Clear-cutting Research Articles

Long‐term impacts of forest disturbances: Comparing cumulative effects of clearcut logging versus landslide on stream conditions and abundance of a headwater stonefly Scopura montana

Abstract When forest disturbance impacts adjacent headwater streams, the recovery of habitat conditions and populations can take over several decades. Thus, considering long‐term, historical legacies of forest disturbances is key for understanding and managing forest–stream linkages. We focused on small‐scale forest disturbances such as small‐block harvesting and landslides. We compared the long‐term (past 100 years) cumulative effects between the anthropogenic and natural forest disturbances on stream conditions and the abundance of a headwater specialist, Scopura montana (Plecoptera: Scopuridae). Sampling was conducted in 10 m reaches of 39 first‐order streams with a catchment area up to 5.9 ha during late summer in central Japan. We quantified past clearcut logging areas using plantation records of each harvest block and past landslide areas from contour maps within each catchment. Piecewise structural equation models using the cumulative area of each forest disturbance as an independent variable, revealed different indirect effects of clearcut logging (average area: 1.74 ha) and landslides (0.21 ha) on S. montana abundance through modified stream conditions. Canopy openness and wetted channel width were higher with a larger logged area, and S. montana abundance was lower with higher water temperature (daily maximum). When the magnitude of clearcut logging was similar to the landslide area (<0.77 ha), the negative relationship between water temperature and S. montana abundance was also significant in the model. Streambed roughness and wetted channel width were greater with larger landslide area but there were no significant links between stream conditions and S. montana abundance. Our results suggest that clearcut logging can cause long‐term impacts by exposing the stream surface to solar radiation owing to delayed canopy closure. The preference of S. montana is for cold water conditions in summer. Controlling forest harvesting along streams could benefit forest–stream management, as could including consideration of disturbance‐driven cycles for sustaining headwater populations.

Valuing natural capital when management is dominated by periods of inaction

AbstractValuing natural assets is important for tracking the performance of management, for sustainability assessments based on wealth accounting, for environmental income and product accounting, and for benefit–cost analysis of specific projects. Developments in valuing natural capital have focused on implicit intertemporal exchange revealed by resource management behavior that maps the state of the natural system in a continuous fashion onto a management response. However, the management of many real assets, including many natural assets, is best described as inaction with punctuated adjustment. We develop natural asset valuation theory and approximation methods for such cases. We illustrate the theory and methods for the case of forests managed through even‐aged management, that is, clear cuts. These forests may provide “passive” or “inaction” value while standing and timber benefits at harvest. We find that the passive flow value of the forests can be positive and depend on site class, and that wealth held in private industrial Oregon Douglas‐fir forests increased over the first decade of the twenty‐first century.

Red-Listed Ecosystem Status of Interior Wetbelt and Inland Temperate Rainforest of British Columbia, Canada

The Interior Wetbelt (IWB) of British Columbia, which includes the globally rare Inland Temperate Rainforest (ITR), contains primary forests poorly attributed and neglected in conservation planning. We evaluated the IWB and ITR using four IUCN Red List of Ecosystems Criteria: geographic distribution, environmental degradation (abiotic and biotic factors), and likelihood of ecosystem collapse. Clearcut logging (3.2M ha) represented 57% of all anthropogenic disturbances, reducing potential primary forest by 2.7 million ha (28%) for the IWB and 524,003 ha (39%) for the ITR. Decadal logging rates nearly doubled from 5.3% to 10.2% from 1970s–2000s. Core areas (buffered by 100-m from roads and developments) declined by 70% to 95% for the IWB and ITR, respectively. Vulnerable was assigned to karst, the only abiotic factor assessed, because it was associated with rare plants. For biotic factors, Old-Growth Birds were Vulnerable, Southern Woodland Caribou (Rangifer tarandus caribou) habitat and Sensitive Fish were Endangered, and Old-Growth Lichens habitat was Critical. Overall, the IWB was ranked as Endangered and the ITR as Critical with core area collapse possible within 9 to 18 years for the ITR, considered one of the world’s most imperiled temperate rainforests.

