Completed research projects

Project manager: Priit Kupper, University of Tartu
Duration: 2021-2024
RMK funding: EUR 195,219

Spruce is one of the most ecologically and economically important tree species in Estonia and throughout Central and Northern Europe. However, ecophysiological models reveal that spruce exhibits a poorer ability to adapt to climate change than other important tree species in the region, and vegetation distribution models predict a northward shift in the distribution area of spruce.

The project will examine how the growth rate and defensive capabilities (resin current, production of protective substances) of Norway spruce change under shifting environmental conditions (availability of water and nutrients, lighting, temperature, competition with neighbouring trees).

The research takes place both in natural spruce forests and in the experimental forest ecosystem FAHM in Järvselja.

Final project report (433.77 kB, pdf)

Project managers: Veiko Uri from the Estonian University of Life Sciences and Kaido Soosaar from the University of Tartu
Duration: 2020-2023
RMK funding: EUR 244,116

An alternative to clear-cutting is being sought in Estonia and Europe, with consideration being given to the broader use of shelterwood and selective felling. While silviculture practices have been developed in Estonia for use in shelterwood cutting, the application of selective felling is relatively creative, depending mainly on the characteristics of the forest. Limited scientific research has been conducted on most of the questions related to selective felling as well.

The project assessed the impact of selective felling on carbon flows and stocks at the ecosystem level in a mature forest compared to clear-cutting and modelled the post-harvest growth of stands.

The results show that the thinning of a mature forest reduces carbon sequestration, but pine stands in less fertile growing areas remained either carbon sinks or neutral. However, the mixed forest growing on a fertile site became a carbon source. The development of the post-cutting carbon balance is determined by the species composition of the stand, the soil, and the degree of thinning. All clearcut areas were carbon sources, with only ground cover growing in these areas in the first years after felling.

Starting the process of selective felling in mature pine forests allows the old stand to be maintained as a selection forest for an extended period. Still, it does not guarantee successful forest regeneration or satisfactory forest productivity and, thus, effective carbon sequestration.

Final project report (156.51 kB, pdf)

Project manager: Ain Kull from the University of Tartu
Duration: 2017-2023
RMK funding: EUR 291,667

The project aimed to create a methodology for monitoring the status of cut-over peatlands and post-restoration changes, to establish monitoring areas in five cut-over peatlands, and to perform integrated monitoring within those areas.

The results of the monitoring confirmed what was already known: that unregulated cut-over peatlands are important sources of CO2 and that their restoration can reduce the flow of CO2 being emitted. It was also confirmed that gas flows are higher during the summer months. At the same time, if the climate changes, it must be considered that winter months, when the soil remains unfrozen, may have a significant impact on the total annual gas flow balance.

The data collected during monitoring will provide the knowledge necessary for the restoration of cut-over peatlands. However, it should be borne in mind that short-term monitoring is insufficient to draw long-term conclusions about the effectiveness of methods, the rate of growth of vegetation cover, or the reduction of greenhouse gas flows. Thus, for example, it was discovered that for the first few years, the greenhouse gas emissions in the area to be restored with moss were affected by the decomposition of straw and dead fragments. On the other hand, the spreading of moss fragments supported a faster rate of growth of vegetation cover in subsequent years.

The high degree of uncertainty is related to the weather, which affects the critically important water level range and the presence of summer moisture. Thus, two years of drought fell within the summer monitoring period, which may have influenced gas emissions, vegetation development, carbon and nitrogen concentrations, as well as changes in water levels. Water levels and vegetation, in turn, have a significant impact on the rate of degradation.

Final project report (6.96 MB, pdf)

Project manager: Kadri Runnel, University of Tartu
Duration: 2018-2021
RMK funding: EUR 152,517

A significant part of Estonia’s protected forests are small fragments of less than 15 hectares, surrounded by commercial forests. Such forest fragments are important because they provide a habitat for many diffuse endangered species. At the same time, they do not form self-regulating natural entities and are threatened by external influences, which is why their natural values are also at risk.

The project examined whether the preservation of natural values in protected forest fragments depends on how the surrounding forests are managed, and management recommendations were drawn up to preserve natural values better.

The sample of sites consisted of 127 forest fragments (0.5-15 ha), the vast majority of which were key habitats and the remaining fragments of protected areas surrounded by managed forests. In addition, the survival of moss in 16 groups of old crop trees was studied as an extreme treatment.

