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Forestry Studies
Journal Prestige (SJR): 0.209

Number of Followers: 1

This is an Open Access Journal

Open Access journal
ISSN (Print) 1406-9954 - ISSN (Online) 1736-8723
Published by Sciendo

[389 journals]

Future possibilities for long-term business cooperation between private
forest owners and forest service providers in Slovenia
- Abstract: Private forest ownership, with small and fragmented forest properties prevailing in Europe, is affected by demographic, economic and social changes as well as by forest-related policy goals. This is reflected in the lack of knowledge about forest management, insufficient forest management and underutilization of forest resources. Considering that, business cooperation between private forest owners and with forest service providers or managers is recognized as one of the key instruments to increase the efficiency of private forest management. The aim of this study is to investigate whether there is a potential for further development of forest lease as form of long-term business cooperation. In this research, interviews (n=8) were conducted with tenants who have signed long-term forest lease contracts with private forest owners in Slovenia. The results show that there are limited possibilities for further development of long-term business cooperation between private forest owners and forest service providers/managers (e.g. forest lease). The results indicate that there are many benefits of long-term business cooperation for both sides, but private forest owners’ interest is questionable. If we want long-term business cooperation (forest lease) to succeed, forest lease should be recognized in legislation, education about business cooperation (forest lease) should be given to public forest service employees, so they could promote forest lease and provide information to private forest owners. In addition, a connection between potential business partners should be established and examples of good practice should be promoted to gain trust between business partners, which could increase private forest owners’ interest and consequently improve private forest management and utilization of forest resources from private forests.
  PubDate: Sat, 13 Apr 2024 00:00:00 GMT
Note on the compatibility of ICOS, NEON, and TERN sampling designs,
different camera setups for effective plant area index estimation with
digital hemispherical photography
- Abstract: Environmental monitoring networks such as the Integrated Carbon Observation System (ICOS) in Europe, the National Ecological Observatory Network (NEON) in the U.S., or the Terrestrial Ecosystem Research Network (TERN) in Australia deploy different sampling schemes for in situ measurements. We report on the intercomparison of measurements of the canopy gap fraction with different digital hemispherical photography setups adopting ICOS, NEON, and TERN sampling schemes. The test was carried out at the Järvselja Radiation Transfer Model Intercomparison (RAMI) birch stand. Results show that spreading out sampling points which cover more of the plot is important for a good representation of the forest as a whole. The NEON tower plot layout scheme may be more prone to errors in overall canopy properties estimation than ICOS or TERN due to its compact sampling layout and should always be used in conjunction with its distributed plots. Different camera setups involving different camera operators, camera bodies, lenses and settings yield slightly varied results, and it is important to ensure that the images are taken in such a way that they would not be over or underexposed, or out of focus. As a conclusion we recommend always to carry out intercomparison measurements with old and new cameras when devices are upgraded. Our study contributes towards establishing the uncertainty and evaluating potential error budget stemming from collecting in situ measurements using different sampling schemes and camera setups.
  PubDate: Sat, 13 Apr 2024 00:00:00 GMT
Highlights of forest science in Estonia
- PubDate: Sat, 13 Apr 2024 00:00:00 GMT
Validation of saw log and technological wood assortment recovery and
reduction predictions based on cut-to-length harvester data
- Abstract: In this study, assortment yields were studied for Scots pine, Norway spruce, birch spp. (silver and downy birch), European aspen, black alder, and grey alder stand elements. Theoretical assortment yields were calculated using the Ozolinš’ stem taper curve, incorporating tree diameters and heights. The modelled results were compared with actual yields provided by the State Forest Management Centre. During the study, differences in timber assortments and firewood yields were modelled compared to actual data. Changes in wood assortment yields, compared with undamaged and straight trees, depended on the tree species, stand site index, and stand element age. For Scots pine, depending on the stand site index and age, the reduction in log volume ranged from 7 to 28% of the total volume of all assortments. For Norway spruce, it was 5–30%, for birch spp. 30–70%, for aspen 50–90%, for black alder 20–50% and grey alder 5–30%. The increase in firewood volume according to the volume of all assortments was 3–4% for Scots pine, 5–14% for Norway spruce and birch spp., and 5–16% for European aspen. The difference between log and firewood changes represents the change in pulpwood. Over time, the need for new studies arises to adapt to evolving industry practices, including changes in log diameters and quality criteria. The appendix outlines steps that programmers can take to utilize the developed model.
