Indicator Of Site Quality Research Articles

Using Qualitative and Quantitative Methods to Choose a Habitat Quality Metric for Air Pollution Policy Evaluation.

Atmospheric nitrogen (N) deposition has had detrimental effects on species composition in a range of sensitive habitats, although N deposition can also increase agricultural productivity and carbon storage, and favours a few species considered of importance for conservation. Conservation targets are multiple, and increasingly incorporate services derived from nature as well as concepts of intrinsic value. Priorities vary. How then should changes in a set of species caused by drivers such as N deposition be assessed? We used a novel combination of qualitative semi-structured interviews and quantitative ranking to elucidate the views of conservation professionals specialising in grasslands, heathlands and mires. Although conservation management goals are varied, terrestrial habitat quality is mainly assessed by these specialists on the basis of plant species, since these are readily observed. The presence and abundance of plant species that are scarce, or have important functional roles, emerged as important criteria for judging overall habitat quality. However, species defined as ‘positive indicator-species’ (not particularly scarce, but distinctive for the habitat) were considered particularly important. Scarce species are by definition not always found, and the presence of functionally important species is not a sufficient indicator of site quality. Habitat quality as assessed by the key informants was rank-correlated with the number of positive indicator-species present at a site for seven of the nine habitat classes assessed. Other metrics such as species-richness or a metric of scarcity were inconsistently or not correlated with the specialists’ assessments. We recommend that metrics of habitat quality used to assess N pollution impacts are based on the occurrence of, or habitat-suitability for, distinctive species. Metrics of this type are likely to be widely applicable for assessing habitat change in response to different drivers. The novel combined qualitative and quantitative approach taken to elucidate the priorities of conservation professionals could be usefully applied in other contexts.

Urbanization effects on spatial-temporal differentiation of tree communities in high-density residential areas

The changing mode of urban development through time can bring a varied landscape mosaic accompanied by spatial-temporal differentiation of urban vegetation. Hong Kong as an ultra-compact city generates intense interactions between trees and urban fabric to highlight urbanization effects on tree communities. The study areas cover public housing estates which accommodate about half of the 7.26 million population. Thirteen site factors related to estate, landform and habitat traits were measured or computed as surrogate urbanization effects. Species composition and diversity of tree communities in 102 estates were assessed by field surveys, including four estate groups: older or newer ones situated respectively in urban core or new towns. They contain 48,823 trees belonging to 232 species with heavy exotic representation. Total tree density and native tree density in newer estates were significantly higher than older ones. Differences in species richness and diversity and native species richness between older and newer estates were not significant, expressing to a certain extent the floristic-homogenization phenomenon. Multi-response Permutation Procedures (MRPP) results showed significant difference in species composition between older and newer estates, which could be explained by variations in development age, density, town plan and pre-urbanization land cover. Nonmetric Multidimensional Scaling (NMDS) results found tree distribution patterns in four estate groups strongly associated with estate area, open space area, estate population, estate age, Shannon index (H′) at planting strip and tree pit, and tree site quality index. Urban-forest management could be improved by adopting more native species and providing high-quality and spacious planting sites to accommodate more and larger trees. The research methods and findings could be used by policy makers and planners in similar large and developing cities to evaluate, design, maintain and enhance urban biodiversity.

Forestry under Climate Change. Is Time a Tool for Sustainable Forest Management?

Changing climate conditions are known to influence forest tree growth response and the CO2 cycle. Dendroclimatological research has shown that the climate signal, species composition, and growth trends have changed in different types of forest ecosystems during the last century. Under current and demonstrated changes in climate variability at the geographic, regional, and local levels tree growth shows also variability and trends that can be non-stationary during time even at relatively short distance between sites. In forest planning and management, yield tables, site quality indices, age class, rate of growth, and spatial distribution are some of the most used tools and parameters. However, these methods do not involve climate variability during time although climate is the main driver in trends of forest and tree growth. Previous research warns about the risk that forest management under changing climatic conditions could amplify their negative effects. For example, changing climate conditions may impact on temperature and/or precipitation thresholds critical to forest tree growth. Forest biomass, resilience, and CO2 storage may be damaged unless forest planning and management implement the relationships between climate variability and trends of tree growth. A positive aspect is that, periods of favorable climate conditions may allow harvesting higher amount of wood mass and storing more CO2 than traditional planning methods. And, the average length of both favorable and adverse periods appears to occur within the validity period of a forest management plan. Here, we show a conceptual development to implement climate variability in forest management in the view of continuing the research.