The study revealed that mosses sensitive to environmental changes are better preserved in clear-cut areas in groups with old crop trees than in dispersed groups of old crop trees, and older broadleaved trees and a mix of different tree species should be preferred in groups of old crop trees. Despite their small size, protected forest fragments proved to be a habitat for many species of conservation value. At the same time, it was found that adjacent cutting reduces the habitats (structural elements) as well as the abundance and species richness of such species in the 30 m edge zone. The 30-metre edge zone studied comprises more than half of the area of the 3-hectare fragments (depending on the shape).

Based on the results, buffer areas would help to maintain the value of protected forest fragments (e.g. key habitats) as habitats for species of conservation value. The purpose of buffer areas is to increase the habitat area of forest fragments and to support the biota of current forest fragments throughout the area, i.e., in the edge areas. As edge effects are likely to increase in the near future due to climate change (e.g. as the frequency of storms increases), leaving buffer areas is also in line with the precautionary principle. To increase the number of fragments, less representative parts of the stand should also be demarcated. In the long term, an unmanaged buffer of at least 30 m ensures the area efficiency of the forest fragments to be protected and prevents accidental damage.

The question of whether edges open to certain directions or any type of forest requires stricter restrictions requires further research. In forest fragments that have already been cut to the edge, the restoration of denser and higher forests (buffering capacity) within at least 30 m of the outer boundary of the forest must be encouraged, including by avoiding cleaning and thinning. The aim is to create a more uniform edge strip on the boundary of the forest fragment that will cover the interior area in the future.

Although the work focused on forest fragments, its recommendations extend to the edges of larger forests with high conservation value, according to the researchers.

Final project report (1.13 MB, pdf)

Project managers: Tiia Drenkhan, Estonian University of Life Sciences, and Kadri Põldmaa, University of Tartu
Duration: 2019-2021
RMK funding: EUR 194,213

The growth of spruce forest stands in fertile habitat types is inhibited by the widespread presence of root rot. The use of Rotstop®, containing the spores of the Phlebiopsis gigantea fungus, helps to alleviate the damage caused by Heterobasidion root disease. During the project, the effectiveness of Rotstop and the effects of processing on biota were analysed. In addition, the effectiveness of other fungal species against Heterobasidion root disease and the infection of different types of forest plants with Heterobasidion root disease were also investigated.

It turned out that spraying stumps with Rotstop remains practical in the control of Heterobasidion root disease, as Phlebiopsis gigantea was detected on stumps treated with Rotstop 12 months later significantly more than on control stumps that were not sprayed with Rotstop. The efficiency of stump processing with Rotstop increases as the temperature rises, i.e. the warmer the weather during stump processing, the more effective the result will be. However, since Heterobasidion spores spread in the air from 0 °C onwards, it is also necessary to perform Rotstop treatment at lower average temperatures than the previously recommended treatment above 5 °C. Previous results show that cutting at lower temperatures does not prevent the spread of infection with Heterobasidion root disease. The use of Rotstop should henceforth be based on the air temperatures of a given year, and stumps should be treated when the average daily air temperature is consistently between 1-4 °C and warmer.

There was no significant difference in the species richness of fungi in stumps treated with Rotstop and stumps that were not: 75% of common fungal families were identified in both sites; however, the diversity of fungi in the treated sites was higher. The use of the Rotstop preparation, therefore, has a neutral effect on fungal diversity – it does not significantly alter the natural fungal composition. Comparing the interaction of potential antagonists with Heterobasidion root disease, it turned out that the fastest growth was in strains 1 and 4 of Phlebiopsis gigantea isolated from Estonia, the growth of which was significantly more rapid than the growth of spruce and pine Heterobasidion root disease. These strains, in particular, could have the potential for further laboratory and field testing.

A parasite (Sphaerostilbella broomeana) specialised in Heterobasidion root disease, and representative of the genus Trichoderma was also frequently found together with pine and spruce Heterobasidion root disease.

Analysis of the roots of the different forest plants planted on the test sites revealed that more open-root spruce and birches were infected with Heterobasidion root disease, while more potted pines and birches were infected with honey fungus. More honey fungus was detected on the roots than spruce Heterobasidion root disease, and potted plants were, in turn, more susceptible to honey fungus infection than open-root plants. It turned out that the potted spruce is not the best suited for cultivation in fertile habitat types due to a significantly higher rate of loss.

