of plants to field capacity every other day during 4 months, and irregular precipitation by pulsed watering of plants where watering was switched every 15 days during these 4 months, with 15 days of watering followed by 15 days without watering. There were significantly higher levels of AM colonization under irregular precipitation regime than under continuous precipitation. Mycorrhizal seedlings had higher biomass than control seedlings. Stomatal conductance and phosphorus mass fraction in shoot and root were also significantly higher for mycorrhizal seedlings. Mycorrhizal seedlings under irregular watering had the highest biomass. Both a larger leaf area and higher assimilation rates contributed to higher biomass. Under irregular watering, the water use efficiency increased in non-mycorrhizal seedlings through a reduction in transpiration, while in mycorrhizal seedlings irregular watering increased transpiration. Because assimilation rates increased even more, mycorrhizal seedlings achieved an even higher water use efficiency. Boswellia seedlings allocated almost all carbon to the storage root. Boswellia seedlings had higher mass fractions of N, P, and K in roots than in shoots. Irregular precipitation conditions apparently benefit Boswellia seedlings when they are mycorrhizal. Electronic supplementary material The online version of this article (doi:10.1007/s00442-012-2258-3) contains supplementary material, which is available to authorized users.

Crown development was monitored for juvenile trees (4–18 m) of the canopy tree species Dicorynia guianensis and Vouacapoua americana in a tropical rain forest in French Guiana. A comparison was made between crown development in closed understorey forest sites (low light) and in canopy gaps (high light); development was expressed by plant traits at multiple levels of organisation. Dicorynia and Vouacapoua responded to gap creation at all organisational levels, but not for all traits. Both species increased their light interception efficiency in the understorey. Firstly, understorey trees produced relatively wide crowns because they did not favour the growth of shoots in the summit of the crown, as did gap trees. Secondly, they reduced self-shading (expressed by leaf area index) by lower sympodial unit production rates, lower leaf production rates per growth unit (only Vouacapoua), and smaller leaf size (only Dicorynia). The reduction in self-shading was weakened by other traits that had the opposite effect on self shading (e.g. longer leaf life span in understorey), and cannot be considered an adaptive response in itself. (3) Understorey trees of Vouacapoua reduced leaf display costs by producing a higher specific leaf area, a shorter space among leaves, a smaller leaf spacing to leaf size ratio, and a longer leaf life span. Thus, all traits contributed to the more economical use of carbon in the understorey. Dicorynia showed the same trends, but not significantly. These results suggest that light availability plays a major role in the development and morphology of trees through its influences at multiple levels of organisation within the crown hierarchy. The two species studied were rather similar in their response at crown level, while they sometimes differed in their responses at the underlying lower organisational levels. The response directions of some individual plant traits were similar for the tall trees studied here and small saplings studied elsewhere. Some of traits investigated here may not be important in the crown level responses of smaller seedlings and saplings, while they are important mechanisms for crown level responses in taller trees.