En France, dans les Alpes-Maritimes, une recherche est menee pour connaitre l' impact eventuel de l' ozone sur l' endommagement foliaire repere ces dernieres annees sur peuplements de pins d' Alep, sylvestre et cembro. L' etude s' effectue dans le cadre d' un contrat franco-italien Interreg 2 et d' un programme Primequal. Cet article donne tout d' abord, les resultats pour l' ete 1999, interessant les niveaux de concentration d' ozone mesures depuis le littoral azureen jusqu' au massif du Mercantour au moyen d' analyseurs physico-chimiques et de capteurs passifs. La dose d' AOT 40 et la somme cumulee des concentrations horaires sont indiquees pour les periodes de mesure estivales. Les capteurs passifs se situent notamment parmi des placettes de suivi d' arbres. Afin d' apprehender l' impact de la pollution par l' ozone sur ces ecosystemes forestiers, des notations d' endommagement foliaire sont effectuees. Des correspondances sont recherchees entre les niveaux moyens d' ozone et les degres d' atteinte des trois principales essences suivies (pins d' Alep, sylvestre et cembro). Il semble y avoir une correlation entre augmentation des concentrations d' ozone et endommagement foliaire au moins en ce qui concerne les pins cembro.

We present here the effects of ambient ozone (O3)-induced decline in carbon availability, accelerated foliar senescence, and a decrease in aboveground biomass accumulation in the Aleppo pine (Pinus halepensis Mill.). Aleppo pine seedlings were continuously exposed in open-top chambers for 39 months to three different types of O3 treatments, which are as follows: charcoal-filtered air, nonfiltered air (NFA), and nonfiltered air supplemented with 40 ppb O3 (NFA+). Stable carbon isotope discrimination (Δ) and derived time-integrated ci/ca ratios were reduced after an accumulated ozone exposure over a threshold of 40 ppb (AOT40) value from April to September of around 20,000 ppb·h. An AOT40 of above 67,000 ppb·h induced reductions in ribulose-1, 5-biphosphate carboxylase/oxygenase activity, aboveground C and needle N and K concentrations, the C/N ratio, Ca concentrations in twigs under 3 mm, and the aerial biomass, as well as increases in needle P concentrations and phosphoenolpyruvate carboxylase (PEPC) activity and the N and K concentrations in twigs under 3 mm. Macronutrients losses, the limitations placed on carbon uptake, and increases in catabolic processes may be the causes of carbon gain diminution in leaves which was reflected as a reduction in aboveground biomass at tree level. Stimulation of PEPC activity, the consequent decreased Δ, and compensation processes in nutrient distribution may increase O3 tolerance and might be interpreted as part of Aleppo pine acclimation response to O3.

A study of the impact of polluted sea-spray on needles of Pinus halepensis (The possible role of surfactants). 1.Air Pollution Research 2. Status Seminar of Tree Physiological Projects

Coastal forest decline due to seasprays has been reported from all continents, both on broadleaves and conifers. The main cause has been identified in the presence of surfactants. Sea winds transport these substances to the leaves, where they are absorbed via cuticula and stomata producing indirect and also direct damage. The scope of this work is the macroscopic and microscopic assessment of the long term effects of polluted seasprays on Aleppo pines in natural conditions from the Saler coastline (Eastern Spain) inwards. Surfactants may be involved in the damage to Aleppo pine in El Saler as more severe episodes of damage have been observed in the last decade

Natural levels of heavy metals (HM) have increased during the industrial era to the point of posing a serious threat to the environment. The use of tree species to record contamination is a well-known practice. The objective of the study was to compare HM levels under different pollution conditions: a) soil pollution due to mining waste; b) atmospheric pollution due to coal-fired power plant emissions. We report significant HM enrichment in Pinus halepensis tissues. Near a burning power plant, Pb content in a tree wood was 2.5-fold higher that in natural areas (no pollution; NP). In mining areas, Cd content was 25-fold higher than NP. The hypothesis that HM contents in tree rings should register pollution is debatable. HM uptake by pines from soil, detoxification mechanisms and resuspended local soil dust is involved in HM contents in wood and bark.

