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PubMed2004

Biomass change in an Atlantic tropical moist forest: the ENSO effect in permanent sample plots over a 22-year period.

There are a number of controversies surrounding both biomass estimation and carbon balance in tropical forests. Here we use long-term (from 1978 through 2000) data from five 0.5-ha permanent sample plots (PSPs) within a large tract of relatively undisturbed Atlantic moist forest in southeastern Brazil to quantify the biomass increment (DeltaM(I)), and change in total stand biomass (DeltaM(stand)), from mortality, recruitment, and growth data for trees >/=10 cm diameter at breast height (DBH). Despite receiving an average of only 1,200 mm annual precipitation, total forests biomass (334.5+/-11.3 Mg ha(-1)) was comparable to moist tropical forests with much greater precipitation. Over this relatively long-term study, forest biomass experienced rapid declines associated with El Niño events, followed by gradual biomass accumulation. Over short time intervals that overlook extreme events, these dynamics can be misinterpreted as net biomass accumulation. However for the 22 years of this study, there was a small reduction in forest biomass, averaging -1.2 Mg ha(-1) year(-1) (+/-3.1). Strong climatic disturbances can severely reduce forest biomass, and if the frequency and intensity of these events increases beyond historical averages, these changing disturbance regimes have the capacity to significantly reduce forest biomass, resulting in a net source of carbon to the atmosphere.

Biomass↗
PubMed2006

Evaluation of carbon uptake and emissions by forests in Korea during the last thirty years (1973-2002).

The contribution of Korean forests to carbon sequestration for anthropogenic carbon emissions was evaluated. In addition, monitoring of carbon species released from forest fires was conducted. Despite a high carbon uptake by Korean forests, a tremendous increase in fossil fuel burning resulted in a small contribution by forests to carbon removal. The removal efficiency had a 5-31% range with an average of 12% during the period 1973-2002. In 2000, the amount of carbon released from burned trees corresponded to 1.6% of carbon uptake by forests. The distribution of surface CO concentration (ppb) derived from MOPITT (Measurement of Pollution in the Troposphere) showed high CO levels over the East/Japan Sea on April 10, 2000 when the largest forest fires occurred along the east coast of Korea. Trajectory analysis and ground CO measurements also indicated that CO levels over the East/Japan Sea were influenced by forest fires. This study suggests that continuous monitoring of carbon emissions from forest fires is needed for a more reliable estimate of carbon flux in the environment.

Carbon↗
PubMed2006

Forest vegetation monitoring and foliar chemistry of red spruce and red maple at Acadia National Park in Maine.

The USDA Forest Service Forest Health Monitoring (FHM) program indicators, including forest mensuration, crown condition classification, and damage and mortality indicators were used in the Cadillac Brook and Hadlock Brook watershed forests at Acadia National Park (ANP) along coastal Maine. Cadillac Brook watershed burned in a wildfire in 1947. Hadlock Brook watershed, undisturbed for several centuries, serves as the reference site. These two small watersheds have been gauged and monitored at ANP since 1998 as part of the Park Research and Intensive Monitoring of Ecosystems Network (PRIMENet). Forest vegetation at Hadlock Brook was dominated by late successional species such as Acer saccharum, Fagus grandifolia, Betula alleghaniensis, Acer rubrum and Picea rubens. Forest vegetation at Cadillac Brook, on the other hand, was younger and more diverse and included those species found in Hadlock as well as early successional species such as Betula papyrifera and Populus grandidentata. Differences in forest species composition and stand structure were attributed to the severe wildfire that affected the Cadillac Brook watershed. Overall, the forests at these ANP watersheds were healthy with a low percentage (</=22%) of trees showing symptoms of damage.Foliar nitrogen (N) concentrations were higher in A. rubrum and P. rubens trees growing in Hadlock Brook watershed, but differences were significant only for P. rubens. Foliar aluminum (Al) concentrations were also higher in both species growing in Hadlock Brook watershed but differences were significant only for A. rubrum. Foliar calcium (Ca) and manganese (Mn) concentrations, on the other hand, were significantly lower in Hadlock Brook watershed for both species. Foliar potassium (K) was significantly higher for P. rubens growing in Hadlock Brook. No differences in foliar concentrations of magnesium (Mg), phosphorus (P), boron (B), copper (Cu) and lead (Pb) were found between watersheds. The higher foliar N concentrations as well as higher foliar concentrations of Ca and Al might indicate early stages of N saturation and acidification in Hadlock Brook watershed as also suggested by Hadlock Brook stream N flux data in published PRIMENet studies at ANP.