Early Holocene bark-stripping damages as an indicator of large herbivores: Evidence from a submerged Mesolithic landscape in the Haväng area, southern Baltic basin

A unique assemblage consisting of 113 pine samples collected from a submerged Mesolithic landscape in the Haväng area, southern Sweden, was examined to assess the presence of large herbivores, as well as changes in wild-game population density and composition. Bark-stripping damages on prehistoric trees is an extremely underutilized source of information about past game-population dynamics, yet our analyzes of wood samples – dated to around 10 500 cal. yr. BP – shows that such material can be successfully used to study the presence and activities of large herbivores, most likely ungulates. To evaluate our results, comparisons have been made with subfossil peatland trees that grew around 6000 years ago, as well as trees from two present day clearcut logging sites in southern Sweden. Furthermore, studies in a wild-game reserve were performed to recognize and understand different types of damages on trees caused by ungulates. Bark-stripping indicate the presence of ungulates, and the rate of damage is commonly associated with the density of the wild game. Bark-stripping was most frequently observed in the submerged wood material from the early Holocene, where damages were detected in 15% of the trees. In comparisons, 11% of the mid-Holocene trees show bark-stripping damages, whereas marks could be detected in the range between 0% and 6% of the trees from the two present-day clearcut logging sites. Our results show that tree-ring analyzes of prehistoric wood can generate information about wild-game dynamics of the past, and thereby being a valuable complement to more commonly used paleoecological and zooarcheological records.

The effect of small (1-ha), 10-year rotational clear cuts on oak regeneration in Pennsylvania and Michigan

Abstract: We examined oak regeneration in small (2.5-acre [1-ha]) rotational clearcuts in central Pennsylvania and northern Michigan. In central Pennsylvania this approach was initiated to improve habitat for ruffed grouse and other early successional wildlife species, while in Michigan it was used to regenerate oak under harsh environmental site conditions associated with sandy soils and early frosts. In our study areas most of the small clearcut stands had greater oak regeneration than was found in a large 39.5-acre (16-ha) clearcuts. In particular, 10-year-old 2.5-acre (1-ha) clearcut stands located within a landscape of previous rotational cuts and remnant mature forest had adequate advanced oak regeneration compared with other age classes. We demonstrate that oak regeneration can be achieved within this type of landscape due to the availability of seed source within small clearcuts from adjacent forest and the reduction of herbivory by white-tailed deer due to an overall availability of plant resources. Therefore, if a rotational clearcut cycle is maintained over time, early successional wildlife habitat can be maintained while the objectives of forest regeneration are met. This type of forest management may be particularly applicable in areas where fire cannot be used to regenerate oak.

Interpolating missing land cover data using stochastic spatial random forests for improved change detection

AbstractForest cover requires large scale and frequent monitoring as an indicator of biodiversity and progress towards United Nations and World Bank Sustainable Development Goal 15. Measuring change in forest cover over time is an essential task in order to track and preserve quality habitats for species around the world. Due to the prohibitive expense and impracticality of mass field data collection to monitor forest cover at regular intervals, satellite images are a key data source for monitoring forest cover globally. A challenge of working with satellite images is missing data due to clouds. Existing methods for interpolating the missing data based on past images, such as compositing, are effective for stable land cover but can be inaccurate for dynamic and substantially changing landscapes. Here we present an adaptation of our recent stochastic spatial random forest (SS‐RF) method, which combines observed data from a prior image and modelled estimates of the current image to produce interpolated land cover values and associated probabilities of those values. Results show our SS‐RF method accurately detected simulated land cover change under both clear felling (0.83 average overall accuracy) and tree thinning (0.85 average overall accuracy). Our method detected forest cover change substantially more accurately than compositing, offering 39% and 12% increases in average overall accuracy for clear felling and tree thinning simulations respectively. However, when natural fluctuation occurs and there is minimal change in land cover, compositing has equivalent or more accurate performance than our method. Overall we find that our SS‐RF method produces accurate estimates under a range of simulated forest clearing scenarios and has a more accurate and robust performance than compositing when modelling noticeably changing landscapes.

Individual decisions drive the changes in movement patterns of ground beetles between forestry management types

Moving from one habitat to another, the dispersal of individuals has consequences for their conditions, population dynamics and gene flow. Our major motivation was to explore the effects of different forestry treatments, such as preparation (partial) cuts and clear cuts, on the selected population of the forest ground beetle, Carabus coriaceus (Coleoptera: Carabidae). We tagged six individuals (three males and three females) with small radio-transmitters and each was released in the treatment habitat core, at the edges and in the core of control forests respectively. The recorded trajectories were divided into two major movement phases: a random walk and a directional movement using hidden Markov models. Our results revealed that in the core zone of preparation cuts, the random walk and the directional movement were equally distributed in the trajectory. A clear directional movement was observed in the clear cuts suggesting the beetles moved directly toward the adjacent (control) forest interior. The trajectories at the edges of both treatments were dominated by the random walk and so for the controls. These results suggest that forest ground beetles can avoid the forestry treatments especially clear cuts, however edge habitats and (the studied) preparation cuts can mitigate the migration constraints due to their more favorable environmental conditions compared to clear cuts.

