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At least 739 records · Page 41Linked to original sources
PubMed2005

Sexual reproduction, clonal diversity and genetic differentiation in patchily distributed populations of the temperate forest herb Paris quadrifolia (Trilliaceae).

Clonal plant species have been shown to adopt different strategies to persist in heterogeneous environments by changing relative investments in sexual reproduction and clonal propagation. As a result, clonal diversity and genetic variation may be different along environmental gradients. We examined the regional and local population structure of the clonal rhizomatous forest herb Paris quadrifolia in a complex of forest fragments in Voeren (Belgium). Relationships between population size (the number of shoots), shoot density (the number of shoots per m2) and local growth conditions were investigated for 47 populations. Clonal diversity and genetic variation within and among 19 populations were investigated using amplified fragment length polymorphism markers. To assess the importance of sexual reproduction, seed set, seed weight and germination success were determined in 18 populations. As predicted, local growth conditions largely affected population distribution, size and density of P. quadrifolia. Populations occurring in moist and relatively productive sites contained significantly more shoots. Here, shoots were also much more sparsely distributed compared to populations occurring in dry and relatively unproductive sites, where shoots showed a strongly aggregated distribution pattern. Clonal diversity was relatively high, compared with other clonal species (G/N ratio=0.43 and Simpson's D=0.81). Clonal diversity significantly (P<0.01) decreased with increasing shoot density while molecular genetic variation was significantly (P<0.01) affected by population size and local environmental conditions. Lack of recruitment and out-competition of less-adapted genotypes may explain the decreased genetic variation in dry sites. Analysis of molecular variance revealed significant genetic variation among populations (PhiST=0.42, P<0.001), whereas pairwise genetic distances were not correlated to geographic distances, suggesting that gene flow among populations is limited. Finally, the number of generative shoots, the number of seeds per fruit and seed weight were significantly and positively related to population size and local growth conditions. We conclude that under stressful conditions populations of clonal forest plant species can slowly evolve into remnant populations characterized by low levels of genetic variation and limited sexual reproduction. Conservation of suitable habitat conditions is therefore a prerequisite for effective long-term conservation of clonal forest plant species.

Magnoliopsida↗
PubMed2006

Successional and physical controls on the retention of nitrogen in an undisturbed boreal forest ecosystem.

Floristic succession in the boreal forest can have a dramatic influence on ecosystem nutrient cycling. We predicted that a decrease in plant and microbial demand for nitrogen (N) during the transition from mid- to late-succession forests would induce an increase in the leaching of dissolved inorganic nitrogen (DIN), relative to dissolved organic nitrogen (DON). To test this, we examined the chemistry of the soil solution collected from within and below the main rooting zones of mid- and late-succession forests, located along the Tanana River in interior Alaska. We also used a combination of hydrological and chemical analyses to investigate a key assumption of our methodology: that patterns of soil water movement did not change during this transition. Between stands, there was no difference in the proportion of DIN below the rooting zone. 84-98% of DIN at both depths consisted of nitrate, which was significantly higher in the deeper mineral soil than at the soil surface (0.46+/-0.12 mg NO(-) (3) -N l(-1) vs 0.17+/-0.12 mg NO(-) (3) -N l(-1), respectively), and 79-92% of the total dissolved N consisted of DON. Contrary to our original assumption that nutrients were primarily leached downward, out of the rooting zone, we found much evidence to suggest that the glacially-fed Tanana River (>200 m from these stands) was contributing to the influx of water and nutrients into the soil active layer of both stands. Soil water potentials were positively correlated with river discharge; and ionic and isotopic (delta(18)O of H(2)O) values of the soil solution closely matched those of river water. Thus, our ability to elucidate biological control over ecosystem N retention was confounded by riverine nutrient inputs. Climatic warming is likely to extend the season of glacial melt and increase riverine nutrient inputs to forests along glacially-fed rivers.

Alaska↗
PubMed2006

Root controls on soil microbial community structure in forest soils.