  PubDate: Sat, 13 Apr 2024 00:00:00 GMT
Effects of four soil types on growth responses and nutrient stoichiometry
in seedlings
- Abstract: Phellodendron chinense is an extraordinary medicinal plant, and its stem bark is a famous traditional Chinese medicine in China, containing a number of phytochemicals with biological and pharmacological functions. Studies have shown that the medicinal ingredients in P. chinense from various regions are different, as soil types might be important factors affecting the growth and quality of P. chinense. In this study, the effects of acidic purple soil, alkaline purple soil, yellow soil and red soil on the growth, nutrient element accumulation and partitioning in P. chinense seedlings were studied. Our results showed that the biomass of leaves and stems in acidic purple soil was significantly higher than in other soils, and the root biomass was significantly lower than that in yellow soil. C, N, P and Ca contents cultured in acidic purple soil were the highest compared to other soils, and K and Mg content were the highest in yellow soil and red soil, respectively. The distribution of carbon between different organs can reflect environmental stress. N has become a limiting factor for the growth and development of P. chinense seedlings. C:N and C:P ratios in the leaves were significantly lower than those in the stem and roots. Among four soil types, the highest N:P ratio was 1.65 in P. chinense seedlings. These results suggest that four soil types may significantly affect the accumulation and distribution of biomass and nutrient elements in P. chinense seedlings. The characteristic patterns in different organs have different responses. Acidic purple soil is more suitable for the growth of P. chinense. These findings will help to understand the distribution characteristics and requirements of nutrient elements in P. chinense seedlings, and further provide a theoretical basis and reference for site selection and cultivation strategy.
  PubDate: Sat, 13 Apr 2024 00:00:00 GMT
Hariliku kuuse ( (L.) H. Karst.) kändude juurimise tootlikkus
juurimisagregaadiga Pallari KH-160 neljal Eesti katsealal
- Abstract: The aim of this paper was to provide an overview of the productivity of the stump lifting device Pallari KH-160, the distribution of working time, and to assess the dependence of the time and productivity of lifting operations on stump diameter in four different sample areas. Viru and Orguse sample areas were located in the Hepatica site type, Elva sample area in the Oxalis site type, and Rõuge test area in the Myrtillus site type. Viru sample area had smaller stumps compared to the others and had more stumps affected by decay. The highest productivity in terms of dry mass or volume was observed in stump lifting in Rõuge sample area, where 9.8 t of stumps were lifted per hour based on dry mass. The productivity of Viru and Orguse sample areas was lower, but these sample areas are located in the Hepatica site type, characterized by limestone substrates and leached soils. In contrast, Elva and Rõuge test areas are in the Oxalis and Myrtillus site types, respectively, with soils that are predominantly sandy. As the diameter of the stumps increased, the time required per stump increased, but the lifting speed per unit mass also increased. In other words, the productivity of lifting in stands with larger stumps is higher than in stands with smaller stumps. For example, the average productivity of lifting 10 cm diameter stumps is 0.8 t/h, for 20 cm stumps it is 2.2 t/h, and for 60 cm stumps it is 11.8 t/h.