SOCIOECONOMIC STATUS AND AGROFORESTRY READINESS: A CASE STUDY OF SELECTED COMMUNITIES IN THE OR TAMBO DISTRICT, EASTERN CAPE IN SOUTH AFRICA

This study pointed to the state of the community in terms of their socio-economic and agroforestry readiness in the OR Tambo District, which receives a median annual rainfall ranging between 800 and >1000 mm. In addition to favourable climatic conditions, the district has two plantations, namely the Mkambathi and Gqukunqa Forestry Enterprises, offering fertile ground to revive existing plantations, meaning that the community could immediately reap the benefits from the clear felling of the existing timber and agroforestry practices. Furthermore, the Agricultural Research Council conducted an assessment in collaboration with the Department of Agriculture, Land Reform and Rural Development aimed at identifying the community’s socio-economic status. Fifty-six community members from five local municipalities were selected, using a purposive sampling technique, and assessed. Quantitative and qualitative research designs were employed, as a structured questionnaire in English was developed, focus group and stakeholder discussions were held, as well as field observations to elicit information for the study. Data were coded, captured, and analysed using the Software Package for Social Sciences. The decantal 1km X 1km approach was followed to determine the climatic conditions of the two plantations. Currently, profitable and suitable crops like dry beans, sugar beans and groundnuts were recommended to the stakeholders for agroforestry integration. The study recommended the establishment of agroforestry in the OR Tambo District as it satisfied the basic requirements for agroforestry readiness, i.e. good climatic conditions, land availability, availability of production inputs and the community’s socio-economic status and involvement, towards food security.

Bryophyte Conservation in Managed Boreal Landscapes: Fourteen-Year Impacts of Partial Cuts on Epixylic Bryophytes

Clear cut harvest simplifies and eliminates old growth forest structure, negatively impacting biodiversity. Partial cut harvest has been hypothesized (1) to have less impact on biodiversity than clear cut harvest, and (2) to encourage old growth forest structures. Long-term studies are required to test this hypothesis as most studies are conducted soon after harvest. Using epixylic bryophytes as indicators, this study addresses this knowledge gap. Fourteen years after harvest, we examined changes in epixylic bryophyte community composition richness and traits, and their microhabitats (coarse woody debris characteristics and microclimate) along an unharvested, partial cuts and clear cuts harvest treatment in 30 permanent plots established in the boreal black spruce (Picea mariana) forests of northwestern Quebec, Canada. Our results were compared to those of an initial post-harvest study (year 5) and to a chronosequence of old growth forests to examine species changes over time and the similarity of bryophyte communities in partial cut and old growth forests. Coarse woody debris (CWD) volume by decay class varied among harvest treatments with partial cuts and clear cuts recording lower volumes of early decay CWD. The epixylic community was richer in partial cuts than in mature unharvested forests and clear cuts. In addition, species richness and overall abundance doubled in partial and clear cuts between years 5 and 14. Species composition also differed among treatments between years 5 and 14. Furthermore, conditions in partial cut stands supported small, drought sensitive, and old growth confined species that are threatened by conditions in clear cut stands. Lastly, over time, species composition in partial cuts became more similar to old growth forests. Partial cuts reduced harvest impacts by continuing to provide favorable microhabitat conditions that support epixylic bryophytes. Also, partial cut harvest has the potential to encourage old growth species assemblages, which has been a major concern for biodiversity conservation in managed forest landscapes. Our findings support the promotion of partial cut harvest as an effective strategy to achieve species and habitat conservation goals.

