Current Forest Management Research Articles

Considerando la adopción efectiva de sistemas agrícolas en el diseño de esquemas para la promoción en el cultivo de árboles, Costa Rica

[Introduction]: The current cultivation of trees is insufficient to cover the national demand for wood, in this way small producers become an alternative solution to this situation, since despite having small areas, in the country there are abundant farms with these conditions; However, the current forest management scheme does not meet adequate standards for the incorporation of these small producers. [Objective]: To present an adaptive forest management scheme (AFMS) to the needs of the small farmer, in addition, to demonstrate the institutional availability to change according to expert criteria. [Methodology]: 1) the factors that influence the decision to adopt an agricultural or forestry production system were identified. 2) a profile of an ideal productive system that met the interests and preferences of the small producer was made, which was compared with the characteristics of agricultural and forestry production. 3) the proposal of an EMFA adjusted to the preferences and interest of the producer was made, which was also compared with the ideal profile. 4) three proposed change actions were presented to experts, obtaining different degrees of possibility of changes in the EMFA. [Results]: The discrepancy of the forest management scheme for the cultivation of trees with the perspective that a small producer has on an ideal production system was evidenced, as well as the substantial improvement that an EMFA would have in the valuation of the small producer and the institutional availability to change the EMFA according to the perspective of the small producers. [Conclusions]: The adjustment of the forest management scheme allows a greater adoption of the activity by the small producer, but it was recognized that any proposal that is made would be successful only if forest governance makes it more flexible and allows change.

Quantifying the Variability of “Fixed-Width” Buffers on Harvested Lands in Western Oregon and Washington

Abstract In contemporary forest management, buffers of unharvested trees are left along streams to protect riparian and aquatic ecosystems. Buffer regulations often focus on specific minimum width requirements, which aid in straightforward regulation and application, but minimum widths also suggest buffered edges are uniform and contain little variability. Conceptual papers suggest that alternative buffer configurations may offer greater flexibility in landscape-level protection, increase forest complexity, and enhance aquatic and riparian biodiversity. However, before considering alternatives to fixed-width buffers, it is necessary to quantify the inherent variability in current buffer practices present on the landscape. In this study, we used aerial imagery to quantify variability of buffer widths in two hundred randomly selected recently harvested units on managed land in Oregon and Washington with both fish-bearing and non-fish-bearing sections of stream. Wider buffers on larger streams had a greater magnitude of variability, but when normalized by stream size, variation was greater in smaller streams, and overall, variation ranged from 25% to 50% of the mean width. Despite local variability, buffer widths rarely fell below 9.14 m (30 ft). The variation quantified here provides an initial measure of variability to inform future management, given emerging interest in variable retention buffers. Study Implications: In contemporary forest management, riparian and aquatic habitat protection usually relies on minimum buffer width regulations. Minimum requirements create the perception that buffered edges are uniform distances from streams containing little variability, so conceptual papers have suggested alternative buffer configurations with variable retention edges to enhance ecological benefits. However, there are several reasons why, in practice, buffer widths may vary substantially from minimum sizes within and across harvest units under current forest management, but this potential variation has not been quantified. Before considering alternative riparian management options, it is necessary to quantify and understand the inherent variability in current practices. By utilizing high-resolution aerial imagery and digital elevation models, we quantified buffer width variation. Using a set of two hundred recently harvested units, we demonstrate notable buffer width variation across managed Pacific Northwest forests. We attribute the variation in buffer widths to the presence of road crossings, tributary junctions, underlying valley slope and slope variation, and flexibility in regulations that may be overlooked in broad evaluations of strict minimum widths. Understanding fundamental information about buffer width variability provides information about current practices and provides a standard against which proposed increases in variability may be compared.

A climate-induced tree species bottleneck for forest management in Europe.