  PubDate: Sat, 13 Apr 2024 00:00:00 GMT
Development of a footprint description tool utilizing SMEAR Estonia
eddy-covariance data and footprint modelling in combination with remote
sensed forest species and land cover data
- Abstract: Understanding how forest ecosystems respond to environmental factors, particularly in the context of global climate change, is essential for devising effective mitigation strategies. This study focuses on quantifying the interaction between forest ecosystems and atmospheric gases. To achieve our objectives, we are using the eddy covariance (EC) flux method to measure air turbulence and gas concentrations above the forest canopy at the Station for Measuring Ecosystem-Atmosphere Relations (SMEAR) in southern Estonia. We apply a flux footprint (FFP) model to describe the spatial extent and position of the surface area contributing to the turbulent flux measurements. The FFP analysis provides valuable insights into the long-term changes in SMEAR Estonia, the FFP and its relationship with forest management and land use changes. Our findings reveal that the FFP area varies from year to year due to changes in wind speed and direction, affecting the contribution of different land cover elements to the overall FFP. The average changes in the FFP area at a height of 30 meters were approximately 4.9%, while those at a height of 70 meters were only 1.6%. Moreover, human activities, such as thinning and clear-cutting, influence the growing stock and increment of forest stands.
  PubDate: Sat, 13 Apr 2024 00:00:00 GMT
An experimental determination of the critical diffusion coefficient and
critical relative humidity (RH) of drying air when optimizing the drying
of three hardwood species (birch, aspen, and black alder)
- Abstract: There are no systematic approaches available in current specialist literature when it comes to the optimization of the process of drying out hardwood species of wood, such as birch, aspen, or black alder, all of which find industrial uses in Estonia. In order to investigate the drying of these three hardwood species, this paper has made use of an experimental and theoretical drying optimization methodology which was developed previously for pine sapwood within the framework of the EIC Grant No. 16200 project. The same methodology was used to determine the critical diffusion coefficient and corresponding critical relative humidity levels (RH) in relation to the surrounding air, with those levels being important from the point of view of drying optimization, and calculating those levels separately for each species of hardwood. For alder it was found that the critical diffusion coefficient is Dcr = 36.57 * (10−4 mm2 s−1), while for aspen the figure was Dcr = 30.71 * (10−4 mm2 s−1), and for birch it was Dcr = 16.35 * (10−4 mm2 s−1). It was found that the time dependencies for the total deformation of different tree species tend to differ considerably, although the same drying regime was used for all of those tree species which were incorporated into the experiments.
  PubDate: Sat, 13 Apr 2024 00:00:00 GMT
The impact of extra long-term storage of logging residues on fuel quality
in Estonian conditions – a case study
- Abstract: The reduction of greenhouse gas (GHG) emissions demands a significant increase in the use of wood as a renewable energy source. However, environmental restrictions determine limits on the further growth of harvesting volume. Therefore, a viable solution to enhance the share of energy wood in Estonia’s energy balance involves focusing on less exploited assortments of raw material and implementing precise logistics planning. In recent years, mild winters have posed challenges to the extraction of residues and local transport of wood fuels, taking place on soft and unfrozen soils. In such conditions, ensuring a reliable supply of wood fuels becomes rather complicated. When piles of logging residues on unfrozen soils are inaccessible, there is a need to process older piles. The quality of wood chips from such piles is lower compared to the norm. To investigate the impact of extra long-term storage of residues in piles, a study was conducted at the Järvselja Training and Experimental Forest Centre. In 2010, sample piles were created in birch and spruce final felling areas. Over an eight-year period, samples were regularly taken from the piles to analyse the properties of woody biomass during storage. The study results indicate that the quality of fuel from covered piles changes slowly during the first two years of storage. Subsequently, the degradation speed equalizes in both uncovered and covered piles. Despite extensive degradation and loss of dry matter during long-term storage (approximately 29% for Norway spruce and 55% for silver birch after eight years), the quality of dry fuels still meets standard requirements and remains acceptable for boiler houses.
