In this study, assortment yields were studied for Scots pine, Norway spruce, birch spp. (silver and downy birch), European aspen, black alder, and grey alder stand elements. Theoretical assortment ...yields were calculated using the Ozolinš’ stem taper curve, incorporating tree diameters and heights. The modelled results were compared with actual yields provided by the State Forest Management Centre. During the study, differences in timber assortments and firewood yields were modelled compared to actual data. Changes in wood assortment yields, compared with undamaged and straight trees, depended on the tree species, stand site index, and stand element age. For Scots pine, depending on the stand site index and age, the reduction in log volume ranged from 7 to 28% of the total volume of all assortments. For Norway spruce, it was 5–30%, for birch spp. 30–70%, for aspen 50–90%, for black alder 20–50% and grey alder 5–30%. The increase in firewood volume according to the volume of all assortments was 3–4% for Scots pine, 5–14% for Norway spruce and birch spp., and 5–16% for European aspen. The difference between log and firewood changes represents the change in pulpwood. Over time, the need for new studies arises to adapt to evolving industry practices, including changes in log diameters and quality criteria. The appendix outlines steps that programmers can take to utilize the developed model.
This paper discloses algorithms for calculating the volume and lateral area of a stem or part of the stem (assortment) using the integral of the Ozolinš’ stem taper curve. An algorithm was also ...developed to change the taper curve constants in case another diameter was measured higher than the breast height. The experiment was performed with 580 Scots pines (
L.) measured in Hiiumaa, which included height, diameter at breast height and diameter from the root collar at a height of 5 m. The volumes of tree stem and assortments were estimated with both – the original and corrected (with the measured additional diameter) Ozolinš’ taper curve. Using the original Ozolinš’ taper curve, the stem volume of pines in Hiiumaa is estimated at 4% higher according to the analysis results of 580 measured trees. In the case of Hiiumaa Scots pines (
L.), it is recommended to use 119.717, −289.805 and 1152.016 as the values of the coefficients a
, a
and a
, respectively, of the Ozolinš’ taper curve equation. In conclusion, for a more accurate assessment of the forest reserve, it is recommended to measure one additional diameter at 5 to 8 m above the root collar on some or all trees.
During three years, 2014–2016, Dutch elm disease (further DED) was investigated on 1225 elm trees at 4 different sampling sites and 2 sub-sites in Estonia. For the first time, both subspecies of the ...invasive pathogen
Ophiostoma novo-ulmi
:
O. novo-ulmi
subsp.
novo-ulmi
, and
O. novo-ulmi
subsp.
americana
, were detected by
col1
and
cu
genes in Estonia and north-eastern Europe.
Ophiostoma novo-ulmi
subsp.
americana
was identified only at one site in northern Estonia, in Tallinn. In addition, during our assessments, the health of elms there appeared worse than at other sampling sites:
O. novo-ulmi
subsp.
americana
demonstrated higher aggressiveness. Simultaneous occurrence of both subspecies and their hybrids was not detected. A repeat survey of 109 elms in 2014 and 2016 demonstrated ca. 22% probability of mortality within 24 months, irrespective of urban vs. rural habitat. In sub-site A1 in Tallinn,
O. novo-ulmi
subsp.
americana
has been found since 2013. DED signs were noted on 39% of all 1225 surveyed trees. Among the assessed elm species,
Ulmus laevis
showed higher resistance than
U. glabra
: 82% and 66% of trees, respectively, showed high vitality. In addition, no
U. laevis
trees were found dead, compared to 18% of the
U. glabra
.
The aim of this paper was to provide an overview of the productivity of the stump lifting device Pallari KH-160, the distribution of working time, and to assess the dependence of the time and ...productivity of lifting operations on stump diameter in four different sample areas. Viru and Orguse sample areas were located in the
site type, Elva sample area in the
site type, and Rõuge test area in the
site type. Viru sample area had smaller stumps compared to the others and had more stumps affected by decay. The highest productivity in terms of dry mass or volume was observed in stump lifting in Rõuge sample area, where 9.8 t of stumps were lifted per hour based on dry mass. The productivity of Viru and Orguse sample areas was lower, but these sample areas are located in the
site type, characterized by limestone substrates and leached soils. In contrast, Elva and Rõuge test areas are in the
and
site types, respectively, with soils that are predominantly sandy. As the diameter of the stumps increased, the time required per stump increased, but the lifting speed per unit mass also increased. In other words, the productivity of lifting in stands with larger stumps is higher than in stands with smaller stumps. For example, the average productivity of lifting 10 cm diameter stumps is 0.8 t/h, for 20 cm stumps it is 2.2 t/h, and for 60 cm stumps it is 11.8 t/h.
