BALTIC FORESTRY

Published by Baltic Forestry

Online ISSN: 2029-9230

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Print ISSN: 1392-1355

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Figure 4. Roundwood sales by state forest enterprises versus profitability ratio In 2006 timber prices remained at the level of 2005, but harvesting costs increased by 15% in real prices. Other costs rose as well, e.g. average salaries of employees at State forest enterprises increased from 1595 to 1924 LTL/month. Under such conditions, the required profitability (7%) was reached only by increase of roundwood sales by 168 thousand m³ (Figure 4). In 2007, real roundwood prices soared, enabling to easily surpass the required profit margin. And again, a decrease in forest utilisation is observed. Generally the fluctuations of harvesting in State forests are low, the annual harvests not deviating more than 10% from the average, in 1998-2007. The extent and direction of the observed fluctuations enable concluding that utilisation of State forests is not driven
Figure 2. The comparison of different prognoses and the harvested volume  
Figure 3. The average real (inflation-corrected ) prices of round wood and pulpwood in Lithuania 1994 – 2007  
Figure 4. Roundwood sales by state forest enterprises versus profitability ratio  
Policy Drivers Behind Forest Utilisation in Lithuania in 1986-2007
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January 2009

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121 Reads

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After regaining the independence, Lithuania was in the process of making transition to the market economy, yet radical societal shifts only moderately affected Lithuanian forestry. This study evaluates the main drivers that stimulated or decreased forest utilisation. Review of numerous sources reveals that the major drivers towards increased utilisation were the economic transition and changes in the resource base. These have been counterbalanced primarily by deeply-rooted normativism, increasing environmental restrictions, economic model of State forestry and sluggish land reform. The study shows that seeking to understand the dynamics of forest utilisation, it is insufficient to focus solely on the available forest inventory as is typically done in forecasts of timber removals. Instead, a holistic analysis is needed, taking into account, inter alia, institutional norms and developments outside the forest sector.
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Intensive forest researcher training and its internationalisation in the Baltic Sea Region

January 2008

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45 Reads

Based on survey of PhD training coordinators, the paper examines the status of doctoral education at universities dealing with higher forest education in the Baltic Sea region. The primary attention is given to intensive courses and possibilities for joint international training. In total, the survey found around 450 PhD students. In 2005, 39 intensive courses, involving at least 5 students, were organised at the surveyed faculties. 15 courses dealt with topics related specifically to forestry, revealing that an average PhD student has a very limited offer of specialised courses directly connected to the thesis work. Low number of students is seen as a primary hindrance for more intensive course activity at national faculties, while the lack of time and financial incentives for teachers hinder organisation of international PhD courses. Overall, the lack of systematic approach to doctoral forest education is observed. Survey respondents are supportive to joint researcher training activities at the regional level.

First commercial thinnings in peatland pine stands: Effect of timing on fellings and removals

January 2005

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47 Reads

The aim of this study was to examine the fellings and removals and their dimension distributions in first commercial thinnings in Scots pine (Pinus sylvestris L.) stands growing on drained peatlands, when the cuttings are carried out at different stages of thinning maturity. The reference for standard thinning maturity was defined as in the present guidelines for silviculture on upland sites in non-industrial, privately owned pine forests in Finland. Experimental and/or simulated thinnings were applied in altogether fifteen stands representing a wide range in site productivity, climate, and time elapsed since first ditching, and premature (7 cases), mature (11), and over-mature (15) stages for thinning. The average stemwood volumes of fellings were 51, 69, and 92 m3ha-1 and those of harvest removals 36, 59, and 84 m3ha-1 for premature, mature, and over-mature cases, respectively. The removals from stands mature and over-mature for thinning were large enough to enable a commercially profitable harvesting operation in most cases, unlike those from the premature stands where the fellings were barely harvestable and consisted of clearly smaller stems. Considering the obvious trends of increasing supply and simultaneously decreasing price competitiveness of pine pulpwood, our results do not support early thinning unless absolutely necessary from the silvicultural point-of-view. Retarding the thinning until the stage when thinning maturity criteria are actually met, i.e. till stand dominant height of ca. 15 m or even further, would result in markedly better harvesting profitability and hence enhance the implementation of thinnings as a part of the best management practices of peatland stands.

Preliminary results from a plantation of semi-arid hybrid of Paulownia Clone in vitro 112® under conditions of the Czech Republic from the first two years

December 2020

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97 Reads

A private owner established a plantation of a semi-arid hybrid of Paulownia Clone in vitro 112® near the village of Střelice u Brna in 2016. We split the plantation according to terrain micro-relief (into three expositions: South slope, Plain area and North slope) and according to the applied biotechnology of planting (into two parts: each with planting into 20 and 30 cm holes in diameter). We tested different winter protection techniques for above and belowground plant organs. The results suggest that plants inside the 30 cm holes survive and grow better than those inside the 20 cm ones, regardless of terrain micro-relief. On the other hand, plants inside the 20 cm holes survive and grow better on flat areas compared to the others. The most effective protection of the root system against frost during the wintertime seems to be simple soil covering. We have also recognized that bandage of non-woven fabric is the best protection for the above-ground parts of the plants. However, growing conditions in the Czech Republic (CR) are different to those in semi-arid climate for which researchers bred the Paulownia Clone in vitro 112®. It is possible to achieve well-growing and surviving Paulownia plants under growing conditions of the CR when appropriate biotechnology and continuous treatment are applied. Keywords: Paulownia Clone in vitro 112®, plantation, exposition, mortality, growth, protection against frost damage

Figure 1. Black-and-white reproduction of the painting of Hans van Essen ‘Still life with a lobster’, painted with oil on two horizontal oak boards. The size of the painting is 60.8 x 91.8 cm²
Figure 2. Location of the ends of boards in an oak log. The two boards of the van Essen painting most probably come from the location A: extending along radial direction without sapwood and pith. After Klein 1998
Dating of a 17th century painting by tree rings of Baltic oak

January 2006

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841 Reads

Tree rings of an oak (Quercus robur L.) panel with painting of the Dutch Hans van Essen, a ’Still life with a lobster’, established the period of origin of that piece of art deposited in the Estonian Art Museum in Tallinn. The ring width sequence was compared with Baltic oak tree-ring chronologies by T. Wazny and J. Hillam and I. Tyers. These references gave the last annual ring of the painted panel to be from AD 1600. High similarity of the tree–ring series shows that the oak of the panel is of Baltic origin. The outermost rings of the oak tree, including the sapwood, have been cut off. The approximate number of sapwood rings of oaks is known. It points the probable painting time between AD 1617 and 1623. This dating fits into the life years of Hans van Essen (1587 or 1589 to 1642 or 1648).

