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.

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.

In the present study, we examined the relationships between (1) N, P, total organic carbon (TOC), and total suspended sediment (TSS) each and stream flow and water table elevation, individually (2) N, P, and TOC, each and TSS, and (3) stream water C/N ratios and stream flow in managed pine forests with various switchgrass treatments implemented on four watersheds in coastal North Carolina plain. The treatments included a young pine forest–natural understorey (27.5 ha), a young pine forest with switchgrass intercropped between pine rows replacing natural understorey (IC) (26.3 ha), a mature thinned pine forest (25.9 ha), and pure switchgrass (27.1 ha). Precipitation, flow, water table elevation, N, phosphate, TOC, and TSS concentrations were measured from November 2009 to June 2014 (switchgrass growth from May 2012 after site preparation (SP) that ended in April 2012). Relationships (α = 0.05) among water quality and hydrologic variables were examined using a Spearman rank correlation coefficient and the principal component analysis (PCA). Nitrogen concentrations on IC were positively correlated with flow during SP. The export of nutrients and sediment from this drained pine plantation forest intercropped with switchgrass was affected by changes in hydrological and biochemical processes regulating the formation and transport of different water quality constituents during both site preparation and pine and switch growth periods. The PCA showed strong interaction between the hydrological and biochemical processes.

Natural regeneration of Korean pine (Pinus koraiensis Siebold & Zucc.) in northeastern China has often been problematic in mixed broad-leaved Korean pine forests (primary forest), but not in deciduous broad-leaved forests (secondary forest). Light transmittance, soil temperature, leaf area index (LAI), height and diameter of Korean pines were estimated in order to examine the contribution of composition and the dynamics of light to Korean pine regeneration in two forests. A spatial point pattern analysis was carried out to investigate the response of seedlings and saplings to light regimes and their relationship with mature trees, graded by size. We draw the following results: (1) light conditions were better in the secondary forest than in the primary forest in late spring (June and July) before the leaf expansion and the secondary forest received more light before leaf expansion and less light penetration in the early summer (August) | (2) our spatial analysis indicated that seedlings are negatively correlated with saplings and exhibit a higher degree of clumping than saplings. Relationships of seedlings with mature pines and all sizes of other mature trees appeared random, whereas saplings were negatively associated with small, medium and large mature trees. Our findings suggest that the effect of forest composition on regeneration mainly occurred before the leaf expansion in late spring.

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.

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.

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.