Effects of logging on the ecological strategy spectrum of a tropical montane rain forest

Ecological strategy is the various adaptation tactics of species to different living conditions, which can reflect their contrasting approaches to survival in varying habitats. The number and relative abundance of species in different types of ecological strategies actually forms an ecological strategy spectrum in a community. Logging is a widespread driver of forest degradation, severely influencing the composition of communities and the ecological strategy spectra in forest ecosystems. Understanding effects of logging on the ecological strategy composition of communities is vital to biodiversity conservation and efficient restoration of degraded forest ecosystems. Yet, the knowledge of how ecological strategies of different communities respond to varying types and intensities of disturbances in tropical forests are largely unknown. Here, by establishing forest dynamics plots (FDPs) in communities experienced increasing logging intensities (no logging (old-growth (OG)), selective logging (SL), and clear-cutting (CL) and measuring plant functional traits in a tropical montane rain forest, we compared the changes in ecological strategies of these stands by using Grime’s competitor, stress-tolerator, ruderal (CSR) scheme and by “StrateFy” ordination method based on measurements of three plant functional traits (Leaf area (LA), leaf dry matter content (LDMC), and specific leaf area (SLA)). Results showed that strategy number increased and ecological strategy spectra of communities changed significantly with increasing logging intensity: the proportion of S-selected strategies decreased while those of C- and R-selected strategies increased with increasing logging intensity. Community-weighted mean CSR (CWM-CSR) strategies of stands shifted from S to the C & R direction, i.e. CWM-C and CWM-R values increased and CWM-S values decreased with increasing logging intensity. Our findings suggest that logging intensity should be carefully controlled in harvesting planning, so that the recovery of species assemblages with multiple ecological strategies can be assured and the ecosystem services from these biodiverse forests can be provided sustainably.

Quad-pol advanced land observing satellite/phased array L-band synthetic aperture radar-2 (ALOS/PALSAR-2) data for modelling secondary forest above-ground biomass in the central Brazilian amazon

ABSTRACT Secondary forests (SFs) are one of the major carbons sinks in the Neotropics due to the rapid carbon assimilation in their above-ground biomass (AGB). However, the accurate contribution of SFs to the carbon cycle is a great challenge because of the uncertainty in AGB estimates. In this context, the main objective of this study is to explore full polarimetric Advanced Land Observing Satellite/Phased Array L-band Synthetic Aperture Radar-2 (ALOS/PALSAR-2) data to model SFs AGB in the Central Amazon. We carried out the forest inventory in 2014, measuring 23 field plots. Supplementary land-use classification history was used to create 120 additional independent sample plots by adjusting growth curves using SFs age and previous land-use intensity from field plots and literature database. Multiple Linear Regression (MLR) analysis was performed to select the best model by corrected weighted Akaike Information Criterion (AICw) and validated by the leave-one-out bootstrapping method. The best-fitted model has six parameters and explained 65% of the above-ground biomass variability. The prediction error was of Root Mean Square Error of the Prediction (RMSEP) = 8.8 ± 3.0 tonnes ha−1 (8.8%). The most explanatory variables for modelling secondary forest AGB were those that result from multiple scattering (Shannon Entropy), volumetric scattering (Bhattacharya decomposition), and double-bounce scattering (ratio VV/HH, vertically transmitted and received polarization/horizontally transmitted and received polarization). Including past-use of SF areas in the model with the Landsat time series classification, as the frequency of clear cuts and the number of years of active land-use before abandonment, the MLR has increased by 10%, achieving 71% of the variability explained by the model. The uncertainty report showed that ground truth AGB estimation (inventory, allometry, and plot expansion factors) might represent 50% of the errors in the modelling estimation. In contrast, Synthetic Aperture Radar (SAR) inversion models (SAR error and regression) have achieved 20%. The results showed that additional information on secondary forest land-use history could improve the performance of AGB recovery models, as well as can be used to expand the sampling units on tropical forests.

Interkingdom plant-microbial ecological networks under selective and clear cutting of tropical rainforest

