European Journal of Forest Research最新文献

Abstract

Tonkin wingnut is the rarest species within the relict tree genus Pterocarya (Juglandaceae), known from only a few isolated stands in the Indo-Burman hotspot. Despite its classification as a vulnerable species, Pterocarya tonkinensis has received comparatively less attention than other wingnut species, leading to a limited understanding of its distribution patterns. In this study, we utilize spatial distribution modeling with MAXENT software and conservation prioritization methods implemented in ZONATION to estimate the potential range of species, identify the key environmental variables influencing its habitat, and designate potential areas for conservation. We used a set of 45 known species populations, the set of bioclimatic variables, and the proximity of watercourses to create the model of the potential range. The results indicate two main centers of potential climatically suitable areas for the species in the future - in southern Yunnan (China) and Vietnam. The calculated total suitable area (292,365.67 km²) is similar to the estimated extent of species occurrence but may decline in the future. Highly suitable areas near the rivers cover around 19,000 km². The most important factors shaping species occurrence were those related to temperature amplitude (around 60% of contribution to the models). The seasonality of precipitation and distance from watercourses also have a significant impact. Assessment of potential reserves has identified the need for protected areas in southern China and points to the possibility of expanding reserves in Vietnam. The fact that river valleys are often densely populated can be an obstacle to the conservation of species.

Riparian buffer zones (RBZs) are an important instrument for environmental policies for water and biodiversity protection in managed forests. We investigate the variation of the cost of implementing RBZs within different property size classes across the size range of non-industrial forest owner properties in Southern Sweden. Using the Heureka PlanWise decision support system, we quantified the cost of setting aside RBZs or applying alternative management in them, as the relative loss of harvest volume and of net present value per property. We did this for multiple simulated as well as real-world property distributions. The variation of cost distribution among small properties was 4.2–6.9 times higher than among large properties. The interproperty cost inequality decreased non-linearly with increasing property size and levelled off from around 200 ha. We conclude that RBZs, due to the irregular distribution of streams, cause highly unequal financial consequences for owners, with some small property owners bearing a disproportionally high cost. This adds to previous studies showing how environmental considerations differentially affect property owners. We recommend decision makers to stimulate the uptake of RBZs by alleviating these inequalities between forest owners by including appropriate cost sharing or compensation mechanisms in their design.

Rosewoods are among the most valuable traded hardwoods, and there is a significant illegal trade. From 2017 onwards the international trade in all species of Dalbergia rosewood is regulated through the Convention on International Trade in Endangered Species of Wild Fauna and Flora. I focus on two species of rosewood that occur in parts of Indonesia, Dalbergia latifolia and D. sissoo, to assess the extent of the illegal trade and to analyse geographical and temporal patterns of wildlife crime. Based on 67 seizure reports from 2014 to 2022 I show that (a) 117 logs of D. sissoo and 4,285 logs of D. latifolia were confiscated, (b) seizures occurred on the islands of Sumatra (16 seizures; 1,190 logs), Java (43; 1,780 logs), and Bali, Lombok, Sumbawa and Timor (8; 1,408 logs), (c) while there was an increase in the number of seizures per year, there were no seasonal differences in seizure activities. For 10% of the logs there was supporting evidence that they were taken from State managed forests and 18% was taken from conservation areas, thus causing more damage than just the removal of individual trees. Seizures in Indonesia over this period equals 0.12 ± 0.04% of the legal rosewood export. The illegal trade is dominated by Indonesians rather than foreign nationals and the direction of trade is towards Java from where > 95% will be exported to China. While policies are in place concerning rosewood seizures and stockpiling (including auctioning or destruction) in practise it is unclear where seized rosewood ends up. When used with caution, analysis of seizure data offers a valuable means to gain insights in illicit activities that normally remain hidden from view.

Functional diversity of bird assemblages has been disproportionally less recognized than taxonomic diversity. Especially, it has been less assessed in temperate primeval forests, serving as a reference point to the vast majority of forests more or less transformed by human activity. Therefore we aimed to determine the functional diversity of bird assemblages at the three levels of forest ecosystem organization: forest types, forest layers, and forest structures, and to determine mechanisms shaping the functional diversity of bird composition under primeval conditions of the Białowieża National Park (NE Poland). We used observations from a regular network of 96 points within six permanent plots in ash-alder and oak-lime-hornbeam forests, and we calculated functional diversity components and community-weighted mean values of birds’ functional traits. Despite higher taxonomic diversity and functional richness in the ash-alder forest, we found higher values of other functional diversity indices the in oak-lime-hornbeam forest. We also found differences in taxonomic and functional diversity among forest layers. We attributed mechanisms shaping the bird assemblages in ash-alder forests with habitat filtering, while niche partitioning or limiting similarity in oak-lime-hornbeam habitat. Bird assemblages on the crown and emergent layers seem to be shaped by niche partitioning mechanisms, whereas bird composition at shrub and understory levels seems to be shaped by habitat filters. Our study revealed that structural diversity at all three levels is crucial for maintaining the functional diversity of bird assemblages in the primeval forest.

