Forestry Practices Research Articles

Determining the habitat fragmentation thru geoscience capabilities in Turkey: A case study of wildlife refuges

Technical forest management started 180 years ago in Turkey, during which time there have been various approaches and policy changes. The primary objective of forestry has been considered as timber production, so the intangible benefits have never been given the proper attention they deserve. The majority of Turkey’s wildlife has prospered within the forest ecosystems. This situation has gradually led to a change of status, so some forests and land areas have been reassigned with the conservation agendas as the primary purpose; however timber production has never slowed down. Thus, operational forestry practices, such as roading, logging, etc., have kept on exploiting these lands to their full extent despite their conservation statuses. In Turkey and anywhere else, since forestry has always evolved around extracting the timber out of the forest lands, the accessibility has long been provided, building roads to take related services to forested ecosystems. The remnants of these roads, along with the more standardized new ones can be found everywhere, regardless of the land status. Such expansion has resulted in habitat fragmentation emerging as a major threat for the protected areas. In this study, the expansion of all-weather and dry-weather accessible roads and suburban spread was examined in two adjacent, Ilgaz and Gavurdagi, wildlife refuges for the years of 1960, 1993, 2010 and 2019, relying heavily on the mapping, geographic information systems (GIS) and remote sensing. It was found that 275.5 km dry-weather roads in 1960 rose to 700 km in 2017, which meant 254% increase. Additionally, when the core along with the surrounding 3000 m buffer area was considered, 51 km all-weather roads in 1960 increased almost four and a half times by 2019. Suburban expansion was relatively stable inside the core area but had almost quadrupled within the surrounding areas, exposing the refuges to more people. These findings indicated that the wildlife habitats of Turkey are fragmented and under heavy human pressure.

Influence of logging on nest density and nesting microsites of cavity-nesting birds in the subtropical forests of the Andes

Abstract Birds select nesting sites with certain characteristics associated with tree age and species that help to prevent or reduce the risk of clutch loss due to predation or unfavourable weather conditions. Logging may reduce the availability of trees and their related features that may be important for cavity nesters. Thus, the aim of this study is to evaluate the effect of logging on nest density, nesting microsite and nest success of cavity nesting birds at Piedmont forests of northwestern Argentina. We monitored these variables at different logged and unlogged sites during four consecutive reproductive seasons and analysed them using univariate analysis and generalized linear models. The main results indicate that logging reduces nest density and changes the characteristics of the nesting microsites. We found that nest success was greater in cavities located higher above the ground and found no evidence of lower nest success at logged sites. This study suggests the need for forest management actions aimed at increasing nesting sites for cavity-nesting birds. For this purpose, management should be focused on the retention of old trees with a diameter >50 cm (both living and dead). The use of reduced-impact logging techniques or forest certifications (e.g. Forest Stewardship Council) could provide alternatives in subtropical forests, as these forestry practices can ensure tree abundance and richness, providing features suitable for cavity-nesting birds (e.g. tree diameter, cavity size and height).

RETHINKING URBAN FORESTRY THROUGH RESOURCES ACCESSIBILITY

Industrial urbanization disconnected city dwellers from direct access to natural resources. Consequently urban forests were introduced into cities for their aesthetic and environmental qualities, and are managed through the practice of urban forestry, which primarily focuses on maintenance services. However, emerging initiatives around the world are expanding the scope of urban forestry practice through the network generated by untapped forestry resources in the city. This study aims to clarify the potential of urban forestry for fostering citizens participation through resources accessibility, by comparing the network of different case studies based on the resources transformation and the members involvement.

Managing climate change microrefugia for vascular plants in forested karst landscapes