We assessed microbial community composition as a function of altered above- and belowground inputs to soil in forest ecosystems of Oregon, Pennsylvania, and Hungary as part of a larger Detritus Input and Removal Treatment (DIRT) experiment. DIRT plots, which include root trenching, aboveground litter exclusion, and doubling of litter inputs, have been established in forested ecosystems in the US and Europe that vary with respect to dominant tree species, soil C content, N deposition rate, and soil type. This study used phospholipid fatty-acid (PLFA) analysis to examine changes in the soil microbial community size and composition in the mineral soil (0-10 cm) as a result of the DIRT treatments. At all sites, the PLFA profiles from the plots without roots were significantly different from all other treatments. PLFA analysis showed that the rootless plots generally contained larger quantities of actinomycete biomarkers and lower amounts of fungal biomarkers. At one of the sites in an old-growth coniferous forest, seasonal changes in PLFA profiles were also examined. Seasonal differences in soil microbial community composition were greater than treatment differences. Throughout the year, treatments without roots continued to have a different microbial community composition than the treatments with roots, although the specific PLFA biomarkers responsible for these differences varied by season. These data provide direct evidence that root C inputs exert a large control on microbial community composition in the three forested ecosystems studied.

Plant Roots↗
PubMed2004

Phylogeography of the component species of broad-leaved evergreen forests in Japan, based on chloroplast DNA variation.

In order to elucidate the past distribution and colonization routes of broad-leaved evergreen (lucidophyllous) forests, we investigated the intraspecific phylogeographic patterns of lucidophyllous forests in Japan and surrounding areas. We selected 6 component species with a similar geographic distributions growing in Castanopsis-dominant forests. We defined possible important refugia during the glacial periods as the regions rich in rare haplotypes (with a frequency of 5% or less), or as regions rich in the number of common haplotypes (with a frequency of more than 5%). We then located the sites of refuge by comparing the intraspecific phylogeographic patterns among 6 component species of lucidophyllous forests with respect to these two parameters (i.e., haplotype uniqueness and the number of haplotypes). The following results were obtained during the course of this study: (1) rare haplotypes were distributed among islands around the main islands of Japan; (2) rare subtypes and the greatest numbers of common haplotypes were observed in Kyushu, a finding which agreed with fossilized pollen data demonstrative of the past existence of refugia in southern Kyushu; and (3) rare haplotypes were found on the Muroto Peninsula, and the second greatest numbers of common haplotypes were observed on the Kii Peninsula, a finding which suggested the existence of additional important refugia along the Pacific coast of Japan during the glacial ages.

Animals↗
PubMed2006

Stand structure and woody species diversity in relation to stand stratification in a subtropical evergreen broadleaf forest, Okinawa Island.

Stand structure and woody species diversity in a subtropical evergreen broadleaf forest grown in a silicate habitat, Okinawa Island, have been investigated on the basis of stand stratification. The forest stand consisted of four layers. The floristic composition of the top and the lower three layers was only slightly similar, although approximately one-third of the species were common to them. Mean tree weight decreased from the top toward the bottom layer whereas tree density increased from the top downward. This trend resembled the mean weight-density trajectory of self-thinning plant populations. The relationship between mean tree height and tree density for the upper two layers supported Yamakura's quasi -1/2 power law of tree height. The values of the Shannon-Wiener index, H', and the equitability index, J', tended to increase from the top layer downward except for the bottom layer. The values of H' and J' were, respectively, 4.83 bit and 0.82 for trees taller than 0.10 m. The lower layers contained many species of smaller height. High species diversity of the forest depended on small trees in the lower layers. Conservation of small trees in the lower layers, especially the bottom layer, is indispensable for sound maintenance of Okinawan evergreen broadleaf forests.

Biodiversity↗
PubMed2005

Eight nonnative plants in western Oregon forests: associations with environment and management.

Nonnative plants have tremendous ecological and economic impacts on plant communities globally, but comprehensive data on the distribution and ecological relationships of individual species is often scarce or nonexistent. The objective of this study was to assess the influence of vegetation type, climate, topography, and management history on the distribution and abundance of eight selected nonnative plant taxa in forests in western Oregon. These eight taxa were selected as being reliably detected by a multi-resource inventory of 1127 systematically-placed plots on non-federal forest lands from 1995 to 1997 by the USFS Forest Inventory and Analysis (FIA) program. One or more of the eight nonnative taxa studied were found on 20% of the sampled subplots in the study area, but relatively few stands were dominated by them. Overall abundance of nonnative taxa was likely much greater, because few composites and graminoids were identified to species in this general-purpose inventory. Distribution of most taxa was more closely associated with low density of overstory trees than with climate. Nonnative taxa were significantly more abundant in stands that had been recently clearcut or thinned than in stands that had not. Frequencies of several taxa decreased with elevation, which may reflect proximity to source populations and intensive land use rather than any climatic constraints. Although the greatest potential for displacement of native forest species appears to be in early-successional communities, the potential for spread of some shade-tolerant evergreen shrubs also seems high.

