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PubMed2003

Ten common mistakes in designing biodiversity indicators for forest policy.

This paper identifies 10 common 'mistakes' in developing and using forest biodiversity indicators from the standpoint of making better forest management choices. The mistakes relate to a failure to clarify the values-basis for indicator selection and a failure to integrate science and values to design indicators that are concise, relevant and meaningful to decision makers. The combined effects of these ten mistakes include inconsistent and indefensible on-ground management strategies and hidden trade-offs at a policy level. They result in frustrated professionals, a confused public, an inability to assess performance with respect to key forest policy objectives and, almost certainly, types and amounts of biodiversity conservation that fail to achieve either scientifically or socially preferred levels. Correcting the mistakes will help to address these problems and, more generally, recognizes the need to better understand the interface between science, public values, and decision making.

Conservation of Natural Resources↗
PubMed2001

[Original humus forms in a semi-deciduous tropical forest in Guadeloupe].

Humus profiles underneath the canopy of dominant tree species in two secondary semi-evergreen forest sites in Grande-Terre (Guadeloupe) were analysed with a micromorphological method. In the vertisol of a tree plantation, the humus formed was rather similar under all tree species being an eumull and essentially due to the activity of the endoanecic earthworm Polypheretima elongata. In a natural secondary forest located on a steep slope and associated with a rendzina soil (without endoanecic earthworms), the humus forms were described at lower, mid- and upper slope. In this forest, two particular humus forms were observed. At the middle slope, underneath the canopy of Pisonia subcordata L. that produces nitrogen-rich litter, a calcareous amphimull, characterised by an OH horizon made of millipede faecal pellets, was formed. In the upper slope, underneath the canopy of Bursera simaruba (L.) Sarg. that produces a litter rich in resins and aromatic compounds that are poorly consumed by soil animals, a dysmull with a thick root mat (OFRh horizon) developed. Other humus forms were intermediate. The formation of these humus forms is discussed.

Animals↗
PubMed2002

Energy evaluation of forest residues originated from Eucalyptus globulus Labill in Galicia.

The possibility of retrieving the energy contained in forest residues originating from wood exploitation in Galicia (Spain) is evaluated. This study was made on Eucalyptus globulus Labill occupying a forest surface of 240000 ha. This species plays an important role in the economical development of Galicia, as it is the main forest species for production of pulp. Sampling was made over 1999 in seven different zones, three main stations plus four selected for comparison, situated in Galicia. The residues originating from cutting were sorted into three different groups and their calorific values were measured by static bomb calorimetry. These calorific values, close to 7200 kJ kg(-1), make possible the use of this residual biomass as an energy source. Calorific values were measured by static bomb calorimeter in an oxygen atmosphere. Flammability was determined using a standard epiradiator. Simultaneously, some other parameters, elementary chemical composition, heavy metal contents, moisture, density, ash percentage after combustion in the bomb, and main bioclimatic characteristics, were also determined.

Bioelectric Energy Sources↗
PubMed2003

Patterns of diversification in two African forest shrews: Sylvisorex johnstoni and Sylvisorex ollula (Soricidae, Insectivora) in relation to paleo-environmental changes.

We analysed the phylogeographic patterns of two congeneric and syntopic species of forest shrews and compared them with biogeographical scenarios proposed for the Central African tropical forest. Our results, based on 82 partial 16s rRNA mitochondrial sequences, suggest that both species must have originated in the Plio-Pleistocene and that their haplotype distributions could reflect the effect of forest fragmentation and expansion associated with paleoclimatic fluctuations during the Pleistocene. However, it seems that the two species responded very differently to environmental changes. While Sylvisorex johnstoni populations exhibit ancient haplotype segregation that may even represent currently unrecognised allopatric species, Sylvisorex ollula haplotypes are much less differentiated and suggest that this taxon has undergone a recent range expansion. The observed differences between these taxa may be explained by their presumably different ecological requirements and colonisation abilities, which in turn may be the result of a significant difference in body size between the two species. In conclusion, our results suggest that it is necessary to incorporate several ecologically well-documented species in studies that attempt to infer evolutionary processes from phylogeographic patterns

Africa, Central↗
PubMed2005

Airborne fungal colonisation of coarse woody debris in North Temperate Picea abies forest: impact of season and local spatial scale.