Acer↗
PubMed2006

Spatial distribution and temporal change of carbon storage in timber biomass of two different forest management units.

Forests make up large ecosystems and can play an important role in mitigating the emissions of CO2, the most important greenhouse gas. However, they are sources of atmospheric carbon when they are disturbed by human or natural causes. Storage of carbon through expansion and adaptive management of forest ecosystems can assist in reducing carbon concentrations in atmosphere. This study proposes a methodology to produce spatially explicit estimates of the carbon storages (aboveground plus belowground) depending on land use/cover changes in two different forest ecosystems during various periods. Carbon storages for each forest ecosystem were projected according to inventory data, and carbon storages were mapped in a geographic information system (GIS). Results showed that total carbon stored in above and belowground of both forest ecosystems increased from one period to other because of especially increase of productive forest areas and decline of degraded forest areas as well as protection of spruce forests subject to insect attacks.

Biomass↗
PubMed1990

Forest responses to tropospheric ozone and global climate change: an analysis.

In this paper an analysis is provided on: what we know, what we need to know, and what we need to do, to further our understanding of the relationships between tropospheric ozone (O(3)), global climate change and forest responses. The relationships between global geographic distributions of forest ecosystems and potential geographic regions of high photochemical smog by the year 2025 AD are described. While the emphasis is on the effects of tropospheric O(3) on forest ecosystems, discussion is presented to understand such effects in the context of global climate change. One particular strong point of this paper is the audit of published surface O(3) data by photochemical smog region that reveals important forest/woodland geographic regions where little or no O(3) data exist even though the potential threat to forests in those regions appears to be large. The concepts and considerations relevant to the examination of ecosystem responses as a whole, rather than simply tree stands alone are reviewed. A brief argument is provided to stimulate the modification of the concept of simple cause and effect relationships in viewing total ecosystems. Our knowledge of O(3) exposure and its effects on the energy, nutrient and hydrological flow within the ecosystem are described. Modeling strategies for such systems are reviewed. A discussion of responses of forests to potential multiple climatic changes is provided. An important concept in this paper is that changes in water exchange processes throughout the hydrological cycle can be used as early warning indicators of forest responses to O(3). Another strength of this paper is the integration of information on structural and functional processes of ecosystems and their responses to O(3). An admitted weakness of this analysis is that the information on integrated ecosystem responses is based overwhelmingly on the San Bernardino Forest ecosystem research program of the 1970s because of a lack of similar studies. In the final analysis, it is recommended that systems ecology be applied in examining the joint effects of O(3), carbon dioxide and ultraviolet-B radiation on forest ecosystems.

Journal Article↗
PubMed2004

Heavy metal pollution and forest health in the Ukrainian Carpathians.

