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  • Open access
  • 36 Reads
Establishment and competition of native forest species in Araucaria angustifolia stands with different coverage degrees in Misiones Argentina

Mixed plantations with native species are a viable tool to meet current wood production and conservation demands that can contribute to the restoration of degraded forests. In Misiones, Argentina, 30000 ha are destined to mono-specific plantations of the native Araucaria angustifolia (Bertol.) Kuntze, for timber purposes. The mixes with other native timber species in uneven-aged plantations have ecological advantages over monospecific stands because they increase biodiversity and complexity. In mixed plantations, competition depends on the availability of resources, but also on the requirements and ages of the trees. Different ages of A.angustifolia plantations represent different coverage intensities, environmental conditions and understory structures, and can be used to protect the seedling of coverage-demanding species during the establishment. Six A.angustifolia stands of different ages, from 2y (1200 trees/ha) to 25y (220 trees/ha), were enriched with native forest species. In each stand, one 100m2 plot for each species was installed. Fifty seedlings of Cabralea canjerana, Peltoforum dubium, Bastardiopsis densiflora or Cordia trichotoma were planted per plot within the planting rows. One year after planting, survival was higher than 70% in all the species and mortality was not associated with the age of the stand. Survivals were not affected by frost although plants have been classified as frost-susceptible. However, growth was lower in the stand where the lower temperatures in winter were recorded. In the older stand, competition did not affect the survival and growth of the species with higher phenotypic plasticity, while it affected the growth of those that have lower plasticity. Results suggest that it is possible to enrich the mono-specific stands of different ages with native timber trees. Therefore mixed plantations of A.angustifolia with other native species can be considered for wood production and conservation purposes in their natural area of distribution, as they increase the connectivity between the remaining rainforests.

  • Open access
  • 33 Reads
Long-Term Wood Micro-Density Variation in Alpine Forests at Central Mexico and Their Spatial Links with Remotely Sensed Information

Ongoing climate variability strongly affects high-elevation forests, influencing the wood formation process (e.g., xylogenesis). Furthermore, spatio-temporal studies to establish links of wood properties and tree performance are needed. Using linear mixed-effects models, empirical cumulative distribution functions, and spatial analysis, we explore time trends and space connections of wood density of Pinus hartwegii Lindl. to remotely sensed variables (Moderate Resolution Imaging Spectro-radiometer MODIS-derived) in two high-elevation forests in México, Tláloc (TLA) and Jocotitlán (JOC) Mountains. Results indicated that elevation and cambial age effects are important factors explaining wood density variation. Minimum earlywood—MID, average—AVE, and maximum latewood density—MXD were statistically similar between mountains (p > 0.05), but TLA showed a significant increase in MID over time with higher values after 1950. Wood density values and spatial correlations were site-dependent with TLA exhibiting the highest correlations between MXD and the Normalized Difference Vegetation Index (NDVI) of the spring season (r = 0.59, p < 0.05). Overall, correlations to remotely sensed information were positive with MXD, negative for MID and divergent for AVE. Historical temperature defines MID along the elevation gradient, while MXD was related to soil moisture only at low-elevation sites where soils are deeper. We found that two high-elevation forests, 115 km away from each other, with similar climate, soil, and vegetation, behaved differently regarding their xylogenesis, indicating the potential of using the link between wood micro-density and remotely sensed information to understand forest response to climate change effects.