Final project report from the Estonian University of Life Sciences (110.04 kB, pdf)
Final project report from the University of Tartu (38.24 kB, pdf)

Project manager: Rein Drenkhan, Estonian University of Life Sciences, and Leho Tedersoo, University of Tartu
Duration: 2016-2019
RMK funding: EUR 299,913

The most profitable forest stands in Estonia are Norway spruce stands. At the same time, the current management methods have failed to ensure the good health of spruce stands.

The project aimed to clarify the impact of the management of forest stands with a spruce majority on the spread of and damage caused by root rot and on the biodiversity of fungi and epiphytes compared to unmanaged stands. The project was carried out in cooperation between the University of Tartu and the Estonian University of Life Sciences.

Research material was collected in 2016 and 2017 and covered spruce stands of thinned and un-thinned fertile habitat types (wood sorrel, hepatica and ground elder), with a total of 185 stands. They were located in different regions of Estonia and were divided into six age classes: 4-20, 21-40, 41-60, 61-80, 81-100 and more than 100 years old.

It turned out that considering the loss of income from all Estonian spruce-majority stands, the damage caused by root rot to the forest owner amounts to EUR 8.5 million per year. As the age of the stand influences the increase in the percentage of root rot in the stand, the number of improvement cuttings and the type of site, the risk of infection with root rot increases when predominant and thicker spruces are subject to improvement cutting. This is mitigated if only one or two improvement cuttings are carried when the stand is younger (up to 15 years), and the stands are left untouched until regeneration cutting. The idea behind improvement cuttings in such young stands is also to form mixed stands to avoid the emergence of monoculture spruce stands.

Since the financial maturity of spruce stands is up to 10 years lower due to root rot damage when compared to the entire theoretical stand, from an economic point of view, lowering the rotation age of spruce stands can be considered a reasonable decision. However, the researchers found that the financial maturity of spruce trees requires more analysis along with adjustments to the spruce growth models.

The amount of deadwood in fertile spruce stands is less critical for the species richness of fungi, moss, and lichens than the research group initially assumed. However, in order to support biota during cutting, dead-standing timber and reclining timber with a higher degree of degradation must be preserved since thinned spruce stands have a smaller volume than un-thinned spruce stands. In addition, the negative impact of lowering the cutting age on lichens can be mitigated by preserving live spruce trees (so-called veteran trees) growing on the edge of the old forest and by preserving the existing stumps and deadwood in the stand before felling, as they help to preserve the populations of habitat specialists after cutting and support the presence and emergence of the necessary microhabitats.

Project Final Report (281.77 kB, pdf)

Project managers: Lauri Vares, University of Tartu, and Omar Parve, Tallinn University of Technology
Duration of the project: 2015–2018
RMK funding: EUR 190,473

The fossil oil- and gas-based economy needs a new, sustainable approach. Renewable wood resources could be the main raw material in the chemical industry. The project explored new technologies for producing high-value chemicals from cellulose that could be used in the material, chemical, and pharmaceutical industries, such as breast cancer treatments, plant protection products for pine weevil control, cosmetics, etc.

During the course of this research, a solution for creating novel polymers based on isosorbide from wood biomass was discovered. Wood-based polymers can be used, for example, in paints, protective layers for paper and cardboard packaging and high-temperature plastics, where fossil styrene and methyl methacrylate are currently in use. The methodology developed in the laboratory can also be applied in manufacturing, with companies continuing to test the solution in different products.

The project was carried out in cooperation between the University of Tartu and Tallinn University of Technology.

Final report from the University of Tartu (496.00 kB, pdf)
Final report from Tallinn University of Technology (262.06 kB, pdf)

Project manager: Veiko Uri, Estonian University of Life Sciences
Duration: 2015-2018
RMK funding: EUR 226,500

Forests are important carbon sinks, and smart forest management makes it possible to further enhance the role of forests in the carbon cycle. The research project assessed the impact of clear-cutting and thinning on the carbon cycle of stands, as well as the impact on some of the most important flows in the nitrogen cycle.

It turned out that following clear-cutting, the successfully renewed pine area became a carbon-sequestering ecosystem in the seventh year after cutting. Since the increment of trees determines carbon sequestration, it is important to renew the clear-cut area quickly and efficiently. Following clear-cutting, the fertile area became a weak carbon source and became carbon-sequestering in the seventh year after cutting.

The results obtained by different methods proved to be consistent with each other, which increases the reliability of the study. The project was carried out in cooperation between the Estonian University of Life Sciences and the University of Tartu.

