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Forestry Studies
Journal Prestige (SJR): 0.209

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This is an Open Access Journal

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

[370 journals]

Comparative testing of two alternating current methods for determining
wood moisture content in kiln conditions
- Abstract: Research into the possibility of applying the electric impedance spectrometry (EIS) method and the dielectric capacitance method (DECM) simultaneously above fibre saturation point (FSP) and in harsh kiln conditions has been relatively scarce. In the framework of this research, tests were carried out on the operational reliability of the measuring capacitor (MEC) prototype used for calibrating the DECM in the harsh internal climate (50°C and 98% RH) of the kiln. Condensation of water vapor on MEC plates, leakage of MEC insulators and the emergence of static electric charges on MEC plates were studied. Quantitative ranges were found for MEC performance-disrupting effects on the parasitic capacities induced by each effect. The DECM was found to be less reliable than the EIS method for application in harsh kiln conditions. Secondly, under the same test conditions and for the same wood species (birch), the possibilities of the DECM method and the EIS method were comparatively modeled with the predetermined Rozema quality criterion of ±1.75% MC for predicting the moisture content (MC) of birch wood above FSP. It was found that, under the same test conditions, the DECM method proved more accurate than the EIS method for predicting birch wood MC above FSP. Based on the tests, it was concluded that DECM can be used in practice by applying a non-destructive method to reliably determine the average moisture content of a wood batch immediately prior to commencing the wood-drying process.
  PubDate: Tue, 11 Jan 2022 00:00:00 GMT
The Forests of Naissaare Island in 1297–1698 in relation to the
development of the City of Tallinn, Estonia
- Abstract: The article explores the development of the North Estonian city of Tallinn and the history of the forests on Naissaar, the greatest of the four offshore islands, in the 13th–17th century. In 1219, the northern part of Estonia was conquered by King of Denmark Waldemar II, who built a new stone citadel on the site of the former Estonian stronghold on the hill of Toompea. Under the sovereign rule of the King of Denmark, North Estonia became the Duchy of Estonia. Subsequently, the citadel developed into the settlement of Toompea, the seat of the governor and state authority, and the surrounding areas into the settlement of Tallinn. In 1248, Tallinn gained Lübeck city rights. King of Denmark Erik VI Menved’s law of 1297 granted the city of Tallinn and Toompea, i.e., the state, joint use of the insular forests. The law came to be interpreted as the beginning of nature conservation in Estonia, as it was the first law regulating forest use and users. Naissaare forest also served as a landmark for sea vessels. As the state did not interfere with the city’s affairs, the latter saw itself as the sole owner of Naissaare Island. Over the next four centuries, Tallinn exploited the Naissaare forests for various purposes. The city managed the forests with relative economy, but not without conflicts, as the provincial government also contended for the use of Naissaare. In 1689, the state asserted its rule over the islands by reduction. The city of Tallinn was forced to terminate the use of Naissaare forests, with the right of forest use reserved to the state.
  PubDate: Tue, 11 Jan 2022 00:00:00 GMT
Study of invasive plants in tropical dry deciduous forests – biological
spectrum, phenology, and diversity
- Abstract: Morni Hills of Panchkula district, Haryana harbor floristically important tropical dry deciduous forests and are quite enriched with the phytodiversity of medicinally important plant species. But these forests are under huge pressure due to anthropogenic activities facilitating the establishment and spread of invasive plant species. So, the present study was conducted in the forests of Morni Hills to understand the ecology of invasive alien plant species growing there. During the study, the area was colonized by many invasive alien plant species, such as Ageratum conyzoides L., A. haustonianum Mill., Chromolaena odorata (L.) R.M. King & H. Rob., Lantana camara L., etc. In terms of longevity, the annual growth form dominated over the perennial. The family Asteraceae was dominant with 11 species, followed by Malvaceae and others. The biological spectrum showed that the dominant life form was therophytes followed by phanerophytes and others, indicating vegetation disturbance while during flowering phenology assessment, maximum plant species were found to be flowering throughout the year. Using the data of flowering (presence or absence), a hierarchical cluster analysis was carried out and a heatmap was prepared. The diversity of invasive plants was calculated along an altitudinal gradient and was found to be changing along with rising altitude in a hump-shaped pattern. The invasive alien plant species cause severe threats to the forest ecosystems. Hence, by policy planning and adopting appropriate management strategies in the forests of Morni Hills, the growth of invasive alien plant species should be controlled to retain the natural ecology of the area.