Large pulses of tree mortality have ushered in a major reorganization of Europe's forest ecosystems. To initiate a robust next generation of trees, the species that are planted today need to be climatically suitable throughout the entire twenty-first century. Here we developed species distribution models for 69 European tree species based on occurrence data from 238,080 plot locations to investigate the option space for current forest management in Europe. We show that the average pool of tree species continuously suitable throughout the century is smaller than that under current and end-of-century climate conditions, creating a tree species bottleneck for current management. If the need for continuous climate suitability throughout the lifespan of a tree planted today is considered, climate change shrinks the tree species pool available to management by between 33% and 49% of its current values (40% and 54% of potential end-of-century values), under moderate (Representative Concentration Pathway 2.6) and severe (Representative Concentration Pathway 8.5) climate change, respectively. This bottleneck could have strong negative impacts on timber production, carbon storage and biodiversity conservation, as only 3.18, 3.53 and 2.56 species of high potential for providing these functions remain suitable throughout the century on average per square kilometre in Europe. Our results indicate that the option space for silviculture is narrowing substantially because of climate change and that an important adaptation strategy in forestry-creating mixed forests-might be curtailed by widespread losses of climatically suitable tree species.

The distribution of tree biomass carbon within the Pacific Coastal Temperate Rainforest, a disproportionally carbon dense forest

Spatially explicit global estimates of forest carbon storage are typically coarsely scaled. While useful, these estimates do not account for the variability and distribution of carbon at management scales. We asked how climate, topography, and disturbance regimes interact across and within geopolitical boundaries to influence tree biomass carbon, using the perhumid region of the Pacific Coastal Temperate Rainforest, an infrequently disturbed carbon dense landscape, as a test case. We leveraged permanent sample plots in southeast Alaska and coastal British Columbia and used multiple quantile regression forests and generalized linear models to estimate tree biomass carbon stocks and the effects of topography, climate, and disturbance regimes. We estimate tree biomass carbon stocks are either 211 (SD = 163) Mg C ha−1 or 218 (SD = 169) Mg C ha−1. Natural disturbance regimes had no correlation with tree biomass but logging decreased tree biomass carbon and the effect diminished with increasing time since logging. Despite accounting for 0.3% of global forest area, this forest stores between 0.63% and 1.07% of global aboveground forest carbon as aboveground live tree biomass. The disparate impact of logging and natural disturbance regimes on tree biomass carbon suggests a mismatch between current forest management and disturbance history.

Understanding small‐scale private forest owners is a basis for transformative change towards integrative conservation

Abstract Balancing societal demands on forests is a major challenge in current forest management. Small‐scale private forest owners are an important ownership group that is rarely addressed directly in this discussion. Our study aims to identify and differentiate between private forest owner groups. Based on this, we take a systemic approach and determine leverage points that can be used to foster transformative change towards integrative conservation‐oriented forest management. We conducted a survey of 1656 small‐scale private forest owners in northwest Germany within a typical European multi‐ownership landscape and formed three clusters based on their activities. While all groups generally perceived nature conservation as important, they differed with regard to their forest management activities. Multiple‐use‐oriented forest owners (45%) were most active, including in terms of conservation measures. Conservation‐oriented owners (25%) mainly focused on passive measures, and conventional owners (30%) showed only a little engagement with conservation‐related activities. Despite the differences, common instruments promoting conservation activities were identified. They included, for example on‐site consultation, information about legal regulations and financial incentives. Based on four system characteristics (parameters, feedback, design and intent), we identified leverage points towards transformative change. The deep and thus effective leverage points are changing the discourse, accounting for the heterogeneity of private forest owners as well as for uncertainty related to climate change and adapting measures to local contexts. Furthermore, working towards increasing awareness, knowledge and interest as well as accounting for the desire for autonomy and control are promising pathways for change. A holistic transformation of forest policy and management towards integrative conservation is urgently needed to meet the current challenges of climate change, biodiversity loss and timber demand. This transformation has to go beyond the adaptation of existing policy instruments and instead focus on systematic and cross‐sectoral changes in the underlying policy orientation, its design and its implementation. Read the free Plain Language Summary for this article on the Journal blog.

Private land management is more important than public land in sustaining oaks in temperate forests in the eastern U.S.

