Search

Abstract This paper presents the Environmental Concern Kuznets Curve (ECKC) theory about decreasing environmental concern in the most developed and protected area-rich countries. We analyzed the relationship between the protected area (PA) coverage, environmental concern and GDP per capita in the 42 most developed countries in the 1990s, 2000s and 2010s. Our conclusion is that 1) as countries develop, environmental protection becomes less dependent on economic development; 2) at high levels of economic development, environmental concern decreases; 3) environmental concern reaches a maximum at 20–30% of PA coverage and decreases beyond this point. The influence of human values and factors at the local level was determined by a national survey (n = 999) on public attitudes toward greater conservation of forests in Slovenia. The results comply with the ECKC theory; the higher the naturalness of forests in the surroundings of a respondent's home, the lower the support for greater conservation. However, the study suggests that human values play a prominent role. Support for conservation largely depended on the respondents' general attitude toward forest cover and growing stock, harvesting intensities, satisfaction with the level of control in forests and concern for the population of protected brown bears. The general belief that ecosystems are fragile and there are limits to growth increased support for conservation by 33%. We conclude that the environment in the most developed countries is likely to experience increasing pressure due to decreasing environmental concern and its decoupling from objective problems. Highlights • At high levels of economic development environmental concern decreases. • Environmental concern reaches a maximum at 20–30% of protected area coverage. • Detailed analysis for the world's best performing country in biodiversity protection. [ABSTRACT FROM AUTHOR]

This study presents economically optimal management of uneven-aged mixed mountain forests that takes into account tree growth variability. We divided 9846 silver fir ( Abies alba), beech ( Fagus sylvatica), and spruce ( Picea abies) trees measured on 898 forest inventory plots in the Snežnik and Leskova dolina management units (4905 ha, Dinaric mountains, Slovenia) into three growth classes (slow-, medium-, and fast-growing trees) to simulate optimal forest management over a period of 100 years with respect to changing tree growth, stand density, diameter distribution, and tree species composition. We developed a density-dependent and stage and growth-structured matrix transition model which-simultaneous to the long-term stand dynamics projection-scheduled optimal harvesting to maximize the net present value using a nonlinear approach. The ecology of tree species was considered by using tree species-specific and stand-density and diameter-dependent logistic functions for ingrowth, transition, and mortality. The model projected a shift in tree species composition from fir-dominated to beech-dominated forests within 100 years. A change from harvesting slow- and fast-growing trees as if they all had medium growth to growth-sensitive harvesting increased the net revenue and maintained the uneven-aged stand structure. Optimal harvest diameters varied among growth classes, time periods, and tree species according to the economic maturity of individual trees and ranged from 12 (pre-commercial thinning) to 72 cm (target diameter). The simulation highlights the potential of improved bio-economic models for increasing yield from uneven-aged forests and scheduling optimal management regimes with multiple objectives. [ABSTRACT FROM AUTHOR]

Fully publicly funded forest planning systems with no individual forest property planning are facing budget cuts and are of limited effectiveness in private forests. A cost-sharing planning instrument that might improve private forest management while providing public budget relief is the forest property plan (FPP). We explored the market for the FPP among private forest owners in Slovenia and estimated the financial implications of adapting the current planning system. We conducted 548 face-to-face interviews with randomly selected private forest owners about their attitudes toward and their willingness to pay (WTP) for the FPP. Of the respondents, 55 % considered the FPP to be a usable instrument, and 34 % would pay for it. The suggested amounts per decade ranged from 5 € to 1500 € with a mean of 135.99 € or 28.31 €/ha. Heckit regression revealed that the primary supporters of the FPP are younger, better educated non-farmers with larger properties and good contacts with the district forester. Aggregating the stated WTP amount to forest owner population, we estimated that on average 17-57 % of the current public budget expenditures for private forest planning-related tasks could be saved annually, depending on the tasks included and the aggregation approach. [ABSTRACT FROM AUTHOR]