  PubDate: Sat, 13 Apr 2024 00:00:00 GMT
Vegetation response to forest ditch reconstruction: Promoting a potential
habitat for insect-pollinated plant species'
- Abstract: In a managed forest landscape, the high degree of human intervention has caused significant shifts in natural processes, and preservation of remaining natural ecosystem features is crucial to safeguard ecosystem functioning and support ecosystem services. While drainage ditches, subject to regular maintenance, are anthropogenically created and maintained infrastructure elements, they may still support diverse environmental conditions and provide habitats for a variety of plant species, including flowering plants important for pollinators. We assessed vegetation composition changes on recently reconstructed and unmanaged forest ditches and ditch edges in a commercial forest in Central Latvia in two surveys (one and five years after the ditch reconstruction). We used generalized linear mixed-effects models to analyze the impact of environmental variables on species richness and detrended correspondence analysis to analyze plant species composition. We found higher total plant species richness and insect-pollinated plant species richness along recently reconstructed ditches. The differences were mainly explained by better light availability beside reconstructed ditches. Anthropogenically created and managed ecosystems may support biodiversity and directly and indirectly contribute to the provision of different ecosystem services, including pollination.
  PubDate: Sat, 13 Apr 2024 00:00:00 GMT
Air pollution monitoring with hybrid and optical sensors in Curitiba and
Araucária, Brazil
- Abstract: Complex mixtures of substances are in the atmosphere and they can cause diseases in humans and biological communities after acute or chronic exposition. This paper focuses on the physical measurement of particulate matter, a proxy for air pollution, and a biological method for mutation assessment due to plants’ exposure to air pollution. The objective of this research was to characterize the air pollution seasonality in municipalities in southern Brazil, and also to understand the relation between air pollution and the biological response of the Tradescantia sp. clone 4430. The optical sensor SDS011 was used for measurements of particulate matter (PM) and the Trad-SHM bioassay was chosen to quantify the mutagenic alterations that occurred in stamen hairs during the study period, with PM data being measured every 5 seconds and the flowers being harvested approximately every two weeks for laboratory analysis. The Pearson test was applied to verify the correlation between PM and mutations in stamen hair as a result of which it was observed that there is a positive correlation between these data, with the highest value found being r = 0.61. Also, the period with the highest occurrence of pink cells was between autumn and spring, the same period in which an unusual increase in PM concentrations was also observed, a period that corresponds to a less favorable dispersion of pollutants in the atmosphere. The use of Tradescantia sp. clone 4430 showed sensitivity to the environments in which it was exposed. Biomonitoring is an important tool for understanding the effects of pollutants on the ecosystem.
  PubDate: Thu, 09 Nov 2023 00:00:00 GMT
Water and carbon balances in a hemi-boreal forest
- Abstract: The carbon and water fluxes and their inter-relations are key aspects of ecosystem dynamics. In this study, regionalization was used in transferring parameters from the GR4J-Cemaneige model calibrated in Reola hydrographic basin to predict daily flows in Kalli basin; both watersheds are located in the southeast of Estonia. Evapotranspiration data was collected from the MODIS sensor of the Terra satellite and from the Station for Measuring Ecosystem-Atmosphere Relations (SMEAR Estonia). Precipitation data was collected from Tartu–Tõravere and SMEAR Estonia stations and river flow from Reola hydrometric station. The year 2011 was used for model warm-up, model calibration was done in 2012–2017 and the 2018–2020 period was used for validation. The GR4J-Cemaneige model was calibrated at Reola Basin, with a Nash-Sutcliffe Efficiency index of 0.73. The 6 constants of Reola subbasin were transferred to Kalli subbasin for river flow simulation. Net ecosystem exchange (NEE) was measured at the 70 m SMEAR tower with the eddy covariance technique. The balances indicate that the ecosystem at Kalli watershed is slowly becoming a source of carbon and less water is available at the catchment reservoir. NEE has increased from -1.23 μmol m-2 s-1 in 2015 to -0.62 μmol m-2 s-1 in 2020, while the delta water storage decreased from 0.24 mm in 2015 to -0.05 mm in 2020. This behavior may increase soil drying and oxidation, and it will probably release more carbon in the future. This research allows a better understanding of the Järvselja hemi-boreal forest water-carbon dynamics.