Mediterranean Europe is experiencing a rise in severe wildfires, resulting in growing socioeconomic and ecological impacts. Postfire restoration has become a crucial approach to mitigate these impacts and promote ecosystem recovery. However, the ecological effects of such interventions are still not well understood. We employed remote sensing techniques to evaluate the impact of postfire emergency stabilization on the recovery of deciduous oak forests in Portugal. Our study encompassed 3013 sampling points located in areas with and without postfire interventions. We chose the Normalized Difference Vegetation Index (NDVI) as an indicator of oak forest recovery over a four-year period following wildfires that took place in 2016 and 2017. We used a Generalized Additive Mixed Model (GAMM) to assess how NDVI changed over time as a function of postfire restoration, fire characteristics, topography, and postfire drought events. We found that postfire restoration had a significant positive effect on NDVI recovery over time, although this effect was small. Severe drought and fire recurrence up to six fires had a negative effect on the recovery of NDVI. Conversely, severe wetness and either low or high burn severities had a positive effect on recovery. Our study emphasizes the importance of monitoring postfire restoration effects on forest recovery to guide restoration planning and improve forest management in burned areas. This becomes even more relevant under increased wildfire severity predicted for the Mediterranean region interacting with other climate-driven disturbances, which will further negatively affect forest recovery.

Abstract

The frequent outbreaks of European spruce bark beetle Ips typographus (L.) have destroyed huge amounts of Norway spruce Picea abies (L.) forests in central and Northern Europe. Identifying the risk factors and estimating the damage level is important for strategic damage control. The risk factors of forest damage by spruce bark beetles have mostly been analyzed on the landscape scale, while the in-stand risk factors have been less investigated. This study aims at exploring the local-scale risk factors in a flat area with spruce-dominated forest in southern Sweden. The investigated factors include four abiotic factors, i.e., soil wetness, solar radiation, slope gradient, and aspect, and three biotic factors, i.e., the number of deciduous trees and trees that died from attacks in previous years that remained (TreesLeft) and removed (TreesRemoved) from the forest stand. We put up 24 pheromone bags in six stands attacked by bark beetle in the previous years, resulting in different numbers of infested trees in each plot. We explored in which microenvironment a pheromone bag resulted in more colonization, the impact radius of each factor, and the necessary factors for a risk model. The environmental factors were obtained from remote sensing-based products and images. A generalized linear model (GLM) was used with the environmental factors as the explanatory variables and the damage levels as the response variables, i.e., the number of attacked trees for the plot scale, and healthy/infested for the single-tree scale. Using 50 m and 15 m radius of the environmental factors resulted in the best fit for the model at plot and individual tree scales, respectively. At those radii, the damage risk increased both at plot and individual tree level when spruce were surrounded by more deciduous trees, surrounded by dead trees that had been removed from the forest, and spruces located at the north and east slopes (315°–135° of aspect, > 2° slope). Soil wetness, solar radiation, and remaining standing dead trees in the surrounding did not significantly impact the damage level in the microenvironment of the study area. The GLM risk model yielded an overall accuracy of 0.69 in predicting individual trees being infested or healthy. Our efforts to investigate the risk factors provide a context for wall-to-wall mapping in-stand infestation risks, using remote sensing-based data.

The objective of this study was to evaluate carbon and (C) and nitrogen (N) of the light organic matter in labile and humic fractions of the soil in a chronosequence of clonal Eucalyptus urophylla. The study was carried out on six different sites in the South-Central region of Maranhão state, northeastern Brazil, inserted in the Cerrado biome. Soil was sampled in five clonal Eucalyptus urophylla S.T. Blake stands of different ages and one in the area with old-growth forest (OG), which represents the native vegetation area. Soil samples were collected in the 0–20, 20–40, and 40–60 cm layers to determine textural class, bulk density, C, and N in the light organic matter of labile and humic fractions. Eucalyptus plantations can have great capacity to increase stocks of soil C and N, humic, and labile fractions over the years, presenting results equal or higher than a native Cerrado forest. Thus, Eucalyptus plantations come as an effective lad use to sink C and increase soil nutrient levels.

