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  • Open access
  • 42 Reads
Adaptive management in relict Mediterranean forests. Thinning enhances long-term growth and resilience to drought in Abies pinsapo.

Abstract

Current climate change is related to increasing frequency and intensity of droughts in the Mediterranean basin. This climate dryness entails a serious impact on the drought-sensitive forests, several of them considered as hot spots of biodiversity. Adaptive management, as experimental thinning, may increase tree-level resources availability, but the long-term stand-level effectiveness of this approach at sustaining forest ecosystem functioning remains uncertain. Here we attempt to place experimental thinning in a climate change context, using as experimental system the drought-sensitive fir Abies pinsapo. We conducted a long-term study (2004-2019), focus on tree basal area increment and quantified the extent to that thinning improved drought resistance, recovery and resilience to drought in the remaining trees. The results support that after the thinning (2004) there was an increase of the BAI in all the studied populations (+21% in Control, +103% in 30% thinning and +135% in 60% thinning ). However, when studying the response of the Abies pinsapo forest strategies after an extreme period of drought, it showed a general decline in resistance values for dry periods ( -49% Control, -45% Intensity 30%, -54 Intensity 60%) as well as for the Resilience values (-19% Control, -25% Intensity 30%, -42% Intensity 60%), contrary to the Recovery values where all plots increased significantly (+61% Control, +34% Intensity 30%, 27% Intensity 60%).

Density reduction provides a promising strategy for minimizing climate change effects on drought-sensitive tree species by improving resources availability to the remaining trees.

  • Open access
  • 78 Reads
A survey on rope-based ascending techniques and materials of professional arborists in Italy

The techniques funded on rope-based access to the tree canopy (the so-called tree-climbing) have been spreading in recent years. A variety of practices such as pruning, felling of trees, cabling, phytosanitary inspections and others, can be carried out using these techniques and the methods allow to operate on trees placed in any location, resulting extremely suitable to maintain trees grown in urban environment. In Italy the number of arborists operating with rope on trees is increasing strongly. They are usually highly specialized professionals and they use specific techniques and materials. Despite the diffusion of these techniques in modern arboriculture, it is not easy to find sound ad updated information and data on them. In this work, based mainly on the answers obtained with a specific questionnaire addressed to 86 Italian professional climbers, some aspects of the applied techniques were reported. The paper shows data on professional training and formation, on the work organization, on the utilized materials and equipment and on the use and maintenance of personal protective equipment (PPE). In general, a large variety of situations are reported, a result probably linked to the fast grown of the sector in the last years.

  • Open access
  • 20 Reads
Impact of climate change on forest management: Białowieża Primeval Forest Case Study

Ecosystems of Białowieża Primeval Forest are characterized by a high degree of naturalness and biodiversity. Changes in species and age structure in the long-term period resulted from both natural processes and human impact (indirectly and directly).
The assessment of changes and knowledge about the current state allows to decide what protective measures should be taken to improve the condition of forest ecosystems. One can also evaluate the processes taking place and their direction, and therefore also assess the need for any actions.
In the conducted research, the changes occurring in forest ecosystems with particular emphasis on spruce were assessed.

An almost 100-year process of evolution of the species share in stands was analyzed up to 2015 using historical forest management and present spatial information data. Habitat data was used to asses the suitable and unsuitable conditions for spruce dominance. In addition, long-term development model was used for forecasting of the share of this species using data from beginning of 2015. Those results were compared with data from more than 500 sample plots measured in 2016-2018, just after bark beetle (Ips typographus) outbreak in 2015.

Spruce has doubled from 12 to 25% its share of the Bialowieża Forests area in the first half of twentieth century and was stable for the second half. Development model run just before the outbreak suggested stable decrease of spruce share in the horizon of 2065 down to 23%. Habitat model from 2015 was suggesting that spruce suitable sites cover only 12% of the area and only 50% of that area being dominated by spruce; the residue growing in unfavorable habitat conditions. Recent outbreak, with no management control, has dwindled spruce share down below 9%, showing habitual model results being better than development model scenario.

  • Open access
  • 14 Reads
Abundance of Viscum in Central Poland - results from large-scale mistletoe inventory

Mistletoe (Viscum album L.) is a semi-parasitic plant and in moderate abundance it does not pose a lethal threat to a tree. However, recent droughts have made heavy impact on forests and mistletoe in recent years began to appear on a larger scale in regions and in places where it has never been a threat before.

The main purpose of this research was to carry out large-scale mistletoe inventory in Central Poland for assessing the number of mistletoe on individual trees and in the stands as well as to test new inventory method adapted to Polish conditions. It is based on random sample plots, each consisting of 15 trees on which impact of mistletoe is assessed.

On every sample plot the mistletoe occurrence, location in the crown, estimate of the percentage within the crown and the number of mistletoe on a tree is assessed. In addition, for further analysis, information on stand (forest habitat type, site index) as well as measured trees (age, diameter, Kraft class, crown length, loss of assimilation apparatus, crown type) levels is recorded.