Recent studies have revealed that interkingdom relationships in below-aboveground metacommunity may contribute to ecosystem functions more than species diversity. While effects of deforestation on aboveground interactions have been well studied, the responses of interactions among plant, soil bacterial and fungal communities to deforestation are pooly understood and their effects on vegetation restoration remain unknown. We sequenced soil 16S rRNA and ITS genes from the primary forest without logging history and secondary forests that had been clear cut or selective cut and left to recover for up to 50 years in the typical tropical rainforest in Hainan Island. Soil bacterial-fungal, plant-bacterial and plant-fungal associations were illustrated via ecological network analysis, and their correlations with plant composition, soil and litter properties were examined to explore the links to ecosystem functions.A higher negative proportion of bacterial-fungal interactions was found in selective cut sites while a higher positive proportion presented in clear cut sites. The changes after selective cut was related to tree composition and reductions in nitrogen and phosphorus content from soil and litter, indicating increased competition for nutrients, decoupling of communities and niche differentiation. The bacterial-fungal interaction changes after clear cut was associated with decrease in tree biomass and soil carbon content while increase in litter carbon content, implying increased co-operation in nutrient strategies and community homogenization. This ecological implications of bacterial-fungal interaction after clear cut was also applicable to plant-microbial interaction showing modular structure and strong across-module associations and significant correlations with litter carbon and soil nitrogen availability, which was indicative of a particular collection of microbial members under given plant species driving by changes in carbon and nitrogen content. Overall, the responses of bacterial-fungal and plant–microbe interactions to selective cut may in term promote the recovery of plant diversity during forest restoration, whereas these responses to clear cut may hinder the recovery of plant community diversity, and more costly restoration approaches based on different tree species planting will be required. This study suggested that the interkingdom interactions in below-aboveground metacommunity are indicative of changes in tree composition and soil fertility during the restoration of logged forest, and changes in such interkingdom interactions could in turn influence plant diversity and soil nutrients transformation.

IMPACT OF EARTHWORMS OF DIFFERENT MORPHO-ECOLOGICAL GROUPS ON CARBON ACCUMULATION IN FOREST SOILS

To date, forest ecology has not made any clear conclusions regarding the impact of large saprophagous invertebrates such as earthworms on soil carbon dynamics. Some authors claim that earthworm activities result in decreased carbon accumulation. Other studies show that earthworms contribute to soil carbon accumulation. At the same time, many studies do not take into account the differences between trophic and digging activity of different morpho-ecological groups of earthworms in different soil horizons. The objective of this study was to carry out differentiated assessment of the impact of different morpho-ecological groups of earthworms on carbon accumulation and correspondent soil parameters (nitrogen content and С/N ratio) throughout the change in forest succession status. Field operations were performed in the spring and summer of 2016 and 2018 in three regions: Bryansk Oblast (Bryansk Forest reserve), Moscow Oblast (Moskva–Oka plain, Valuyevsky urban forest) and Northwest Caucasus (Krasnodar Krai, Apsheron forestry; Republic of Adygeya, Caucasian Biosphere Reserve). Three main stages of coniferous-broadleaf forest restoration after clear cuttings were identified in each region. Three test plots 50х50 m were allocated for each stage; geobotanical and soil descriptions as well as earthworm registration were carried out on each plot. It was found out that during the change in forest succession status the species composition and the set of morpho-ecological groups of earthworms became more complicated, but there was no successive replacement of any groups with others. Ambiguous effects of different morpho-ecological groups of earthworms on carbon accumulation in forest soils were revealed. Negative correlation was found between the total biomass of earthworms feeding on the soil surface (epigeic, epi-endogeic and anecic species) and litter store. In the humus horizon, the biomass of epi-endogeic species was positively correlated with the content of carbon. C/N ratio and nitrogen content are unidirectionally correlated with the biomass of earthworms in the horizons of their activity: with an increase in the biomass of earthworms of different morpho-ecological groups, the C/N ratio decreases, and the nitrogen content increases.

Modelling effects of regeneration method on the growth and profitability of Scots pine stands

ABSTRACT Despite numerous studies there are still uncertainties regarding regeneration strategies that are optimal for productivity and profitability. Thus the aim of this study was to establish effects of three regeneration methods (planting, direct seeding and natural regeneration) on the production and profitability of Scots pine (Pinus sylvestris L.) stands in southern Sweden. Long-term stand development was simulated, with the StandWise application of the Heureka decision support system, starting from short-term regeneration outcomes observed in several field experiments at sites with relatively high productivity (H100 site indices, i.e. heights of dominant pines at 100 years: 27–30 m). Financial and production results of each approach were assessed in terms of Land Expectation Value (LEV) and Mean Annual Increment (MAI), respectively, across a whole rotation. Planting on clear-cuts with 1600–3265 seedlings per hectare resulted in the highest profitability and production, whereas high-density planting (10,000 seedlings per hectare) resulted in negative LEV. However, sensitivity analysis showed that the results depended on the interest rate. Retention of seed-trees incurred additional costs relative to single-operation clear felling. In contrast, retention of shelter-trees had good financial results (at 0% and 2.5% interest rate), although they depended on the site index and average tree size.