Plantations of exotic trees were proposed as an alternative to restore native forests in degraded lands, because they can attract seed dispersers and modulate the microclimate beneath their canopies. However, the large-scale introduction of exotic tree plantations can negatively affect native species by high competitiveness for soil resources and light, while they can also release allelopathic compounds that inhibit the germination and growth of other plants. In this study, we tested the suitability of Eucalyptus camaldulensis plantations to assist the restoration of degraded lands in central Mexico, which were originally covered with oak forests. For this, we sampled soil seed banks within forest remnants and plantations, which showed that the animal-mediated dispersal of oak propagules from forests inwards plantations is reduced. Additionally, we conducted germination trials that evidenced that the leaves of Eucalyptus trees contain allelopathic compounds that inhibit the germination of oaks seeds, also showing that these compounds accumulate in the soil of plantations. We finally conducted field experiments in which soil form forests and plantations were translocated between these two habitats, and acorns were sowed on both soil types. These field experiments revealed that, besides the accumulation of allelopathic compounds in soils of plantations, oak recruitment in these habitats is also impaired by unfavorable microclimatic conditions. Therefore, we conclude that Eucalyptus plantations are not promoting the recovery of native oak forests in central Mexico and, instead, alternative ecological restoration methods should be applied for reaching this aim.

Abstract

Paulownia fortunei, one of the world’s fastest growing timber tree species, is universally applied with fertilizer as a management approach to meet the nutrient requirements for efficient cultivation. The substantial effects of fertilizer on soil microorganisms in Paulownia plantations have been empirically tested; however, the successive chronosequence of soil microbial carbon and nitrogen functional genes under different fertilizer application durations remains limited. The objective of this study was to explore the characteristics of soil microorganisms involved in carbon and nitrogen cycling and greenhouse gas (GHG) production under different fertilizer application durations. Different fertilizer treatments, i.e., the short-term group (SG) versus the long-term group (LG), and durations were applied to subtropical plantations in southern China and compared with zonal evergreen broad-leaved forests. Results showed that fertilizer treatment significantly increased the relative abundance of Acidobacteriota and the expression of nirK and nosZ. The functional groups that dominated metabolism in SG and LG treatments belonged to Actinobacteria and Acidobacteriota, respectively, suggesting that the nutrient preference of microorganisms in forest soil may change from copiotrophs to oligotrophs with increasing fertilizer application duration. Correlation network analysis showed that the communities that dominated the carbon and nitrogen cycles belonged to Actinobacteria and Acidobacteriota, respectively, and were closely related to ammonium nitrogen and available iron. Actinobacteria and Acidobacteriota were likely the major taxa that affected soil GHG production under different fertilizer application durations. We concluded that long-term fertilizer use changed the preference of microbial nutrient uptake into recalcitrant nutrients, and the sensitivity of the microbial community to nutrients gradually decreased with increasing fertilizer application time. The dominant Actinobacteria affected soil carbon and nitrogen cycles largely by stimulating denitrification to increase the release of nitrous oxide, which might lead to the loss of nitrogen components and the intensification of the GHG effect with increasing fertilizer application time.

In IUFRO experimental plots of 1969–1970, two 'Italian' provenances, I11 and I15, of unknown genetic origins, have consistently exhibited remarkable performance and stability over time and space in previous studies. It was deemed essential to acquire knowledge about the genetic origin area and conduct a genetic characterization of these two Italian provenances for their formal registration. Considering the observed intraspecific genetic variation across the American geographic cline, it was imperative to ensure that the selected provenances adequately represented diverse eco-physiological regions within the species range. To achieve this, most likely American provenances were selected, building upon historical document hypotheses and aiming to cover various geo-climatic areas. Specifically, five coastal variety and three interior variety provenances were chosen, two for each major geo-climatic region. The results obtained, using seven microsatellites, through four genetic structure analysis methods, predominantly attributed I11 to the area around 1080 origin, Washington Cascades region and 1094, Oregon Coast area. Similarly, I15 was primarily attributed to the area around the 1096 provenances, the Oregon Cascades region, compared to other coastal areas it appeared to differ. Among the three interior origins, 1162 from Arizona, Interior South area, exhibited intermediate genetic characteristics between the two varieties, despite its geographical location falling within the range of the interior variety. Similar to our expectations, comparing the distinct characteristics of the origin areas for each Italian provenance, it becomes feasible to complete their certification as 'seed stands' and to plan an appropriate management strategy for the species' diffusion.