Preserving the abundance and stocking of oaks (Quercus spp.) has become increasingly challenging in temperate hardwood forests of the eastern US in recent decades due to a remarkable shift in dominance to mesophytic species (e.g., red maple Acer rubrum). Studies have shown that efforts to sustain oaks while restraining maples yield limited success. Given that a significant portion of forestlands in the eastern U.S. are privately owned, it is critical to assess whether current forest management on cross-ownership forests can achieve those objectives. However, such assessments are rare. In this study, we employed a landscape modeling approach to investigate the long-term outcomes (i.e., 150-year forest composition and structure) of business-as-usual management and alternative management in a large, temperate hardwood forest landscape in Ohio, US. The business-as-usual management continues the current existing management practices, whereas the alternative management increases the pace and scale of forest management on both private and public lands to favor oaks. We compared the basal area and relative dominance for oaks (including Q. alba, Q. coccinea, Q. prinus, Q. rubra, and Q. velutina) and maples (including A. rubrum, A. saccharinum, and A. saccharum). Our results demonstrate that the implementation of business-as-usual management practices on both private and public lands may not effectively ensure the long-term sustainability of oak populations, but instead promote the proliferation of maple species over time. By contrast, alternative management on both private and public lands can effectively sustain oaks across a range of diameter classes while mitigating the growth of large, dominant maples. Our study emphasizes the influential role of private lands in driving oak-maple dynamics at the regional scale, as they can generate significant regional effects even when public lands continue with their business-as-usual management practices. Starting conditions based on landownership are crucial considerations for understanding these dynamics over time.

Effectiveness of conservation measures to support biodiversity in boreal timber-production forests

Large parts of the boreal forest ecosystems have been greatly affected by human use, and the current timber-oriented forest management practice that dominates boreal forests is proven to cause biodiversity and ecosystem services declines. These negative effects are mitigated in various ways, including in-situ measures implemented upon harvest. The measures comprise trade-offs between economic and ecological aims; thus, requiring solid knowledge of their effectiveness. However, comprehensive literature review of the effectiveness of such measures is scarce. We aim to fill part of this void by reviewing the scientific literature that have gauged effects of four in-situ conservation measures: green tree retention (GTR), patch retention (PR), dead wood retention (DW) and riparian buffer zones (RB). Two outcomes were considered, species richness and species abundance across taxa. From a total of 3012 initial papers, 48 met our inclusion criteria that generated 238 unique results. Results were grouped according to control. 178 studies used mature, unlogged forest as control. Out of those, 68% of the findings were not significant, i.e., suggesting no significant impact of harvest with biodiversity measures on species richness and species abundance compared to no harvest. Eighteen percent of the observations showed negative effects and 14% of the observations showed positive effects compared to no harvest. Sixty studies used harvest with no measures as control, of which 45% showed significant positive effects, meaning that compared to harvest with no measures, harvest with conservation measures has positively effects on species richness and abundance. However, 43% of the studies found no significant effect of the implemented conservation measures compared to harvest with no measures taken. The relatively few significant results reported restrain distinct conclusions on the effectiveness of the assessed conservation measures, but some degree of conservation measure is likely to have positive effects on biodiversity in timber-production forest. However, the scientific basis does not allow for pointing to threshold levels. Higher transparency of study design and statistical results would allow us to include more studies. There is a clear need for more research of effectiveness of common conservation measures in timber-production forests in order to strengthen the knowledge basis. In particular, there are few studies that employ harvest without any conservation measure as control. This is pivotal knowledge for forest managers as well as for policymakers for preserving biodiversity and the ecosystems in forest.

Diversification of forest management can mitigate wind damage risk and maintain biodiversity

Mitigating future forest risks, safeguarding timber revenues and improving biodiversity are key considerations for current boreal forest management. Alternatives to rotation forestry likely have an important role, but how they will perform under a changing climate remains unclear. We used a boreal forest growth simulator to explore how variations on traditional clear-cutting, in rotation length, thinning intensity, and increasing number of remaining trees after final harvest (green tree retention), and on extent of continuous cover forestry will affect stand-level probability of wind damage, timber production, deadwood volume, and habitats for forest species. We used business-as-usual rotation forestry as a baseline and compared alternative management adaptations under the reference and two climate change scenarios. Climate change increased overall timber production and had lower impacts on biodiversity compared to management adaptations. Shortening the rotation length reduced the probability of wind damage compared to business-as-usual, but also decreased both deadwood volume and suitable habitats for our focal species. Continuous cover forestry, and management with refraining from thinnings, and extension of rotation length represent complementary approaches benefiting biodiversity, with respective effects of improving timber revenues, reducing wind damage risk, and benefiting old-growth forest structures. However, extensive application of rotation length shortening to mitigate wind damage risk may be detrimental for forest biodiversity. To safeguard forest biodiversity over the landscape, shortening of the rotation length could be complemented with widespread application of regimes promoting old-growth forest structures.