  PubDate: Tue, 11 Jan 2022 00:00:00 GMT
Diversity of dominated communities on the Kamchatka Peninsula
- Abstract: On the Kamchatka Peninsula, Far East Russia, Pinus pumila-dominated communities occur from sea level up to 1200 m and geographically from the southern extremity of the peninsula up to the Kamchatka Isthmus and the Koryak Upland. Variation in species composition and abundance in P. pumila stands are determined mainly by the habitat’s moisture, soil fertility (expressed as the litter-humus coefficient) and altitude. The fertility level of the habitats has a significant positive impact especially on the abundance of the herb layer species, and to a lesser extent on the cover of the shrub layer. The growth of dwarf-shrubs and lichens is inhibited in habitats with better fertility. In relation to the fertility gradient, the vertical structure of the communities is also changing explicitly; the thickness of snow cover and exposition has a modest effect on the vegetation of P. pumila stands on Kamchatka. The analysed set of 272 relevés were clustered into six community type groups: (i) pure dwarf-pine communities, (ii) shrub-rich communities, (iii) dwarf-shrub-rich communities, (iv) herb-grass-rich communities, (v) moss-rich communities and (vi) lichen-rich communities; further 18 community types were established. They have a fairly good correspondence with most of the syntaxa described by previous scholars, but this is not always the case.
  PubDate: Tue, 11 Jan 2022 00:00:00 GMT
Jalakasurma levikust ja ohtlikkusest Eestis
- Abstract: This review provides an overview of and describes the current situation of Dutch elm disease (DED), which is one of the most devastating diseases for elms worldwide and in Estonia. It is known that in Estonia DED’s agent Ophiostoma ulmi has been damaging elms since the 1930s. Today a new species Ophiostoma novo-ulmi is considered to be an agent of DED. Since 2013 the current epidemic has been recorded in most of the counties of Estonia. The both known DED agents, Ophiostoma novo-ulmi subsp. novo-ulmi and O. novo-ulmi subsp. americana were molecularly detected on Ulmus spp. Additionally, one hybrid pathogen of the subspecies (americana x novo-ulmi) was identified in northern Estonia. Also, the health status of elms and the potential vector agents of the pathogen are discussed and recommendations for disease management are provided.
  PubDate: Tue, 11 Jan 2022 00:00:00 GMT
Changes during twelve years in three mature hemiboreal stands growing in a
radiation model intercomparison test site, Järvselja, Estonia
- Abstract: In 2007, three mature hemi-boreal stands were selected from Järvselja forest district, South-East Estonia to establish one-hectare-large test plots for the international inter-comparison experiment of radiation models (RAMI). All trees with a stem diameter at breast height greater than 4 cm were mapped and measured in the field. In summer 2019, the forests were inventoried again. Here we present a summary of changes that occurred in the forest structure – mainly growth and mortality. In the birch stand basal area G has increased from 23.3 m2 ha-1 to 28.2 m2 ha-1 in the upper layer and the number of trees N has decreased from 654 to 565 ha-1. In the upper layer of spruce stand G has increased from 30.9 m2 ha-1 to 35.4 m2 ha-1 and N has decreased from 774 to 724 ha-1 and N substantially decreased in the lower layers from 912 to 577 ha-1. In the pine stand G has increased from 28.3 m2 ha-1 to 29.1 m2 ha-1 and N decreased from 1116 to 971 ha-1. The three test stands can be used now for validating remote sensing data-based estimates of forest inventory variables at single tree level.
  PubDate: Tue, 11 Jan 2022 00:00:00 GMT
L.: An Overview
- Abstract: The Turkey oak is a frequent tree species in the Mediterranean climate zones of southern Europe and Asia Minor. It has been used in the human diet, for medicinal purposes, firewood and charcoal production. Like all oaks, Turkey oak is suffering from dieback and decline owing to the combination of several detrimental factors, such as insects, diseases and unfavorable environment, leading to their deterioration and sometimes resulting in their early death.
  PubDate: Tue, 11 Jan 2022 00:00:00 GMT
Remote-sensing support for the Estonian National Forest Inventory,
facilitating the construction of maps for forest height, standing-wood
volume, and tree species composition
- Abstract: Since 1999, Estonia has conducted the National Forest Inventory (NFI) on the basis of sample plots. This paper presents a new module, incorporating remote-sensing feature variables from airborne laser scanning (ALS) and from multispectral satellite images, for the construction of maps of forest height, standing-wood volume, and tree species composition for the entire country. The models for sparse ALS point clouds yield coefficients of determination of 89.5–94.8% for stand height and 84.2–91.7% for wood volume. For the tree species prediction, the models yield Cohen's kappa values (taking 95% confidence intervals) of 0.69–0.72 upon comparing model results against a previous map, and values of 0.51–0.54 upon comparing model results against NFI sample plots. This paper additionally examines the influence of foliage phenology on the predictions and discusses options for further enhancement of the system.