Figure 1. Phenological network and phenoclimatic regions of Lithuania  
Figure 2. Deviations in dates from the multi-annual average of the beginning of Corylus avellana flowering and Acer platanoides leaf colouring and length of spring-summer period  
Table 2 . Slopes of the linear regressions (days per year) of the beginning of phenological phases and length of spring- summer period during 1961-2010
Table 3 . Correlation coefficients (r) between dates of the beginning of Corylus avellana phenological phases and tem- perature (T) and precipitation (P)
Dates of the beginning of phenological phases of indicator plants and length of spring-summer period in Lithuania
Influence of Climate Change on the European Hazel (Corylus avellana L.) and Norway Maple (Acer platanoides L.) Phenology in Lithuania During the Period 1961-2010

January 2012

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143 Reads

The study was conducted at Voice Branch of the Lithuanian Research Centre for Agriculture and Forestry employing the archival data of phenological observations in Lithuania during 1961-2010. The aim of the research was to estimate the influence of climate change on phenological phases of spring and autumn indicator plants (Corylus avellana L. and Acer platanoides L.) and the length of spring-summer period in Lithuania during 1961-2010. In Lithuania, over the 50 years flowering time of spring season indicator European hazel (Corylus avellana L.), which starts on March 27 on average, exhibited higher variation (SD = 16.1) and earlier onset (-0.43 days per year) compared with the beginning of Norway maple leaf colouring. Larger scale of advance in 1981-1990 (-3.92 days per year) and 1991-2000 (-1.28 days per year) periods are associated with the increased average air temperature related to climate warming. Reliable correlations (p-value <0.01) between the dates of European hazel phenological phases and the average air temperatures of January April were established. Norway maple (Acer platanoides L.) leaf colouring started on September 16 on average and just slightly varied during the entire study period (SD = 4.9). The influence of meteorological conditions on the beginning of Norway maple leaf colouring was very weak (r <0.3 in 72.5 % of cases). Variations of the beginning of spring season affected the length of spring-summer period. It was determined that the length of spring-summer period strongly correlated with the dates of the beginning of flowering of spring season indicator European hazel (R2 0.8492, p-value <0.01).

The patterns of wolf attacks on humans: An example from the 19th century European Russia

January 2017

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277 Reads

Wolf attacks exhibit distinct patterns in attacks on humans with different consequences. We analyzed 483 wolf attacks recorded during 1841-1861 in European part of Russia to reveal temporal patterns of wolf attacks. According to our results, wolf predatory attacks dominated in summer, whereas attacks of rabid wolves took place predominantly in winter. While the number of rabid attacks correlated with human density taking place usually near settlements, the number of predatory attacks did not. Nearly all victims of predatory attacks (99%) were children under 15 years of age, the age of victims was mostly unknown in rabid attacks. Using a generalized linear mixed model (GLMM), we provide the first evidence for 11 year cycle in rabid wolf attacks on humans. Although the rabies has been virtually eliminated in many European countries, it remains as a major threat to livestock and humans in some European countries and in Russia, providing a potential ground for rabies to return sporadically to currently rabies-free areas, and wolves can be considered as a significant vector for the spread of the disease.

Figure 1. A. A map of Gotland showing Natura 2000 areas based on Birds Directive and Habitats Directive. B. Alley of Fraxinus excelsior in Gotland year 2015 showing variable degree of tolerance of individual trees to ash dieback pathogen Hymenoscyphus fraxineus 
Figure 2. A. Allekvie wooded meadow and B. Hörnse wooded meadow in Gotland with planned management measures to sustain trees of ash and elm and associated biodiversity (maps are adapted from the restoration plans of Länsstyrelsen Gotlands Län) 
Natura 2000 habitats dominated by ash and elm, invaded by alien invasive fungi on the Gotland island of Sweden: An overview

January 2017

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403 Reads

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Natura 2000 sites in Gotland are unique and possess very high nature conservation values. Both ash and elm are the typical tree species in several key habitats of Natura 2000 sites and accommodate a high number of associated (red-listed) species. Recent invasion of Dutch elm disease and ash dieback pathogens threatens elm and ash existence, and threatens the integrity of Natura 2000 sites. Management measures undertaken are aimed primarily at sustaining ash and elm, and associated biodiversity, and thus aimed at sustaining high nature conservation values of Natura 2000 sites.

Production Efficiency of Independent Finnish Sawmills in the 2000's

January 2011

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36 Reads

Using stochastic frontier analysis and unbalanced panel data from 2000-2007, this study assesses Finnish independent sawmills' technical efficiency. The estimation results indicate that sawmills function under their efficient production frontier. The average technical efficiency has been 0.81 during the study period implying a moderate possibility to increase production by rationalising and optimising the use of current production technology. The results also show that although the sawmills are heterogeneous in their production efficiency, the average technical efficiency has neither improved nor worsened during the study period.

Sap flow in xylem of mature norway spruce: A case study in northwestern Latvia during the season of 2014-2015

January 2017

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54 Reads

Sap flow velocity (SFV) in sapwood of a mature Norway spruce (Picea abies (L.) Karst.) was monitored in the northwestern part of Latvia by the heat ratio method during 2014-2015. The effect of temperature and soil water potential was assessed by a bootstrapped Pearson correlation analysis. Seasonal and daily variation of SFV was observed. The highest SFV was observed in late April and during summer months whilst the lowest SFV occurred in winter months. During most of the studied period, SFV correlated with temperature. A negative effect of temperature was observed in summer suggesting occurrence of water and/or heat stress. The effect of soil water potential also has been significant in summer supporting the occurrence of water deficit conditions. During the dormant period, SFV was low, but still it reacted to temperature, suggesting that tree has been physiologically active. Nevertheless, sap flow differed between the inner and outer part of sapwood likely due to the differences in area of foliage of different age.

Poplars (Populus spp.): Ecological Role, Applications and Scientific Perspectives in the 21st Century (Review paper)

January 2014

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459 Reads

In the few last decades, the genus Populus has gained a unique position in ecology, commercial applications and science. The special role of riparian habitats in the maintenance of ecological balance between aquatic and land habitats places poplars, cottonwoods and aspens at the center of efforts for their protection and restoration as one of the most important tree participants of riparian forests. Although the urban role of poplars has been reduced, their economic importance has been increasing rapidly as a result of improved methods of cultivation, the introduction of many new hybrids with desirable features, political guidelines for biomass production and their potential for phytoremediation. Successful sequencing of the Populus trichocarpa genome became the driving force for further wide-ranging research on poplars and made P. trichocarpa a model tree for plant biology (especially genetics). However, ecological actions require financial support, profitability of plantations established for bioenergy production or for bioremediation of contaminated sites is highly dependent on the proper selection of suitable cultivars for specific tasks and local environment, and the use of poplar to produce proteins is indefinite future because of the controversy that in society raise genetically modified organisms. This article reviews the current data on poplars from ecological, functional and scientific perspectives, showing that it is necessary to combine all these aspects to usability poplar possible to maximize profits (not just financial), and reduce risk.


Figure 1. Agricultural area (excluding special agricultural production) in Wielkopolska region in 2002 and 2016 in relation to farm size (Eurostat 2019)
Figure 2. Location of sample plots
Location of the analysed woody linear landscape elements
The loss of woody linear landscape elements in agriculture landscape in Wielkopolska region (Poland) in 21th century

January 2021

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136 Reads

With the loss of natural and semi-natural habitats, the diversity and the amount of ecosystem services that can be provided in the agricultural landscape are diminishing, and self-regulatory abilities decrease. The aim of the research (72 sample plots – 1 x 1 km squares, mean time span equal to 8 years) was to recognise the changes in the number and length of woody (tree or shrub) linear landscape elements, and the number of solitary trees in the Wielkopolska region to verify how rapid development of agriculture in Poland in the 21st century affects the landscape structure. The analyses show a decline by 9.3% (from 2.17 to 1.97 km/km2) in length of woody linear elements, 7.4% (from 16.5 to 15.0 per km2) in number of woody linear elements, and 14.6% (from 28.8 to 24.4 per km2) in solitary trees. The loss was significantly faster in the period (2017-2018) of liberalisation of the regulations on tree and shrub removal, mainly due to a high rate of removal in plots located in an urbanized landscape. The decrease in length of woody linear elements occurred in all the categories of their location distinguished in the study (by 9-41% in a category). The highest loss occurred in the woody linear elements located along melioration ditches and water courses, along roads, and in the outskirt of towns. These changes are similar to those occurring in the 20th century in western Europe. The decrease in the number of woody linear landscape elements and solitary trees can be considered an indicator of the unsustainable agriculture management.