Life-cycle impact assessment of hardwood forest resources in the eastern United States

To explore the carbon sequestration potential of hardwood forests in the eastern United States, the forest vegetation simulator (FVS) and life cycle assessment (LCA) were integrated to analyze the forest carbon dynamics for the four subregions of the eastern United States: northeast (NE), mid-Atlantic (MA), southeast (SE), and north central (NC). This study quantitatively assessed current forest management practices for timber production and their associated life-cycle environmental impacts. The system boundary was selected to be consistent with the A1 module (extraction and upstream production) required by an Environmental Product Declaration (EPD) for wood products. The results indicate that uneven-aged (UA) forest management yields higher carbon stocks and growth than even-aged (EA) management across all subregions. In contrast, clearcutting under EA management results in higher carbon removal. It was found that fuel consumption-related greenhouse gas (GHG) emissions for manual and mechanized harvesting systems for both management types ranged between 9.13 and 12.15 kg of CO2 equivalent per cubic meter (kg CO2e/m3), with an average of 11 kg CO2e/m3 of hardwood timber harvested across all subregions. It is estimated that 63–187 megajoules (MJ) of energy is needed to produce 1 m3 of hardwood sawlogs. The extraction and loading processes contributed more to the total GHG emissions than the felling and processing within the system boundary. The study concludes that UA management led to higher forest carbon and net carbon balance (excluding carbon stock) compared to EA management in the eastern U.S. hardwood forests. Forest management strategies should be determined based on the ecological goal of increasing forest carbon stock and the economic goal of maximizing revenue from the timber market. The findings of this study have implications for policymakers and forest managers in mitigating climate change and carbon sequestration through sustainable forest management for timber production.

Potential of continuous cover forestry on drained peatlands to increase the carbon sink in Finland

Land-based mitigation measures are needed to achieve climate targets. One option is the mitigation of currently high greenhouse gas (GHG) emissions of nutrient-rich drained peatland forest soils. Continuous cover forestry (CCF) has been proposed as a measure to manage this GHG emission source; however, its emission reduction potential and impact on timber production at regional and national scales have not been quantified. To quantify the potential emission reduction, we simulated four management scenarios for Finnish forests: (i) The replacement of clear-cutting by selection harvesting on nutrient-rich drained peatlands (CCF) and (ii) the current forest management regime (BAU), and both at two harvest levels, namely (i) the mean annual harvesting (2016–2018) and (ii) the maximum sustainable yield. The simulations were conducted at the stand scale with a forest simulator (MELA) coupled with a hydrological model (SpaFHy), soil C model (Yasso07) and empirical GHG exchange models. Simulations showed that the management scenario that avoided clear-cutting on nutrient-rich drained peatlands (i.e. CCF) produced approximately 1 Tg CO2 eq. higher carbon sinks annually compared with BAU at equal harvest level for Finland. This emission reduction can be attributed to the maintenance of a higher biomass sink and to the mitigation of soil emissions from nutrient-rich drained peatland sites.