The Ukrainian Carpathians are characterized by high air pollution caused by emissions from numerous industries. We have been monitoring the state of forests in this region since 1989. The highest levels of tree defoliation (>30%) are found close to industrial emission sources and in the upper mountain forests of the Ivano-Frankivsk and Chernivtsi regions. This is caused by a combination of strong anthropogenic influences (pollution, illegal uses, recreation) as well as poor site and climatic conditions. In the Ivano-Frankivsk region, Cd and Mo accumulate in forest soils; Cr, Mo and Zn soil concentrations are higher than their limit levels; and Pb concentrations exceed toxic levels close to industrial areas (10% of the region territory). Local background levels of heavy metals are greatly exceeded in snow close to industrial regions. Analysis of correlation matrices shows that the chemical elements Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, V and Zn occur at pollution levels in natural ecosystems in the Ukrainian Carpathians. Maximum concentrations of toxic elements occur in the oak forest zone; the most industrially developed area of the region. Toxic heavy metals in the Ukrainian Carpathians forests enter with precipitation and dustfall, then become fixed in soil and accumulate in leaves, needles of vascular plants and mosses. Concentrations of these metals decrease with altitude: highest in the oak forests, less in beech, and lowest in the spruce forest zones. However, some chemical elements have the highest concentrations in spruce forests; V in needles, As in snow, and Ba and Al in soils.

Air Pollution↗
PubMed2006

Epidemiology of malaria transmission in forest and plain ecotype villages in Sundargarh District, Orissa, India.

A study of the epidemiology of malaria transmission was undertaken in 13 tribal villages located in forest and plain areas of Sundargarh District of Orissa state, India, from January 2001 to December 2003. In forest areas, intense transmission of malaria is attributed to the highly anthropophagic vector Anopheles fluviatilis sibling species S and is complemented by A. culicifacies sibling species C. In plain areas, A. culicifacies sibling species C is responsible for malaria transmission. The entomological inoculation rate in the forest and plain areas was 0.311 and 0.014 infective bites/person/night, respectively, during 2003. Malaria transmission is perennial both in forest and plain areas but is markedly low in the plain area compared with the forest area. Plasmodium falciparum accounted for 85.0% of the total malaria cases during the study period. In forest and plain areas, the number of P. falciparum cases per 1000 population per year was 284.1 and 31.2, respectively, whereas the parasite rate was 14.0% and 1.7%, respectively. In forest areas, clinical malaria occurs more frequently in children aged 0-5 years and declines gradually with increasing age. The study showed that villages in forest and plain areas separated by short geographical distances have distinct epidemiology of malaria transmission.

Adolescent↗
PubMed1996

Vertical gradients of ozone and carbon dioxide within a deciduous forest in Central Pennsylvania.

Ambient concentrations of ozone (O(3)) and carbon dioxide (CO(2)) were measured at locations from the forest floor to the top of the canopy in a deciduous forest at the Moshannon State Forest in northcentral Pennsylvania. O(3) concentrations were measured from May-September for three years (1993-1995) while CO(2) concentrations were measured only during July and August of 1994. O(3) concentrations increased steadily during the day at all locations, peaking during the middle to late afternoon hours. O(3) concentrations then steadily declined to their lowest point, just before dawn. Vertical O(3) concentration gradients varied seasonally and among years. However, O(3) concentrations were highest within the forest canopy and lowest at the forest floor, with an average difference of approximately 13%. Differences in O(3) concentrations between the canopy and forest floor were greatest at night. O(3) concentrations were slightly higher at locations within the canopy than above the canopy. CO(2) concentrations were consistenly higher near the forest floor and were higher above the canopy than within the canopy. CO(2) concentrations were higher at night than during the day at all locations, especially near the forest floor.

Journal Article↗
PubMed2003

Forest policy in the EU and its influence on the plant diversity of woodlands.

The concept of sustainability in forestry has a long tradition in Europe. However, the perception of 'sustainable management of forests' has changed in accordance with the changes in society, which has made growing demands on ecological, economical, and social functions on forests in recent years. Following the so-called 'Helsinki-process', the EU member states have decided on general guidelines for sustainable management and for the conservation of forest biodiversity. Six criteria and 27 descriptive and quantitative indicators have been defined for the assessment and monitoring of sustainable forest management. Criterion no. 4, relating to semi-natural ancient woodland as a potential vector and source of high biodiversity and respective forest policies, provides the central theme for this paper. The paper is focused on the diversity of vascular plants and explores the possibility that isolated recent woodland could contribute to plant species diversity. Measures are suggested for forest management at forest stand and landscape levels which could enhance the diversity of typical forest plants.