  PubDate: Thu, 09 Nov 2023 00:00:00 GMT
The model of stand basal area gross growth on the data of the Estonian
Network of Forest Research Plots
- Abstract: The stand level gross volume increment models are used to estimate the future production of tree stands. Very often, the stand growth and yield in the models used in practice are described by the tree volume increment that includes the diameter growth function with the tree height together with stem taper as the input variables. The currently used function of stand volume increment in Estonia included also stand relative density as an additional input variable. In the current study, we developed a basal area increment function based on the periodic measurement data of the Estonian Network of Forest Research Plots (ENFRP). As in the earlier model of stand volume increment developed by Priit Kohava, in the current model the basal area increment of tree species is developed for a pure stand, and for mixed stands, the proportion of the tree species’ basal area is used. The tests in our data indicated that the periodic increment prognosis had good fit in the case of variable share of tree species in the main storey and coincide with the earlier studies by Finnish and Swedish colleagues. The developed model of basal area increment predictions are expectedly higher than the earlier model predictions for the most tree species and stand relative densities.
  PubDate: Thu, 09 Nov 2023 00:00:00 GMT
Acorn production of pedunculate oak in northeast of Ukraine
- Abstract: We analysed the quantity and quality of Quercus robur L. acorns after years with a very poor yield under the canopy of natural oak stands of various compositions, ages and stock densities in the northeastern part of Ukraine. We determined the mass of 1,000 healthy and damaged acorns of the current year. The levels of variability were estimated for the number and mass of acorns under the canopy of the studied stands. The dependences of the number of acorns on the age of oak stands and their stock density were studied. The total number of acorns under the canopy of natural oak stands was 9,900–19,000 seeds per hectare with a total mass of 26.8–54.1 kg per hectare in 2020 and 8,600–17,200 seeds per hectare with a total mass of 22.7–48.4 kg per hectare in 2021. The proportion of damaged acorns was about 70% both in 2020 and 2021. The largest number of acorns was concentrated under healthy trees (without signs of decline) that had a well-developed crown and, therefore, received more sunlight and heat. The identified quantitative and qualitative estimates and acorn spreading pattern need to be considered when selecting sites for further natural seed regeneration in old-aged oak stands.
  PubDate: Thu, 09 Nov 2023 00:00:00 GMT
Assessment of the soil-protecting services of the forest ecosystem: a case
study in Ilam catchment, Iran
- Abstract: The natural forests of western Iran play a key role in delivering services and goods to local society. Nonetheless, this forest ecosystem, despite its importance, is threatened by natural factors and anthropogenic activities, resulting in decreasing soil quality and soil erosion. The present research aimed to assess the effects of the forest ecosystems on soil erosion control in Ilam catchment in southwest Iran. For this purpose, after estimating the soil loss in natural conditions (NC), we predicted the amount of soil erosion under two scenarios: (i) convert natural forest with 20% canopy cover to destructed forest with 0% canopy cover (SC.1), (ii) increase forest cover by 40% (SC.2). Our results indicate that the estimated mean soil erosion was within the range of 9.36 t ha-1 yr-1 in irrigated and garden use to about 256 t ha-1 yr-1 in bare soils under NC. We found that when converting natural forest to destructed forest, the mean annual soil erosion rate increased 105.75 t ha-1 yr-1, 118.1 t ha-1 yr-1, and 19.57 t ha-1 yr-1 in the dense forest, sparse forest, and Agri-Forest use, respectively. These results show the protective effect of the forest against soil erosion.
  PubDate: Thu, 09 Nov 2023 00:00:00 GMT
Dynamics of chemical and microbial properties of Algerian forest soils:
Influence of natural and anthropogenic factors (Northwest of Tlemcen)
- Abstract: In Djebel Fellaoucene, mattorals and their regressive and progressive dynamics are affected by several factors, namely climate, geography, human activities, overgrazing and fires. This research aims to investigate whether these factors have an impact on the structural dynamics of the area’s forest soils and show a correlation between the soils’ chemical and microbial properties and these factors. In this regard, we have analysed chemical properties: organic matter, pH, conductivity, calcium carbonate (CaCO3), moisture and carbon as well as microbial properties: basal respiration, microbial biomass and metabolic quotient (qCO2), all from 80 soil samples collected from degraded mattorals on different altitudes and exposures. Principal Component Analysis (PCA) which has been made revealed that soil dynamics and correlations between chemical and microbial properties depend on the aforementioned factors; an increase in moisture, organic matter, carbon and conductivity as well as a decrease in the mass and bacterial respiration in the North-exposed sites under anthropogenic pressure and overgrazing by sheep and goats. Whereas opposite results were found in the South-exposed sites degraded by fires and undergrazing by cattle. Anthropogenic pressure and overgrazing in sites which have recently been burned lead to a decrease in microbial properties despite an increase in organic matter and moisture content. Qualifying and quantifying the impact of these degradation factors on forest soils allows us to establish effective restoration, conservation strategies and defend rangelands in arid areas.