Height of the Mass Point and Some Properties of Crown of 26 Year Old Scots Pine and Lodgepole Pine as Potential Parameters for Wind Damage in Zvirgzde, Latvia

May 2014

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33 Reads

Experimental plantation of exotic species and provenances of trees have been established to assess possibilities to increase productivity of stands. However, risks related with various hazards must be evaluated before commercial use of novel (introduced or exotic) tree provenances or species. One of such risks is wind damage, which can be related with crown properties and physical stability of trees. Lodgepole pine (Pinus contorta var. latifolia) from three provenances and local Scots pine (Pinus sylvestris) at the age of 26 years from experimental trial in central part of Latvia in Zvirgzde were sampled. Mass of branches in four quarters of crown, mass of stem and parameters of branches were measured. Height of the mass point of aboveground part of trees and distribution of crown biomass was determined and compared between provenances of lodgepole pine (LP) and Scots pine (SP). Similarity of distribution of crown biomass was determined by cluster analysis and the relationship between crown biomass and properties of stems and crowns were determined. Height of mass point correlated with height of the tree, which was significantly higher for Summit Lake provenance of LP. However, the relative height of mass point was similar for LP and SP, ranging from 31.8 to 43.6% of tree height. The properties of crowns and trees differed between species; aboveground biomass was higher, branches were longer and thicker for SP. LP had higher ratios of branch mass-tree height, and branch mass-branch length. Only several parameters such as ratio of branch-stem mass, height of lowest living branch and diameter of the thickest branch in first two meters differed between provenances of LP. Four groups of trees established according to cluster analysis of crown biomass distribution consisted of trees from different provenances and species of trees and had different patterns of crown biomass distribution. Biomass of upper half of crown, length of crown, and branch length differed between groups of trees distinguished according to the distribution of crown mass.

Productivity and Time Studies of MB Trac 900 Tractor at Beech Stands on Mountainous Areas in Turkey

January 2010

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50 Reads

The purpose of this study is to investigate the productivity of the MB Trac 900 tractor during extraction of beech timber from stand of oriental beech in the North of Turkey. By using the methods of time study, the productivity of MB Trac 900 tractor was determined considering two different average skidding distances (i.e. short : 55 m and long: 105 m). The research results implied that some working characteristics of the MB Trac 900 tractor such as skidding distance, load volume, time consumption of handling operations and fuel consumption had an important impact on productivity of the tractor. Hourly productivity was computed as 14.580 m(3)/hour for the average skidding distance of 55 m while it was 8.850 m(3)/hour for the average skidding distance of 105 m. The cost of skidding was 3.5 $/m(3) and 9.6 $/m(3) for the specified average skidding distances, respectively. The average load volume for each cycle was found to be 1,490 m(3) and 2,130 m(3), respectively.

The growth of lodgepole pine (Pinus contorta var. Iatifolia Engelm.) in a reclaimed oil shale mining area, abandoned agricultural land and forestland

January 2009

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52 Reads

The main objective of the study was to analyse lodgepole pine (Pinus contorta var. latifolia Engelm.) growth in relation to soil nutrients in a reclaimed oil shale mining area (ROSMA), abandoned agricultural land (AAL) and forestland (FL). The growth-soil interactions and soil-needle chemical relationships were analysed and compared in lodgepole pine plantations at various sites. The impact of soil conditions on tree growth was significant; the height and diameter of trees were different between the studied sites. Despite the higher P and K concentrations in the soil in ROSMA, the concentrations of these elements in needles were lower compared to the AAL and FL. This may be caused by the high value of soil pH and K / Ca antagonism. Although the concentrations of the elements in the needles were lower in ROSMA, the needles were longer and heavier. This was possibly due to the higher N and P use efficiency in the lodgepole pine plantation in the ROSMA. The growth of lodgepole pine was better in more fertile environments, in our study the AAL or on the clay substrates of ROSMA compared to the FL.



Figure 1. Site location and aspect. a) Map of Germany including the natural distribution range of Picea abies in grey; b) Map of the study region including coniferous forests in grey. The black dot indicates the sampling site; c) Monitored Picea abies trees, and d) radius dendrometer. Data source: Free GIS data DIVA, EUFORGEN, EEA 
Figure 2. Precipitation anomalies recorded at the Geisenheim climate station from 1999 to 2014 with respect to the 1961-1990 mean. Black bars refer to the whole year and grey bars to the vegetation period from April to October. The dashed box highlights the period covered by the dendrometer analysis 
Figure 3: Hourly stem radius changes: (a) from April 2012 until December 2014 for each tree PA1 to PA4; (b) from August 27, 2013 to August 30, 2013 for PA1 over a period without rainfall, and (c) from July 08, 2014 to July 10, 2014 for PA1 over a rainy period. Stars refer to calendar week (CW) of abrupt stem radius changes 
Figure 4. Monthly mean circadian cycle for each tree. Data include averaged hourly values from April 20, 2012 to December 31, 2014. ,R represents the deviation from the mean stem radius 
Hourly resolved climate response of picea abies beyond its natural distribution range

January 2017

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229 Reads

Norway spruce (Picea abies (L.) Karst.) is an economically significant species of timber industry in Germany. However, previous studies reported a drought sensitivity of spruce questioning the suitability of this species when exposed to future climate change. We analyse the species’ climate sensitivity by comparing high-resolution stem radius changes of four spruce trees with prevailing weather conditions from April 2012 to December 2014. The study is based on dendrometer data recorded in the Taunus (Germany) in a forest plantation beyond the species natural distribution range. The sub-hourly dendrometer data are decomposed to emphasize diurnal growth patterns and compared with related weather patterns. Our results show that both climate and photoperiod control the timing of spruce growth. Daily radial changes are best explained by relative humidity and temperature variations, but a distinct precipitation signal is not detected. The missing precipitation response is likely related to well-developed Stagnosols at the sampling site in the Taunus preventing transpiration stress to occur. These findings suggest that a balanced water supply attenuates the trees’ climate sensitivity even beyond the species natural distribution range and highlights the significance of site selection in plant performance assessments.

Figure 1. Simulated probabilities of obtaining a given number of trees per hectare in planting (above), direct seeding and natural regeneration (below) for Norway spruce on a disctrenched site of medium fertility (MT). Dashed and solid lines represent, respectively, the probability of good and moderate regeneration result  
Figure 2. Distribution of regeneration result of the simulated stands. The establishment of seedlings was stochastically simulated for spruce planting (above), direct seeding and natural regeneration (below) on a disc-trenched site of medium fertility (MT)
Figure 3. Distribution of the number of seedlings on the plots of the simulated stands. The establishment of seedlings was stochastically simulated for spruce planting (above), direct seeding and natural regeneration (below) on a disc-trenched site of medium fertility (MT)  
Predicting establishment of tree seedlings in regeneration areas of Picea abies in southern Finland

January 2013

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140 Reads

This study predicts the establishment of regeneration of Norway spruce (Picea abies (L.) Karst.) in 3-, 4- and 5-year-old regeneration areas planted, direct-seeded and naturally regenerated, respectively, in southern Finland. Establishment of regeneration was described by the number of planted, direct-seeded and natural tree seedlings, as well as by the heights of spruces and broadleaves. For each regeneration method, establishment of regeneration was modelled by fitting a multilevel multivariate model to regeneration survey data. Site and soil quality and the method of site preparation were used as explanatory variables. Stochastic simulations that accounted for the random between-stand and within-stand variation in the regeneration result were conducted to compare the uncertainty and the need for removal of broadleaves (i.e. early cleaning) involved in different methods of regeneration for spruce. Using disc trenching as soil preparation method, the probability of good regeneration result for planting, direct seeding and natural regeneration was 58%, 34% and 38%, respectively. Using mounding, the probability of good regeneration result for planting increased to 73%. The risk of failed or poor regeneration in planting, direct seeding and natural regeneration was 3%, 37% and 32%, respectively. When considering only those simulated stands in which at least half of the plots required cleaning, 40% of planted stands, 99% of direct-seeded stands and 89% of naturally regenerated stands were deemed to require treatment. Planting was the most effective and guaranteed method of regeneration. Direct seeding and natural regeneration of spruce entail a high risk of failure.