Coarse woody debris is important for mycodiversity in forest ecosystems, but its availability in managed stands is reduced. Leaving dead wood during felling is suggested as an option to sustain and restore the diversity. However, little is known what fungi would colonise freshly cut wood left on managed sites, and how the colonisation process is influenced by ecological factors. During summer and autumn, 120 freshly cut Picea abies stem sections over 8 cm in diameter were placed upright in mapped locations over two discrete plots separated by 100 m in a north-temperate forest. After seven weeks the sections were collected, and isolation and identification of fungi was done from their upper surfaces. In all 943 fungal strains were isolated, representing 97 species. Species richness in the summer survey was 42.5% higher than during the autumn survey. Low species similarity characterized the different seasons (Sorensen indices: S(S) = 0.36 and S(N) = 0.34) and for 21 species (22%) observation frequency was significantly affected by season. As a result, community structures in summer and autumn differed notably (z-test; P < 0.001). Species richness between the two plots differed by less than 10%, but there were 64 species (66%) found only in one of them, thus qualitative similarity was low (S(S) = 0.49). Quantitative similarity was higher (S(N) = 0.63), indicating that the dominant species colonised wood to a similar extent in both areas. Fungal community structure differed significantly among the two plots (z-test; P < 0.001). Our data showed that freshly cut CWD contributed to mycodiversity in managed north-temperate forest, providing habitats for numerous individuals from over 100 species. The fungal community within a single stand differed markedly both across small distances and over the seasons. In order to sustain and enhance mycodiversity in managed stands. coarse wood should always be left during harvesting. This study also demonstrates the importance of molecular identification and ITS sequence databases for exploring fungal diversity in natural communities.

Air Microbiology↗
PubMed2002

Application of the multimedia urban model to compare the fate of SOCs in an urban and forested watershed.

A multimedia model has been developed to estimate the dynamics of semivolatile organic compounds (SOCs) in urban areas. The model is based on a Level III fugacity model of Mackay and consists of six compartments: air, surface water, sediment, soil, vegetation, and an organic film that coats impervious surfaces. The model was used to illustrate the effect of impervious surfaces in urban areas by parametrization for downtown, Toronto, Canada, and modification of the same area to simulate forested conditions. With illustrative emissions of PCB homologues to air, the model indicates that most chemicals are lost by advection, with the remainder undergoing air-to-surface (organic film or vegetation) transfer. Under urban conditions chemicals with Log[K(OA)] < 7.5 volatilize from the film into air where they are susceptible to advection and photolytic degradation. Chemicals with Log[K(OA)] > 7.5 are washed off the film to surface waters where they may undergo volatilization, advection, sedimentation, and degradation. Both loss mechanisms from the film increase the overall mobility of SOCs in the urban relative to the forested environment. In forested areas, vegetation more efficiently accumulates gas- and particle-phase SOCs and subsequently transfers them to surface soils, the greatest chemical reservoir, where they are relatively immobile.

Cities↗
PubMed2001

Persistence of the insecticide Dimilin 45 ODC on conifer forest foliage in an Atlantic-climate ecosystem.

The oil formulation of diflubenzuron (Dimilin 45 ODC) persisted for 10-12 weeks on the foliage of a conifer forest in an Atlantic-climate ecosystem. Within 22-30 days following treatment, 55-80% of the insecticide had been removed from the foliage. During this period, the concentration of diflubenzuron was higher than 370 ng g(-1). Aerial application at 56.3 g of Al ha(-1) resulted in deposition levels of the insecticide ranging from 867.5 to 1824.4 ng g(-1), depending upon forest characteristics. The results showed that aerial application is only a suitable technique for the treatment of forest areas with dense foliage and/or high tree density and no more than 15% of tree-free area. The only metabolite detected was 2,6-difluorobenzamide, and this persisted on foliage until the first rainfalls occurred. An empirical mathematical correlation was found to express the influence of meteorological variables--rainfall, solar radiation and temperature--on the persistence of the insecticide. These results suggested that degradation of diflubenzuron on foliage could be due to photodegradation. Some recommendations were made to optimize the deposition of the insecticide on foliage and to minimize its persistence and the off-site spray drift.

Diflubenzuron↗
PubMed2004

Fluxes and reservoirs of trichloroacetic acid at a forest and moorland catchment.