  PubDate: Thu, 09 Nov 2023 00:00:00 GMT
Assessing the efficiency of the forestry sector in EU countries
- Abstract: This paper deals with a quantitative assessment of the production efficiency of the forestry sector in EU countries, which is largely neglected in the literature. Only a few studies have been conducted so far, processing data mainly in the first half of the last decade. In contrast to these studies, in this article we focus on the period between 2016 and 2020. Therefore, the main objective of this paper is to compare the efficiency of the forest sector to fill the gap. The empirical results of this study show that the leaders in this sector are Germany, Finland, and the Czech Republic. These countries are fully efficient throughout the period under review. In contrast, Bulgaria lags far behind, with an efficiency score typically around 35%. The results of the cluster analysis show that although countries have similar characteristics, their efficiency scores are not necessarily at the same level.
  PubDate: Thu, 09 Nov 2023 00:00:00 GMT
Methodology for the assessment of damage and economic losses from harm to
forest ecosystems as a result of armed aggression
- Abstract: Significant changes in the environment have caused awareness of the strategic importance of forests as a factor in global environmental security, and socio-economic development of territories. Evidence of this are many international acts, including the provisions of the New EU Forest Strategy for 2030. However, in areas where hostilities are taking place, forests are being destroyed en masse, leading to systemic losses, the restoration of which will require large investments, efforts, and a long period of time. Therefore, it is important to improve the mechanisms for recovering compensation from the aggressor country, whose actions have led to losses from loss or damage to forest ecosystems. In this case, justification of the amount of compensation plays a significant role, and therefore there is a need to develop methodological approaches to their definition. Based on the summary of international practices, guidelines of international organizations, regulations of Ukraine, and scientific publications on the assessment and compensation of environmental damage, the author used a systematic approach that combines the assessment of damage from loss or damage to forest ecosystems and the cost of their restoration. The methodology involves taking into account the degree of damage in determining losses, lost profits, and costs of restoration of forest ecosystems in the context of forest ecosystem services – Provisioning Services, Regulating Services, Supporting Services, or other ecosystem maintenance services; Cultural Services, such as educational, aesthetic, and cultural heritage values, recreation, and tourism. The author proposes relevant methods for each component of the assessment and the relevant indicators. In determining the sets of indicators the author used those that can be calculated based on objective data, or that have an international practice of their calculation. The choice of data sources for the calculation of damage and losses from losses or damage to forest ecosystems and objects within them, caused to Ukraine as a result of hostilities, is stipulated.