Figure 3. Relevance between total annual ring width of the last five years and the stem diameter: A – healthy stand; B – increased risk stand; C – non-promising stand
Determining the growth potential for even-aged stands of Norway spruce (Picea abies (L.) karst.)

January 2007

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100 Reads

Under the forest growing conditions of Latvia the 30-40 year-old pure stands of spruce undergo abrupt changes. While in some stands an intensive volume growth in high quality stems continues, other stands decline, losing productivity and even breaking down. By using a method developed for this purpose, growth potential for even-aged pure stands of spruce in 355 forest compartments in eight regional forestries of Stock Company "Latvijas valsts me square i" was analysed. Out of the compartments analysed healthy and promising stands were 26%, hopeless unpromising stands 11%, and increased risk stands 63%. The loss of growth potential for spruce could only partially be explained by the impact of site type or regional differences. The results of the given study suggest that this process is related to the ecological demands of Norway spruce as a shade tolerant tree species.

Cone Bagging Hinders Cone and Rust Development of Picea Abies

January 2009

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17 Reads

Fruiting and sporulation of Norway spruce cone rusts were investigated in northern Finland. Pistillate flowers and developing cones were bagged at three intervals during the growing season to hinder cone infection by cone rusts, Thekopsora areolata and Chrysomyxa pirolata. The bagging of cones hindered the maturation and sporulation of T. areolata aecia in pistillate cones covered in May, although it also significantly retarded the development of these cones. The bagging fully restricted the formation of C. pirolata fruitbodies in cones. The amount of infected cones, however, was very small in general, regardless of the coverage of cones or lack of it during the growing period. In October 40% of the unbagged cones bore T. areolata aecia and 7% C. pirolata aecia. All of the unbagged cones developed normally and the rusts in the infected ones sporulated. Insects were more significant and common than rusts in 2007. The results indicated that rust colonization and fruiting are greatly dependent on the undisturbed development of spruce cones. The total lacking of T. areolata spermogonia in the infected cones implies that rust infection process can occur even without basidiospores. The small amount of cone scales bearing fruitbodies of both of the rust species suggests that they hinder the spread of infection of one another in the same cones.

Surface retention of polyurethane and acrylic coatings on impregnated spruce wood (Picea abies Karst) and comparison with some wood preservatives

February 2022

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73 Reads

The natural spruce wood has low resistance against biological degradation and weather effects, so further protection is required, up to meeting the durability requirements for wood used in exterior classes. According to the wood preservatives standards, coatings as water repellents belong to the group OS (organic solvent) preservatives. The coatings have a water-repellent function, and they are not toxic, so these advantages make them usable like impregnation material. The objective of this work is impregnation of the spruce wood (Picea abies Karst) using the “Double vacuum process” with coating material based on polyurethane and acrylic isocyanate resins and determinate the coatings quantity in wood. The impregnation efficiency is expressed through the retention. The coatings retention is compared with the minimal standard prescribed retention of the preservatives, most frequently used, namely creosote, copper chrome arsenate (CCA) and waterborne copper-rich systems like copper azole (CBA-A, Thanalite E), to show the efficiency of the applied double vacuum process. The coating retention is not significantly different from the minimum prescribed retention of creosote and amounts 118 - 149 kg/m3 or 32 to 38 times higher than the recommended retention of CCA or CBA-A for wood protection in the exterior use. The polyurethane and acrylic wood coatings can be successfully applied for wood impregnation purposes. Key words: impregnation, retention, spruce wood, polyurethane coatings, acrylic isocyanate coatings.

Needle Structure in Relation to boron Fertilization in Picea abies (L.) Karst. Stands Suffering from Growth Disturbance

January 2008

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10 Reads

Bushy growth, a typical symptom of boron (B) deficiency, has caused enormous economical losses in Norway spruce (Picea abies (L.) Karst.) stands on extensive areas in eastern central Finland, and thus has created a need to determine ways of protecting forest health and productivity. To find out if microscopy could have potential for a diagnostic tool of B deficiency before visible damage, B concentrations, number of sclerenchyma cells earlier connected to B availability, and the area of central cylinder earlier connected to water availability, were studied in the current needles from about 30-year-old mature healthy (H) and damaged (D) spruce trees in autumn of B fertilization and two years later in eastern central Finland. The treatments, given on 15-17 May 2000, were: no fertilization (0), B supply (B; 2.0 kg B ha -1 as borax), B+P supply (B+P; 2.0 kg B ha -1 and 40 kg P ha -1 as superphosphate) and N supply (N; 200 kg N ha -1 as urea). The needle B concentrations significantly increased in the trees given B, and were higher in the needles from healthy (H) trees compared to those from damaged (D) trees. This difference reduced by the third autumn indicating recovery of the roots of the trees, which showed recovery of shoots in earlier study. The area of the central cylinder reflected water availability during needle development. The number of sclerenchyma cells was low in needles from 0 (no fertilization) and N trees and increased in trees fertilized by B and B+P. Low number of sclerenchyma cells has potential for diagnosing the B deficiency, but more background knowledge about the effects of other stress factors is still needed.

Reintroduction of the European silver fir (Abies alba Mill.) in Białowieża Forest

December 2020

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49 Reads

In 1996 and 1998, Professor A. Korczyk created a half-sib plantation of the European silver fir (Abies alba Mill.) in the Polish part of Białowieża Forest (Hajnówka Forest District, sub-district Wilczy Jar, subcompartments 416Ag and 416Сf). The planting was carried out in furrows at a spacing of 1.3 x 1m in three plots of 0.22 ha each in an area of fresh forest. To grow the seedlings, seeds from the “Tisovik” tract (in the Belarusian part of Białowieża Forest) were used. According to some researchers, the Abies alba in this tract has a natural origin and is a relic of Białowieża Forest. Given this circumstance, and also in connection with the mass drying-out of the Norway spruce (Picea abies (L.) Karst.), there is a practical interest in studying the growth of fir crops in this territory. The results of our studies (2018) indicated the very intensive growth of this species in 22-year-old cultures (subcompartment 416Ag, plot 1, 10 half-sib families). The trees showed no signs of disease or insect damage, the crowns were conical in shape and the shoots were densely covered with needles. The good state of the forest planting can be considered as evidence of soil hydrological conditions suitable for growth and meeting the A. alba’s ecological and biological needs, as well as confirmation of its autochthonous nature.

Insects Infesting Norway Spruce (Picea abies Karst.) Branches in Clear-cuts and Adjacent Stands

January 2010

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24 Reads

For the determination of forest entomofauna migration, the assessment of its distribution is very important. The investigation was carried out in 2004-2006 in in the clear-cuts of Norway spruce (Picea abies Karst.) in Dubrava Experimental and Training Forest Enterprise. The aim of the present work was to estimate the distribution of xylobiont insects breeding under the bark of spruce branches in the clear-cuts and adjacent spruce stands. The assessment of underbark xylobiont insects was made using a method of sample branches and eclector traps. During the research, 1272 spruce branches were examined. A total of 32 insect species in spruce branches were found. The number of phytophagous and entomophagous species was 19 and 11, respectively. The Coleoptera order dominated comprising 93.7% of all xylobiont insects in spruce branches. Pityogenes chalcographus was the most abundant species (75.6% of beetles in total) among the coleopterans. The mean number of phytophages and entomophages was significantly (p <= 0.05) 3 times less in the clear-cuts, than in the adjacent stands. Shannon's index showed poor species diversity, and was 0.3 (in the clear-cuts) and 1.34 (in adjacent stands). The difference was statistically significant (t >= 1.96, p <= 0.05). Sorenson's similarity measure of xylobiont insects species was 0.51 in the clear-cuts and adjacent stands.