Microrefugia are small areas that support favourable climate and allow species to persist during regional and global climate changes. Dolines in karst landscapes may provide such areas for many climate change-vulnerable species. Here we provide a better understanding on how plant species indicate changes in their environment (temperature, soil moisture and light availability) after a few years of partial canopy removal from dolines and their close surroundings (logged areas: >1 ha). We place our results in the context of the most widely used forest management practices within the study area (Mecsek Mts, Hungary), in addition to presenting a general framework for the maintenance of doline microrefugia in forested karst landscapes. Three types of habitats were investigated: dolines before logging, dolines after logging, and the forested plateau. Three large dolines and three sites on the plateau were selected for vegetation sampling. All dolines were sampled before logging and 5–10 years after partial canopy removal. Logging resulted in a 50–80% reduction of canopy cover in the dolines and their close surroundings. We established a transect across each doline from north to south passing through doline bottoms, and across each plateau site. We estimated the percentage cover of vascular plant species (tree saplings – up to 1 m in height, shrubs and herbs) along the transects using 1 m × 1 m vegetation plots, determined the diagnostic species of the doline and plateau habitats, and used multivariate methods and linear mixed-effects models during analyses. Plant species indicated clear gradients of the main microclimatic factors within the dolines and that significant changes took place after logging. Canopy removal caused substantial changes in the main microclimatic factors of most doline microhabitats (e.g., south-facing slopes). The vegetation of the dolines before logging indicated moister conditions than that of the plateau and cooler and shadier conditions than that of the dolines after logging. These and our previous results suggest that logging may directly and indirectly influence dolines to be microrefugia under global warming. By applying our framework to refugia conservation and management for the karst landscape in the Mecsek Mts, we can conclude that the protection of old forests and natural forest dynamics in as many large dolines as possible and the implementation of close-to-nature forestry practices may be essential to maintain regional biodiversity in the long run.

The use of measurable traits of trunk and crown to assess the biosocial classes of oak trees (Quercus robur L.)

The crown class assessment is a key element in forestry practice. It is a traditional method that finds application in thinning plans, assessment of site index, tree competition, or crown condition. Assigning trees into a given class is done during field surveys and requires precision and experience to avoid inaccuracy. Therefore, Kraft’s system has often been criticized and modified. Thus, in our study, we aimed to analyse whether the directly measured traits of trunk and crown of oak trees (Quercus robur L.) can be applied to crown class assessment. For this purpose, we used the principal component analysis (PCA) and nonlinear kernel principal component analysis (KPCA) based on measurable traits of trunk and crown, i.e., the height of the tree, the diameter at breast height, the length of the crown, and the field crown projection area. In total, we measured 286 mature trees in three oak stands located in western Poland. Results indicate that all chosen traits of trunk and crown allowed, though not always perfect, to assign the trees into given crown classes. The greatest contribution to crown class distinction had the diameter at breast height and the parameters of crown, i.e., and the field crown projection area. Furthermore, results show that the best method of assigning the trees into biosocial classes is the KPCA Gauss, considering the percentage explanation of the total variability, and KPCA Laplace, considering the visual division. In the latter, the multivariate analysis resulted in a similar crown class assignment as the field-assigned method. However, its application requires measurements that make it neither cheaper nor faster than a traditional crown class assessment. It indicates that a traditional field-assigned method, despite its subjectivity, should continue to be of great importance in forestry practice. Moreover, the alternative traits of trunk and crown can be a potentially useful statistical substitute for crown class assessment. Keywords: crown class, oak stand, trunk and crown traits, multivariate methods

In-situ calibration of stand level merchantable and sawlog volumes using cut-to-length harvester measurements and airborne laser scanning data

Abstract Forest management inventories assisted by airborne laser scanning (ALS) can be used to predict different forest attributes. These predictions are utilized in practical forestry, but in the case of timber assortment-specific volumes, the ALS-based predictions can be inaccurate. This causes uncertainty in harvest planning. However, ALS-based predictions can be calibrated to achieve greater accuracy with local measurements. In this study, we used ALS data and accurately positioned cut-to-length harvester measurements from Norway spruce (Picea abies (L.) Karst.) dominated clear-cuts. We fitted linear mixed-effects (LME) models with exponential correlation structure for merchantable volume and sawlog volume for 225 m2 cells. Our aim was to study the effect of local harvester measurements on the accuracy of stand level merchantable and sawlog volumes. LME-based predictions were calibrated repeatedly up to 40 times as the cutting progressed. ALS data and harvester measurements were used to predict both the random effects and residual errors for each validation unit. At best, relative root mean square error (RMSE%) of initial predictions of 15.4 per cent for merchantable volume and 22.1 per cent for sawlog volume were reduced to 4.1 and 5.3 per cent, respectively, when measurements from 40 harvested cells of size 225 m2 were used. These results suggest that spatially accurate harvester data could be utilized during harvesting to increase the accuracy of volume and timber assortment predictions.