  • Open access
  • 26 Reads
Nutrient Sustainability in Swiss wood extraction

We here present the approach to be implemented in the frame of a Swiss research project that recently started (July 2020). The overall aim is to protect the forest soil fertility and biodiversity. When choosing an extraction method, the nutrient storage of a respective forest stand should be considered in order to prevent the exploitation of the site-specific nutrient pool. This topic is timely because full-tree harvesting for energetic purposes increased continuously in the last years. In addition, summer logging in foliage state is under discussion due to the climate change that increasingly reduces the winter harvesting periods. We aim to determine the current nutrient pools of different Swiss forest sites by conducting comprehensive soil analyses considering pH-value, exchangeable nutrient cations (Ca, Mg, K, Na, Mn, Fe, Zn), as well as contents of nitrogen, sulfur, phosphorus and carbon(org). Furthermore, nutrient fluxes like weathering rate, deposition and soil leaching are considered. Resulting site-specific data are combined with expected nutrient removals over one rotation period depending on tree species composition, forest stand development and extraction methods. In the frame of this project, two case studies will be implemented in beech woodland stands on sediments of the early and late Pleistocene serving as a data basis to calculate nutrient balances and to formulate management recommendations. In the long-term, we aim to apply this method to overall Switzerland and develop a software that allows an automatically calculation of site-specific nutrient-balances in order to support future forest management planning and decision-making processes.

  • Open access
  • 35 Reads
EFFECTS OF MICROWAVE DRYING ON MOISTURE CONTENT DEPENDING ON WOOD CHIP SIZE DISTRIBUTION

The storage of wood chips with a high moisture content under inadequate conditions may adversely affect their quality. Elevated microbial activity in the material leads to a loss of dry weight, greenhouse gas emissions, and heating up of the heap, which in extreme cases may significantly lower the quality of wood chips or even cause spontaneous ignition. During the storage of large quantities of wood chips, it is necessary to decrease moisture content from 60–90% to less than 40% for transportation, and to less than 25% for effective combustion. One way of reducing moisture content is microwave drying.

The study involved short-term microwave drying of three kinds of wood chips (pine, maple, and shiny cotoneaster) divided into several size fractions. The fractions were obtained using a separator with mesh diameters of 3.15 mm, 8 mm, 16 mm, 31.5 mm, 45 mm, and 63 mm (according to PN-ISO 565:2000 and PN-ISO 3310-2:2000). Wood chip samples were exposed to microwaves in a SHARP R-200 oven for 30 s, 60 s, and 90 s. Subsequently, a VIGOcam V50 thermographic camera was used to record the surface temperature of the samples, and the loss of moisture was determined by comparing sample weight before and after microwave exposure.

The study showed that due to the selective nature of the process, the power of the microwave generator and exposure time should be adjusted taking into consideration the size fraction and weight of wood chip samples. Microwave irradiation heated the wood chips to over 100°C, with unfractionated samples reaching lower maximum temperatures. Smaller wood chips were found to lose moisture more slowly. Thermographic analysis showed that temperature differences within individual samples decreased with the degree of sample homogeneity.

  • Open access
  • 61 Reads
Coniferous cones as a forestry waste biomass - a source of antioxidants

The cones of conifers are a waste biomass, potentially be utilized for a variety of purposes, including the extraction of bioactive materials, particularly antioxidant polyphenols. In the present work we conducted a comparative analysis of the antioxidant content of selected taxa that are either common in Hungary or that have not yet been investigated in any great detail (Cedrus atlantica, Larix decidua, Picea abies, Pinus mugo, Pinus nigra, Pinus sylvestris, Pinus wallichiana, Tsuga Canadensis, Tsuga heterophylla, Chamaecyparis lawsoniana, Taxodium distichum, Thuja occidentalis, Metasequoia glyptostroboides, Thuja orientalis, Cryptomeria Japonica, Cunninghamia lanceolata). A comparison of different maturation stages (green, mature, and opened cones) was carried out for the assigned taxa. Folin-Ciocâlteu total phenol content, ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays were used to assess the antioxidant contents. Total antioxidant power was determined by a scoring system that combined the three assay results. For each taxon the overall best results were found for green cones, followed by mature, and opened cones. Taxa with the highest scores were Tsuga Canadensis, Metasequoia glyptostroboides, Chamaecyparis lawsoniana, Cryptomeria Japonica, Thuja orientalis and Picea abies. High-performance liquid chromatographic/tandem mass spectrometric profiling of the polyphenols was completed for selected samples. Results provide a basis for future bioactivity testing of these samples. The research was supported by the ÚNKP-20-5-12 New National Excellence Program of the Ministry for Innovation and Technology and by the János Bolyai Research Scholarship of the Hungarian Academy of Sciences.