Reintroduction of the European silver fir (Abies alba Mill.) in Białowieża Forest

December 2020

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6 Reads

In 1996 and 1998, Professor A. Korczyk created a half-sib plantation of the European silver fir (Abies alba Mill.) in the Polish part of the Białowieża Forest (Hajnówka Forest District, sub-district Wilczy Jar, subcompartments 416Ag and 416Сf). The planting was carried out in furrows at a spacing of 1.3 × 1 m in three plots of 0.22 ha each in an area of fresh broadleaved forest. To grow the seedlings, seeds from the “Tisovik” tract (in the Belarusian part of the Białowieża Forest) were used. According to some researchers, the Abies alba in this tract has a natural origin and is a relic of the Białowieża Forest. Given this circumstance, and in connection with the mass drying-out of the Norway spruce, Picea abies (L.) Karst., there is a practical interest in studying the growth of fir establishment in this territory. The results of our studies (2018) indicated the very intensive growth of this species in 22-year-old cultures (sub-compartment 416Ag, plot 1, 10 half-sib families). The trees showed no signs of disease or insect damage, their crowns were conical in shape and the shoots were densely covered with needles. The good state of the forest planting can be considered as evidence of soil and hydrological conditions suitable for growth and meeting the ecological and biological requirements of A. alba, as well as confirmation of its autochthonous nature. Key words: Abies alba, reintroduction, half-sib plantation, Białowieża Forest

Above-ground biomass models of 40-year-old Norway Spruce in Latvia

January 2017

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26 Reads

The importance of wood biomass as a source of bioenergy at wider scales, i.e. for a centralized production of heat and electricity, is increasing. Hence, precise estimates of biomass are necessary for the calculation of available resources and carbon budget. Mathematical models based on easily measurable variables can notably facilitate the estimation of biomass of trees. However, such models are usually locally (regionally) applicable. The biomass of the aboveground parts (stems and branches and total) and the dimensions were measured for 29 Norway spruce (Picea abies (L.) Karst.) trees at the age of 40 years, representing the eastern part of Latvia. Different linear models were fitted to the biomass data; tree height (H), stem diameter at 1.3 m height (D) and their combinations were used as the independent variables. The estimates of stem biomass and their mean relative errors were compared between the best of the developed models, traditionally used derivatives of wood volume tables and models developed for Finland by J. Repola (2009). A linear model with D and H as two independent variables showed the best fit to the biomass of stem; the power model with D²H as the independent variable performed best for the total aboveground biomass; the branch biomass was best predicted by the power model based on D. The mean relative errors of the stem and total aboveground biomass was ca 8%, while the model of branch biomass had higher relative error, ca 20%. The estimates of stem biomass by the traditionally used volume tables and the developed models did not differ significantly, but the relative errors were lower for the developed model. However, the relative errors of the stem biomass estimated by the volume tables were correlated with D, suggesting systematic bias. The developed models performed better than those established in Finland, which underestimated stem and branch biomass, but overestimated the total aboveground biomass and had significantly higher relative errors of the estimates.

Studies of ectomycorrhizal fungi above- and belowground in the 50-year-old Pinus sylvestris L. forest

January 2008

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13 Reads

The assemblage structure of ectomycorrhizal fungi above- and belowground in the 50-year-old pine (Pinus sylvestris L.) forest was determined in this study. The community was composed of 53 species, the majority of which belonged to the genera Cortinarius, Russula, Amanita and Tricholoma. Cantharellus cibarius and Paxillus involutus were the dominant species making up the largest part of the sporocarp biomass and determining harvest in the studied forest type. Twenty ectomycorrhizal morphotypes were determined belowground. Morphanatomical analysis and PCR-RFLP were used to determine morphotypes. The maximum species richness above ground was characteristic of September while variation in the diversity of ectomycorrhizal morphotypes per vegetation season was very marginal and not significant.

Figure 1. Dependence between aboveground biomass (kg) and stem diameter at 55 cm height above ground (mm) of the model trees of all plantations
Table 5 .
Above-ground biomass of willow energy plantations in Lithuania: Pilot study

January 2017

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171 Reads

Growing of willow (Salix sp.) plantations for energy production is an opportunity to get additional biomass-for-energy without increasing forest felling. This study objective was to create a non-destructive method for the estimation of aboveground yield of willows, which could be suitable for practical use in commercial short rotation willow plantations in Lithuania. Willow plantations of different 1–6-year old were chosen for the study. For the detailed measurements, the model stems and representative plant samples were taken. A strong dependency between the dry aboveground biomass of willow stems and stem diameter (R² = 0.95) was determined and the model M = 0.0003 × D2.4311(where M is the dry biomass; D is the diameter at 55 cm above the ground; a and b are constants of regression parameters) was worked out for the estimation of dry above-ground biomass of willow plantations. The study results showed that the annual dry aboveground biomass of willows varied in a wide range, from 2 to 10 t ha⁻¹per year. The annual increment higher than 6 t ha⁻¹was found for the older than 4 years plantations grown in more fertile soil (sandy loam), which was additionally fertilized and weeded; also, these plantations had lower initial plant density. The obtained tendencies suggest that it would be reasonable to prolong the rotation period of willow plantations in order to increase annual yield. The study results also supported the idea that more fertile sites should be preferred for cultivation of the commercial willow plantations.


Above-ground Biomass in Young Grey Alder (Alnus incana [L.] Moench.) Stands

January 2011

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15 Reads

Presented is a method for estimating the amount of leafless naturally moist above-ground biomass in one-to-five-year-old untended naturally grey alder regenerating stands with the respective values calculated by using easy-to-measure stand parameters like the average height and the number of stems (root suckers, stool shoots, coppice, or saplings) per unit area. An equation is proposed for estimating the amount of biomass in one-to-five-year-old grey alder growth: biomass (M) is calculated as a function of the average stem height (H(v)) and the number of stems (N) per ha: M = 0.0536.H(v)(2.2516).N,(R(2)=0.905; P<0.05). The biomass of untended young grey alder stands is calculated from the average stem height of H(v) = 0.8-4.8 m in one-year-old and five-year-old stands, respectively, with the number of stems per 1 ha ranging from 10,000 to 100,000. The calculations show that, with the average stem height in one-to-five-year-old grey alder stands increasing only by 0.1m, the amount of above-ground biomass increases by an average of 30%, provided the number of stems per ha is the same; in case the number of stems is by 10,000 larger, the biomass increase is by 40%. The research shows that the amount of naturally moist biomass in one-to-five-year-old untended grey alder stands is uneven with the variations depending on stand age and stem dimensions. The amount of biomass in untended grey alder stands depending on the stand density varies in a fairly wide range: from 0.9 t.ha(-1) to 7.7 t.ha(-1) ha in one-year-old stands; from 2.2 t ha(-1) to 23.6 t.ha(-1) in two-year-old stands; from 5.2 t.ha(-1) to 28.9 t.ha(-1) in three-year-old stands; from 7.3 t.ha(-1) to 57.4 t.ha(-1) four-year-old stands; from 15.2 t.ha(-1) to 64.4 t.ha(-1) per ha in five-year-old stands.