European black poplar ( Populus nigra L.) has become threatened by the widespread disappearance of riparian forests in Europe. Gene introgression through hybridization with related, non-indigenous poplar taxa may additionally reduce the population size and genetic diversity of native black poplar. We assessed the exposure of native black poplar in Slovenia to genetic introgression using a combination of habitat and gene flow models. The habitat model was built with data mining on forest inventory data employing classification decision trees. Dispersion distances for pollen, seeds and vegetative parts at 0.9% and 0.001% of adventitious presence threshold were assessed using modified gene flow models. To protect native black poplar, protection zones around native black poplar stands were proposed. Since the population of native black poplar may be exposed to various introgression pressures (e.g., the vicinity of exotic, genetically compatible poplar plantations, or feral populations potentially initiated along transport corridors or rivers), we assessed the intensity of introgression pressure by intersecting the occupied and potential habitat with the introgression pressure areas. In 2010, native black poplar occurred on 43,756 ha (2.2% of the total Slovenian territory), while the suitable habitat extended up to 108,724 ha (5.4%). The protection zones were 0.5–4.6 times larger than the occupied and potential habitat depending on the selected threshold and the type of dispersion vector. In the worst case scenario, 45.1% of protection zones would be exposed to high hybridization pressure. We recommend extending the proposed methodological approach to other regions with endangered black poplar. [ABSTRACT FROM AUTHOR]

Underuse of nonindustrial private forests in developed countries has been interpreted mostly as a consequence of the prevailing noncommodity objectives of their owners. Recent empirical studies have indicated a correlation between the harvesting behavior of forest owners and the specific conceptualization of appropriate forest management described as "nonintervention" or "hands-off" management. We aimed to fill the huge gap in knowledge of social representations of forest management in Europe and are the first to be so rigorous in eliciting forest owner representations in Europe. We conducted 3099 telephone interviews with randomly selected forest owners in Slovenia, asking them whether they thought they managed their forest efficiently, what the possible reasons for underuse were, and what they understood by forest management. Building on social representations theory and applying a series of structural equation models, we tested the existence of three latent constructs of forest management and estimated whether and how much these constructs correlated to the perception of resource efficiency. Forest owners conceptualized forest management as a mixture of maintenance and ecosystem-centered and economics-centered management. None of the representations had a strong association with the perception of resource efficiency, nor could it be considered a factor preventing forest owners from cutting more. The underuse of wood resources was mostly because of biophysical constraints in the environment and not a deep-seated philosophical objection to harvesting. The difference between our findings and other empirical studies is primarily explained by historical differences in forestland ownership in different parts of Europe and the United States, the rising number of nonresidential owners, alternative lifestyle, and environmental protectionism, but also as a consequence of our high methodological rigor in testing the relationships between the constructs. We suggest developing natural resource management concepts that emphasize forests not just as ecosystems, but as socialecological systems. [ABSTRACT FROM AUTHOR]

In survey-based segmentation of forest owners, two threats to the validity of results have largely been ignored: (1) response style bias and (2) the robustness of the statistical methods. This study demonstrates response style bias detection, presents an approach for correcting for acquiescence – the systematic tendency to agree with survey items, and explores the sensitivity of a probabilistic clustering algorithm to requirements for the validity of the typology. Structural equation modeling and Monte Carlo data generation techniques were employed to detect acquiescence and estimate its effect on construct validity. A survey of the relevance of management information for private forest owners (N= 364) was used as an example. Although acquiescence was confirmed, it had minor effect on the results and no effect on the substantive construct. Uncertainty about the number of forest owner types and membership can be reduced by using probabilistic clustering and observing the number of clusters while changing the requirements for the validity of clusters. The expectation maximization algorithm proved to be robust even to stringent requirements for the validity of clusters. By controlling for response style and the robustness of statistical methods, the validity of private forest owner typologies can be better ensured. [ABSTRACT FROM PUBLISHER]

