Recent evidence from novel phytotron and free-air ozone (O3) fumigation experiments in Europe and America on forest tree species is highlighted in relation to previous chamber studies. Differences in O3 sensitivity between pioneer and climax species are examined and viewed for trees growing at the harsh alpine timberline ecotone. As O3 apparently counteracts positive effects of elevated CO2 and mitigates productivity increases, response is governed by genotype, competitors, and ontogeny rather than species per se. Complexity in O3 responsiveness increased under the influence of pathogens and herbivores. The new evidence does not conflict in principle with previous findings that, however, pointed to a low ecological significance. This new knowledge on trees' O3 responsiveness beyond the juvenile stage in plantations and forests nevertheless implies limited predictability due to complexity in biotic and abiotic interactions. Unravelling underlying mechanisms is mandatory for assessing O3 risks as an important component of climate change scenarios.

The experiment was carried out on a short rotation coppice culture of poplars (POP-EUROFACE, Central Italy), growing in a free air carbon dioxide enriched atmosphere (FACE). The specific objective of this work was to study whether elevated CO2 and fertilization (two CO2 treatments, elevated CO2 and control, two N fertilization treatments, fertilized and unfertilized), as well as the interaction between treatments caused an unbalanced nutritional status of leaves in three poplar species (P. x euramericana, P. nigra and P. alba). Finally, we discuss the ecological implications of a possible change in foliar nutrients concentration. CO2 enrichment reduced foliar nitrogen and increased the concentration of magnesium; whereas nitrogen fertilization had opposite effects on leaf nitrogen and magnesium concentrations. Moreover, the interaction between elevated CO2 and N fertilization amplified some element unbalances such as the K/N-ratio. CO2 enrichment reduced foliar nitrogen and increased the magnesium concentration in poplar.

The use of agroforestry crops is a promising tool for reducing atmospheric carbon dioxide concentration through fossil fuel substitution. In particular, plantations characterised by high yields such as short rotation forestry (SRF) are becoming popular worldwide for biomass production and their role acknowledged in the Kyoto Protocol. While their contribution to climate change mitigation is being investigated, the impact of climate change itself on growth and productivity of these plantations needs particular attention, since their management might need to be modified accordingly. Besides the benefits deriving from the establishment of millions of hectares of these plantations, there is a risk of increased release into the atmosphere of volatile organic compounds (VOC) emitted in large amounts by most of the species commonly used. These hydrocarbons are known to play a crucial role in tropospheric ozone formation. This might represent a negative feedback, especially in regions already characterized by elevated ozone level. Growth and management of agroforestry plantations will be influenced by climate change.

The present study aimed to elucidate the atmosphere-forest exchange of ammoniacal nitrogen (NHX-N) at a young larch ecosystem. NHX-N exchanges were measured at a remote site in northernmost Japan where 4-year-old larches were growing after a pristine forest had been clear-cut and subsequent dense dwarf bamboo (Sasa) had been strip-cut. The site was a clean area for atmospheric ammonia with mean concentrations of 0.38 and 0.11 μg N m⁻³ in snowless and snow seasons, respectively. However, there was a general net emission of NHX-N. The annual estimated emission of NHX-N of 4.8 kg N ha⁻¹ year⁻¹ exceeded the annual wet deposition of 2.4 kg N ha⁻¹ year⁻¹, but the weekly exchange fluxes may have been underestimated by 28-60%. The main cause of the ammonia loss from the young larch ecosystem was probably enhanced nitrogen supply stimulated by the cutting of the pristine forest and Sasa, in particular, the Sasa.