Research undertaken in Kozienice Forest (100 km south from Warsaw) had taken into account 300 sample plots on which 4500 trees were assessed. Preliminary results show that about 10% of trees are infected by mistletoe, more than 80% of which were infected heavily by more than 6 specimen.

  • Open access
  • 25 Reads
Broad-leaved and Coniferous Forest Classification in Google Earth Engine using Sentinel Imagery

Knowledge of forest structure is key to understanding, managing, and preserving forest biodiversity and function. With the well-established need within the remote sensing community for better understanding of canopy structure, in this paper, the effectiveness of Sentinel-2 imagery for broad-leaved and coniferous forest classification within the Google Earth Engine (GEE) platform has been assessed. Here we used Sentinel-2 image collection from the summer period over North Macedonia when the canopy is fully developed. For the sample collection of the coniferous areas and the accuracy assessment of the classification, we used imagery from the spring period when the broad-leaved forests are in early green stage. Support Vector Machines (SVM) classifier has been used for discriminating forest cover groups, namely broadleaved and coniferous forests. According to the results more than 90% of the canopy in North Macedonia are broad-leaved, while less than 10% are conifers. The results in this study showed that with the use of Google Earth Engine, Sentinel-2 data alone can be effectively used to obtain rapid and accurate mapping of main forest types (conifers-broadleaved) with fine resolution.

  • Open access
  • 39 Reads
Transport cost estimation model of the agroforestry biomass in a small-scale energy chain

The delivery of biomass products from the production place to the point of final use is of fundamental importance within the constitution of energy chains based on the biomass use as renewable energy source. Transport can be one of the most economically expensive operations of the entire biomass energy production process, which limits choices in this sector, often inhibiting any expansive trends. An accurate geographic identification of the locations of the different biomass sources, can be used to estimate the potential available biomass for energy transformation in a small-scale supply chain. This tool can be useful also to develop a map of the economic sustainability of biomass sources in a specific territorial area. This work reports the results of a study focused on assessing the sustainability of transport costs calculated in relation to different types of biomass sources present in proximity of a biomass power plant of a small-scale energy supply chain, located in central Italy. The study geographically located and assessed residual biomass through remote sensing and photo-interpretation. The estimation of the residual biomass present on the territory was carried out on each land use separately. The elements involved in the calculation of the transport cost concerned the identification of the area under study on the basis on a maximum travel time of 60 minutes. The transport costs model considered the available options of the road network practicability, in relation to the characteristics and morphology of the territory. The proposed analysis allows to highlight and visualize on the map the areas of the territory characterized by greater economic sustainability in terms of lower transport costs (including load a unload) of residual agroforestry biomass from the collection point to the final point identified with the biomass power plant of the small-scale energy supply chain considered.

  • Open access
  • 15 Reads
Role of phytopathogenic fungi in forest plant breeding – Development of DNA-based quick tests for quality assurance in forest plant production

The production of healthy seed and plant material is a fundamental prerequisite for the establishment of ecologically stable and economically productive forest stands. Nevertheless, as in the past, forest plant production is threatened by biotic harmful factors and new, invasive species are becoming increasingly important as a result of climate change and globalization.

DNA-based methods have significantly accelerated the detection of plant pathogens, but are time-consuming, costly and require extensive equipment. Loop initiated isothermal amplification (LAMP) is an efficient and cost-effective alternative to the classical polymerase chain reaction (PCR). The reaction takes place as a one-step assay at a constant temperature and can be evaluated visually.

In the project “TreeLAMP”, a LAMP method is established for Rhabdocline pseudotsugae, one of the most important needle pathogens of Douglas fir. To date, 32 LAMP primer sets have been derived from the internal transcribed spacer (ITS) region of ribosomal DNA (rDNA) and tested. The results showed clear differences between the primer sets both in terms of reaction rate and concentration of the amplified products. Following extensive work to optimize the LAMP reaction, a method is now available that allows the reliable detection of R. pseudotsugae at a constant temperature (65°C) and a reaction time of 1.5 hours. The detection limit is currently at 0.02 pg/µl R. pseudotsugae DNA. The current focus of the project is the optimisation of DNA extraction. In addition to conventional DNA kits, methods adapted to the detection procedure are used, which allow DNA extraction to be carried out quickly and without great technical effort.

  • Open access
  • 54 Reads
Therapeutic functions of forests and green areas with regard to the universal potential of sensory gardens.