Attending to nature: Understanding care and caring relations in forest management in the UK

Increasing threats from pests and diseases fundamentally question what forest management is and must do in the 21st century. The sociological concept of ‘care’ offers new understandings of forest management as intimate and emotional relationships between people and trees. In this paper, we examine the empirical realities of conservation forest management at a UK publicly owned site to reveal the social, economic, and institutional contexts of care and caring relations and their role in management decisions.This in-depth qualitative case study uses walking interviews with staff from all levels of the organisation and participatory data testing to show how care underpins the work of forest management, that forests are made and sustained through caring practices, and that management decisions are influenced by caring relations. Through the care framework we highlight the complexities of real-life decision-making and offer implications for forestry policy and practice. Applying the well-established components of care in a new setting, wherein the caring relations involve nonhumans, we extend care theory and demonstrate the potential of the single case study for deeply contextual forest and conservation research.

Use of multiple LIDAR-derived digital terrain indices and machine learning for high-resolution national-scale soil moisture mapping of the Swedish forest landscape

Spatially extensive high-resolution soil moisture mapping is valuable in practical forestry and land management, but challenging. Here we present a novel technique involving use of LIDAR-derived terrain indices and machine learning (ML) algorithms capable of accurately modeling soil moisture at 2 m spatial resolution across the entire Swedish forest landscape. We used field data from about 20,000 sites across Sweden to train and evaluate multiple ML models. The predictor features (variables) included a suite of terrain indices generated from a national LIDAR digital elevation model and ancillary environmental features, including surficial geology, climate and land use, enabling adjustment of soil moisture class maps to regional or local conditions. Extreme gradient boosting (XGBoost) provided better performance for a 2-class model, manifested by Cohen’s Kappa and Matthews Correlation Coefficient (MCC) values of 0.69 and 0.68, respectively, than the other tested ML methods: Artificial Neural Network, Random Forest, Support Vector Machine, and Naïve Bayes classification. The depth to water index, topographic wetness index, and ‘wetland’ categorization derived from Swedish property maps were the most important predictors for all models. The presented technique enabled generation of a 3-class model with Cohen’s Kappa and MCC values of 0.58. In addition to the classified moisture maps, we investigated the technique’s potential for producing continuous soil moisture maps. We argue that the probability of a pixel being classified as wet from a 2-class model can be used as a 0–100% index (dry to wet) of soil moisture, and the resulting maps could provide more valuable information for practical forest management than classified maps.

Symbolic interaction and its influence on cooperation between private forest owners

Organizations, such as forest management cooperatives (FMCs), are established to support private forest owners to deal with structural and natural challenges that they cannot handle on their own. In 2018, Feil et al. found in a nationwide survey that only 30% of German private forest owners are members of FMCs. This low participation rate of private forest owners in FMCs in Germany poses a problem for the further development of organizations that can better consider the needs of private forest owners and also meet the timber market's long-term requirements for larger quantities of timber as well as become an equal negotiation partner of the sawmill industry. This problem can be attributed to social interactions, which are considered influential for cooperation between private forest owners.This paper aims to highlight different groups of private forest owners in Germany and their cooperation based on social interaction. To do so, it refers to the categories of actor-centered institutionalism (ACI) and complements these with symbolic interactionism. Methodologically, the paper is based on a quantitative online survey of 1007 private forest owners in Germany. The survey itself was prepared by the authors and conducted by the pollster firm forsa, Germany in the period from 14 to 29 July 2020. In addition to standard research topics in forest related research, such as family tradition and income generation, the questionnaire also focused on social interaction. A hierarchical cluster analysis based on the values of a principal component analysis (PCA) was used both to ensure a neutral view on the data and to create heterogeneous groups of private forest owners.Four distinct clusters were defined through the cluster analysis: “actively exchanging”, “perceivers”, “uninterested” and “self-referential”. These clusters differ mainly in relation to their preferred forms of social interaction.It can be concluded that not only communication but also social interaction in the form of symbolic interaction has an influence on forest owners' cooperation with FMCs. For forestry practice, this means that in regions where there are currently no FMC members, new members could be won in the future by creating forest management activities that encourage cooperation with FMCs.