Knowledge about the seasonal dynamics of tree growth and its relationship with environmental factors is necessary to eliminate the uncertainty due to ongoing climate change and for more precise ...growth modelling when re-measurements are done periodically. Despite the increasing number of studies monitoring seasonal wood formation, a considerable part of European forests, including Estonia, lacks such information. In this article, we present a date-dependent model for determining the share of seasonal radial growth for the three most common tree species in the region (Scots pine, Norway spruce and silver birch) for Estonian conditions. Since seasonal tree growth monitoring data were unavailable for Estonia, we used published seasonal radial growth data from Lithuania by
. We tested four functions (Kumaraswamy, Weibull, Gompertz and logistic) on obtained data to approximate the seasonal development of radial growth. Kumaraswamy’s function could track the course of seasonal radial growth gains the best; thus, this function was chosen for further use. We obtained data on intra-annual radial growth from published research studies from neighbouring countries and determined the dates of growth initiation and cessation for Estonian conditions. Finally, we combined Kumaraswamy’s function and the predicted radial growth onset and cessation dates into the model that could predict the seasonal growth course and thus were able to estimate the share of newly formed increment from the dates.
The stand level gross volume increment models are used to estimate the future production of tree stands. Very often, the stand growth and yield in the models used in practice are described by the ...tree volume increment that includes the diameter growth function with the tree height together with stem taper as the input variables. The currently used function of stand volume increment in Estonia included also stand relative density as an additional input variable. In the current study, we developed a basal area increment function based on the periodic measurement data of the Estonian Network of Forest Research Plots (ENFRP). As in the earlier model of stand volume increment developed by Priit Kohava, in the current model the basal area increment of tree species is developed for a pure stand, and for mixed stands, the proportion of the tree species’ basal area is used. The tests in our data indicated that the periodic increment prognosis had good fit in the case of variable share of tree species in the main storey and coincide with the earlier studies by Finnish and Swedish colleagues. The developed model of basal area increment predictions are expectedly higher than the earlier model predictions for the most tree species and stand relative densities.
Soil microbiome has a pivotal role in ecosystem functioning, yet little is known about its build-up from local to regional scales. In a multi-year regional-scale survey involving 1251 plots and ...long-read third-generation sequencing, we found that soil pH has the strongest effect on the diversity of fungi and its multiple taxonomic and functional groups. The pH effects were typically unimodal, usually both direct and indirect through tree species, soil nutrients or mold abundance. Individual tree species, particularly
Pinus sylvestris
,
Picea abies
, and
Populus x wettsteinii
, and overall ectomycorrhizal plant proportion had relatively stronger effects on the diversity of biotrophic fungi than saprotrophic fungi. We found strong temporal sampling and investigator biases for the abundance of molds, but generally all spatial, temporal and microclimatic effects were weak. Richness of fungi and several functional groups was highest in woodlands and around ruins of buildings but lowest in bogs, with marked group-specific trends. In contrast to our expectations, diversity of soil fungi tended to be higher in forest island habitats potentially due to the edge effect, but fungal richness declined with island distance and in response to forest fragmentation. Virgin forests supported somewhat higher fungal diversity than old non-pristine forests, but there were no differences in richness between natural and anthropogenic habitats such as parks and coppiced gardens. Diversity of most fungal groups suffered from management of seminatural woodlands and parks and thinning of forests, but especially for forests the results depended on fungal group and time since partial harvesting. We conclude that the positive effects of tree diversity on overall fungal richness represent a combined niche effect of soil properties and intimate associations.