A significant part of the world's population lives in urban areas, where there are many stressors. Studies show that the less green in the neighbourhood, the higher level of cortisol, the "stress hormone", in the blood of residents. The health benefits of contact with nature has been widely researched. They are described, among others, by “Nature Therapy Theory”. One example of this form of therapy is forest bathing, also known as shinrin-yoku, a practice that combines a series of outdoor exercises and tasks based on mindfully using all five senses. There are also “Therapeutic landscapes”, which are places that for various reasons can have a beneficial effect on health and well-being. Moreover, a positive impact on behaviour and interpersonal self-improvement has "Wilderness therapy". This therapy combines experiential education, individual and group therapy with adventure-based therapy in a wildlife environment. Research show that physical activity in the natural environment is preferable to physical activity in a closed space in terms of the feeling of relaxation, well-being, reduction of stress and aggression. Furthermore, the therapeutic properties of various plant communities have a wide range of impact on specific medical aspects, including disinfection, blood pressure lowering, anti-asthma, or immune-boosting etc.

In the category of green areas which on a small area intensify feelings are sensory gardens. They also have great potential for eliminating stress symptoms and stimulating sensory feelings among people with disability. Sensory gardens, being an element of universal recreational development in urban and suburban conditions, can perfectly fulfil social, educational and therapeutic functions. Their distinguishing feature is a strong influence on non-visual senses. The space adapted to the needs of people with disability gives a sense of security, provide greater independence, can be used for passive and active therapy, and constitute a zone of social inclusion. Sensory gardens can be considered as an example of a comprehensive development of green areas that meets the requirements of universal design.

The presented study is a review. The authors show that providing urban communities a therapeutic contact with nature through the use of urban forests is a very important aspect of improving the quality of life. Special attention was paid to the potential of sensory gardens in the designing of recreational development which may be an opportunity to reduce the process of social exclusion of people with disability in the local environment.

  • Open access
  • 22 Reads
The Technical Quality of Wood of Scots Pine (Pinus sylvestris L.) of Diverse Genetic Origin

This work contains the preliminary results of research into the technical quality of wood from Scots pine trees of diverse genetic origin, grown on an experimental plot at the Forest Experimental Station in Rogów. These are the parent stands numbered 5 (Bory Tucholskie region 130 m a.s.l.), 7 (Lasy Napiwodzko-Ramuckie 145 m a.s.l.), 10 (Puszcza Piska 145 m a.s.l.), 12 (Puszcza Biała 95 m a.s.l.), 13 (Lasy Namysłowsko-Ostrzeszowskie 190 m a.s.l.), 15 (Puszcza Knyszyńska 165 m a.s.l.) and 16 (Bory Nowotarskie 590 m a.s.l.). The tested wood was obtained in 2018 from trees aged 52 years. The research material came from 100 trees in total. After felling, two logs approximately 0.5 m in length were cut from each tree. The height on the tree from which the material was taken ranged from breast height (1.3 m) to approximately 2.5 m. Next, planks were cut from the logs in a north–south direction; these were precisely described, and then left to season. The work included the measurement and statistical analysis of one physical property, wood density [kg/m3], and of the following mechanical properties: compressive strength along the fibres, Rc12 [MPa]; static bending strength, Rg12 [MPa]; modulus of elasticity under static bending, Eg12 [MPa]; and indices of strength quality of the tested mechanical properties, JRc12, JRg12, JEg12 [km]. Origin was shown to have a significant influence on wood density, compressive strength, static bending strength, and modulus of elasticity under static bending. The highest mean density was found for trees originating from stand 10 (537 kg/m3). The highest values of compressive strength were obtained for trees originating from stands 5 (45 MPa), and the highest static bending strength and modulus of elasticity under static bending were obtained for trees originating from stand 12 (102 and 9825 MPa respectively).

  • Open access
  • 59 Reads
Modelling of Elevated Temperature Performance of Adhesives Used in Cross Laminated Timber: An Application of ANSYS Mechanical 2020 R1 Structural Analysis Software

There is difficulty in accurately modelling adhesive influence in structural performance of cross laminated timber (CLT), due to a lack of available knowledge on the heat performance of adhesives. Therefore, the main aim of this research was to evaluate the thermal and mechanical properties of adhesives used in production of engineered wood products like CLT. The properties of the timber species and the adhesive types used in the simulation were derived from published literature and handbooks. ANSYS mechanical 2020 R1 was employed because it has a provision for inserting the thermal condition and the temperature of the system set to the required one for analysis. The simulations were conducted for temperatures 20, 100, 140, 180, 220 and 260 oC, within which Zelinka et al conducted their experiments, which have been the basis for the current study. The main findings were, the adhesive layer had little influence on the thermal properties of CLT composite (solid wood had the same thermal properties as CLT), but had a significant effect on the structural properties of CLT composite, the stresses and strains of the simulated wood species reduced with increase in temperature, the adhesives strengths at room temperature were greater than for solid wood at the same temperature and finally, the stresses and strains of the simulated wood adhesives reduced with increase in temperature. It is also important to note that computations for temperature distribution from the char layer were lower than computed using heat transfer equation, and the simulated values from steady state model. All in all, the objectives of this research were met and more research in thermal structural modelling using ANSYS should be conducted in the future.

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