Understanding introduction history: Genetic structure and diversity of the edible ectomycorrhizal fungus, Suillus luteus, in Patagonia (Argentina)

ABSTRACT Suillus luteus is a common ectomycorrhizal (EM) fungus associated with several Pinus species. It is distributed throughout the Northern Hemisphere and has been introduced into South America and New Zealand. We examined the genetic structure and population biology of S. luteus, which was introduced into Patagonian plantations with Pinus species in Argentina. Overall, 106 samples were collected at 11 geographically separated sites (i.e., Pinus plantations) along a latitudinal gradient in Patagonia (ca. 38°–46° south latitude). Phylogenetic analyses confirmed placement in S. luteus. Genetic analysis demonstrated moderate within-site genetic diversity, but low differentiation between sites. No clear clusters were detected geographically or in relation to host species of Pinus. Our results suggest that the weak genetic structure of the species reflects the short time that has elapsed since the introduction of S. luteus into Patagonia, and its expansion with exotic afforestation there. Moreover, the lack of structure is consistent with a founder effect, suggesting the introduction of a small number of genets that spread throughout all the plantations. Therefore, the high level of gene flow and weak genetic structure observed are probably related to the anthropogenic movement of inoculum associated with forestry practices.

Influence of Forest Conditions on the Spread of Scots Pine Blister Rust and Red Ring Rot in the Priangarye Pine Stands

Scots pine blister rust and red ring rot are common on Scots pine throughout its entire range. Specialists do not explain a significant variation in the prevalence of the diseases uniquely since it depends on complex ecological and silvicultural factors. The aim of this research is to study the influence of forest growth conditions on the incidence of Scots pine blister rust and red ring rot in pine stands of the Priangarye (territory located along the lower reaches of the Angara within the Krasnoyarsk Krai). The research methods included a detailed forest pathological examination of prevailing pine forest types, specific symptom-based macroscopic diagnosis of the diseases, data analysis using parametric and non-parametric statistical tests. Forest growth conditions indicators included type of forest, habitat conditions, and bonitet class of forest stands. The incidence of Scots pine blister rust and red ring rot in pine forests of the Priangarye reaches the extent of moderate and severe damage, respectively. The prevalence of Scots pine blister rust is significantly higher in low-bonitet lichen pine forests; the incidence rate increases along the gradient of decreasing fertility and soil moisture level. The incidence of red ring rot is significantly higher in herb-rich pine forests, in gradations of maximum soil fertility and medium soil moisture. The revealed patterns are explained by the bioecological characteristic features of pathogens (for red ring rot—additionally by factors of structural immunity in pine trees). The results of the research should be recognized in the organization of forestry practice.

Climate Analogues for Temperate European Forests to Raise Silvicultural Evidence Using Twin Regions

Climate analogues provide forestry practice with empirical evidence of how forests are managed in “twin” regions, i.e., regions where the current climate is comparable to the expected future climate at a site of interest. As the twin regions and their silvicultural evidence change with each climate scenario and model, we focus our investigation on how the uncertainty in future climate affects tree species prevalence. We calculate the future climate from 2000 to 2100 for three ensemble variants of the mild (representative concentration pathway (RCP) 4.5) and hard (RCP 8.5) climate scenarios. We determine climatic distances between the future climate of our site of interest ‘Roth’ and the current climate in Europe, generating maps with twin regions from 2000 to 2100. From forest inventories in these twin regions we trace how the prevalence of 23 major tree species changes. We realize that it is not the ‘how’ but the ‘how fast’ species’ prevalence changes that differs between the scenario variants. We use this finding to develop a categorization of species groups that integrates the uncertainty in future climate. Twin regions provide further information on silvicultural practices, pest management, product chains etc.

Planning and Planting Future Forests with Climate Change in Mind

The climate is warming too fast for some trees to catch up. Planting seeds from warmer regions can bolster future forests, but that requires a significant shift in forestry practice.