A survey of habitats on agricultural land in Estonia II. Detailed interpretation of the habitats’ landscape ecology and how this relates to alien plant species

The main objectives of the paper are to provide a description of the ecological character of Estonian agricultural landscapes and also their contribution to biodiversity resources. Agricultural landscapes are vulnerable to alterations in environmental factors and management that lead to changes in the balance of plant species and, therefore, to modifications in the structure and character of vegetation. The results show that the distribution and expansion of alien plant species contributes significantly to changes in the composition native plant species in Estonia. Such species are spreading rapidly in Estonia and elsewhere in Europe, leading to major changes in local vegetation and damage worth billions of Euros to the European economy every year (European Commission, 2020). Field visits to representative sites were made to record vegetation data from agricultural landscapes from 2015 to 2017. 35 dispersed random 1-km squares were selected according to the extent of the eight classes of the Environmental Classification of Estonia. 250 sample plots were thus recorded from the 1-km squares, using predetermined rules for their location. 453 vascular plant species (27% of all Estonian species) were recorded in 11 habitats (neglected patches, abandoned patches, clear cuts, forests, tall herbs, patches of alien plant species, mixed grasslands, water margins, lines of scrub/trees, field edges, roadsides). These results indicate the efficiency of small stratified samples and are relevant at a broader scale in Europe for monitoring and surveillance of habitats. Mixed grasslands were later excluded from the analyses as there were insufficient samples. 19 alien plant species were recorded in 141 plots, whereas the cover of alien species was over 25% of the plot in 38 plots. Mature forests had the fewest aliens and roadsides the most, emphasizing the importance of dispersal by vehicles. The most common high cover species were Bunias orientalis, Galega orientalis, Sambucus racemosa, and Melilotus albus. The dispersal of the most common aliens shows the role of management, as these species had the highest cover in linear features especially in roadsides and field edges. The first part of the paper provides tables of the mean figures for the ten habitats of Ellenberg values and the frequency of competitors, stress-tolerators and ruderal species (CSR), which are indicative of the quality and characteristics of the habitats. The second part of the paper provides detailed interpretations of each of the ten habitats based on statistical analyses, combined with the experience of the second author to describe the ecological significance of the habitats. The habitats vary from tall herbs, which are of minimal ecological importance, to water margins and roadsides, which are important for seed dispersal, as well as a resource of biodiversity. Each of the habitats is set in the context of the Estonian landscape, and their contribution to biodiversity is described.

Constitutive and inducible chemical defences in nursery-grown and naturally regenerated Norway spruce (Picea abies) plants

Nursery-grown Norway spruce Picea abies seedlings are often heavily attacked by the pine weevil Hylobius abietis on clear-cuts the first years after planting. Because the seedlings are not resource-limited during the growing phase in the nursery they are expected to invest less in defence than naturally regenerated seedlings already present on the clear-cuts. The latter have had to cope with various environmental stressors that could make them invest more in defence. We tested if naturally regenerated plants have stronger chemical defences than nursery-grown plants. Nursery-grown plants were planted in-between naturally regenerated plants on fresh clear cuts, and phenolic and terpene compounds in the stem bark were measured after one growing season. To test both constitutive and inducible defences, plants were either wounded, painted with methyl jasmonate (MeJA) to induce defences, or given a combination of both treatments. Growth and pine weevil attacks of the plants were registered.Nursery-grown plants had higher total concentrations of phenolic compounds and lower concentrations of terpenes than naturally regenerated plants. These opposite responses were reflected in very different compound profiles in the two plant types. We suggest the differences between plant types to be results of differences in plant age, stress level, genetic origin or possibly a combination of these factors. Most compounds showed no response to wounding, MeJA-treatment or wounding and MeJA-treatment combined, but the terpenes 3-carene, eucalyptol, limonene and para-cymene had higher concentrations in MeJA-treated nursery-grown plants than in control plants. These compounds are known to be effective in conifer resistance against weevils and bark beetles. Overall, 27% of our 400 study plants had signs of pine weevil damage after 3 ½ months in the field. However, treatment or plant type had no significant effect on whether plants were attacked or not and this might have been a result of the relatively low overall level of attacks in this study. Further studies are needed to disentangle the importance of plant age, stress level, genetic origin and resource availability for chemical defence mechanisms of young Norway spruce plants, as strengthening the natural resistance of nursery plants may be increasingly important in a future with less pesticide use.