Final project report (702.34 kB, pdf)

Project manager: Meelis Pärtel from the University of Tartu
Duration: 2015-2018
RMK funding: EUR 195,000

Species in need of protection can be found in both natural and commercial forests. The biodiversity assessment metrics used so far do not allow for a proper assessment of the status of species and the effectiveness of conservation activities.

A system of metrics was developed to assess forest biodiversity: indices of the completeness and characteristics of the biotic community. To this end, plants, mosses and lichens from natural forests were described on the basis of the dark diversity concept and the link between protected forest areas and the distribution of biodiversity was assessed. The completeness of the community was most affected by the continuous forest on a 2 km scale. Biodiversity metrics were tested in different economic forest systems, and a prototype of the smart application was developed. The results will contribute to the development of nature-friendly forest management. The project was carried out in cooperation between the University of Tartu and the Estonian University of Life Sciences.

Final project report (1.29 MB, pdf)

Project manager: Ülo Mander from the University of Tartu
Duration of the project: 2013–2016
Project funding: EUR 160,000

More than a third of Estonian forests have been drained, but there was no data on whether forests growing faster because of drainage help to prevent global warming or even accelerate it. The main question of the project was whether drained forests absorb more greenhouse gases than they emit.

As a result of the study, it turned out that drained swamp pine and spruce stands typically cooled the climate. Drained swamp birch stands were carbon neutral, and in their further management, attention should be paid to making the carbon and nitrogen balance more climate-friendly. For example, instead of downy birch, you can plant birch or coniferous trees.

Final project report (2.31 MB, pdf)

Project manager: Asko Lõhmus, University of Tartu
Duration of the project: 2013-2016
Project funding: EUR 197,450

The capercaillie is a woodland grouse with high habitat demand and declining abundance, whose conservation measures so far have not yielded the desired results.

The project aimed to explain the habitat use of the capercaillie and the factors limiting it in a comparative way in the natural and commercial forest landscape. The project had three components: 1) a telemetry study to describe habitat use, 2) a study on the presence of the capercaillie in the diet of predators, 3) a restoration study to assess whether and how quickly it is possible to make the managed forest more suitable as a habitat for the capercaillie with cuttings and closing ditches.

It was found that the continuing decline in the capercaillie population is determined by its breeding success, which is generally low in Estonia. Although there have been a few more successful years, they are unable to compensate for the general downward trend in population. Changes in the habitat of the capercaillie favour predators and reduce the diet of the capercaillie chicks.

A combination of drainage ditch closures and different cutting techniques was used in the pilot areas set up to explore habitat restoration possibilities. It turned out that when planning nature conservation works and closing ditches, less cutting should be done in protected areas to protect the capercaillie.

Final project report (418.10 kB, pdf)

Project managers: Kalev Sepp, Estonian University of Life Sciences, and Erik Terk, Tallinn University
Duration of the project: 2013-2015
RMK funding: EUR 98,538

The research aimed to develop a suitable methodology for RMK to assess the impact of clear-cutting and prevent potential conflicts. The methodology must be systematic, considering the complexity and balance of the impacts, and oriented towards reducing and preventing the adverse effects of forest management and increasing the positive impact in the long term. The study was carried out in cooperation between the Estonian University of Life Sciences and Tallinn University.

Final project report (75.29 kB, pdf)

Project manager: Allan Sims, Estonian University of Life Sciences
Duration: 2012-2015
RMK funding: EUR 60,000

As a result of the project, Estonia got its very own bark algorithm. It states how thick the bark is and what the diameter of the wooden part is, depending on the tree species and its location in Estonia. With the help of an algorithm, harvesters and sawmill lines can more precisely estimate the thickness of a log’s bark in the future.

Final project report (691.57 kB, pdf)

Project manager: Ivar Sibul, Estonian University of Life Sciences
Duration: 2012-2015
RMK funding: EUR 139,740

Young, newly planted coniferous trees are threatened by the large pine weevil, which loves to eat the bark of a tree and can cause the death of a young tree. It is estimated that a quarter to a third of the pine trees and spruce planted will die in Estonia due to the pine weevil.

The project examined whether the impact of insect pests on the next generation of forests could be reduced by using environmentally friendly repellents such as biowax.

The results were quite promising; at the same time, it became apparent during the course of extensive testing that the efficacy of the preparation Actara, which has been used in RMK’s plant nurseries so far, is very low. As a result of the study, RMK stopped using Actara in 2016, and the first plants protected by biowax were planted in the forest, especially in areas where the likelihood of a large pine weevil attack is highest.