We studied the impacts of site, stand and tree variables on the diameter growth of beech trees (Fagussylvatica L.) on carbonate bedrock and examined to what extent the regional diameter growth model can be used at the forest type level. Based on 12,193 permanent sampling plots (500 m2 each) with 94,770 beech trees, we first developed a linear mixed-effect model of the periodic diameter increment at the regional level (Dinaric region, Slovenia, 1.7 thousand km2). Subsequently, we parametrized the model for five forest types within the region (submontane, thermophilous, montane, upper montane and subalpine) and used a homogeneity-of-slopes model to test whether the covariates have different effects in the five forest types. The regional model suggested the positive impact of tree diameter (nonlinear), tree diameter diversity, mean diurnal temperature range and mean annual temperature and the negative impact of basal area, proportion of beech, inclination, rockiness and annual amount of precipitation. Stand basal area and the proportion of beech contributed > 50% of the total explained diameter increment variability, followed by tree diameter (44%), topographic (3%) and climatic variables (< 2%). The regional model was well transferable to forest types; the only variable with a significantly different effect in forest types was tree diameter. However, models at the forest type level differed with respect to the slopes and significance of several predictors, wherein coefficients for some predictors were even of opposite sign. Not all predictors from the regional model were included in the forest type models if predictor selection and model parameterization were performed independently for each forest type. Our study suggests that some growth characteristics of beech can be detected at the regional level only, while analyses at the forest type level can reveal significant differences in beech growth response to tree, stand and environmental variables. [ABSTRACT FROM AUTHOR]

• Asymmetric effects of precipitation anomalies on beech growth were detected with forest inventories. • More extreme precipitation anomalies had disproportionally large effects on diameter growth. • Growth reductions in dry extremes were 3 times greater than growth increases in wet extremes. • Stand basal area, the social status of a tree and tree species diversity significantly affect growth. In temperate forests, precipitation-productivity relationships have usually been considered linear and symmetric, i.e. under conditions of nominal precipitation variability, trees are able to compensate for reduced growth during dry extremes with increased growth during wet extremes. However, under severely dry/wet conditions tree responses may be nonlinear and asymmetrical. Forest inventory data and standardized drought indexes such as the Standardized Precipitation Index (SPI) can be used to test for asymmetries in the relationship between aboveground net primary production and precipitation. Based on forest inventory data from Slovenia (51,734 plots, 365,885 individual tree measurements in the period 1992-2013), we estimated the effect of precipitation anomalies on the diameter increment of European beech in various climatic, site and stand conditions. Beech responds asymmetrically to precipitation anomalies even under moderately variable precipitation. An individual tree growth model with 3 tree, 5 stand, 6 site and 4 climate variables explaining 32.6% of the total variance suggests that growth reductions in extremely dry periods are 3.0 times greater than growth increases in extremely wet periods. A comparison of 108 natural cubic spline tree diameter models shows that giving more weight to more extreme deviations from average summer precipitation explains significantly more variance compared to using the average SPI in the summers between the two censuses. We conclude that negative asymmetry can be detected on a temporal scale of a decade with much coarser data than tree-ring chronologies. However, even under |SPI| > 1.5 and a negative trend in the SPI on 60% of the plots at an average rate of -0.2/year, precipitation anomalies contributed < 1% to the diameter increment compared to stand (57%) and site (4%) factors. At the same magnitude of climate anomalies and the same stand density and levels of competition, beech is expected to grow better in structurally and compositionally diverse stands. [ABSTRACT FROM AUTHOR]

Global forests are the main component of the land carbon sink, which acts as a partial buffer to CO 2 emissions into the atmosphere. Dynamic vegetation models offer an approach to projecting the development of forest carbon sink capacity in a future climate. Forest management capabilities are important to include in dynamic vegetation models to account for the effects of age and species structure and wood harvest on carbon stocks and carbon storage potential. This article describes the implementation of a forest management module containing even-age and clear-cut and uneven-age and continuous-cover management alternatives in the dynamic vegetation model LPJ-GUESS. Different age and species structure initialisation strategies and harvest alternatives are introduced. The model is applied at stand and European scales. Different management alternatives are applied in simulations of European beech (Fagus sylvaticus) and Norway spruce (Picea abies) even-aged monoculture stands in central Europe and evaluated against above-ground standing stem volume and harvested volume data from long-term experimental plots. At the European scale, an automated thinning and clear-cut strategy is applied. Modelled carbon stocks and fluxes are evaluated against reported data at the continent and country levels. Including wood harvest in regrowth forests increases the simulated total European carbon sink by 32 % in 1991–2015 and improves the fit to the reported European carbon sink, growing stock, and net annual increment (NAI). Growing stock (156 m 3 ha -1) and NAI (5.4 m 3 ha 1 yr 1) densities in 2010 are close to reported values, while the carbon sink density in 2000–2007 (0.085 kg C m -2 yr 1) equates to 63 % of reported values, most likely reflecting uncertainties in carbon fluxes from soil given the unaccounted for forest land-use history in the simulations. The fit of modelled and reported values for individual European countries varies, but NAI is generally closer to reported values when including wood harvest in simulations. [ABSTRACT FROM AUTHOR]