Closing the research-implementation gap: Integrating species and human footprint data into Argentina's forest planning

Closing the research-implementation gap is key for advancing biodiversity conservation. One approach is to generate ecologically relevant spatial datasets that integrate easily with existing management plans. Our goal was to identify priority forest conservation areas in Argentina by combining species distributions, human footprint data, and existing forest zoning. We: (i) mapped potential habitat distributions of 70 plant and animal species associated with forests, and of recognized social and ecological importance, (ii) combined the species distributions with human footprint data to identify priority conservation areas, and (iii) evaluated the juxtaposition of our priority conservation areas with current forest management zones. We found that priority conservation areas (i.e., high number of species and low human footprint) are poorly protected by the current zoning scheme. While the Andean-Patagonian region had a substantial portion (57 %) of priority conservation areas in high protection zones, in four other forest regions we evaluated, only 16–37 % of priority areas had high protection levels. Of great concern are the Chaco and Espinal regions, where 36 % and 39 %, respectively, of priority conservation areas are in low protection zones, where conversion to other uses (row crops, livestock) is allowed. Our results provide new spatial information to managers and conservationists highlighting where current forest zoning performs well, and where it may warrant re-evaluation. Overall, our study highlights the value of integrating species distributions and human footprint maps into existing land use plans to guide conservation efforts in data-poor countries, and is an example of a strategy for closing the research-implementation gap.

Adapted forest management to improve the potential for reindeer husbandry in Northern Sweden

In northern Sweden, improvements of grazing conditions are necessary for the continuation of traditional, natural pasture-based reindeer husbandry. Ground and tree lichen constitute the main fodder resource for reindeer during winter but have reached critically low levels. Using a forest decision support system, we prescribe adapted forest management to improve the preconditions for reindeer husbandry and compare outcomes with the continuation of current forest management. We found that adapted management increases the forest area with ground lichen habitat by 22% already within 15 years, while a continuation of current management would result in a further decrease in ground lichen. Tree lichen habitat can be retained and increased in all scenarios, which is important in a changing climate. Compared to a continuation of current practices, adapted management with significantly improved conditions for lichen resulted in a decrease in net revenues from wood production by 11–22%.

Pan-European Criteria for Sustainable Forest Management - Attitudes of Forestry Professionals in the Federation of Bosnia and Herzegovina

Climate change is recognized as a global threat that negatively impacts biodiversity and forest resources. The use of existing indicators for sustainable forest management (SFM) related to biodiversity and climate change, as well as the development of new indicators, will help assess how forest management practices impact biodiversity enhancement and climate change mitigation. A Pan-European set of criteria and indicators has been developed as a policy instrument for monitoring, evaluating, and reporting on the progress in implementing SFM. In Bosnia and Herzegovina and Western Balkans in general, the Pan-European set of criteria and indicators is an insufficiently researched topic and there is a lack of scientific research conducted regarding their development and implementation. Through the analysis of the current situation in forestry of the Federation of Bosnia and Herzegovina (FBiH), regarding the compliance and importance of the Pan-European criteria for SFM, this paper aims to explain how the international process of development and application of the Pan-European criteria for SFM can contribute to the improvement of the situation in forestry and the creation of a consistent forest policy in FBiH. The survey among forestry professionals (n=360), from the public forest administration and public forest companies in FBiH, included the sets of questions related to socio-demographic characteristics, assessment of compliance and importance of six criteria of SFM. Research results revealed that forestry professionals are mainly males, on average 41 years old, with 13 years of working experience. The majority of forestry professionals in FBiH are not familiar with Pan-European criteria for SFM, and have a low level of their understanding. On average, forestry professionals indicated that the Pan-European criteria for SFM were of high importance, while compliance with current forest management activities were rated lower on average. The large differences between responses regarding the average rating of compliance and importance of the Pan-European criteria for SFM indicate their low level of implementation in FBiH forest management activities. Accordingly, the results indicate that there is a need to organize educational lifelong learning programs in FBiH forestry sector, involving forestry professionals and other interested parties, to generate knowledge related to the Pan-European criteria for SFM and the concept of SFM in general.