Predictive approaches to forest site productivity: recent trends, challenges and future perspectives

In the framework of sustainable forest management, measuring site quality and predicting site productivity remain a major forestry topic. Over the past years, it has been fostered by a number of site-growth modelling studies seeking to establish quantitative relationships between site index and explicit biophysical indicators. In addition, comparative modelling studies of site index and site productivity have highlighted limited accordance of their environmental determinism, questioning site index as a reliable indicator of site quality. Lastly, processbased modelling approaches have recently arisen as a means to predict site productivity over large regions. All theseinvestigationshavehoweverdrawnlimitedattentioninrecentsyntheses.Inthisreview,weprovideanoverview of the literature on these site-growth studies. Concepts and vocabulary related to site productivity are introduced. Taking regional studies as a baseline, we first highlight recent progress regarding the geographic areas encompassed, and the major role played by NFI programmes and spatialized environmental information. A trade-off between model accuracy and geographic extent is suggested, pointing out potential deficiencies in the modelling of site-growth associations, insufficient accuracy or resolution in climatic data, or uncontrolled factorsinsite-growthmodelsthatemergeonahigherspatialscale.Inappropriateuseofbiophysicalclassifications where environmental factors remain implicit is also emphasized. In a next step, wediscuss earlyand mostrecent indications on weaknesses of the site index concept when applied over large regions, including its differential response to climate relative to site productivity, regional variations in site index curves, site index dependence on standdensityandsubsequentlyonregionalsilviculturalpractices.Theroleofgeneticstructureoftreepopulations anditsintegrationintosite-growthstudiesisalsoreviewedanddiscussed.Theinterests,limitsandrecentadvances of process-based models as an alternative to evaluate site productivity are considered, as they may overcome some of the previous limitations. We last draw challenges and perspectives on the issue. We suggest that the accuracy ‐ and the need ‐ of site index as a founding concept of forestry science is questioned, by building direct productivity‐environment relationships based on NFI databases as a realistic option at hand. We formulate perspectives regarding the accuracy, resolution and enlargement of environmental indicators currently used, the inclusion of information on genetic structure of tree populations in the context of adaptation to future climate change, as well as the use of site productivity models in forest management.

Ground vegetation as an indicator of site quality: effect of non-site factors on the productivity of newly established chestnut plantations in northwestern Spain

The growth of 67 young hybrid (Castanea × coudercii A. Camus) and pure sweet chestnut (Castanea sativa Mill.) plantations was studied in relation to ground vegetation (GV) and non-site factors such as type of site preparation, weed control (WC), disease-related damage and prior land use. The classification and regression trees procedure was used to analyse the data. Ground vegetation communities accounted for a large amount of variability in the site index (SI) and were found to be useful as predictors of chestnut site quality. The presence of broom communities indicated the best site for establishing chestnut plantations, whereas bracken and bramble communities indicated poorer conditions, although those sites can still be considered suitable for growing chestnut. Terrain covered with herbaceous communities also indicated intermediate or even good site conditions. The poorest sites were the heathlands. As regards non-site factors, only weed control was found to be a significant variable. Ground vegetation caused a significant reduction in tree growth, indicating the importance of carrying out regular weeding to improve productivity. The most positive effect of weeding on height growth was detected in terrain covered by gorse and broom, and the least positive effect was observed in heathland. The findings are important for forest management purposes, as evaluation of ground vegetation will enable rapid prediction of site productivity classes in afforested areas and help in selecting the best land for planting this species in reforestation programmes.

Análise de rejeitos como indicador de qualidade nos serviços radiológicos do Hospital Universitário da Universidade Federal da Paraíba

Resíduos de serviços de saúde; Controle de qualidade; Radiografia.