Table 2 . Testing of moisture meters on birch specimens 
Table 4 . Modelling of moisture meters on black alder spec- imens. Independent variable in regression model is moisture meter reading in MC % 
Modelling of moisture meters on birch specimens. Independent variable in regression model is moisture meter reading in MC % 
Modelling of Resistance-Type Wood Moisture Meters for Three Deciduous Tree Species (Black Alder, Birch, Aspen) in Moisture Contents Above Fibre Saturation Point

May 2014

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742 Reads

For fast detection of wood moisture content (MC), handheld resistance-type and capacitance-type electrical moisture meters are widely used. In moisture contents above the fibre saturation point (FSP), the measuring accuracy and precision of resistance-type moisture meters starts to progressively decrease as the wood MC increases. The aim of this research was to quantitatively explore this well-known qualitative trend. Three different resistance-type wood moisture meters from leading manufacturers were compared. The display readings of the moisture meters were compared by using the absolute MCs determined for relevant specimens with the oven-dry method. The specimens with the dimensions of 100x60x60 mm (length x width x thickness) were made of three different tree species (black alder, birch, aspen); a total of 60 specimens per each tree species were used. The specimens were dried in a climatic chamber under equal conditions (32°C and 98% RH) until the desired MC was achieved. All wood MC measurements were conducted at a room temperature of 20°C. Modelling of experiment data confirmed the progressive increase in the absolute error in a single measurement of wood MC with resistance-type moisture meters as the average absolute MC rose. Based on the model, the absolute error on the same confidence level (95%) and for the average MC of 27% was ± 3.9% MC, for the average MC of 60% it was ± 10% MC, and for the average MC of 97% the absolute error was ± 17.5% MC. The best prediction error in wood average MC predicted on the basis of the same model was ± 1.12% MC. The same model was used to predict the resolution of resistance-type moisture meters for the above-mentioned average MCs, which was found to be approximately 1% MC.

Modelling of frame saw blade abrasion in the kerf in sawing softwood logs

January 2008

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42 Reads

The effect of friction and abrasion of frame saw blades side planes in a kerf when sawing pine and spruce sawlogs in the top end diameter classes' interval 18-40 cm was modelled accordingly to resultant saw blade thickness and surface hardness. Gradually diminishing saw blade thickness eliminates initial surface hardness of cold rolled strip steel. Hardness and thickness of new and used frame saw blades interrelationships on the abrasion zone of frame saw blades were discussed. Phenomena's of thickness diminution were established showing good correlation between thickness and surface hardness. The effect of asymptotic stabilization of hardness after certain depth of wear on saw blade side planes has been stated. Further recovery of surface hardness alongside the blade length seemed to be related to the typical saw,log diameter classes' distribution (18-40 cm) at the Lithuanian frame sawmills.

Genetic Polymorphism of Wild Pear Accessions Collected in Lithuania

January 2013

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146 Reads

Wild pear (Pyrus pyraster (L.) Burgsd.) is pear species growing naturally in Lithuania and is related to cultivated pear (Pyrus communis L.). In some cases, plants identified as P. pyraster represent various stages of hybridization between original P. pyraster and P. communis. Therefore a boundary between cultivated pear, naturalized plants and wild pear is ambiguous. There is limited information on genetic variation and structure of P. pyraster population. The aim of our study was to characterize morphological traits and microsatellite loci of pear originally collected from different localities of Lithuania as naturally growing specimens, presently grown in germplasm collection at the Institute of Horticulture Lithuanian, Research Centre for Agriculture and Forestry (IH LRCAF), and establish capacity of the markers to assess genetic structure of the pear population and suitability for species specific identification. Assessment of thirteen morphological parameters revealed high variation among Pyrus accessions. Morphological differences among the accessions were quantitative rather than qualitative. Characterization of 9 polymorphic microsatellite loci of 84 pear accessions identified 152 polymorphic alleles. The allele number per locus ranged from 12 to 20. The most polymorphic microsatellite loci were EMPc106, EMPc117, NB109a and CH02c 11. High genetic polymorphism was demonstrated by genetic relationship and heterozygosity analysis among accessions. Lower Ho than He values indicated possible occurrence of self fertilisation in naturally growing pears. It was shown that morphological variability of Pyrus accessions weakly reflects genetic variation among them. The results of the molecular marker analysis of the accessions of free growing pear collection provided information about genetic background of local pear population that would be useful for restoration and maintaining of genetic diversity of forests.

Figure 1. Average element breakdown
Table 2 . Main data about processor performance
Figure 2. Standard deviation vs. study duration (in number of iterations)  
Determining observer and method effects on the accuracy of elemental time studies in forest operations

January 2013

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189 Reads

The authors conducted a comparative study of continuous timing and work sampling, as applied by different observers. Twelve researchers were split into two groups and carried out the same study, switching method every half an hour. The study lasted 3 hours, corresponding to 6 iterations (3 iterations per method). Statistical analysis of data confirmed that both methods may determine elemental breakdown with the same accuracy. Observer-induced variability had a minor effect, and only on those time elements that were short and occurred less frequently. Error increased as the study progressed, as the likely result of observer fatigue. Again, this trend was significant for short elements and not significant for longer ones. This study may offer a warning against over-detailing elemental breakdown. Work cycles should be split in as many elements as strictly necessary for achieving the specific purpose of the study. Splitting them in too many elements just for the sake of description is counterproductive, because it places an excessive strain on the observer and it may increase the risk of errors. A simple study design will facilitate replication by a number of different researchers, regardless of method.

Quarantine pathogen lecanosticta acicola, observed at its jump from an exotic host to the native Scots pine in Estonia

January 2018

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614 Reads

In October 2016, the causal agent of Brown Spot Needle Blight (BSNB) Lecanosticta acicola (Thüm.) Syd. was discovered for the first time on young native Scots pines in a small mixed mountain pine/Scots pine stand in central-eastern Estonia. The pathogen was isolated from both pine species and identified by molecular methods. Both ITS sequences were deposited in GenBank. It is the first record of the fungus on Scots pine in northern Europe confirmed by the molecular methods. An intensive monitoring of this EPPO quarantine pest has started at this apparently initial point of infection of BSNB in Estonia and in other mixed exotic/native pine stands. When searching for Scots and other pine species in northern Estonia infected by L. acicola, Pinus × rhaetica Brügger was added to the world host list of L. acicola.


Table 4 . Only EC and pH of paved forest road showed a significant relationship
Figure 1. Monthly precipitation, number of rainy days (Kartaloglu, 2011), EC and pH of precipitation  
Acidity (pH) and Electrical Conductivity Changes in Runoff Water from Ditches of Paved and Unpaved Forest Roads

January 2015

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839 Reads

Temporal acidity (pH) and electrical conductivity (EC) changes in runoff water determined through sediment traps established on unpaved (UPFR) and paved forest road (PFR) ditches and in an undisturbed (UA) forest land. Research was carried out one year with monthly samplings from November 2009 to October 2010. In runoff water, pH was changed between 5.15 pH and 7.32 pH, and EC was between 58.35 ģS/cm and 198.09 ģS/cm. Both EC and pH of runoff water showed significant variations among experiment sites and months. Runoff EC and pH sourced from PFR showed a significant relationship in regressions with same parameters of precipitation indicating that EC and pH of runoff sourced from paved forest road were related directly to precipitation chemistry. However, to indicate a definite trend or difference is difficult despite significant differences among road types and sampling times.