Final project report (234.47 kB, pdf)

Project manager: Hardi Tullus, Estonian University of Life Sciences
Duration of the project: 2011-2014
Project funding: EEK 2,176,614 / EUR 139,111

The project analysed the suitability of shelterwood cutting as a management technique in areas where clear-cutting is not favoured for various reasons, such as the forests in the limited management zones of protected areas.

During the implementation of the project, 60 demonstration sites were established for studying shelterwood cutting methods; the ecological, economic and social aspects of shelterwood cutting were studied; an assessment of the impact of shelterwood cutting on forest biodiversity was carried out, and proposals were drawn up to amend the Forest Act and the rules on forest management.

The established experimental areas are used for training and advising forest owners and employees of the state forest. Scientific research and monitoring of changes in the forest are planned to be done in the experimental areas in the long term.

Final project report (359.20 kB, pdf)

Project manager: Mait Lang from Estonian University of Life Sciences
Duration of the project: 2011–2012
RMK funding: EEK 284,768 / EUR 18,200

The aim of the project was to develop a methodology for estimating forest inventory variables based on lidar measurements and multispectral data for the Aegviidu test area, based on data collected between 2008 and 2010. For this purpose, on the basis of the collected data, different indicators were assessed at the level of allocation and plot in the test areas, and an analysis was performed to determine whether it would also be possible to obtain estimates by stand elements or at least by the most common tree species in Estonia.

In order to determine the height of the stand, a digital land cover surface height model based on stereo pairs of aerial images or based on lidar data was tested according to the plots, and the possibilities to apply this methodology in practice in large areas were assessed.

The study showed that, based on lidar data, it is possible to predict the height of a stand quite accurately, but not the growing stock. Further development is needed in order to better determine forest indicators using remote-sensing methods. The study supported RMK’s vision to implement forest inventory based on remote sensing.

Final project report (1.45 MB, pdf)

Project manager: Veiko Uri, Estonian University of Life Sciences
Duration: 2011–2014
RMK funding: EEK 2,262,498 / EUR 144,600

Stump lifting is not widespread in Estonia, even though stumps are a considerable source of raw materials for energy production. Also, stump lifting may be necessary under certain conditions to suppress pathogens. The aim of the project was to identify the silvicultural and environmental aspects of stump lifting.

The project assessed the parameters of the stumps stored as a result of the measurements carried out on the plots, including the reserve and the energy value. In addition, the impact of stump lifting on soil fertility, the emergence and growth of reforestation, the spread of pathogens, and the characteristics of infection were thoroughly analysed.

Final project report (732.31 kB, pdf)

Project manager: Piret Lõhmus, University of Tartu
Duration: 2008–2011
RMK funding: EEK 582,415 / EUR 37,223

The project focused on the identification of potentially endangered forest biota in the context of the exponential increase in the use of slash. It is expected that taking into account the research results will enable the forest manager to organise the collection of slash without endangering the survival of bark- and wood-related species.

Final project report (147.15 kB, pdf)

Project manager: Raul Rosenvald, Estonian University of Life Sciences
Duration: 2008–2011
RMK funding: EEK 1,426,868 / EUR 91,193

The project assessed the impact of forest drainage on fish fauna, amphibians, moss, beetles and the black stork.

It was found that the ditch network created as a result of forest drainage provides feeding grounds and habitats, including by increasing biodiversity and abundance, but it is of inferior quality compared to natural water body types. In addition, the ditch network also reduces the quality of natural water bodies.

Reconstruction should increase the variability of anthropogenic flow rates in man-made watercourses, and create ponds and sedimentation basins that reduce the impact of rapid dehydration on biota.

Although the species composition of swamp forests changes after drainage, significant species richness and abundance of studied molluscs, mosses and insects have emerged in the drained peatland forests.

Final project report (402.93 KB, pdf)

Project manager: Allan Sims, Estonian University of Life Sciences
Duration: 2008–2011
RMK funding: EEK 1,200,000 / EUR 76,694

The aim of the project was to create a stand growth model based on tree growth and drop-out equations, which would enable the forest manager to more accurately predict changes in the forest stand characteristics than before. The models currently in use are not precise enough, and if they continue to be used, scientists say there is a risk that incorrect management decisions will be made.

Final project report (574.69 kB, pdf)