An Assessment of Mangrove Management during the Colonial and Post-Colonial Periods

Mangroves of the east coast of India were brought under intensive management by the colonial authorities during the late 19th century. They were treated as forests rather than as wetlands, and hence management procedures developed for the terrestrial forests were applied to mangroves. Apart from this, the British foresters had limited mangrove tree mensuration data. This inadequacy in data led to the application of inappropriate silviculture methods such as clear felling to harvest mangrove wood products. This method triggered a chain reaction, that changed the biophysical condition of the clear-felled areas, which in turn prevented the regeneration of mangrove species. The same silvicultural system was followed during the post-colonial period leading to extensive degradation of mangroves.

Assessment of living ground cover under the influence of logging activities in the taiga zone

The influence of logging activities on the taiga ecosystems of the North-West is ambiguous. As a result of clear felling, tree and shrub vegetation is destroyed, which subsequently, as a result of a sharp change in environmental factors, makes a fundamental change in the biodiversity of the living ground cover. There is a complete change of botanical forest species that are part of the living ground cover for the species diversity characteristic of open landscapes. The overgrowth of clearings with grasses and undergrowths occurs depending on the typological characteristics of the felled stand and the season of the felling year. The subsequent overgrowth of clearings with herbaceous vegetation depends not only on the species composition of reforestation species, but also on various natural conditions - the features of the relief, climatic, soil and hydrological conditions. Therefore, the process of restoration of felling areas is not always positive. In order to ensure rational, sustainable and sustainable forest management, it is necessary for timber industry organizations and specialists of the forestry complex to use various measures prescribed in the “Methodological Recommendations for the Conservation of Biological Diversity in Timber Harvesting in the Vologda Region”.

Detecting the effects of logging and wildfire on forest fuel structure using terrestrial laser scanning (TLS)

Recent logging and wildfire have been linked to increased fire severity in forests around the world. The mechanisms driving this association are uncertain but increased vertical fuel connectivity in recently disturbed forests is often suggested as a possible cause. These suggestions often assume that the forest canopy is lost after logging and wildfire. However, the resprouting Eucalypt forests of south-eastern Australia may differ as the canopy can rapidly recover after wildfire, and some of the canopy is retained after logging to reflect this ecology. By contrast, stand replacement is common after wildfire in non-resprouting Eucalypt forests, which are also typically subject to clear-fell logging. Vertical fuel connectivity is not routinely measured in Australian forests due to the difficulty in reliably measuring tall elements of the fire fuel array. Here, we quantify the connectivity of understorey and canopy fuel using terrestrial laser scanning, to determine if it is affected by logging and wildfire history. We compare these findings between forests dominated by resprouting and non-resprouting Eucalypt species. The connectivity between the understorey vegetation and the canopy decreased with time since logging in both forest types, but only increased with time since wildfire in non-resprouting forests. These changes were largely driven by the increasing canopy base height. These findings support suggestions that logging and wildfire increase fire severity by increasing the vertical connectivity of fire fuel. However, this is only applicable where the canopy is replaced after disturbance, which does not happen after fire in resprouting Eucalypt forests. This research provides new insights into species dependent disturbance and fuel dynamics that are applicable to fire prone forests around the world.

Tribological Performance Investigation of a Commercial Engine Oil Incorporating Reduced Graphene Oxide as Additive.

We investigated the tribological behavior of commercialized, fully synthetic engine oil upon the incorporation of reduced graphene oxide in seven different concentrations between 0.01 and 0.2 wt %. Stability of the prepared samples was assessed by turbidimetry and dynamic light scattering measurements, and their tribological properties through a reciprocating tribometer, using a steel ball on special cut steel blocks. The addition of 0.02 wt % of reduced graphene oxide led to an improvement of the tribological behavior compared to the pristine engine oil, by significantly lowering the friction coefficient by 5% in the boundary lubrication regime. Both the surfaces and the reduced graphene oxide additive were thoroughly characterized by microscopic and optical spectroscopy techniques. We also verified that a protective layer was formed between the worn surfaces, due to the presence of reduced graphene oxide. Carbon accumulation and various additive elements such as Ca, Zn, S and P were detected on the rubbing surfaces of both the ball and the block through energy-dispersive X-ray spectroscopy. Finally, it was shown that the wear scar diameter on the surface of the steel ball was lower by 3%, upon testing the engine oil sample containing reduced graphene oxide at concentration 0.02 wt %, compared to the control sample.