Topsoil acidity of forested mineral lands in Estonia

February 2019

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59 Reads

The active acidity (pH) of forested mineral lands’ topsoil, its relationships with alternative soil acidity characteristics and the influence of soil acidity on forest soils’ profile fabric and functioning are analysed in the pedo-ecological conditions of northeastern Europe. The active acidity of the forest floor (O-horizon) was taken as the baseline for this analysis. The acidity of the forest floor was studied in accordance with the underlying soil horizons, which are humus and/or raw-humus horizons in the more fertile soils, whereas in less fertile soils, they are podzolized horizons. The data on soil acidity are presented by main soil types, forest site types, forest humus cover types (pro humus forms) and forest stand groups. In this work, the influences of forest floor acidity on mineral topsoil fabric, soil processes and peculiarities of carbon sequestration are explained. The active acidity of the forest floor provides a great indicative value in elucidating the regularities of the forest soil cover, as a whole, formation and functioning. For evaluating the normality of soil functioning, or the absence of disturbances in ecosystem functioning, the intervals of soil type specific reference pH levels have been established.

Fig. 1 - Scores of principal component analysis for (a) Norway spruce; (b) Scots pine; (c) Siberian pine. 
Fig. 2-Selection of wavelengths corresponding to the highest value of variable importance in the projection scores of partial least squares regression for: (a) Norway spruce; (b) Scots pine; (c) Siberian pine.
Estimating Crown Defoliation and the Chemical Constituents in Needles of Scots Pine (Pinus sylvestris L) Trees by Laboratory Acquired Hyperspectral Data

October 2014

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108 Reads

The studies, which involve the potential of imaging spectrometry, are among the most promising ones in forest health assessment. This study estimated crown defoliation and the concentrations of some chemical constituents in the needles of Scots pine (Pinus sylvestris L.) trees using laboratory acquired hyperspectral data. Needle samples from 67 Scots pine trees, which showed crown defoliation within the range from 0% to 80% (using 5% gradation), were collected in two mature stands located in the eastern Lithuania. The concentrations of ten chemical elements in the needles were also measured. The hyperspectral reflectance data of the needle samples was recorded under laboratory conditions using a VNIR 400H portable hyperspectral imaging camera operating in the 400-1,000 nm range. Principal component analysis and linear discriminant analysis were used to classify the needle samples into defoliation classes and partial least squares regression was used to predict the concentration of chemical constituents by means of hyperspectral reflectance data. Spectral reflectance data was found to poorly discriminate the needle samples into defoliation classes assessed using 5% steps (kappa statistic was 0.29 and 0.26 for the previous and current year needles, respectively). However, combining the samples into four damage classes, according to the UNECE/FAO definition (none: under 10%; slight: > 10-25%; moderate: > 25-60% and severe: over 60%) improved the spectral reflectance data discrimination ability significantly for the previous year (kappa statistic was 0.50), but not significantly for the current year (kappa statistic was 0.35) needles. Classification into three damage classes (under 30%; > 30-50% and over 50%) was perfect (kappa statistic 1.0). A moderate prediction potential was found for the nitrogen (correlation coefficient between actual and predicted values estimated using cross-validation; R = 0.61), phosphorus (R = 0.57), zinc (R = 0.57), calcium (R = 0.56), manganese (R = 0.49) and potassium (R = 0.40) concentrations, but was poor for boron (R = 0.33), iron (R = 0.26), magnesium (R = 0.20) and copper (R = 0.20) in the current year needles.

Figure. 3. Dendrogram showing the relationships between two pine species in all characteristics at different stand age (abbreviations: you-juvenile age, mid – middle age, mat – mature age, which correspond 2 nd , 5 th and 11 th age class of stand) based on the trait average
Figure 1. Mean (±SE) of urease, dehydrogenase , phosphatase, protease, potential nitrification activity and fungi amount in the soil of the pine species investigated at each age classes. Ps – P. sylvestris, Pm – P. mugo; (2c, 5c 11c – 2 nd , 5 th and 11 th age class of stand)  
Figure 4. Plotting of estimated properties of soil and needle components (fungi, bacteria, ph, urease, dehydrogenase, soil C, soil N, needle N, needle C/N) in tridimensional perspective on factorial axis. Different shapes indicate pine species: diamonds indicate P. mugo and pyramids – P. sylvestris . Variance explained by Factor1, Factor2 and Factor3 was accordingly 3.18, 1.70 and 1.25  
Needle Litter Decomposition of Native Pinus sylvestris L. and Alien Pinus mugo at Different Ages Affecting Enzyme Activities and Soil Properties on Dune Sands

January 2013

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155 Reads

Drifting dunes in the Curonian Spit of western Lithuania were covered by native Pinus sylvestris and alien Pinus mugo species. With planting of non-native species there is a need for studies which could evaluate the effect of alien and native plant species on soil ecosystem properties. We measured soil fungi amount, microbial enzyme activity, needle decomposition rate, respiration intensity, and soil and needle chemical composition from nearby pairs of native and alien pine species at different ages from several sites on the dunes (Lithuania). A total of 18 sampling sites of close- growing P. sylvestris and P. mugo were selected with stand ages ranging from 14 to 120 years, representing three age classes. Needles of P. sylvestris showed a faster decomposition rate than P. mugo. Needles of P mugo had lower nitrogen content, higher C/N ratio and lignin content compared to P sylvestris. The mass loss of needle litter was also positively correlated with C/N ratio and with fungi abundance in soil. Soil under Pinus sylvestris has higher C and N concentration than under P. mugo. The tendencies showed that there were more fungi in the soil under P sylvestris than under P. mugo. Soil enzyme activity was lower in the P. mugo plots. The activities of invertase, dehydrogenase, alcaline phosphatase, protease, potential nitrification activity increased gradually with the development of forests after afforestation. These results suggest that due to the differences in litter properties and decomposition rates, changes may occur in microbial properties and nutrient cycling in the forest ecosystems.

Asesment of the effect of beaver foraging activities on the alteration of waterside forests in northern and middle taiga of Russian Karelia

July 2020

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15 Reads

The territory of the Republic of Karelia is latitudinally elongated and traversing two boreal subzones such as the northern and middle taiga. Pine and spruce stands predominate in the northern taiga, while forests in middle taiga are more diverse, represented by secondary stands, and often dominated by deciduous species. These factors define the foraging behaviour of beavers and their role in alteration of riparian forests. Dispersing in the northern taiga, beavers tend to choose waterside areas with a higher proportion of deciduous species. However, such habitats occupy less than 1% of the forested area in this subzone, so the overall effect of beaver foraging on forest stands would be minor. On the other hand, inside beaver colonies, stand alteration is far more pronounced than changes in colonies in the middle taiga, and the effects are the following: 1) waterside forests in the northern taiga lose 2.5 times more deciduous trees than those in the middle taiga (61.4 and 26.3 %, respectively); 2) in waterside stands, aspen is totally removed, the share of conifers is doubled, and the share of birch is reduced (in the middle taiga, the share of birch around beaver colonies slightly increases, and the share of aspen is reduced by a factor of 1.5); 3) beavers in the north of Karelia consume thick birch trees more often than in the south of the region; 4) the regeneration capacity of damaged trees in the north is lower than in the south of Karelia. Keywords: beavers, foraging activities, waterside forests, northern and middle taiga, tree stands

Figure 3. Basal area increment (BAI) of all tree species during three 7-year periods before and after the subsiding event in 1998; alder and rowan as comprising the smallest BAI are not named in the figure
Figure 5. Trunk perimeter versus age of spruce trees; the extrapolated approximate age of the spruces with a perimeter = 25 cm is 50 years 
Tree Growth in an Area Subsided due to Mining Activities in Northeast Estonia

January 2010

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114 Reads

The radial growth of altogether 105 trees of spruce, pine, birch, aspen, black alder and rowan, growing ill an area subsided due to mining activities in northeast Estonia, was measured. The tree-ring series were cross-dated and averaged according to tree species, and a possible influence of the surface deformation on tree growth was looked for. For the same reason, the annual basal area increment was calculated. It appeared that the subsiding event in 1998 has mostly resulted in an increase rather than a decrease of tree growth.