Climate↗
PubMed2006

Monitoring of biodiversity indicators in boreal forests: a need for improved focus.

The general principles of scale and coarse and fine filters have been widely accepted, but management agencies and industry are still grappling with the question of what to monitor to detect changes in forest biodiversity following forest management. Part of this problem can be attributed to the lack of focused questions for monitoring including absence of null models and predicted effects, a certain level of disconnect between research and management, and recognition that monitoring can be designed as a research question. Considerable research from the past decade has not been adequately synthesized to answer important questions, such as which species or forest attributes might be the best indicators of change. A disproportionate research emphasis has been placed on community ecology, and mostly on a few groups of organisms including arthropods, amphibians, migratory songbirds, and small mammals, while other species, including soil organisms, lichens, bats, raptors, some carnivores, and larger mammals remain less well-known. In most studies of community ecology, the question of what is the importance, if any, of the regularly observed subtle changes in community structures, and causes of observed changes is usually not answered. Hence, our ability to deal with questions of persistence is limited, and demographic research on regionally-defined key species (such as species linked to processes, species whose persistence may be affected, species with large home ranges, species already selected as indicators, and rare and threatened species) is urgently needed. Monitoring programs need to be designed to enable managers to respond to unexpected changes caused by forest management. To do this, management agencies need to articulate null models for monitoring that predict effects, focus fine-scale monitoring on key species (defined by local and regional research) in key habitats (rare, declining, important) across landscapes, and have a protocol in place to adapt management strategies to changes observed. Finally, agencies must have some way to determine and define when a significant change has occurred and to predict the persistence of species; this too should flow from a well-designed null model.

Biodiversity↗
PubMed2005

Relationship between basal soil respiration rate, tree stand and soil characteristics in boreal forests.

Soil respiration is considered to represent the overall microbial activity reflecting mineralisation of organic matter in soil. It is the most commonly used biological variable in soil studies. In long-term monitoring of forested areas, there is a need for reference values for soil microbiological variables in different forest ecosystems. In this study we describe the relationship between soil respiration rate, tree stand and humus chemical characteristics of boreal coniferous forests stands. Soil respiration rate was higher in pine dominated than in spruce dominated study sites when the result was calculated on dry matter bases. However, when calculated on area bases, the result was opposite and no difference was found when the soil respiration rate was calculated on organic carbon bases. Irrespective of the main tree species, the soil respiration rate was equal in different development classes but not equal in soil fertility classes, i.e. within forest site types based on differences in ground vegetation. Respiration rates were clearly higher in mesic sites when calculated on dry matter, C(org) or area bases. However, soil respiration rate did not correlate with soil chemical variables indicating site fertility. Soil respiration rate on dry matter basis was at a lower level in the south and on more fertile sites, and on the other hand at a higher level in older stands and on sites with a thicker organic layer.

Carbon Dioxide↗
PubMed2006

Evaluating kriging as a tool to improve moderate resolution maps of forest biomass.

The USDA Forest Service, Forest Inventory and Analysis program (FIA) recently produced a nationwide map of forest biomass by modeling biomass collected on forest inventory plots as nonparametric functions of moderate resolution satellite data and other environmental variables using Cubist software. Efforts are underway to develop methods to enhance this initial map. We explored the possibility of modeling spatial structure to make such improvements. Spatial structure in the field biomass data as well as in residuals from the map was investigated across 18 ecological zones in the Interior Western U.S. Exploratory tools included directional graphs of summary statistics, three dimensional maps, Moran's I correlograms, and variograms. Where spatial pattern was present, field and residual biomass were kriged, and predictions made for an independent test set were evaluated for improvement over predictions in the initial biomass map. While kriging has some potential benefit when analyzing the field data and exploring spatial structure, kriging residuals resulted in little or no improvement in the initial biomass map developed using Cubist software. Stationarity assumptions, variogram behavior, and appropriate model fitting strategies are discussed.

Biomass↗
PubMed2006

Identification of sex pheromone components of a New Zealand geometrid moth, the common forest looper Pseudocoremia suavis, reveals a possible species complex.