The alteration of natural tree species composition is defined as the deviation of the current tree species composition from that of the natural state. It can be used as a measure of human influence on forest vegetation, and thus as an indicator of the naturalness of forest vegetation. The aim of the study was to develop a standard procedure for estimating the alteration of natural tree species composition, to explain factors driving alteration and to examine its significance for susceptibility of forest stands to natural disturbances. The alteration of natural tree species composition was estimated for the Dinaric region (5556 km2, Slovenia) by the Robič Index of Dissimilarity (RID), ranging from 0 (completely natural) to 100 (completely altered). The index was calculated on the compartment level (24 ha each on average) with data on current and potential natural forest vegetation. The influence of human activities on tree species alteration was examined by using topographic and accessibility variables. The susceptibility of forest stands to natural disturbances was analysed with data on sanitary felling. In the study area, the natural tree species composition of forest stands is moderately preserved; the average value of RID was 50.05, ranging from 1.76 to 100, and the coefficient of variation was 0.49. The alteration of the natural tree species composition of forest stands is primarily the result of forest management and past land use, conditioned either by topography or accessibility of forests. The degree of alteration of tree species composition decreased along the gradients of rockiness, inclination and elevation. A greater degree of alteration appeared on the slopes of intermediate and south facing aspects than on north facing slopes, and in areas that were closer to the forest edge. A higher level of alteration significantly increases the susceptibility of forest stands to natural disturbances. The procedure represents a novel approach in modelling the alteration (naturalness) of tree species composition of forest vegetation. It is applicable at different spatial scales and fosters an understanding of the patterns of tree species composition under the influence of human activity across forest landscapes. [ABSTRACT FROM AUTHOR]

• Soil is a stronger driver of forest productivity than climate or topography. • Stand and tree growth rates differ significantly between soil units. • The soil unit is a more important variable in tree growth than in stand growth. • Most tree species exhibit the highest and the lowest growth on different soil units. • Most of the studied tree species grow most poorly on calcareous Leptosols. We determined the size of differences in stand and tree growth in semi-natural forests with respect to 16 reference soil groups. The forest area of Slovenia (11.8 thousand km2) was used as the study area, and reference soil units were derived from the national soil map at a 1:25,000 scale consisting of 10,781 polygons with an average size of 117.95 ha. Stand growth was defined as periodic stand basal area increment, while the growth of Norway spruce, silver fir, Scots pine, European beech and sessile oak trees was estimated by the periodic diameter increment of 238,349 dominant trees on 67,061 permanent sampling plots. A linear fixed-effects model and linear mixed-effect models were used for studying stand and tree growth in different site, stand and tree conditions. The soil unit was the dummy variable with Dystric Cambisols set as the reference category. Soil contributed 4.3 % to the explained variability of basal area increment and 4–27 % to the explained variability of the diameter increment of the five tree species. Soil was a stronger driver of stand and tree growth than climate or topography. Stand and tree species production rate on soil units was in the interval of −28 % to +5 % and −47 % to +14 % of that on the reference soil unit, respectively. Stand growth was the highest on Eutric Gleysols and the lowest on Histosols, and tree species generally exhibited the highest and the lowest growth rates on different soil units. We suggest that soil should be considered in growth models and studied interrelatedly with climatic, site and stand variables. [ABSTRACT FROM AUTHOR]