Table 4 . Invertebrate fauna of the herb layer of riparian communities in South Karelia at non-beaver sites and aban- doned beaver sites (Danilov et al. 2007)
Changes in ecosystems of the middle taiga due to the impact of beaver activities, karelia, russia

January 2012

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236 Reads

Ecological consequences of beaver activity at water-bodies in southern Karelia were assessed. Vegetation succession induced by beaver foraging and construction activity was studied; the effect of long-term forest flooding on invertebrate and small mammal fauna. Beaver foraging activity results in the loss of 23.2 to 92.1% of aspen, 3.0 to 26.5% of birch and nearly all willow from the riparian plant community. Beaver dam construction induces the formation of wetland communities of mixed categories, including Sphagnum communities getting overgrown with birch, sedge-Sphagnum, Sphagnum-cotton grass, and various dwarf shrub-Sphagnum communities dominated by one or another dwarf shrub species. Organic carbon and the total nitrogen content in the soils of former beaver ponds increases, whereas pH decreases (Sidorova and Fyodorov 2007). The abundance and species composition of invertebrate and small mammal fauna also change significantly within the drained pond area. The number of invertebrates at beaver ponds increases 2 - 2 1/2 times. Expansion of the terrestrial invertebrate fauna goes along with increase in its species and age diversity. In some surveys, the abundance of small mammals dropped nearly 10 times - from 7.0 animals per trap-day in reference plots to 0.67 in abandoned beaver sites. In other surveys, the abundance of shrews and voles increased 2-2.5 times.

Salinity and temperature influencing seed germination of Mediterranean Aleppo pine (Pinus halepensis Mill.): an ecological adaptation to saline environments

August 2021

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77 Reads

In Mediterranean basin, Pinus halepensis Mill. is the dominant conifer used in afforestation and landscape projects. The ecological, aesthetic and commercial benefits make this conifer a precious tree for both woody production and land rehabilitation. Nevertheless, detailed studies on the adaptation of this tree to abiotic environmental constraints in the Mediterranean areas remain limited up until now. Therefore, laboratory experiments were conducted to assess the effects of the interactive impact of temperatures and salinity on the germinability potential of P. halepensis seeds. The cones of P. halepensis used in this experiment were harvested from the Gotaïa forest at Djelfa province, Algeria. The seeds were removed from their cones and surface-sterilized by soaking for five min in 10% NaClO. Seeds were germinated at three temperature regimes (10–20 °C, 15–25 °C and 20–30 °C) and four levels of salinity (0, 50, 100, and 150 mM NaCl) at photoperiodic lighting (16 h of light : 8 h of dark). For each treatment 04 replicates of 25 seeds were placed in Petri dish with 5 ml of test solutions. A completely randomized design (CRD) was used for the experiment. Results revealed that the uppermost germinability was recorded in distilled H2O and the progressive enhancement of NaCl significantly (P < 0.001) suppressed germination. At 15–25 °C (dark : light thermoperiod), P. halepensis seeds showed approximately 90% of germination at 0 mM NaCl. However less germination percentage (GP) was obtained at 10–20 °C and 20–30 °C. Values of Timson’s index were also suppressed significantly (P < 0.001) with an increase under salt stress at all thermoperiods but at least at 15–25 °C. These funding suggest that seeding of P. halepensis may be an effective path for rehabilitation of degraded lands where salinity and drought are major features of the arid ecosystems. Yet, this conclusion still needs verification by field experiments. Key words: Pinus halepensis; arid zones; sowing dates; afforestation; salt tolerance

In vitro screening of Latvian isolates of Bjerkandera adusta and Sistotrema brinkmannii as potential biocontrol agents against Heterobasidion root and butt rots

May 2022

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88 Reads

Root and butt rots caused by Heterobasidion spp. are destructive diseases of conifer forest stands that may be controlled by spraying freshly cut stumps with chemical or biological treatments, including the effective and widely used biological control agent Phlebiopsis gigantea. In this study, we tested in vitro different Latvian isolates of the fungal species Bjerkandera adusta and Sistotrema brinkmannii for their antagonistic activity against both Heterobasidion species present in Northern Europe and Baltic countries, namely H. annosum and H. parviporum, using Latvian isolates of P. gigantea and the Rotstop® strain as controls. The growth rate of isolates on agar media and their ability to produce oidia or conidia were also assessed. In general, B. adusta performed better than S. brinkmannii. Some isolates of B. adusta ranked similarly to those of P. gigantea in terms of oidia production, growth rate and ability to overgrow the mycelium of both H. annosum and H. parviporum. These isolates will be further tested in field conditions. Key words: biological control, antagonistic fungi, fungal isolates

Advancing height growth models for the improved forest reproductive material of the main tree species in Latvia

January 2023

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103 Reads

The breeding of economically important forest tree species in the Baltic Sea region has contributed notably to the availability of quality wood for bioeconomy. Accordingly, the altered stand dynamics of improved trees should be identified and incorporated in growth models to accurately reflect these gains. Such advanced models can be used for assessment of different alternatives, e.g. strategies for increased carbon sequestration. We tested and modified dynamic forms of the King-Prodan height growth function based on the remeasured National Forest Inventory plots in Latvia to predict the growth of improved Scots pine, Norway spruce and silver birch forest reproductive material (FRM) categories ‘qualified’ and ‘tested’ using height measurements from progenies of 371, 390, and 690 open-pollinated families, respectively. Both categories had steeper growth trajectories at young age compared to an unmodified function. Growth of category ‘tested’ for pine and birch exceeded that of category ‘qualified’ across the modelled age range, while trajectories mainly overlapped for spruce on lower site indices. The functions with FRM category-specific multipliers more accurately reflect the actual growth of improved stands, advancing planning of timely management activities like thinning. The single model with category-specific set of multipliers may be easy applicable in practice or incorporated in growth simulators without increased complexity for end-users. However, the predictions are limited to the sites with medium and high site indices, where improved planting stock is typically used. Keywords: GADA approach, dynamic modelling, tree breeding, FRM categories

Collar rots in forests of Northwest Germany affected by ash dieback

January 2017

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123 Reads

The formation of collar rots in association with ash dieback was studied under different site conditions. The fungal community associated with lesions, necroses and stem collar rots, especially the occurrence of Hymenoscyphus fraxineus at these symptomatic plant tissues, was investigated. Filamentous fungi and Phytophthora spp. were isolated from affected tissues of stem collar rots of various developmental stages. Tissue samples of collar rots were collected from 32 ash trees in seven different forest plots located in Northwest Germany. Obtained isolates were assigned to morphotypes and identified based on mycelial morphology and by molecular methods. Primary agents causing collar rots were identified and the influence of site conditions was derived. The studied stem collar rots were assigned to five symptomatic categories: (0) without collar rots or lesions, (1) emerging collar rots, (2) larger collar rots without visible wood decay, (3) advanced collar rots with visible wood decay and (4) collar rots, necroses or lesions associated with dark sap oozing. In most of the studied collar rots that were collected in Schleswig- Holstein and Lower Saxony, H. fraxineus was isolated and assumed to be the primary agent. From samples of category 0 neither H. fraxineus nor other fungi or Phytophthora species were isolated. From collar rots of the other symptomatic categories, varying quantities of endophytic, saprotrophic and pathogenic species had been isolated. Overall, the number of isolated species was higher in advanced stages of collar rot. Most common species were H. fraxineus and Neonectria punicea, followed by Diaporthe eres, Botryosphaeria stevensii, Gibberella sp., Fusarium solani and Cadophora sp. However, collar rots in early stages were only associated with H. fraxineus and N. punicea. Armillaria or Phytophthora species were only isolated from advanced collar rots or occurred under special side conditions.