The reduction of greenhouse gas (GHG) emissions demands a significant increase in the use of wood as a renewable energy source. However, environmental restrictions determine limits on the further ...growth of harvesting volume. Therefore, a viable solution to enhance the share of energy wood in Estonia’s energy balance involves focusing on less exploited assortments of raw material and implementing precise logistics planning. In recent years, mild winters have posed challenges to the extraction of residues and local transport of wood fuels, taking place on soft and unfrozen soils. In such conditions, ensuring a reliable supply of wood fuels becomes rather complicated. When piles of logging residues on unfrozen soils are inaccessible, there is a need to process older piles. The quality of wood chips from such piles is lower compared to the norm. To investigate the impact of extra long-term storage of residues in piles, a study was conducted at the Järvselja Training and Experimental Forest Centre. In 2010, sample piles were created in birch and spruce final felling areas. Over an eight-year period, samples were regularly taken from the piles to analyse the properties of woody biomass during storage. The study results indicate that the quality of fuel from covered piles changes slowly during the first two years of storage. Subsequently, the degradation speed equalizes in both uncovered and covered piles. Despite extensive degradation and loss of dry matter during long-term storage (approximately 29% for Norway spruce and 55% for silver birch after eight years), the quality of dry fuels still meets standard requirements and remains acceptable for boiler houses.
Understanding how forest ecosystems respond to environmental factors, particularly in the context of global climate change, is essential for devising effective mitigation strategies. This study ...focuses on quantifying the interaction between forest ecosystems and atmospheric gases. To achieve our objectives, we are using the eddy covariance (EC) flux method to measure air turbulence and gas concentrations above the forest canopy at the Station for Measuring Ecosystem-Atmosphere Relations (SMEAR) in southern Estonia. We apply a flux footprint (FFP) model to describe the spatial extent and position of the surface area contributing to the turbulent flux measurements. The FFP analysis provides valuable insights into the long-term changes in SMEAR Estonia, the FFP and its relationship with forest management and land use changes. Our findings reveal that the FFP area varies from year to year due to changes in wind speed and direction, affecting the contribution of different land cover elements to the overall FFP. The average changes in the FFP area at a height of 30 meters were approximately 4.9%, while those at a height of 70 meters were only 1.6%. Moreover, human activities, such as thinning and clear-cutting, influence the growing stock and increment of forest stands.
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
has been damaging elms since the 1930s. Today a new species
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,
subsp.
and
subsp.
were molecularly detected on
spp. Additionally, one hybrid pathogen of the subspecies (
x
) 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.
The threat to
spp. has risen in Estonia, apparently due to the trade of infected elm plants and changing climatic conditions having contributed to the invasion of new pathogens and their vectors. It is known that in Estonia Dutch Elm Disease (DED) has had a devastating impact on elms since the 1930s. Today its agent
has been replaced by a new, apparently an invasive species
in most countries of Europe, as well as in Estonia. Since 2013 the health status of elms in Estonia has worsened substantially.
The aim of this research was to analyse the current spread of DED until 2020, specify the taxonomy of pathogens, evaluate the health status of host plants, and analyse the control options of the disease.
Visual assessment has been provided for the period of 2014 to 2020. Methods and results for the years 2014–2016 are presented in a previous paper (see
).
More precise monitoring of Dutch elm disease in Estonia started in 2014. A preliminary map of DED was provided on the basis of the assessments of the distribution (records). Thereafter, in the period of 2014–2020 more than 2,200 trees of genus
, mostly
were assessed. Also, over 500 samples were collected of which 183 pure cultures of
were isolated and analysed with different molecular primers (
). In the period of 2018–2020, DED was detected in 14 counties of the total of 15 counties in Estonia. The analyses show that
subsp.
is widely spread; however,
subsp.
was detected only in northern Estonia and on Hiiumaa island in western Estonia (
). For the first time the hybrid pathogen (
x
) was detected at a sampling site at Kose in northern Estonia (
).
Our investigation demonstrated that in terms of the use of
as an amenity tree species
could be considered more prospective than
because the health of
is significantly better and DED is not so devastating to the host. Also, we have to test resistant hybrid elms in our environmental conditions before starting massive planting in our green areas. All the plant material should meet the local standard on Quality Requirements for the Nursery Plants (see
). We have created several provenance trials in Estonia to qualify tolerant elm species or origins in the future.
DED control is complicated because effective universal control methods are not available. Thus, a good sanitation program together with a reliable survey is needed. Symptomatic elms should be felled and completely destroyed; this seems to be the most effective method for DED control. Introduced planting material should be certified and controlled to minimise the invasion of diseases and pests.
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