Conservation of Natural Resources↗
PubMed2005

PCBs and selected organochlorine compounds in Italian mountain air: the influence of altitude and forest ecosystem type.

Passive air samplers (polyurethane foam disks) were deployed on an altitudinal transect in the rural Italian Alps to investigate the potential influence of forest cover on air concentrations. Samplers were exposed overtwo periods, each of several weeks, either in clearings or in forests. In the first period, there was high leaf coverage (high leaf area index, LAI); in the second, the LAI was low after the autumnal leaf fall. PCBs sequestered in the PUF generally declined with altitude, for example, in the clearings PCBs-28, 52, 90/101, 118, and 138, all showed statistically significant declines (p < 0.05). The mass of HCB sequestered increased with altitude, evidence of cold condensation. Ratios of the forest:clearing concentrations were calculated; this ratio expresses the filtering ability of forests to deplete air concentrations compared to the adjacent clearings. During the high LAI sampling period, these depletion factors ranged between 0.93 and 0.54 and were inversely correlated with temperature-corrected log K0A. This relationship was notobserved during the low LAI sampling period. The depletion factors were normalized using the LAI to give a density independent depletion factor (DIDF). The slopes of the correlations with K0A were comparable for broadleaf or coniferous forests at different altitudes, suggesting that leaf surfaces determine the exchanges with air. Broadleaf forests at 1000 and 1400 m showed similar behavior, while a conifer forest at 1800 m gave depletion factors which were higher by about a factor of 2. It is suggested that DIDF can be used in regional environmental fate models to estimate the contribution of forests to contaminant fate.

Air Movements↗
PubMedDate not supplied

Canada's National Forest Inventory (responding to current information needs).

Canada's current National Forest Inventory is a periodic compilation of existing inventory material from across the country. While the current approach has many advantages, it lacks information on the nature and rate of changes to the resource, and does not permit projections or forecasts. Being a compilation of inventories of different dates, the current national forest inventory cannot reflect the current state of the forests and therefore cannot be used as a satisfactory baseline for monitoring change. The current format of Canada's National Forest Inventory has served its purpose by providing national statistical compilations and reporting. However, its useful life is coming to a conclusion. To meet new demands, Canada is considering a new National Forest Inventory design consisting of a plot-based system of permanent observational units located on a national grid. The objective of the new inventory design is to assess and monitor the extent, state and sustainability of Canada's forests in a timely and accurate manner. Details of the new inventory design are described. A strategy to respond to Canada's national and international forest reporting commitments through a National Forest Information System is also discussed.

Canada↗
PubMed2004

Vulnerability of Mid-Atlantic forested watersheds to timber harvest disturbance.

Forested watersheds of the Mid-Atlantic Region are an important economic resource. They are also critical for maintaining water quality, sustaining important ecological services, and providing habitat to many animal and plant species of conservation concern. These forests are vulnerable to disturbance and fragmentation from changing patterns of land use in the Mid-Atlantic Region, and from harvests of commercially mature and relatively inexpensive timber. The U.S. Department of Agriculture Forest Service (USDA-FS) Forest Inventory and Analysis (FIA) compiles data on forest condition by state and county. We have transformed these FIA data to a U.S. Geological Survey (USGS) 6-digithdrologic unit code (HUC 6) watershed base, and projected trends in timber growth, inventory, and harvest to 2025 using a timber economics forecasting model (SRTS). We consider forest sustainability from the perspective of timber production, and from the perspective of landscape stability important to conservation values. Simulation data is combined with FIA planted pine acreage data to form a more complete picture of forest extent, composition, and silvicultural practice. Early recognition of prevailing economic trends which encourage the fragmentation of mature forests due to increasing timber harvests may provide managers and policy makers with a planning tool to mitigate undesirable impacts.