  PubDate: Thu, 04 May 2023 00:00:00 GMT
Puude hooajalise radiaalkasvu mõõtmiskuupäevaks moodustunud osa
arvutusmudel Eesti tingimuste jaoks
- Abstract: SummaryKnowledge of the seasonal dynamics of tree growth and its relationship with environmental factors is necessary to eliminate climate change’s current uncertainty and to model growth accurately. Despite the increasing number of studies on the seasonal growth of trees, such knowledge is lacking in a significant part of Europe, including the Estonian hemiboreal forest. To accurately determine the time between two measurement occasions in the Estonian Network of Forest Research Plots data analysis, it is necessary to consider how much intra-annual growth has been formed at the moment of the re-measurement occasion, because measurement dates usually do not coincide. In this article, we present a model that enables predicting tree seasonal cumulative relative growth at any date for environmental conditions in Estonia.Since seasonal tree growth observations in Estonia are still ongoing, the relative radial growth model developed in this study relies on data of neighbouring countries. We used growth data for Scots pine, Norway spruce and silver birch published by Vitas (2011) which describes relative radial growth over the season. We tested four sigmoid functions (Kumaraswamy (equation 1), Weibull (equation 2), Gompertz (equation 3) and logistic (equation 4)) to model the intra-annual growth dynamics. Guided by the nature of the seasonal growth process of trees, we chose the Kumaraswamy function to estimate the cumulative relative radial growth of trees. For silver birch, this function also had the smallest residual standard error on Vitas’ (2011) data, however, for conifers, a statistically better fit was obtained with the Weibull function (Table 2, Figure 1).For the selected function to correctly determine the course of growth, the beginning (onset) and end of growth are necessary to ascertain, but currently these data are still not available for Estonia. Thus, we used the published research data from neighbouring countries, Lithuania and Finland (Table 1). Since Estonia is located north of Lithuania, the growing season in Estonia probably starts later and ends earlier. There are several studies about Finland where the seasonal growth of trees should start later and end earlier than in Estonia (Jyske et al., 2014; Mäkinen et al., 2008; Schmitt et al., 2004). The data of the beginning (A) and end (B) of the seasonal radial growth of trees collected from the scientific literature (Table 1) were approximated with a linear model (equation 5). The linear model (equation 5) results (Table 3, Figure 2) revealed that the beginning and end of the seasonal radial growth of the trees depend on the geographical latitude (LAT) and the measurement method (M). The effect of the tree species (PL) factor was not statistically significant in this model.By predicting the onset A and end B of the seasonal radial growth with equation 5 for Estonian conditions (geographic north latitude 58.5 degrees and dendrometer method), we obtained 132.2 and 238.5, respectively, for Scots pine, 132.2 and 234.1 for Norway spruce and 134.6 and 233.7 days for silver birch from the beginning of the year. Using the above estimates, Figure 3 presents the model predictions of the seasonal relative radial growth with the Kumaraswamy function (equation 1, Table 2) for Estonian conditions.The beginning and end of the growth period varies from year to year (Tarand et al., 2013). Our model is universal, so the user can determine the start and end day of growth according to the weather conditions and geographical location (Western Estonian islands vs South-Eastern Estonia). Further research is needed for this.In order to obtain a more accurate model of intraseasonal growth dynamics and for other tree species in Estonia, it is necessary to carry out long-term, labour-intensive research.
  PubDate: Thu, 04 May 2023 00:00:00 GMT
Diversity and management of homestead resources: The case of Sandwip
Upazila, Chittagong, Bangladesh
- Abstract: Homestead resource utilization is widespread in Asia, while centuries of traditional approaches have been increasing throughout South Asia. Homestead resources are vital to maintaining sustainable life and livelihood of local people in Bangladesh and people in remote areas as coastal zones are mostly engaged with their homestead resources. The study was conducted in Sandwip Upazila (sub-district) of Chittagong district to assess the diversity of plant species, species richness, homestead management practices, and their contribution to the socio-economic condition of the rural households. Ninety household interviews were conducted using a semi-structured questionnaire following stratified sampling to fulfill objectives. A total of 57 tree species under 28 families, including timber, fruits, fuel wood, and multi-purpose tree species were found in the study area. Among the identified 57 tree species under 28 families, 49% are fruit species, while the mean value of Shannon-Wiener Index and evenness of species were 3.32 and 1.89, respectively. Also, the Species Richness Index for Maitbhanga and Sarikait unions was 15.20 and 15.36, respectively, while 52% of the respondents identified market or private nurseries as their source of planting materials. Besides, 71.11% of the respondents replied that protection measures are taken for protecting planting seedlings, while seedlings were used mostly for a better survival rate. Damaged by animals, storms, and pests were identified as most problems faced by households in homestead resource management. This study may help policymakers, including local communities to take proper necessary actions to ensure sustainable management of diversity of homestead resources in local areas of Bangladesh.
  PubDate: Thu, 04 May 2023 00:00:00 GMT

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