Few studies have focused on the effects of long-term forest plantations on the soil profile of carbon (C) and nitrogen (N) stocks. In this study, we selected 78-year-old tree plantations that included three coniferous tree species (i.e., slash pine, hoop pine and kauri pine) and a Eucalyptus species in subtropical Australia. We measured soil extractable organic C (EOC) and N (EON) contents and total C and N stocks under different tree species on the forest floor and along a soil profile to 100 cm depth. The results showed that Eucalyptus had significantly higher soil EOC contents (3.3 Mg ha⁻¹) than the other tree species (EOC of 1.9–2.3 Mg ha⁻¹) and had significantly higher EON (156 kg ha⁻¹) contents than slash pine (107 kg ha⁻¹). Eucalyptus had significantly higher soil C (58.9 Mg ha⁻¹) and N (2.03 Mg ha⁻¹) stocks than the other tree species (22.3–27.6 Mg C ha⁻¹ and 0.71–1.23 Mg N ha⁻¹) at 0–100 cm depth. There were no differences in soil C stocks at the 0–100 cm depth among the coniferous tree species. Forest floor C stocks had stronger effects on mineral soil total N stocks than fine root biomass, whereas fine root biomass exerted stronger effects on soil total C stocks at the 0–100 cm depth than forest floor C and N stocks. Our results addressed large differences in soil C and N stocks under different tree species, which can provide useful information for local forest management practices in this region.

Wastewater plants generated annually millions of tons of sewage sludge (SS). Large amounts of this organic residue are spread on agricultural lands as a fertilizer, although it is viewed as a major potential source of contamination, presenting a danger to the terrestrial and aquatic environments. This study was undertaken to evaluate the impact of this practice on the duckweed Lemna minor and the snail Cantareus aspersus. Sludge was applied to soil either at six different loading rates equal to 0, 0.4, 3, 10, 30, and 60 tons dry matter (DM) ha⁻¹ for L. minor test or at three rates equal to 0, 30, and 60 tons DM ha⁻¹ for C. aspersus test. At the highest rate of SS application (60 tons DM ha⁻¹), the eluates showed that an increase in pH (6.1) resulted in a decrease in Al levels. Thus, the high stimulation of L. minor growth observed after this high rate of SS application can be explained by (i) a reduction in Al toxicity after precipitation and (ii) macro- and micronutrient enrichment. At a rate of SS application of only 30 tons DM ha⁻¹, growth appeared to be slightly significant (p < 0.05), in spite of the significant increase in essential mineral elements. However, it is very difficult to discriminate between Al toxicity and pH effects. For the test with C. aspersus, the snail biomass was not affected by sludge application over the exposure period. Mortality was extremely low, with a rate of less than 4 % at the last sampling date. Yet, Cu, Pb, and Cd accumulated significantly in the soft body of snails exposed to SS application, suggesting that the amount of metals excreted is lower than that absorbed. In contrast, Zn levels remain constant, inferring that absorption and elimination of Zn are balanced at the beginning of the experiment.

The Forest Stewardship Council (FSC) was the first non-governmental organization composed of multi-stakeholders to ensure the social, environmental, and economic sustainability of forest resources. FSC prohibits certain chemicals and active ingredients in certified forest plantations. A company seeking certification must discontinue use of products so listed and many face problems to comply with these constraints. The aim of this study was to assess the impacts of certification on pest management from the perspective of Brazilian private forestry sector. Ninety-three percent of Brazilian FSC-certified forest companies rated leaf-cutting ants as “very important” pests. Chemical control was the most important management technique used and considered very important by 82 % of respondents. The main chemical used to control leaf-cutting ants, sulfluramid, is in the derogation process and was classified as very important by 96.5 % of the certified companies. Certified companies were generally satisfied in relation to FSC certification and the integrated management of forest pests, but 27.6 % agreed that the prohibitions of pesticides for leaf-cutting ant and termite control could be considered as a non-tariff barrier on high-productivity Brazilian forest plantations. FSC forest certification has encouraged the implementation of more sustainable techniques and decisions in pest management in forest plantations in Brazil. The prohibition on pesticides like sulfluramid and the use of alternatives without the same efficiency will result in pest mismanagement, production losses, and higher costs. This work has shown that the application of global rules for sustainable forest management needs to adapt to each local reality.