Conservation of Natural Resources↗
PubMed2000

Offset of the potential carbon sink from boreal forestation by decreases in surface albedo.

Carbon uptake by forestation is one method proposed to reduce net carbon dioxide emissions to the atmosphere and so limit the radiative forcing of climate change. But the overall impact of forestation on climate will also depend on other effects associated with the creation of new forests. In particular, the albedo of a forested landscape is generally lower than that of cultivated land, especially when snow is lying, and decreasing albedo exerts a positive radiative forcing on climate. Here I simulate the radiative forcings associated with changes in surface albedo as a result of forestation in temperate and boreal forest areas, and translate these forcings into equivalent changes in local carbon stock for comparison with estimated carbon sequestration potentials. I suggest that in many boreal forest areas, the positive forcing induced by decreases in albedo can offset the negative forcing that is expected from carbon sequestration. Some high-latitude forestation activities may therefore increase climate change, rather than mitigating it as intended.

Atmosphere↗
PubMed2002

Quantifying nitrogen-fixation in feather moss carpets of boreal forests.

Biological nitrogen (N) fixation is the primary source of N within natural ecosystems, yet the origin of boreal forest N has remained elusive. The boreal forests of Eurasia and North America lack any significant, widespread symbiotic N-fixing plants. With the exception of scattered stands of alder in early primary successional forests, N-fixation in boreal forests is considered to be extremely limited. Nitrogen-fixation in northern European boreal forests has been estimated at only 0.5 kg N ha(-1) yr(-1); however, organic N is accumulated in these ecosystems at a rate of 3 kg N ha(-1) yr(-1) (ref. 8). Our limited understanding of the origin of boreal N is unacceptable given the extent of the boreal forest region, but predictable given our imperfect knowledge of N-fixation. Herein we report on a N-fixing symbiosis between a cyanobacterium (Nostoc sp.) and the ubiquitous feather moss, Pleurozium schreberi (Bird) Mitt. that alone fixes between 1.5 and 2.0 kg N ha(-1) yr(-1) in mid- to late-successional forests of northern Scandinavia and Finland. Previous efforts have probably underestimated N-fixation potential in boreal forests.

Acetylene↗
PubMed2006

Epidemiology of tick bites and borreliosis in children attending kindergarten or so-called "forest kindergarten" in southwest Germany.

The so-called "forest kindergartens" have been increasingly popular in Germany since the beginning of the 1990s. These are nurseries located in forested areas where children spend all-season full-time outdoors. Fifty-three kindergartens in the state of Baden-Württemberg, Germany participated in this study. In a prospective clinical cohort study, the child's personal data, history, protective parental habits concerning tick bites, number of tick bites, and cases of borreliosis were recorded monthly (March-October 2004) using a questionnaire. Altogether, 1,707 children of 25 "forest kindergartens" (506 children) and 28 conventional kindergartens (1,201 children) were included. The response rate was 75% in "forest kindergartens" and 65% in conventional kindergartens. In the "forest kindergartens", 1,503 tick bites especially on the trunk and on the head were found, whereas 502 tick bites were registered in conventional kindergartens. Sixteen cases of borreliosis were diagnosed (10 in "forest kindergartens", six in conventional kindergarten), most frequently manifesting as erythema migrans. Children attending a "forest kindergarten" have a 2.8 times increased risk of experiencing tick bites and a 4.6 times increased risk of suffering from borreliosis compared to conventional kindergarten in Germany, although protective parental behavior in "forest kindergarten" children was significantly better than that in conventional kindergarten.

Animals↗
PubMed2006

[Tick bites and borreliosis in children attending forest kindergarten: a challenge for prevention].