Identifying Optimal Forest Management Maximizing Carbon Sequestration in Mountain Forests Impacted by Natural Disturbances: A Case Study in the Alps

The role of forests in mitigating climate change by acting as a carbon sink is becoming increasingly important. Forest management practices can either positively or negatively affect the ability of forests to mitigate climate change. The objectives of our study were to: (a) investigate the effects of natural disturbances on long-term carbon sequestration dynamics in forests and (b) identify opportunities to adapt current forest management practices to increase carbon sequestration in forests. The study focused on mixed mountain forests in the Slovenian Alps, dominated by Norway spruce, and used the SLOMATRIX model to simulate forest development. Three forest management scenarios were simulated: (1) no management, (2) business-as-usual and (3) an optimized scenario maximizing carbon sequestration in forests while achieving the required harvest. Our results indicate that both forest management practices and natural disturbances have an impact on carbon sequestration dynamics. Optimizing harvests resulted in changes in the diameter structure and species composition of the harvested trees. Although natural disturbances can hinder the mitigation of climate change impacts, they can also catalyze forest adaptation to climate change and reduce the time required to reach carbon equilibrium.

Natural Forests or Cultural Forests? Forest Changes within Italian Protected Areas in the Last 85 Years

The cultural dimension of many forests is not adequately considered by current forest definitions, policies, inventories, and management. Moreover, the concept of “protected area” as a synonym of “natural area” ignores that many forests today included in protected areas (PAs) have been managed and exploited for centuries. The abandonment of rural areas that occurred in the last 60 years in EU countries caused the expansion of forests, with the risk of a homogenization of forest typologies, the loss of cultural features, and the loss of biodiversity at the landscape scale. The aim of this study is to investigate the origin and evolution of forests within Italian PAs in the last 85 years through GIS-based spatial analyses. In 1936, only a minority of the surface included in current PAs was covered by forests, ranging from 32% in Natura 2000 sites to 35% in regional PAs. Forest surface in Italian PAs increased in the last 85 years (from +33.1% in regional PAs to +45.2% in national PAs), mainly due to secondary successions, with a growth rate in Natura 2000 sites equal to 8709 ha/year. In regional PAs, 40.1% of the current forest cover originated after 1936, and this percentage increases to 43% in Natura 2000 sites and to 44.7% in national PAs. The altitudinal range of 500–1000 m a.s.l. is the one most affected by forest spread. In addition, most of the forests in 1936 were regularly managed as coppice: 44% in national PAs, 56% in Natura 2000 sites, and 62% in regional PAs. The study confirms that most of the forest surface included in Italian PAs has a clear cultural origin and is the consequence of the abandonment of pastures and/or cultivations that occurred in the last 85 years. PA management should take into consideration that open areas are shrinking and that the diversity of habitats and forest communities is strongly linked to the persistence of traditional human activities. The current forest characteristics (species composition, vertical and horizontal structure) are also the result of past management, and only active management of forest resources can counteract the homogenization of forest communities and landscape structure.

Optimal maximum benefit model and prediction of carbon sequestration: A case study of the Greater Khingan Mountains

In order to make better use of the value of forest carbon sequestration and other aspects, this paper reformulate the forest management plan including deforestation in addition to the current conventional forest management plan. Moreover, we take into account the carbon sequestration benefits of forest products, analyze and predict the carbon sequestration amount of forests and forest products over time, and the deforestation amount including environmental damage and economic benefits, and put forward some reasonable suggestions based on the results achieved.In order to discuss the applicability of the model, we apply the model to the Greater Khingan Range to predict the carbon sequestration of the entire forest and its forest products 100 years from now, and to explore the best management options for the Greater Khingan Mountains. The result we obtain is that the final total carbon sequestration of Greater Khingan Range and their forest products is 2,461,259,714.52 tons after 100 years. Meanwhile, on the reasonable assumption that the Greater Khingan Mountains consist of only two kinds of trees, each time 0.8904% of the area of pine trees is cut, giving the forest 0.5 years of recovery time; by cutting 0.2326% of Betula platyphylla area at a time, with an interval of 0.8 years for recovery, best management is achieved.

Sustainable use of forests

Sustainable use of forests

Spaceborne LiDAR reveals the effectiveness of European Protected Areas in conserving forest height and vertical structure

The effectiveness of Protected Areas in conserving forest ecosystems has been examined at the continental scale using area-based habitat parameters, but knowledge of the three-dimensional structure of forest habitats is still lacking. Here, we assess the effectiveness of European Protected Areas in conserving the vertical structure of forests by analysing more than 30 million records from the Global Ecosystem Dynamics Investigation (GEDI), a spaceborne LiDAR (Light Detection And Ranging) mission. We compare a suite of indicators of the vertical structure of forests inside and outside nearly 10,000 protected areas. We find that European forests are on average 2 m taller and vertically more complex in protected areas than in nearby unprotected areas, albeit with some regional differences. At the same time, forests outside protected areas show greater variations in canopy height than inside, probably as a result of past and current forest management operations. Our findings highlight the positive imprint of environmental policies on forest structure across Europe and underscore how spaceborne LiDAR enables the large-scale monitoring of forest vertical structural attributes that are key to conservation and restoration policies.