In the Mediterranean ecosystem, wildfires are very frequent and the predicted future with a probable increase of fires could drastically modify the vegetation scenarios. Vegetation fires are an important source of gases and primary emissions of fine carbonaceous particles in the atmosphere. In this paper, we present gaseous and particulate emissions data from the combustion of different plant tissues (needles/leaves, branches and needle/leaf litter), obtained from one conifer (Pinus halepensis) and one deciduous broadleaf tree (Quercus pubescens). Both species are commonly found throughout the Mediterranean area, often subject to wildfires. Experiments were carried out in a combustion chamber continuously sampling emissions throughout the different phases of a fire (pre-ignition, flaming and smoldering). We identified and quantified 83 volatile organic compounds including important carcinogens that can affect human health. CO and CO₂ were the main gaseous species emitted, benzene and toluene were the dominant aromatic hydrocarbons, methyl-vinyl-ketone and methyl-ethyl-ketone were the most abundant measured oxygenated volatile organic compounds. CO₂ and methane emissions peaked during the flaming phase, while the peak of CO emissions occurred during the smoldering phase. Overall, needle/leaf combustion released a greater amount of volatile organic compounds into the atmosphere than the combustion of branches and litter. There were few differences between emissions from the combustion of the two tree species, except for some compounds. The combustion of P. halepensis released a great amount of monoterpenes as α-pinene, β-pinene, p-cymene, sabinene, 3-carene, terpinolene and camphene that are not emitted from the combustion of Q. pubescens. The combustion of branches showed the longest duration of flaming and peak of temperature. Data presented appear crucial for modeling with the intent of understanding the loss of C during different phases of fire and how different typologies of biomass can affect wildfires and their speciation emissions profile.

Polycyclic aromatic hydrocarbons (PAHs) are emitted into the atmosphere from combustion of fuels, such as emissions from traffic in urban areas, which on their terms can be important sources for the translocation of these toxic compounds to the surrounding region. Pine needles can be used as time–integrated passive air–samplers for PAHs. Pine needles were collected between 2009 and 2011 along a spatial gradient (5km) from urban background sites towards sites situated in a natural park (Collserola) within the metropolitan area of Barcelona. City samples showed PAH levels that were two times higher than the levels in the natural park. A seasonal trend was reflected by the substantially higher PAH levels in pine needles collected in the colder sampling period than those collected in the warmer period. The observed trend can be explained in terms of source emission strength, dilution and photo–chemical degradation, while also gas–pine needles partitioning may have played an important role. The city is the major source area for the translocation of PAHs towards the nearby natural park.

En France, dans les Alpes-Maritimes, une recherche est menée pour connaître l'impact éventuel de l'ozone sur l'endommagement foliaire repéré ces dernières années sur peuplements de pins d'Alep, sylvestre et cembro. L'étude s'effectue dans le cadre d'un contrat franco-italien Interreg 2 et d'un programme Primequal. Cet article donne tout d'abord, les résultats pour l'été 1999, intéressant les niveaux de concentration d'ozone mesurés depuis le littoral azuréen jusqu'au massif du Mercantour au moyen d'analyseurs physico-chimiques et de capteurs passifs. La dose d'AOT 40 et la somme cumulée des concentrations horaires sont indiquées pour les périodes de mesure estivales. Les capteurs passifs se situent notamment parmi des placettes de suivi d'arbres. Afin d'appréhender l'impact de la pollution par l'ozone sur ces écosystèmes forestiers, des notations d'endommagement foliaire sont effectuées. Des correspondances sont recherchées entre les niveaux moyens d'ozone et les degrés d'atteinte des trois principales essences suivies (pins d'Alep, sylvestre et cembro). Il semble y avoir une corrélation entre augmentation des concentrations d'ozone et endommagement foliaire au moins en ce qui concerne les pins cembro

We present here the effects of ambient ozone (O₃)-induced decline in carbon availability, accelerated foliar senescence, and a decrease in aboveground biomass accumulation in the Aleppo pine (Pinus halepensis Mill.). Aleppo pine seedlings were continuously exposed in open-top chambers for 39 months to three different types of O₃ treatments, which are as follows: charcoal-filtered air, nonfiltered air (NFA), and nonfiltered air supplemented with 40 ppb O₃ (NFA+). Stable carbon isotope discrimination (Δ) and derived time-integrated c i/c a ratios were reduced after an accumulated ozone exposure over a threshold of 40 ppb (AOT40) value from April to September of around 20,000 ppb·h. An AOT40 of above 67,000 ppb·h induced reductions in ribulose-1,5-biphosphate carboxylase/oxygenase activity, aboveground C and needle N and K concentrations, the C/N ratio, Ca concentrations in twigs under 3 mm, and the aerial biomass, as well as increases in needle P concentrations and phosphoenolpyruvate carboxylase (PEPC) activity and the N and K concentrations in twigs under 3 mm. Macronutrients losses, the limitations placed on carbon uptake, and increases in catabolic processes may be the causes of carbon gain diminution in leaves which was reflected as a reduction in aboveground biomass at tree level. Stimulation of PEPC activity, the consequent decreased Δ, and compensation processes in nutrient distribution may increase O₃ tolerance and might be interpreted as part of Aleppo pine acclimation response to O₃.