The concentrations and input/output fluxes of trichloroacetic acid (TCA) were measured in all relevant media for one year at a 0.86 km2 upland conifer plantation and moorland catchment in SW Scotland (n > 380 separate samples analyzed). Annual wet precipitation to the catchment was 2.5 and 0.4 m for rain and cloud, respectively. TCA input to the catchment for the year was 2100 g, predominantly in rainwater (86%), with additional input via cloudwater (13%) and gas plus particle dry deposition (1%). There were no seasonal trends in TCA deposition, and cloudwater concentration was not enhanced over rainwater. TCA in precipitation exceeded concentrations estimated using currently accepted routes of gas-phase oxidation from anthropogenic chlorinated hydrocarbon precursors, in agreement with previous studies. Export of TCA from the catchment in streamwater totalled 1970 g for the year of study. The TCA concentration in streamwater at outflow (median 1.2 microg L(-1)) was significantly greater than that before the stream had passed through the conifer plantation. To well-within measurement uncertainties, the catchment is currently at steady-state with respect to TCA input/output. The catchment reservoir of TCA was dominated by soils (approximately 90%), with the remainder distributed in forest litter (approximately 9%), forest branchwood and stemwood (approximately 0.7%), forest foliage (approximately 0.5%), and moorland foliage (approximately 0.1%). Although TCA is clearly taken up into foliage, which consequently may be important for the vegetation, this was a relatively minor process for TCA at the catchment scale. If it is assumed, on the basis of laboratory extraction experiments, that only approximately 20% of "whole soil" TCA measured in this work was water extractable, then total mass of TCA in the catchment is reduced from approximately 13 to approximately 3.5 kg. Comparing the latter value with the annual flux yields an average steady-state residence time for TCA in the catchment of approximately 1-2 y, if all TCA is involved in catchment turnover. Considering that other evidence indicates the lifetime of TCA in soil and biota is considerably shorter than this (weeks rather than years), the magnitude of the TCA reservoir is suggested to be strong evidence for net natural TCA production in soils and/or that the majority of TCA in the reservoir is not involved with external fluxes.

Caustics↗
PubMed2004

Methylmercury and total mercury in plant litter decomposing in upland forests and flooded landscapes.

The overall objectives of this study were to examine the effects of flooding on the decomposition and mercury (Hg) content of tissues from plants common to boreal upland forests at the Experimental Lakes Area in northwestern Ontario. We used litterbags to study changes in total Hg (THg), methyl Hg (MeHg), carbon (C), and nitrogen (N) in 12 different plant tissues (birch, alder, blueberry, and Labrador tea leaves, bunchberry plants, jack pine needles, Sphagnum spp., Polytrichum spp., and Pleurozium spp. bryophytes, lichen, and fresh and extensively decomposed wood) placed on unflooded boreal forest soils and in experimentally created reservoirs over an approximately 800 day period. Rates of decomposition (as indicated by differences in the percentage of C and N mass left in the tissues over time) were slower in plant tissues placed on unflooded soils compared to the same tissues that were inundated in reservoirs. Depending on tissue type and initial THg concentrations, decomposing litter on both unflooded and flooded soils was either a source or a sink for THg. Tissues where initial THg concentrations were greater than 30 ng g(-1) represented a source of THg to the surrounding environment, whereas tissues that had initial concentrations of less than 30 ng g(-1) gained THg mass. Initial rates of change in THg were more rapid in plant tissues placed in reservoirs compared to the same plant tissue placed on unflooded soils, but there were no differences in final THg masses after approximately 800 days. Plant tissues placed in reservoirs exhibited large increases in MeHg mass, whereas MeHg mass decreased in the same plants placed on unflooded soils. This is the first study examining THg and MeHg cycling in decomposing plants in upland boreal forests and reservoirs.

Environmental Monitoring↗
PubMed2006

Accumulation of persistent organic pollutants in canopies of different forest types: role of species composition and altitudinal-temperature gradient.

Leaves from the dominant tree species in three different alpine forests were sampled along an altitudinal gradient and analyzed for HCB, alpha- and gamma-HCH, and PCBs. The mean canopy concentration was calculated, considering the relative abundance of each species in the respective forest. Compound fractionation occurred in the vegetation along the altitudinal/temperature gradient. Results were compared with air concentrations and in-field plant/air partition coefficients (K(PA)) were calculated for each species; this showed differences between broadleaves and needles. The mean canopy/air partition coefficient (K(CA)) was also calculated by averaging results from single species. The variability of persistent organic pollutants distribution in canopies is discussed considering two main factors, the altitudinal/temperature gradient and the species composition. The latter is responsible for most of the concentration variability of the more volatile compounds. A model to calculate dry gaseous deposition to different forest canopies is presented.

Air Pollutants↗
PubMed2002

Evaluation of metric precision for a riparian forest survey.