  PubDate: Thu, 11 Mar 2021 00:00:00 GMT
Aerolaserskaneerimise kasutamine metsakorralduse alusena
- Abstract: In this summary, we give an overview of the application of airborne laser scanning (ALS) data for predicting the main forest inventory variables in Estonia. When Estonia being one of the few countries with wall-to-wall ALS availability, the need for applicable models for Estonian forests was imminent. Over the past decade, different studies have been carried out to develop models for standing wood volume, forest height, canopy cover, canopy base height, and methods for monitoring height growth and detect small-scale harvests. The main findings showed strong correlations for all the studied parameters and different methods utilizing low-density lidar data for practical forest inventory purposes. Options for using repea ted ALS measurements for continuous forest inventory are discussed.
  PubDate: Thu, 11 Mar 2021 00:00:00 GMT
Options for estimating horizontal visibility in hemiboreal forests using
sparse airborne laser scanning data and forest inventory data
- Abstract: Horizontal visibility v in hemiboreal forest transects was measured in the field and then predicted, both from forest inventory (FI) data and from airborne laser scanning (ALS) data. Stand density N and mean diameter at breast height D were used as arguments in an FI predictive model assuming Poisson distribution of trees on a horizontal plane. It was found that a lack of FI data on forest regrowth and understorey trees caused v to be overestimated. Point cloud metrics of sparse ALS data from summer 2017 and spring 2019 were used as predictive variables for v in regression models. The best models were based on three variables: the 10th percentile of the point cloud height distribution, relative density of returns in a horizontal layer ranging 0.7–2.2 m above the ground, and canopy cover. The models had a coefficient of determination of up to 67% and a residual standard error of less than 25 m. In forests in which fertile soil produces rapid height growth of understorey woody vegetation after recent thinning, visibility was found to be substantially overestimated because the understorey was not detected by the lidar measurements.
  PubDate: Thu, 11 Mar 2021 00:00:00 GMT
Harvendusraietel toimunud metsaõigusnormide rikkumise juhtumite
hindamine
- Abstract: Three cases of violation of forest management regulations in Estonia in 2004, 2005 and 2007 are presented in the study where the required lower limit of basal area after thinnings was not followed. These stands were revisited in 2017 to assess the impacts of such thinnings. The actual thinnings were well justified from the silvicultural and economic viewpoints. All three stands were ecologically in good condition in 2017. Also, all three stands had already reached the required age or dimensions allowing regeneration cutting in 2017. Forest management regulations on thinning did not work well in the studied cases and therefore some changes in the current regulations are necessary in Estonia.
  PubDate: Thu, 11 Mar 2021 00:00:00 GMT
Microsatellite analysis of genetic diversity in Czech populations of
European beech ( L.)
- Abstract: European beech (Fagus sylvatica L.) is one of the most important broadleaved tree species in Europe both ecologically and economically. Nowadays, in the Czech Republic, beech is underrepresented in forest tree species composition, and there are tendencies to increase its proportion. When reintroducing beech, genetic variability, along with other factors, play a key role. The main aim of this study was to evaluate the genetic diversity of ten selected indigenous beech populations across the Czech Republic. Two hundred and fifty individuals were genotyped on 21 polymorphic nuclear microsatellite markers, which were amplified using two newly assembled multiplexes. According to the results, observed heterozygosity (Ho) among populations ranged from 0.595 to 0.654 and expected heterozygosity (He) from 0.650 to 0.678. That is comparable with the findings in other European studies. The high discriminatory power of the assembled multiplexes was confirmed by calculating the Probability of Identity among both unrelated and related individuals. Principal Coordinate Analysis (PCoA) based on Nei's genetic distances revealed that there are genetic differences among populations resulting in three approximate clusters (geographically north, south-east, and south-west). Nevertheless, the results implicate that on a geographical scale of the Czech Republic, the distance is unlikely to be the primary driver of genetic differentiation.