Carbon stocks and accumulation rates in tropical secondary forests at the scale of community, landscape and forest type

Rapid increases of secondary forest areas in the tropics make understanding of their carbon dynamics critical to estimate net CO2 emissions and uptake. This understanding is needed for performance based mechanisms that aim to halt global warming (REDD+). Despite the importance of secondary forests to global C cycling, the impacts of recovering secondary vegetation on C dynamics are poorly understood. We present carbon stocks and accumulation rates in biomass and soil pools, using as a basis of analysis 87 sampling plots established along a secondary forest chronosequence derived from shifting cultivation. We test the influence of age, land-use intensity (prior land-use history) and two site quality indices on the size of the C stocks and C accumulation rates. Biomass and Total C pools were positively correlated with age and negatively with LU intensity, whereas C accumulation rates had opposite signs for both parameters. Soil C did not show any variation along the age gradient, but C in the upper 20cm was positively correlated to both site quality indices. The LU-intensity influenced the tree C stock in the younger plots. We propose a nested approach in which detailed studies can be up-scaled to landscape and regional estimates of carbon pools in forest fallow and undisturbed forests and carbon accumulation rates in forest fallow.

Site Productivity and Forest Carbon Stocks in the United States: Analysis and Implications for Forest Offset Project Planning

The documented role of United States forests in sequestering carbon, the relatively low cost of forest-based mitigation, and the many co-benefits of increasing forest carbon stocks all contribute to the ongoing trend in the establishment of forest-based carbon offset projects. We present a broad analysis of forest inventory data using site quality indicators to provide guidance to managers planning land acquisition for forest-based greenhouse gas mitigation projects. Specifically, we summarize two condition class indicators of site productivity within the FIA forest inventory database—physclcd and siteclcd—as they relate to current aboveground live tree carbon stocks. Average carbon density is higher on more productive sites, but compared to the overall variability among sites, the differences are relatively small for all but the highest and lowest site classes. Some minor differences in eastern- versus western-forests were apparent in terms of how carbon on the least productive sites differed from most other forest land over time. Overall results suggest that xeric sites in most regions as well as sites that correspond to the lowest, non-productive classifications of forest land should preferentially not be used forestry-based greenhouse gas mitigation projects, but all other forest areas appear to be suitable.

PREDICTION OF STEM VOLUME OF ALSTONIA MACROPHYLLA GROWING AS EVEN-AGED MONOCULTURES USING DIAMETER AT BREAST HEIGHT AND TOTAL HEIGHT

A growth model to predict the stem volume of Alstonia macrophylla was constructed in this study using data collected from 23 plantations from Galle, Matara, Ratnapura and Kalutara districts. Trees own variables were mainly used as explanatory variables in this study and in addition, site quality indices were also tested. At the preliminary analysis, two different site quality types were identified for the selected plantations. Therefore, first, each site quality data set was separately fitted to the theoretical models developed in this study. The selected models indicated a high modelling efficiency and a negligible bias. Although the possibility of using a common model for both site types was tested, results proved that it was not possible. Therefore it was decided to recommend two models (same structure with different sets of statistical parameters) for two site types for the field use with the help of a given guideline to identify the plantations grown in two site types.

Estimating trembling aspen productivity in the boreal transition ecoregion of Saskatchewan using site and soil variables