Gas chromatography-electroantennographic detection analysis of sex pheromone gland extracts of the common forest looper Pseudocoremia suavis (Lepidoptera: Geometridae), a polyphagous defoliator of introduced Pinaceae and many New Zealand trees, revealed four compounds that elicited antennal responses. The two major active compounds (6Z)-cis-9,10-epoxynonadec-6-ene and (3Z,6Z)-cis-9,10-epoxynonadeca-3,6-diene were identified by comparison with known standards. Of the two minor active compounds, one was tentatively identified as (3Z,6Z)-cis-9,10-epoxyhenicosa-3,6-diene, whereas the other could not be identified because of insufficient amounts in extracts. (6Z)-cis-9,10-Epoxynonadec-6-ene, (3Z,6Z)-cis-9,10-epoxynonadeca-3,6-diene, and (3Z,6Z)-cis-9,10-epoxyhenicosa-3,6-diene were present in P. suavis gland extracts from Eyrewell Forest, a Pinus radiata plantation in the South Island of New Zealand, in a ratio of 35:65:5, respectively. Trapping trials in Eyrewell Forest established that (6Z)-cis-9,10-epoxynonadec-6-ene attracted male P. suavis. However, addition of (3Z,6Z)-cis-9,10-epoxyhenicosa-3,6-diene to the lure at <10% of (6Z)-cis-9,10-epoxynonadec-6-ene reduced capture of male moths, suggesting that one of its enantiomers was acting as a behavioral antagonist. During January-March of 2005, a blend trial involving single, binary, and ternary mixtures of the three components at Eyrewell Forest and at three other sites (two in the South Island and one in the North Island) revealed the existence of a second taxon of P. suavis at the three additional sites that was attracted to lures containing (3Z,6Z)-cis-9,10-epoxynonadeca-3,6-diene, either singly or in binary and ternary mixtures with (6Z)-cis-9,10-epoxynonadec-6-ene and (3Z,6Z)-cis-9,10-epoxyhenicosa-3,6-diene. This second taxon was not attracted to lures loaded solely with (6Z)-cis-9,10-epoxynonadec-6-ene.

Animals↗
PubMed1977

A yellow fever epizootic in Zika Forest, Uganda, during 1972: Part 2: Monkey serology.

During the 1972 yellow fever epizootic in Zika Forest, Uganda, sera from 21 monkeys shot in a number of forests around the Entebbe area were tested for the presence of a number of arbovirus antibodies. All sera were tested for antibodies against Chikungunya (CHIK), O'nyong-nyong (ONN), Zika, yellow fever (YF) West Nile (WN) and Wesselsbron (WESS) by the haemagglutination-inhibition (HI) test. Because of the crossreaction within the flaviviruses (group B arboviruses) mouse protection test (PT) was also carried out on the sera against YF, WESS and Zika viruses. Serological studies carried out on monkey sera from different parts of Uganda, including the Entebbe area, during 1968 gave results which reflected a surprisingly low rate of YF immune monkeys (3%) throughout the country compared with the rate of over 40% immune monkeys obtained by Haddow et al. in 1951. 40% of the monkey sera collected during 1972 were immune to YF by the PT. Since no YF virus had been isolated between 1968 and 1972 the results indicate strongly that the monkeys in the Entebbe area were involved in the epizootic of 1972. No sick or dead monkeys were found in all the forests checked around Entebbe area during the epizootic. This indicates that the animal-to-animal cycle of the equatorial African forests involved the mild endemic infection characteristic of a virus in its natural habitat and infecting its natural host.

Animals↗
PubMed1983

Leishmaniasis in Brazil: XX. Prevalence of "enzootic rodent leishmaniasis" (Leishmania mexicana amazonensis), and apparent absence of "pian bois" (Le. braziliensis guyanensis), in plantations of introduced tree species and in other non-climax forests in eastern Amazônia.

In Amazonian Brazil most human leishmaniasis is due to Leishmania braziliensis s.l. and is acquired during the clearing of primary climax forest. One of the largest deforestation projects has taken place on the JARI property where plantations of exotic tree species are grown for paper pulp. The ability of the regional leishmaniasis enzootics to invade plantations was investigated. CDC light-trap catches indicated the phletobomine vectors of Le. b. guyanensis (causing "pian bois" in man) to be very scarce in JARI plantations compared to native-forest controls. It is concluded (drawing on other observations) that the vectors of "pian bois" are unlikely to thrive in any secondary forest. In contrast, catches from mammal traps and rodent-baited (Disney) traps demonstrated the presence in JARI plantations of infected Proechimys guyannensis and large populations of Lutzomyia flaviscutellata, respectively the major rodent reservoir and sandfly vector of Le. mexicana amazonensis. Alone amongst the local vectors of human cutaneous leishmaniasis, Lu. flaviscutellata is adapted to non-climax forests (primary or secondary, natural or man-made; synopsis given). It is predicted that the public health importance of Le. m. amazonensis is unlikely to diminish following the development of Amazônia. This is worrying because ca. 30% of Le. m. amazonensis infections in man cause highly-disfiguring, incurable "diffuse cutaneous leishmaniasis".