The role of a fiber sourcing standard in the sustainable management of forests in Georgia, United States

The Sustainable Forestry Initiative (SFI) Fiber Sourcing (FS) standard fosters responsible fiber procurement by certified wood-consuming mills. This study assesses the effectiveness of the SFI-FS standard in increasing the implementation of forestry best management practices (BMPs) and quantifies its impact by surveying logging companies and certified mills in Georgia, United States. About 55% of the logging companies who responded to our mail survey indicated that the SFI-FS standard had increased the statewide BMP implementation rate. Environmental benefits topped the list of perceived benefits of BMPs, while BMP implementation costs and operational difficulties were the most frequently reported concerns. In 2019, the average BMP implementation rate of loggers trained under the Georgia Master Timber Harvester (GAMTH) program was 6.3% higher than non-GAMTH loggers. Certified mills reported consuming a combined roundwood volume equivalent to about 72% of the total roundwood consumed in Georgia. Moreover, we find that a) logging companies with larger capital investments, and b) certified mills engaging with the loggers in terms of communication of conservation practices, may fare better towards increasing BMP implementation. Our results indicate that the SFI-FS standard positively influences the sustainability of forest resource management on non-certified forestlands in Georgia. Our findings directly relate to the sustainability of 116 million hectares of forestland owned by families across the United States.

Forest management affects seasonal source-sink dynamics in a territorial, group-living bird

The persistence of wildlife populations is under threat as a consequence of human activities, which are degrading natural ecosystems. Commercial forestry is the greatest threat to biodiversity in boreal forests. Forestry practices have degraded most available habitat, threatening the persistence of natural populations. Understanding population responses is, therefore, critical for their conservation. Population viability analyses are effective tools to predict population persistence under forestry management. However, quantifying the mechanisms driving population responses is complex as population dynamics vary temporally and spatially. Metapopulation dynamics are governed by local dynamics and spatial factors, potentially mediating the impacts of forestry e.g., through dispersal. Here, we performed a seasonal, spatially explicit population viability analysis, using long-term data from a group-living territorial bird (Siberian jay, Perisoreus infaustus). We quantified the effects of forest management on metapopulation dynamics, via forest type-specific demography and spatially explicit dispersal, and how forestry impacted the stability of metapopulation dynamics. Forestry reduced metapopulation growth and stability, through negative effects on reproduction and survival. Territories in higher quality natural forest contributed more to metapopulation dynamics than managed forests, largely through demographic processes rather than dispersal. Metapopulation dynamics in managed forest were also less resilient to disturbances and consequently, may be more vulnerable to environmental change. Seasonal differences in source-sink dynamics observed in managed forest, but not natural forests, were caused by associated seasonal differences in dispersal. As shown here, capturing seasonal source-sink dynamics allows us to predict population persistence under human disturbance and to provide targeted conservation recommendations.

PRACTICAL ASPECTS OF IMPROVING FOREST SEED ZONING

When using forest seeds for the needs of reforestation and afforestation, the requirements of forest seed zoning should be observed, which regulates the permissible directions and distances of movement of seeds of a particular species of forest trees and shrubs, taking into account their geographical and edaphic origin. Forest seed zoning provides the most rational use of the genotypic potential of a certain species of woody plants in different types of forest vegetation conditions and is an important stage in the organization of forest seed business on a genetic and selection basis. The task of the article is to identify a number of problematic issues in forest seed production, to identify areas where it is possible to address the issue of improving forest seed zoning in the context of forest seed and nursery development in modern conditions. New terminology is proposed and the essence of the proposed normative and legal documents is introduced from the perspective of adaptation of forest seed and nursery to the introduction of conditions for obtaining and circulation of forest reproductive material to the level of compliance with the requirements applicable in EU countries. The issue of improving forest seed zoning in the context of the development of forest seed production and nurseries becomes especially relevant in the process of solving the problem of putting forest reproductive material into circulation, according to the draft Law of Ukraine "On Forest Reproductive Resources" (2019). This article analyzes the forestry aspects of zoning of the territories of Ukraine used in forestry practice, and proposes the improvement of forest seed zoning in the direction of forest efficiency and the criteria for assessing the population and ecosystem functionality of forests. Also, the improvement of forest seed zoning is considered from the applied standpoint of ensuring the conditions for obtaining and putting into circulation forest reproductive material. This is a key issue for the transfer of forest seed and nursery of Ukraine to the level of compliance with the requirements applicable in the countries of the European Union.