Pinno, B. D. and Bélanger, N. 2011. Estimating trembling aspen productivity in the boreal transition ecoregion of Saskatchewan using site and soil variables. Can. J. Soil Sci. 91: 661–669. The productivity of trembling aspen, as expressed by site quality index (SQI), in natural stands growing on three different soil parent material types (fluvial, lacustrine and glacial till) in the boreal transition ecoregion of Saskatchewan was evaluated by using soil and site variables. The soil and site variables used were either general categorical variables, such as parent material and ecosite, or continuous variables, such as soil texture (percent sand or clay), pH, carbon, nitrogen, C:N ratios, and elemental composition. It was not possible to reliably estimate SQI using only categorical site variables or continuous soil variables when all plots were grouped together. However, when plots were grouped by parent material type, over 45% of the variability in trembling aspen productivity was explained using the common soil measurements of texture and pH. In estimating SQI, there was an interaction between both pH and soil texture with parent material. On fluvial and lacustrine parent materials, increased clay content was positively correlated with SQI, but was negatively correlated with SQI on till, while pH was positively correlated with SQI on fluvial parent material, but negatively on lacustrine. Including more sophisticated measures of soil nutrient availability in the forest floor and BC horizons did not improve the SQI prediction. This study indicates that it is possible to estimate trembling aspen productivity using simple site and soil variables, provided that differences in soil properties within parent material groupings are considered in the analysis.

Quality and Accuracy of Sexual Health Information Web Sites Visited by Young People

We assessed online sexual health information quality and accuracy and the utility of web site quality indicators. In reviewing 177 sexual health web sites, we found below average quality but few inaccuracies. Web sites with the most technically complex information and/or controversial topics contained the most inaccuracies. We found no association between inaccurate information and web site quality.

A preliminary survey of the insects collected using mushroom baits in native and exotic New Zealand woodlands

The insects associated with the fruiting bodies of macrofungi are an important component of woodland biodiversity. A preliminary survey of the woodland insects associated with macrofungi was undertaken using commercial mushrooms as a standard bait. Adult insects were collected in different categories of woodland (native mixed forest; native Nothofagus forest; exotic conifers; restoration/conservation areas) at 17 sites on the South Island of New Zealand. In total, 2429 specimens were collected, consisting of 1282 Coleoptera, 1022 Diptera and 125 Hymenoptera. Several newly-described genera and species of Diptera were recorded, indicating that the use of unconventional collecting techniques such as bait trapping can be useful in augmenting site-species inventories. Different orders of insects showed different patterns in terms of their abundance and species richness amongst the different categories of woodland. Coleoptera were more abundant and species-rich in native mixed and Nothofagus forests than in plantations of exotic conifers, and were very poorly represented in urban conservation/restoration sites. However, Diptera and Hymenoptera were most abundant and diverse in stands of exotic conifers such as Pinus radiata plantations and urban conservation sites. The results indicate that monoculture plantations of exotic tree species can compare favourably to native forests in terms of richness and diversity of insect faunas and, although faunistically poor, urban reserves can also play a valuable role in maintaining indigenous invertebrate biodiversity at a local level. Some species, such as the agyrtid beetle Zeanecrophilus prolongatus, were found primarily in native forest, and the occurrence of such species might be utilized as indicators of site quality in remnant patches of woodland.

Tree Growth Prediction in Relation to Simple Set of Site Quality Indicators for Six Native Tree Species in the Philippines

The gain in precision to explain the variation on tree growth performance as a function of a set of site indicators was analysed in a stepwise form, increasing its complexity and costs. Six native timber tree species were commonly found on farmer's fields and planted under different types of agroforestry systems. Localization of trees to be used for measurement was achieved through individual interviews to assess timing of introduction of trees. Results proved that native tree species planted on farmers' fields have similar growth rate other exotic timber species asSwietenia macrophyllathat are widely spread in the Philippines. Nevertheless, the large fraction of the variation in tree performance that could not be explained by the biophysical site indicators measured implies that farmers take considerable risk in planting trees on the basis of current “scientific” knowledge. The complement of “site characteristics” is probably “management”, and the low determination of tree growth by site properties may in fact be good news for the farmers.