  PubDate: Thu, 11 Mar 2021 00:00:00 GMT
About the history of conflicts over urban forestry in Estonian towns
- Abstract: The article explores conflicts related to forests and parks of Estonian towns from the Middle Ages to the 1940s. A brief overview is first given of the development of urban forestry in Estonia. There are also cases where the loss of urban forests and the related problems that arose could have led to conflicts, but for certain reasons they did not emerge. The main focus of the research is on Tallinn and its nearby island of Naissaare and, to a lesser extent, on the town of Haapsalu. The cases with the probability of conflict are described on the example of Tallinn, Tartu and Pärnu. It is apparent that conflicts or preconditions for their emergence were caused by various reasons, both at the state and town level where local authorities and ownership relations played their role. But the causes of the conflicts can also be traced to the wider clash between military and political causes, economic development and the general public.
  PubDate: Thu, 11 Mar 2021 00:00:00 GMT
An indirect approach to predict deadwood biomass in forests of Ukrainian
Polissya using Landsat images and terrestrial data
- Abstract: Spatially explicit and consistent mapping of forest biomass is one of the key tasks towards full and appropriate accounting of carbon budgets and productivity potentials at different scales. Landsat imagery coupled with terrestrial-based data and processed using modern machine learning techniques is a suitable data source for mapping of forest components such as deadwood. Using relationships between deadwood biomass and growing stock volume, here we indirectly map this ecosystem compartment within the study area in northern Ukraine. Several machine learning techniques were applied: Random Forest (RF) for the land cover and tree species classification task, k-Nearest Neighbours (k-NN) and Gradient Boosting Machines (GBM) for the deadwood imputation purpose. Land cover (81.9%) and tree species classification (78.9%) were performed with a relatively high level of overall accuracy. Outputs of deadwood biomass mapping using k-NN and GBM matched quite well (8.4 ± 2.3 t·ha−1 (17% of the mean) vs. 8.1 ± 1.7 t·ha−1 (16% of the mean), respectively mean ± SD deadwood biomass stock), indicating a strong potential of ensemble boosters to predict forest biomass in a spatially explicit manner. The main challenges met in the study were related to the limitations of available ground-based data, thus showing the need for national statistical inventory implications in Ukraine.
  PubDate: Thu, 11 Mar 2021 00:00:00 GMT
Potential of ecological modelling and smart-drainage development for
mitigating adverse effects of future global change-type droughts for the
Estonian forest sector
- Abstract: Global change-type droughts will become more frequent in the future and threaten forest ecosystems around the globe. A large proportion of the Estonian forest sector is currently subject to artificial drainage, which could probably lead to negative feedbacks when water supply falls short because of high temperatures and low precipitation during future drought periods. In this short article, we propose a novel research perspective that could make use of already gathered data resources, such as remote sensing, climate data, tree-ring research, soil information and hydrological modelling. We conclude that, when applied in concert, such an assembled dataset has the potential to contribute to mitigation of negative climate change consequences for the Estonian forest sector. In particular, smart-drainage systems are currently a rare phenomenon in forestry, although their implementation into existing drainage systems could help maintain the critical soil water content during periods of drought, while properly fulfilling their main task of removing excess water during wet phases. We discuss this new research perspective in light of the current frame conditions of the Estonian forest sector and resolve some current lacks in knowledge and data resources which could help improve the concept in the future.
  PubDate: Thu, 11 Mar 2021 00:00:00 GMT
Forest cover dynamics of the Bazoy Siberian pine ( Du Tour) forest from
1915 to 2015
- Abstract: The article considers the long-term (100 years) dynamics of the forest cover of the southernmost unit of Siberian pine forests on the West Siberian plain. A key feature of forest management is that Siberian pine seeds are a valuable food product and, when cutting forests, this tree species, as a rule, is preserved. The basis of the experimental data was the material of the national forest inventories of 1915, 1974 and 2015 for a total area of 1,420.41 ha. During the period from 1915 to 2015, the forested area changed slightly (96.2 and 94.0%), while the share of Siberian pine stands increased significantly from 48.4 to 58.7%. Grassy Siberian pine forests (32.1%) of optimal age (120–140 years), which are characterised by the best seed productivity and the largest share of Siberian pine in the community (77%), predominate. Basically, human economic activity results in an increase in the area of Siberian pine stands, when deciduous stands with Siberian pine undergrowth are used for fuel and as building material. A decrease in the area of Siberian pine forests occurs mainly under the impact of fires. In the conflagrations of 1915–1920, 7 to 38% of silver birch forests have no Siberian pine undergrowth and are considered long-term secondary communities. In the remaining area, the proportion of Siberian pine undergrowth is 20–30% with a density of 800–1200 seedlings ha−1, which is sufficient for the natural formation of Siberian pine forests.