AIM: The aim of this study was to analyse the influence of preventive measures on the risk of being bitten by a tick and of suffering from borreliosis in children attending so-called 'forest kindergartens' (nurseries located in forested areas where children spend all-season full-time outdoors), compared to children attending regular kindergartens. In addition, we aimed to analyse sources of information and the risk of being bitten more than once. METHODS: 53 kindergartens (25 forest kindergartens, 28 regular kindergartens) in the state of Baden-Württemberg, Germany participated in this study and protective parental behaviour was recorded. In a prospective cohort study, the numbers of tick bites and cases of borreliosis were recorded monthly (March to October 2004) using a questionnaire. The influence of preventive measures was estimated using multivariate log-binomial regression. RESULTS: Altogether, 1707 children of 'forest kindergartens' (506 children) and regular kindergartens (1201 children) were included. Parental protective behaviour was significantly better in forest kindergartens compared to regular kindergartens. There were no substantial differences between effect estimates after stratification for parental protective behaviour. For children attending a 'forest kindergarten, the adjusted risk ratio of being tick bitten was 2.6 (3.3-3.0) which was only slightly different from the unadjusted risk, ratio. CONCLUSION: Although protective parental behaviour in 'forest kindergarten' children was significantly better compared to regular kindergarten, children in forest kindergartens are at a considerable risk of tick bites and borreliosis. Implementing effective preventive measures against borreliosis represents a public health challenge.

Borrelia↗
PubMed2006

Condition and fate of logged forests in the Brazilian Amazon.

The long-term viability of a forest industry in the Amazon region of Brazil depends on the maintenance of adequate timber volume and growth in healthy forests. Using extensive high-resolution satellite analyses, we studied the forest damage caused by recent logging operations and the likelihood that logged forests would be cleared within 4 years after timber harvest. Across 2,030,637 km2 of the Brazilian Amazon from 1999 to 2004, at least 76% of all harvest practices resulted in high levels of canopy damage sufficient to leave forests susceptible to drought and fire. We found that 16+/-1% of selectively logged areas were deforested within 1 year of logging, with a subsequent annual deforestation rate of 5.4% for 4 years after timber harvests. Nearly all logging occurred within 25 km of main roads, and within that area, the probability of deforestation for a logged forest was up to four times greater than for unlogged forests. In combination, our results show that logging in the Brazilian Amazon is dominated by highly damaging operations, often followed rapidly by deforestation decades before forests can recover sufficiently to produce timber for a second harvest. Under the management regimes in effect at the time of our study in the Brazilian Amazon, selective logging would not be sustained.

Biomass↗
PubMed2000

Managing forests for wood yield and carbon storage: a theoretical study.

Which forest management regimes best achieve the dual objectives of high sustained timber yield and high carbon storage, including the carbon stored in soil and wood products? A mechanistic forest ecosystem simulator, which couples carbon, nitrogen and water (Edinburgh Forest Model), was calibrated to mimic the growth of a pine plantation in a Scottish climate. The model was then run to equilibrium (1) as an undisturbed forest, (2) removing 2.5, 10, 20 or 40% of the woody biomass each year (3) removing 50% of the woody biomass every 20 years, and (4) clear-felling and replanting every 60 years as in conventional plantations in this climate. More carbon was stored in the undisturbed forest (35.2 kg C m(-2)) than in any regime in which wood was harvested. Plantation management gave moderate carbon storage (14.3 kg C m(-2)) and timber yield (15.6 m(3) ha(-1) year(-1)). Notably, annual removal of 10 or 20% of woody biomass per year gave both a high timber yield (25 m(3) ha(-1) year(-1)) and high carbon storage (20 to 24 kg C m(-2)). The efficiency of the latter regimes could be attributed (in the model) to high light interception and net primary productivity, but less evapotranspiration and summer water stress than in the undisturbed forest, high litter input to the soil giving high soil carbon and N(2) fixation, low maintenance respiration and low N leaching owing to soil mineral pool depletion. We conclude that there is no simple inverse relationship between the amount of timber harvested from a forest and the amount of carbon stored. Management regimes that maintain a continuous canopy cover and mimic, to some extent, regular natural forest disturbance are likely to achieve the best combination of high wood yield and carbon storage.

Journal Article↗