A Multivariate Linear Mixed-Effects Model for the Generalization of Sample Tree Heights and Crown Ratios in the Finnish National Forest Inventory

Abstract The aim of this article was to develop a prediction model that could use the geographically representative but locally sparse sample tree data of the Finnish National Forest Inventory (FNFI) efficiently and account for the correlation structures in these data when generalizing sample tree characteristics over tally trees by species. The sample tree characteristics modeled were tree height and the ratio of live crown length to tree height. These are needed for all FNFI tally trees to obtain their stem volumes and biomasses. As a result, a multivariate linear mixed-effects model with species-specific parameters designed for the multiresponse FNFI data was developed. The fixed parts of the two linear models of the simultaneous system consist of both tree and stand-level independent variables such as dbh, mensurable stand characteristics, and site quality indicators. Because of the hierarchically correlated data, the intercepts and the slopes (i.e., the coefficients associated with tree characteristics) in the two models were assumed to vary randomly over clusters and forest stands within them. The random coefficients were also associated with components for random species effects. The selected formulation of the random parts of the models makes it possible to obtain localized species-specific curves for clusters and forest stands even with one measured sample tree. The results show that the multivariate mixed-effects model with species-specific components is a stable, efficient predictor and well applicable to locally sparse but geographically representative data of the FNFI type.

Explaining patterns of deformity in freshwater turtles using MacCulloch’s hypothesis

A growing body of literature details the effects of teratogenic chemicals on embryonic development in freshwater turtles. However, other factors affecting developmental deformities have not been recently considered and evaluation of the significance of deformities in adults is lacking. We collected 193 wild Midland Painted Turtles ( Chrysemys picta marginata Agassiz, 1857) and 39 Common Snapping Turtles (Chelydra serpentina (L., 1758)) from an uncontaminated site in Ontario and recorded incidence of deformity of the shell, limbs, face, and tail. We tested MacCulloch’s hypothesis (that incidence of deformity increases along a latitudinal gradient) by comparing our data with previously published deformity records from both uncontaminated and heavily polluted sites at varying latitudes. Incidence of nonembryonic deformity varied among wild populations and was not correlated with pollution levels. Thus adult deformity cannot be used as an indicator of site quality. Frequency of deformity increased with latitude in C. picta, supporting MacCulloch’s hypothesis, whereas deformities in C. serpentina did not. We refer to essential differences in the biology of the two species to explain this disparity and recommend that latitudinal variation be included as a covariate in the future when developmental trends are compared among distant sites.

The role of permanent site factors in the assessment of soil treatment effects: A case study with a site preparation trial in jack pine plantations on glacial outwashes

In silvicultural trials, the confounding influence of permanent soil properties is assumed to be minimal. A covariance analysis using total elemental concentrations of parent material (geochemistry) and soil particle size distribution (texture) was used to understand the role that these variables could play in tree growth and foliar nutrient status, and in the growth response to site preparation of 16- to18-yr-old jack pine plantations growing on seemingly homogeneous glacial outwash deposits. Three treatments were tested in a replicated design: direct plantation, and site preparation with TTS or with Bräcke. The combination of particle size distribution and soil geochemistry explained the site quality index (SQI) in control plots (R2 = 0.94) better than soil texture alone. In all plots, SQI was strongly related to K and Mg concentrations in foliage and in humus and, to a lesser degree, to foliar N concentrations. A covariance analysis using soil texture and geochemical composition indicated that while site preparation had an effect on tree growth, the sites that responded the most to site preparation were the ones with the lowest growth potential as determined by soil texture and geochemistry. Key words: Silviculture, site preparation, site quality index, growth, permanent soil factors, texture, geochemistry, nutrition

Determination of Spacecraft Landing Footprint for Safe Planetary Landing

A methodology is developed based on a ballistic analysis to estimate the landing footprint associated with the powered terminal descent phase of a spacecraft soft landing. The analysis is based on an idealized two-impulse thrust maneuver and leads to an analytical expression for the elliptical boundary of the landing footprint. The objective is to develop a computationally efficient method to estimate the landing footprint for use in an on-board fuzzy-logic based inference engine for real-time hazard avoidance. The inference engine combines an estimate of the landing footprint with information about the safeness of the landing terrain to construct an overall landing site quality index. The landing site quality index is a critical parameter that enables the spacecraft to make intelligent real-time decisions about landing safely on unknown and hazardous terrains. The footprint generated from the ballistic analysis is also compared with the footprint resulting from numerically integrating a representative guidance law.