  • Open access
  • 24 Reads
Constitutive chemical compounds in different tissues of seven pine species and their relationship with susceptibility to pine-wood nematode (Bursaphelenchus xylophilus).

Pine-wilt-disease was detected in Galicia (NW of Spain) in 2010. Two-year-old seedlings of seven pine species were inoculated with B. xylophilus, and three different groups were stablished: non-susceptible (P. canariensis, P. taeda, P. halepensis, and P. pinea); susceptible (P. pinaster, P. radiata), and highly-susceptible (P. sylvestris). We aimed to determine interspecific variation of constitutive compounds levels groups and species, and their relationships with nematode multiplication and mortality.

Needles of non-susceptible group had significantly less water and more Nitrogen, Potassium, Iron, and starch than the others groups; Cortex + phloem of non-susceptible group had more Nitrogen, Phosphorus, Manganese, and Starch and less Potassium, Calcium, Iron, Total polyphenols, Condensed tannins and Liposoluble substances than the highly susceptible group; xylem of non-susceptible group had more N, P, Mg, Mn, Total polyphenols, and Starch than the other groups.

Higher levels of constitutive N and/or Starch in any tissue was related with less mortality and nematode multiplication; Higher P in the three tissues was also correlated with less nematode multiplication. Moreover, Liposoluble substances, Soluble carbohydrates and Condensed tannins concentrations in the needles were negatively correlated with nematode multiplication. On the contrary, needles water and K were positively correlated with mortality and nematode invasion.

  • Open access
  • 87 Reads
A QGIS based workflow for optimized cable road layout planning

Cable-based technologies have been a backbone for harvesting on steep slopes and providing Ecosystem Services. The planning of a cable road is a complex task. It essentially comprises the definition of the start and end points of a cable road, as well as the intermediate supports. It must be ensured that the permissible forces (in particular skyline tensile forces) are not exceeded, that there is a sufficient clearance between the load path and the ground, that suitable anchor trees are found and that at the same time the number of intermediate supports is minimised as far as possible. On the other hand, for ergonomic and silvicultural reasons (work safety, damages to the forest), the suspension rope should be as high as possible. In practice, the search for a solution is often iterative; especially with long lines, several attempts may be necessary until a good line is found. The presented QGIS plugin searches automatically for the optimal cable road layout, so the planning process can be considerably simplified and obtained solutions are more cost-efficient.

The plugin is designed for Central European conditions and assumes a standing skyline (fixed anchored skyline at both ends). For the calculation of the mechanical properties of the skyline a close to catenary method is used (Zweifel 1960). When testing the feasibility of the cable line, care is taken that 1) the maximum permissible stresses in the skyline are not exceeded, 2) there is a minimum distance between the load path and the ground and 3) when using a gravitational system, there is a minimum inclination in the load path. The newly developed method calculates the load path curve and the forces occurring in it more accurately than other tools available on the market. We further present a method to identify potential support and anchor trees directly from remote sensing data, which is as well integrated in the plugin. This ensures that there are effectively trees at the proposed intermediate positions and that the solution can be implemented in practice. Results of tests which will be carried out in forest enterprises in Austria and Switzerland will also be discussed.

  • Open access
  • 18 Reads
Histology of Austrocedrus chilensis roots during infection by Phytophthora austrocedri