Animals↗
PubMed1994

Novel approaches to the estimation of intake and bioavailability of radiocaesium in ruminants grazing forested areas.

It is difficult to measure transfer of radiocaesium to the tissues of forest ruminants because they can potentially ingest a wide range of plant types. Measurements on undomesticated forest ruminants incur further difficulties. Existing techniques of estimating radiocaesium intake are imprecise when applied to forest systems. New approaches to measure this parameter are discussed. Two methods of intake estimation are described and evaluated. In the first method, radiocaesium intake is estimated from the radiocaesium activity concentrations of plants, combined with estimates of dry-matter (DM) intake and plant species composition of the diet, using plant and orally-dosed hydrocarbons (n-alkanes) as markers. The second approach estimates the total radiocaesium intake of an animal from the rate of excretion of radiocaesium in the faeces and an assumed value for the apparent absorption coefficient. Estimates of radiocaesium intake, using these approaches, in lactating goats and adult sheep were used to calculate transfer coefficients for milk and muscle; these compared favourably with transfer coefficients previously obtained under controlled experimental conditions. Potential variations in bioavailability of dietary radiocaesium sources to forest ruminants have rarely been considered. Approaches that can be used to describe bioavailability, including the true absorption coefficient and in vitro extractability, are outlined.

Animal Feed↗
PubMed1988

Response to heavy nitrogen applications in fertilizer experiments in British forests.

Increasing concern over the level of nitrogen inputs to forests in polluted rain has led to a number of suggestions of possible adverse consequences under the general heading of nitrogen saturation. A saturated ecosystem may be one (a) in which the trees show no growth response to the addition of further nitrogen, (b) in which addition of further nitrogen leads to growth disturbances or reduction, or (c) in which elevated nitrogen inputs lead to increased losses of nitrate in streamwater. Experience gained from forest fertilizer experiments is used to examine each of these suggestions. A definition involving a lack of growth response (a) is shown to be based on a lack of understanding of the continuing changing patterns of nitrogen demand and mineralization in even-aged forests. Similarly, using growth disturbances (b) is unsatisfactory because, it is suggested, these are either secondary deficiencies that appear once growth accelerates with added nitrogen or are a consequence of changing growth with increasing size. A definition based on increased loss of nitrate is, by analogy with the situation for sulphate, at least superficially attractive. However, the fact that nitrate retention is predominantly biological, rather than chemical, makes for difficulties and the limited evidence available suggests that many exceptions and variations may exist. Whilst experience with forest fertilizers might not be entirely apposite, for example foliar uptake from polluted rain may be a factor, it is urged that at least any hypothesis put forward should be compatible with information gained from fertilizer trials.

Journal Article↗
PubMed1988

Foliar sulphur species in pine: a new indicator of a forest ecosystem under air pollution stress.

An eleven-year foliar sulphur (S) monitoring program was carried out from 1976 to 1986 near a sulphur recovery-gas plant in west-central Alberta, Canada, as part of a case study designed to determine the effects of chronic, low concentration sulphur gas emissions on the forest ecosystem surrounding the gas plant. Measurements of both foliar total sulphur (ST) and foliar inorganic sulphur (SO4-S) concentration in lodgepole x jack pine trees at the end of each of the 11 growing seasons were taken to provide an indication of S loading of the forest from industrial sulphur emissions. To measure the state of the forest ecosystem, foliar ST was separated into foliar accumulated sulphur (inorganic sulphur or SO4-S) and foliar assimilated sulphur (organic sulphur or S0) and the ratio of SO4-S/S0 taken. Foliar S0 was calculated as the difference between foliar ST and foliar SO4-S. The median SO4-S/S0 ratio, with all three years of needles considered, varied from 0.29 at a reference location (AV) to 0.88 at the location with the highest stress (AI). The corresponding mean values ranged from 0.3 at the reference location to 2.2 at the location of highest stress. The mean seasonal photosynthetic rate of current year's foliage of the pine trees and soil pH were reduced at a stressed location (AI) compared to the reference location (AV), between 1976 and 1981. Over this same time period the mean foliar SO4-S/S0 ratio increased from 0.4 +/- 0.1 to 1.0 +/- 0.3 at the stressed location (AI) and remained nearly the same at the reference location (AV) at 0.3 +/- 0.1. This research suggests that the foliar SO4-S/S0 ratio is a useful indicator of the state of forest ecosystems under S air pollution stress. It is concluded that foliar S separated into various fractions has potential as an early warning environmental management tool.