This article evaluates the performance of a protocol to monitor riparian forests in western Oregon, United States based on the quality of the data obtained from a field survey. Precision is the criteria used to determine the quality of 19 field and 6 derived metrics. The derived metrics were calculated from the field data. The survey consisted of 110 riparian sites on public and private lands that were sampled during the summers of 1996 and 1997. In order to calculate metric precision, some of the field plots were re-measured. Metric precision was defined in terms of the coefficient of variability (CV) and standard deviation and then compared with a pre-defined data quality objective (DQO). A metric was considered precise if the CV met or exceeded the DQO. The geomorphology metrics were not precise while the forest stand inventory metrics and forest cover metrics, with some exceptions, were precise. The precision for many of the field and derived metrics compared favorably with the level of precision for similar metrics reported in the literature. Recommendations are made to improve the precision for some metrics and they include changing the way precision is calculated, re-defining the field protocol, or improving field training.

Calibration↗
PubMed2002

The accuracy of forest damage assessments--experiences from Sweden.

In this article the consistency of forest damage assessments on conifer trees is analysed, by using different methods in estimating the accuracy in assessments of defoliation and discolouration. The data originate from control surveys in the Swedish national forest damage survey, as well as from national and international training courses. Standard deviation of differences in the assessment of defoliation on single trees is found to be about 10% units for Norway spruce and 8.5% for Scots pine. Problems in correctly assessing damaged Scots pine trees and discoloured Norway spruce trees are revealed by measures of agreement (Kappa statistic). Results from several years of national training courses indicate that, on an average, the observer teams do not significantly differ from a national standard, but significant differences between observer teams are found. The presented estimates indicate a substantial within observer error compared to the between observer error. The results indicate that the long-term development of forest damage, rather than short-term fluctuations, is the most important information from these kinds of inventories.

Environmental Monitoring↗
PubMed2002

Losses of nitrogen and phosphorus from agricultural and forest areas in Finland during the 1980s and 1990s.

The temporal changes and spatial variability of phosphorus and nitrogen losses and concentrations in Finland during the period 1981-1997 were studied in 15 small agricultural and forested catchments. In addition, four coastal river basins with high agricultural land use located in southern Finland were included in the study in order to assess the representativeness of agricultural loss estimates from small agricultural catchments. The mean annual loss specific for agricultural land was estimated to be on average 110 kg km(-2) a(-1) for total phosphorus and 1500 kg km(-2) a(-1) for total nitrogen. The results from small agricultural catchments were in agreement with the corresponding loss estimates from rivers, with an average of 137 kg km(-2) a(-1) for total phosphorus and 1800 kg km(-2) a(-1) for total nitrogen. The results from the studied agricultural catchments and rivers during the period 1981-1997 suggest that weather-driven fluctuation in discharge was usually the main reason for changes in nutrient losses, and little or no impact of changes in agricultural production or management practises can be observed. In forested areas the total phosphorus loss (average 9 kg km(-2) a(-1)) and total nitrogen loss (average 250 kg km(-2) a(-1)) were lower than in agricultural areas. In forested catchments the impact of forestry operations, such as clear-cutting and fertilization, and the impact of atmospheric nitrogen deposition can be seen in changes in nutrient losses.

Agriculture↗
PubMed2002

A methodology to estimate carbon storage and flux in forestland using existing forest and soils databases.

Sequestration of carbon through expansion and management of forestland can assist in reducing greenhouse gas concentrations in the atmosphere. Quantification of the amount of carbon presents an ongoing challenge that calls for new approaches. These new approaches must seek to simplify the science-based accounting of carbon storage and flux, while adhering to general principles of greenhous gas accounting. Quantifying change in carbon storage and carbon flux consists of two steps: developing a baseline of carbon storage, and measuring resulting storage and flux following a change of conditions. A methodology is proposed that accomplishes both steps, applicable to an aggregate-level analysis using the state of Iowa (U.S.A.) as a case study. The method combines existing databases from the U.S. Forest Service (USFS) and U.S. Department of Agriculture (USDA), and merges these with the methods of Birdsey (USDA. 1992. 1995: IPCC, 1997: EIIP, 1999) for partitioning carbon stocks into storage pools. Forested ecosystems in the study area contain approximately 137.3 metric tons organic carbon per hectare, or 114 million metric tons of carbon in aggregate. Of this total, 44.7 million tons are stored in biomass tissue, and 69.2 million tons of carbon are contained in soils. Carbon flux due to forests in the state of Iowa is estimated to be a net annual sequestration (removal from the atmosphere) of 4.3 million metric tons of CO2-equivalent, approximately 5% of the net annual CO2-equivalent emissions from the state (Ney et al.. 1996).