LandTrendr smoothed spectral profiles enhance woody encroachment monitoring

Secondary succession (SS) is one of the main consequences of the abandonment of agricultural and forestry practices in rural areas, causing -among other processes- woody encroachment on former pastures and croplands. In this study we model and monitor the spatial evolution of SS over semi-natural grassland communities in the mountain range of the Pyrenees in Spain, during the last 36 years (1984-2019). Independent variables for ‘annual-based’ and ‘period-based’ modeling were drawn from a suite of Surface Reflectance Landsat images, LandTrendr (LT)-algorithm-adjusted images and LT outputs. Support vector machine (SVM) classifiers were trained and tested using all possible variable combinations of all the aforementioned datasets. The best modeling strategy involved yearly time series of LT-adjusted Tasseled Cap Brightness (TCB) and Wetness (TCW) axes as predictors, attaining a F1-score of 0.85, a Matthew Correlation Coefficient (MCC) of 0.67 and an AUC 0.83. Woodlands encroached above 480,000 ha of grasslands and crops during the study period. A model using LT outputs for the whole period also denoted good performance (F1-score = 0.85, MCC = 0.75) and estimated a similar area of woodland expansion (~509,000 ha), but this ‘period’ approach was unable to provide temporal information on the year or the encroachment dynamics. Our results suggest an overall proportion of 66% for the Pyrenees being affected by SS, with higher intensity in the west-central part, decreasing towards the eastern end.

Riparian Timber Harvest Intensity Affects Diets of Appalachian Brook Trout

AbstractStream‐dwelling Brook Trout Salvelinus fontinalis rely heavily on terrestrial invertebrates, especially when aquatic prey is limited. We examined the effects of an experimental harvest of riparian timber on the diet and condition of Brook Trout in late summer. We evaluated the effects of two riparian harvest intensities (50% and 90% of the basal area harvest) in each of two streams on the diet, consumption, abundance, and condition of Brook Trout in summer. The diets and consumption patterns of Brook Trout were affected by the percentage of riparian timber harvest. Timber harvest increased the use of aquatic invertebrates—primarily via increased consumption of crayfish. In the 90% treatments, the use of terrestrial invertebrates by Brook Trout declined primarily due to the decreased use of Lepidoptera. Overall, consumption levels in the 50% treatments were nearly double those in the reference or 90% treatments. A common forestry best management practice is to limit riparian harvest to 50% of the basal area. Provided water quality and quantity are not affected, our study suggests that a 50% timber harvest limitation in the riparian area may provide at least a temporary boost in consumption due to an increase in the use of aquatic insects.

Tolerant semiaquatic bugs species (Heteroptera: Gerromorpha) are associated to pasture and conventional logging in the Eastern Amazon

The aim of the present study was to evaluate how environments modified by conventional logging (CL), reduced-impacted logging (RIL), and pastures (PST) surrounding streams affect environmental characteristics and semiaquatic bugs assemblages (Gerromorpha), in the eastern Amazon. The following hypotheses were tested: (i) environmental heterogeneity in streams is lower in areas with more intensive practices (e.g. CL and PST); (ii) species richness and abundance are also lower in streams located in areas with more intensive practices, while more preserved areas have higher richness and abundance; and (iii) species composition shall be affected by changes in forestry practices, thus causing differences between treatments according to species tolerances. We observed that although PST and CL have higher environmental heterogeneity and alpha diversity, respectively, these treatments are associated with the presence of tolerant species and are different from the forest regarding composition (species identity) and species distribution pattern. On the other hand, forest and RIL areas did not have differences regarding habitat characteristics, environmental heterogeneity, alpha diversity, composition and species distribution pattern. This indicates that RIL can maintain a considerable part of habitat integrity and Gerromorpha assemblage composition.

Determination of standards of raw timber natural losses due to shrinkage at long-term dry storage

The aim of the article is to describe the issue of determining the characteristics and parameters of raw timber natural losses due to shrinkage at long-term storage, defining the theoretical basis for creating standards, and verify its finding by means of a case study in raw timber storing. This issue is very topical in forestry practice in the Czech Republic as well as in other countries. The lower and upper limits of the standards were calculated, and the proposed mean value was grouped according to woody plants that reflected the most frequent commercial usage with respect to subsequent processing. Subsequently, experimental verification was carried out on a representative sample of 2 209.99 m3 of raw timber of Norway spruce (Picea abies /L./ H. Karst.) at selected forest administrations. Furthermore, the article addresses the related accounting and tax issues of the standards of natural losses of raw timber. Currently, no legislation mandates an entity to establish standards.