Phytophthora austrocedri was identified as the primary pathogen causing the “Mal del ciprés” disease in Patagonian forests, which leads to the mortality of the endemic conifer Austrocedrus chilensis. Trees present withering foliage and defoliation, as well as root necrosis that may extend to the stem. This study aimed to describe the histological alterations occurring during P. austrocedri infection of roots of A. chilensis seedlings. Inoculations were performed by placing agar plugs colonized with the pathogen mycelium in direct contact with the roots. Histological studies of root sections were performed four weeks post-inoculation. Safranin-fast green, phloroglucinol-HCl, toluidine blue, lugol and diaminobenzidine stains were used to describe and compare anatomo-histological features observed in roots of non-inoculated versus inoculated seedlings. In healthy tissues, the presence of lignified Phi thickenings in radial and tangential walls of cortical cells was evidenced. These structures are reported for the first time for A.chilensis. The presence of hyphae and oospores in inoculated plants confirmed the success of colonization of the pathogen in roots. In inoculated roots, a disorganization of tissues with collapse of parenchymal cells was evidenced. In addition, it was observed necrosis of the epidermis and of the cortical parenchyma, and alterations in parenchyma cells (loss of turgor and content, cells without starch, and abnormal accumulation of phenolic compounds). Lignin content was not affected by the presence of the pathogen. The area occupied by Phi thickenings was smaller in P.austrocedri-colonized tissues, and these structures showed an accumulation of phenolic compounds, that was absent in healthy tissues. Parenchymal cells, the first rows of tracheids, as well as rays, showed an active production of hydrogen peroxide in areas invaded by the pathogen. Results evidenced that A. chilensis triggers mechanisms to restrict and resist the infection, but P. austrocedri manages to evade them and finally colonizes and degrades host tissues.

  • Open access
  • 15 Reads
Sustainable Practices in Furniture Design: Can Green Practices Influence Competitiveness?

Furniture represents a significant component of hardwood utilization and production internationally, and sustainable design practices are becoming more widespread in response to increased consumer demand for green products. In this research, we consider ecosystem services - the benefits people derive from ecosystems - from a secondary wood products perspective. We review and synthesize the literature surrounding the design, use, and disposition of wood furniture and related products in global markets. We consider emerging and innovative design strategies for wood (for example in biomimicry) as well as topics that have been gaining traction for several years (i.e. green supply chain management, eco/environmental labels, and willingness to pay for green products). An overarching theme is to consider how firm competitiveness can be influenced, or even enhanced, by green practices in design and associated communications with consumers. With a trend toward increasing customization in the secondary wood product marketplace, the role of design might be changing. However, design remains a critical product development function in modern markets, and designers are well-positioned to influence sustainable material utilization as well as improve product use and lifespan. The role of product design is expected to remain significant as consumers value green practices and have more product choices in an increasingly customized economy.

  • Open access
  • 18 Reads
Initiation of embryogenic suspensor masses in Austrocedrus chilensis, a vulnerable conifer

Austrocedrus chilensis is a Cupressaceae native to Patagonia. Phytophthora austrocedri is a soil-borne pathogen that causes severe mortality of A. chilensis. Since factors associated with the spread of the disease are difficult to control, propagation and planting of tolerant individuals seems to be the best solution. At present, a micropropagation protocol for Austrocedrus has not been developed. The aim of this study was to contribute to the development of a somatic embryogenesis protocol. The effect of culture medium, collection date and seed family on embryogenic tissue initiation and proliferation in Austrocedrus was analyzed. Immature seeds were collected from selected 11 healthy trees from open pollinated natural stands. Sampling was done every 15 days from the end of December to mid-February 2020. Six media treatment were used: EDM, SH and DCR, supplemented with 3% sucrose, 4.5µM 2,4-dichlorophenoxyacetic acid, 2.2µM benzyladenine, 3g/l gellan gum and a mixture of aminoacids(aa) (EDMaa, SHaa, DCRaa); or the same media but instead of aa it was added 1g/l L-glutamine, 0.5g/l Myoinositol and 1g/l activated charcoal(AC) (EDMglu, SHglu, DCRglu). The best percentages of extrusion were observed from material collected in January 3 and January 22 in EDMaa (12.7%, 52%) and SHaa (7.8%, 67.7%), indicating seed collection time is critical for obtaining a high embryogenic mass initiation. The highest initiation percentages were obtained with seed families 4, 5 and 11 (12, 18.5 and 21.3%, respectively), indicating the initiation process was genotype dependent. As a result, 324 embryogenic callus were obtained. Proliferation was performed in EDMaa and SHaa media with 4.5g/l gellan gum. However, callus proliferated only when previously obtained in EDMglu or SHglu, denoting the importance of AC in the extrusion process. Embryogenic cells lines represented 0.6% of total number of callus. This work is the first report of success in obtaining embryogenic cell lines for A. chilensis.

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