Journal Article↗
PubMed1988

Forest health surveys--a critique.

Surveys of forest health, as presently undertaken, provide information on the general condition of forests. They integrate the effects of all factors, biotic and abiotic, of which pollution is but one, that affect trees. Most surveys are based on the assessment of crown density and crown discoloration. These assessments are subjective and serious errors can occur. In some cases, the sampling design that has been adopted is not the most suitable for the forest area under investigation. The blanket application of a systematic sampling design based on a 16 by 16 km grid is particularly questionable in view of the variation in the nature of Europe's forests. Comparisons, either between regions or through time, may or may not be valid, depending on how the surveys are conducted. Although much progress has been made, standardisation within Europe has not yet been achieved and it is therefore difficult to make comparisons between the results obtained by different countries.

Journal Article↗
PubMed1992

Chemical climatology of high elevation spruce-fir forests in the southern Appalachian mountains.

The physical and chemical climatology of high elevation (> 1500 m) spruce-fir forests in the southern Appalachian mountains was studied by establishing a weather and atmospheric chemical observatory at Mt Mitchell State Park in North Carolina (35 degrees 44' 05" N, 82 degrees 17' 15"W). Data collected during the summer and autumn (May-October) of 1986, 1987, and 1988 are reported. All measurements were made on or near a 16.5 m walk-up tower extending 10 m above the forest canopy on Mt Gibbes (2006 m msl), which is located approximately 2 km SW of Mt Mitchell. The tower was equipped with standard meteorological instrumentation, a passive cloud water collector, and gas pollutant sensors for O3, SO2, NOx. The tower and nearby forest canopy were immersed in clouds 25 to 40% of the time. Non-precipitating clouds were very acidic (pH 2.5-4.5). Precipitating clouds were less acidic (pH 3.5-5.5). The dominant wind directions were WNW and ESE. Clouds from the most common wind direction (WNW) were more acidic (mean pH 3.5) than those from the next most common wind direction (ESE, mean pH 5.5). Cloud water acidity was related to the concentration of SO4(2-), and NO3- ions. Mean concentration of H+, NH4+, SO4(2-), and NO3- ions in the cloud water varied from 330-340, 150-200, 190-200 and 120-140 micromol litre(-1) respectively. The average and range of O3 were 50 (25-100) ppbv (109) in 1986, 51 (26-102) ppbv in 1987, and 66 (30-140) during the 1988 field seasons, respectively. The daily maximum, 1-h average, and 24-h average concentrations were all greatest during June through mid-August, suggesting a correlation with the seasonal temperature and solar intensity. Throughfall collectors near the tower were used to obtain a useful estimate of deposition to the forest canopy. Between 50-60% of the total deposition of SO4(2-) was due to cloud impact.

Journal Article↗
PubMed1994

Forest fire emissions in Portugal: a contribution to global warming?

A forecast of expected evolution of carbon dioxide (CO(2)) emissions in Portugal between 1988 and 2010 is presented. Predictions show that CO(2) emissions will almost double in the next twenty years. The equivalent potential CO(2) emissions from nitrogen oxides (NO(x)) and volatile organic compounds (VOC), for a time horizon of 20 years, is also presented. NO(x) and VOC emissions seem to make a significant contribution to the global warming potential of Portuguese emissions. Estimates of CO(2) emissions due to forest fires have been made, oriented towards the study of the Portuguese contribution to the global warming. If the burned area exceeds 100 000 ha this contribution could reach 7% of the total Portuguese CO(2) emissions. The global warming potential of Portuguese forest emissions were also calculated. The climate change predicted to Portugal could be responsible for an increase in the forest fires and consequently for a greater contribution of its emissions to the total values. It was concluded that it is important to quantify emissions of the greenhouse gases, including the contribution of forest fire emissions, not only in Portugal, but in all the Southern European countries.

Journal Article↗