  PubDate: Thu, 11 Mar 2021 00:00:00 GMT
Common ash ( L.) in Ukrainian forests and its successful natural
regeneration
- Abstract: The natural distribution area of common ash (Fraxinus excelsior L.) in the forests of Europe and Ukraine has been determined through the analysis of scientific works of Ukrainian and foreign researchers. According to the reference materials on the current state of Ukrainian forests (25 administrative regions), it is established that ash forests cover an area of about 150,000 ha or 2.4% of the total area of the country’s forests. Among them, common ash stands account for almost 87% or 130,000 ha; the rest are stands of introduced ash species, namely F. pennsylvanica Marsh., F. americana L., and F. lanceolata Borkh. The average age of ash stands is 59 years. Only 6.4% (8,300 ha) of the total area of ash forests is covered by pure ash stands, and the remaining area (93.6% or 121,700 ha) are mixed ones. It is revealed that the optimal natural and climatic conditions for the emergence, preservation and successful growth of natural regeneration of ash trees are fresh and moist fertile sites (rich in minerals) with well-drained soils, the light of at least 5–6% of that on an open space, and without abundant live ground cover. The highest number of seed regeneration of ash, about 7,000–8,000 stems ha−1 on average, was found under the canopy of mixed (ash share in the composition was 10 to 20% by stock) old (over 100 years old) stands with a relative density of stocking of 0.7–0.8. Promoting the natural seed regeneration of ash trees can be an effective way of increasing the sustainability of such stands and will ensure their preservation in the forests of Ukraine and in deciduous forests of Europe as a whole.
  PubDate: Thu, 11 Mar 2021 00:00:00 GMT
The effect of planting, seeding and soil preparation on the regeneration
success of Scots pine ( L.) on drained peatlands – 10-year results
- Abstract: We studied the effect of regeneration (planting/seeding) and soil preparation methods (no soil preparation/scalping/mounding) on the regeneration success of Scots pine (Pinus sylvestris L.) on three drained peatland Scots pine stands in northern Finland. After ten years, planting and sowing showed no differences in the total number of Scots pine seedlings (one seedling per sowing spot accepted) with the exception of the Sievi experiment. Without soil preparation the total number of Scots pine seedlings was 350–600 per ha. Scalping increased the number of Scots pine seedlings to 550–900 per ha, with the exception of seeding at Sievi. In mounded plots, with the exception of seeded plots at the Sievi site, the number of planted or seeded seedlings was 1,325–2,350 per ha. The number of crop seedlings in all the experiments and for all the soil preparation treatments reached the target of 2,000 seedlings per ha if naturally regenerated Scots pine, Norway spruce (Picea abies (L.) H. Karst.) or birch (Betula spp.) seedlings were accepted as such. Moose (Alces alces L.) damage in Scots pine crop seedlings ranged from 4% in Sievi to 65% in Simo. The proportion of planted or seeded Scots pines of the crop seedlings was 23% in unprepared plots, 30% in scalped plots and 75% in mounded plots. Mounding increased the share of Scots pine seedlings in the overall crop seedlings. Planted seedlings were taller than seeded seedlings. Planting in mounds gave the best overall results in terms of the number of crop seedlings and their height ten years after the treatment.
  PubDate: Fri, 18 Sep 2020 00:00:00 GMT
Mean height or dominant height – what to prefer for modelling the site
index of Estonian forests'
- Abstract: The availability of a large amount of data from reliable sources is important for forest growth modelling. A permanent plot where trees are repeatedly measured provides a clearer picture of stand alterations. Various factors, including forest management, affect forest growth and accuracy of its assessment. In Estonia, mean height as a regression height prediction at mean square diameter is commonly used in forest management practice. Alternatively, dominant height can be used. The main advantage of using dominant height instead of mean height is that the growth of dominant trees is not so strongly affected by stand density (thinning). The aim of our research was to investigate the difference between mean height and dominant height when used as stand height. The research was based on the Estonian Network of Forest Research Plots (ENFRP). As a result, we found that the average mean height change was significantly greater in the case of thinning when compared to undisturbed stand development, whereas, the average dominant height change in the case of thinning compared to undisturbed development was less significant. As a side result, we developed a regression model that can be used for calculating the dominant height of the main tree species using stand attributes (mean height, quadratic mean diameter and density) with a residual standard deviation of 0.466 m.
  PubDate: Fri, 18 Sep 2020 00:00:00 GMT
One hundred years of academic forestry education in Estonian
- PubDate: Fri, 18 Sep 2020 00:00:00 GMT