Predicting productivity of trembling aspen in the Boreal Shield ecozone of Quebec using different sources of soil and site information

Site quality index (SQI) of trembling aspen ( Populus tremuloides Michx) in the Boreal Shield of Quebec was predicted using two sources of information: (1) mappable permanent site variables derived from permanent sampling plots and other sources and (2) measured soil and site properties including both biological and permanent site variables. General mappable information did not produce reasonable relationships ( R 2 < 0.25) with SQI while measured variables were able to explain much of trembling aspen SQI variability. For the two parent material types found in our study, i.e. fluvial and till, there was no difference between median SQI values between groups. However, different soil and site variables were better at predicting trembling aspen productivity for the individual parent material types. As much as 60% of the variability in trembling aspen productivity was explained when both biological and permanent site variables were considered in stepwise regression models. When treated individually, models developed for fluvial sites better explained trembling aspen productivity compared to models developed for till sites. Moreover, the ability of the model to predict trembling aspen productivity on till sites when using permanent site variables alone, e.g. soil texture, elemental chemistry and elevation was decreased ( R 2 < 0.3). This indicates that the inclusion of biological site variables such as overstory species composition and forest floor properties provide a major contribution to SQI prediction and are necessary to yield high R 2. Overall, the data indicate that the traditional mapping of landscape attributes such as drainage and deposit as well as inferred soil geochemistry do not contribute much to explaining SQI. At present, field measurements are needed to predict SQI with a reasonable degree of precision within a forest management unit.

Estimation of forest biophysical variables from Indian Earth Observation Satellite Cartosat‐1 stereo data

Indian Earth Observation Satellite Cartosat‐1 data were evaluated for the estimation of biophysical variables, including as tree height, crown diameter, canopy density and canopy gap, that are crucial for the estimation of stand volume, biomass and generation of site index (an indicator of site quality of growing stock). Investigations were carried out at a site covering the major dominant forest species grown in India. Cartosat‐1 stereo data were analysed in conjunction with differential global positioning system (DGPS) measurements to generate a digital elevation model (DEM) and an orthoimage, which were used to estimate the biophysical variables. Analysis using grey‐level co‐occurrence texture measures was performed for separation of forest species, homogeneity of the classes of forest stands, stratification and measurement of crown area, canopy gap and stand density. Field measurements of tree height, diameter at breast height (DBH), stand density, age and crown diameter were conducted for each stand. Empirical models for the estimation of DBH were developed and validated with Cartosat‐1‐derived height and crown diameter. Measured and estimated values were found to be in close proximity to each other. A local contrast co‐occurrence measure (contrast, mean and variance) was suitable for the estimation of average crown diameter, stand density and canopy gap area for each forest stand class. The texture image provided information on structural attributes (i.e. stand density, crown diameter and canopy gap of the forest tree stands). The results presented in this study show that the Cartosat‐1‐derived DEM and orthoimage have potential for the estimation of stem volume, growing stock conditions, and biomass and site index for important timber species.

Piping Plover Chick Foraging, Growth, and Survival in the Great Plains

Abstract: We tested the hypothesis that piping plover (Charadrius melodus) habitat quality and chick survival on the Missouri River, USA, were lower on a cold‐water reservoir and downstream from a hypolimnetic (cold‐water) release dam with diel water fluctuations (Garrison Dam) than downstream from an epilimnetic dam (Gavins Point Dam). Plovers in adjacent alkali wetlands provided an index to the maximum reproductive potential in the region. Chicks gained weight more rapidly in the alkali wetlands than on epilimnetic and hypolimnetic river reaches. Invertebrate numbers and biomass were higher in the wetlands and epilimnetic reach, but chick survival was lower on the epilimnetic reach. Thus, piping plovers adapted to a variety of prey densities, and other factors, likely predation, reduced survival rates in the epilimnetic reach. Temporal and spatial variability in site quality indices suggests the need for a regional management strategy with different strategies at each site. Managers can minimize effects of local fluctuations in resource abundance and predators by ensuring protection of or creating geographically dispersed habitat. (JOURNAL OF WILDLIFE MANAGEMENT 72(3):682–687; 2008)