Atmosphere↗
PubMed2003

Contrasting allozyme and RAPD variation in spider populations from patchy forest habitats.

During the last 1000 years, massive deforestation events have occurred in Flanders (the northern part of Belgium) and the remaining forests have become very isolated patches. It is expected that organisms bound to these patchy forest habitats and with limited dispersal capacities will likely experience strong effects of genetic drift. One such organism is the spider Coelotes terrestris. Allozyme data suggested that 10 Flemish populations of this spider showed little genetic variation, as only one out of 20 loci was polymorphic (phosphoglucose isomerase). In view of this result, we used random amplified polymorphic DNA (RAPD) markers to test whether this lack of allozyme diversity is an inherent feature of the populations and/or species studied or whether it rather reflects a characteristic of the markers and/or methods used. Since the RAPD data revealed a substantial amount of genetic diversity in the same 10 populations, our results suggest that the latter is true. Furthermore, the RAPD data agree with the expectations for an organism with low dispersal capacities that has lived in isolated forest patches for at least 200 generations. Supplemented with the results of other techniques and studies, these findings might be of importance for the future conservation of this spider species in Flanders.

Animals↗
PubMed2003

A national ozone biomonitoring program--results from field surveys of ozone sensitive plants in northeastern forests (1994-2000).

Ozone biomonitoring is a detection and monitoring technique that involves documenting ozone-induced visible injury to known ozone-sensitive species under conditions of ambient exposure. The USDA Forest Service administers a long-term, nationwide ozone biomonitoring program to address public and scientific concerns about ozone impacts on forest health. A systematic grid is used as the basis for biomonitoring site locations. At each site, trained field crews evaluate a maximum of thirty plants of up to six species and record the amount and severity of leaf-injury on individual plants. Injury from ozone was found more often on biomonitoring sites in the eastern Unites States than in the interior or west-coast areas. Further results from the northeast reveal that in any year, there is a higher percentage of ozone-injured plants with more severe symptoms in areas with relatively high ozone concentrations than in areas with relatively low ozone. In very dry years (e.g., 1999) the percentage of injured plants and injury severity estimates are both sharply reduced even though ambient ozone exposures are high. These findings demonstrate that biomonitoring data provide meaningful evidence of when high ozone concentrations during the growing season have biological significance. Any assessment of ozone stress in the forest environment must include both biomonitoring (i.e., plant response) and air quality data to be complete.

Air Pollutants↗
PubMedDate not supplied

Biotic diversity of Natchez Trace State Forest, western Tennessee.

We carried out a multiple-scale assessment of biotic resources within Natchez Trace State Forest (NTSF) in western Tennessee, focusing on the relation between biotic communities and seven previously developed ecological land types (ELT, based on topography and soils). We wanted to test the functional ability of ELTs for biodiversity stewardship. Woody and herbaceous flora as well as herpetofauna and avifauna communities had substantial differences between upland and lowland forests. However, none of the faunal communities distinguished among upland ELTs. In addition, herbaceous taxa also failed to distinguish upland ELTs. The results suggest the present use of ELTs at NTSF will not be a helpful guide to land stewardship focusing on biodiversity. The disturbance history of the Forest and the mobility of animals are given as potential explanations for a poor relationship between abiotic ELTs and the resident biota.

Animals↗
PubMed2004

Synthesis of HNO3 from organic matter and its influence on nutrient replenishment in forest soils.

Chemical analyses during a decade of bulk precipitation, throughfall, humus water and soil water in forest plots ranging from sand to silt of Pleistocene origin in Flanders (N-Belgium) prove that previous and present weathering is predominantly due to synthesis of HNO3 from soil organic matter. The HNO3 reacts with silicates and possibly PO4(3-) species, releasing Al, Fe, nutrient base cations and H2PO4-, and is transformed into NO3-. In all soils solubilized Al3+ is predominantly associated with NO3- and with some organic bases in the coarse-textured soils with undisturbed or previously plowed spodic B horizon. The amounts of ions leached, especially Al3+ and NO3-, are much higher in the sandy than in the silty soils as a result of a stronger neutralization of acidity in the silty soils. Nutrients, leached from the soil, have to be replenished in some way for a sustained forest growth. N- and S-species must come from the atmosphere. Basic cations and P-species have to be supplied out of the solid phase. The concentrations of NO3- in the soil water show that the liberation of these elements from the solid phase is performed by HNO3. Especially in the coarse-textured soils the need for NO3- is high. Therefore, instead of being a real hazard for the forest ecological system, supplementary addition of HNO3 or NH3 can be beneficial.

Belgium↗