Is the Current Forest Management to the Northernmost Population of Cordulegaster heros (Anisoptera: Cordulegastridae) in Central Europe (Czech Republic) Threatening?

Cordulegaster heros is included in the EN category on the IUCN Red List for the territory of the Czech Republic, where it inhabits an area of approximately 100 km2. All of the localities are located in the forest complex in Chřiby hills, and all of the forests fall into the category of management forests. Most of the forest stands have a high and very high degree of naturalness; they are natural forest stands. The predominant management units are Nutrient sites in middle elevations (78.2% of the area) and Oligotrophic sites in middle elevations (2.1% of the area), with stand types of Fagus sylvatica representing 92.5% of the area, and forest stand types of Quercus sp. representing 5.7% of the area. The wider alluvia in forest streams are classified as being in management unit alder and ash sites on waterlogged and floodplain soils (1.1%), with the forest stand type of Alnus glutinosa. The forest stands are restored by regeneration under shelterwood (97.8% of the area). The waterlogged alluvia, if a separate management unit is established for them, are restored by a regeneration by strip method. Realistically, seven factors were recorded in C. heros habitats, but they mostly have only point effects. Within forestry management, the factors of logging directly in the habitats and the subsequent transport of harvested timber in the habitat were recorded. The most intrusive effects were found on tractor logging roads, where fine soil washes into the stream and causes prolonged turbidity. Of the water management structures in the study area, logging roads with bridges and culverts are constructed, stream banks are reinforced with longitudinal walls at points, and stone steps in the channels are constructed only sporadically. The current forest management system can be described as a nature-friendly system, and therefore, it fully ensures the conditions for the survival of the C. heros population in the Czech Republic.

Understorey structural complexity mediated by plantation management as a driver of predation events on potential eucalypt pests

Current forest management aims to reduce the economic and environmental impact of pests on forest ecosystem productivity and to develop sustainable control approaches. The enemies hypothesis states that more diverse plant communities support a greater number and diversity of predators and parasitoids leading to a reduction in pest damage via top-down control. In forests, research on the enemies hypothesis typically focuses on tree species diversity. Here, we modify this hypothesis to determine how structural complexity of the forest understorey, as mediated by management, influences the abundance of predators and predation events on potential forest insect pests. To test this, we studied Eucalyptus sp. plantations managed under two approaches of tree establishment, hypothesising that those managed under the less disturbed system of regrowth (regeneration from clear cut stumps) will have greater vegetation structural complexity, predator abundance and predation events (as an indirect measure of predation rate) than the more disturbed seedling planting system. In six stands of each management type, we measured vegetation understorey layers (ground-, shrub- and sub-canopy cover), predator abundance (insectivorous birds, spider web counts) and predation events (artificial larvae attacks, spider web prey items).Vegetation structural complexity, abundance of insectivorous birds and spider webs, and artificial larvae attacks and web prey items were all greater in the regrowth than in the seedling stands. Path analysis evidenced direct support for our modified enemies hypothesis for birds, the regrowth management with low disturbance levels after clearcutting promotes both predator abundance and predation events via increased vegetation structural complexity. However, for spiders the increase in web abundance and predation events was directly and positively associated with regrowth management, but there was no indirect link via vegetation structural complexity, suggesting other factors driven by forest management are important.Manipulative experiments explicitly exploring the cause-and-effect relationship between predation rates and herbivory rates and consideration of the economic implications of the different approaches are required before changes to management are implemented. Our study agrees with the overarching paradigm in sustainable forest management that promotion of structural complexity will be beneficial to biodiversity, ecosystem function and resilience.