Kalev Jõgiste

• Doctor of Philosophy
• Professor at Estonian University of Life Sciences

Wind disturbance and climate change increase the risk of major European spruce bark beetle (ESBB) outbreaks. In order to understand the drivers behind the spread, we used a combination of the Random Forest algorithm and logistic regression mixed modelling to generate robust results. We analysed tree and stand characteristics, level of infestation,...

Trees that survive disturbances are important biological legacies that facilitate forests' recovery and enhance their structural and species diversity, substantially contributing to the resilience of these ecosystems. The dynamic pattern of legacy syndromes sets the understudied aspects of survivors of wind disturbance into focus. Several factors a...

Shelterwood cutting (SC) has been highlighted as an alternative method to clear-cut (CC)-based even-aged forest management. However, compared to CC, the effect of SC on stand carbon (C) balance is still poorly understood at the ecosystem level. We examined the prompt effect of SC versus CC on ecosystem net primary production (NEP) on a short-term s...

Figure S1. Estimated marginal means of a)tree species richness, b)proportion of deadwood substrate, c)proportion of mound substrate, d)proportion of pit substrate, grouped by treatment. Means followed by a common letter are not significantly different according to the Tukey-test.

Climate change accompanied by altered natural disturbance regimes threatens the resilience of boreal and hemiboreal forests. Bryophytes, an important part of plant biomass and diversity, fulfill numerous important functions in forests, thus markedly contributing to the resilience of these ecosystems. We studied abundance, richness, diversity and co...

The herbaceous understory is a key component of forest biodiversity. Moreover, it holds the capability to alter the dynamics and composition of the overstory. Severe wind disturbance changes the conditions in a forest ecosystem radically, causing alteration of understory characteristics as well. In this paper we analyze impacts of different storm d...

The study area is in the Järvselja Training and Experimental Forest Centre, Estonia. The conservation of Järvselja old-growth forest started in 1924 when the area was excluded from all management activities and left to natural development. The aim of this study is to analyse the methods for calculating single tree height, tree stem lateral surface...

The anticipated increase in extreme disturbance events due to climate change is likely to expose Norway spruce (Picea abies (L.) Karst.) dominated forests in northern Europe to new conditions. Empirical data on the resilience of such natural (unmanaged) forests to disturbance and the long-term patterns of regeneration in its aftermath are currently...

Changes in climate, land use, and land management impact the occurrence and severity of wildland fires in many parts of the world. This is particularly evident in Europe, where ongoing changes in land use have strongly modified fire patterns over the last decades. Although satellite data by the European Forest Fire Information System provide large-...

Forests are the dominant land cover in Nordic–Baltic countries, and forestry, the management of forests for improved ecosystem-service (ES) delivery, is an important contributor to sustainability. Forests and forestry support multiple United Nations Sustainability Goals (UN SDGs) and a number of EU policies, and can address conflicting environmenta...

Global forest area is declining rapidly, along with degradation of the ecological condition of remaining forests. Hence it is necessary to adopt forest management approaches that can achieve a balance between (1) human management designs based on homogenization of forest structure to efficiently deliver economic values and (2) naturally emerging se...

In light of the difficulties in stand volume estimation of natural forests, we analyzed height–diameter relationships and derived a set of height estimation equations for volume estimation for naturally developing forest ecosystems, using the Järvselja old-growth and the Laeva commercial forest in Estonia as a case study. This contribution presents...

In this review and synthesis paper, we review the resilience of secondary forests to climate change through the lenses of ecosystem legacies and landscape diversity. Ecosystem legacy of secondary forests was categorized as continuous forest, non-continuous forest, reassembled after conversion to other land uses, and novel reassembled forests of non...

Growth of CO2 concentration level has strong interactions with forests. Forests are able to sequester carbon (C) through photosynthesis and can help to mitigate the effects of climate warming, as well as to reduce the CO2 concentration in the atmosphere. Drought and other extreme weather conditions play a key role in ecosystem functioning and the C...

Forest ecosystems are shaped by disturbances and functional features of vegetation recovery after disturbances. There is considerable variation in basic disturbance characteristics, magnitude, severity, and intensity. Disturbance legacies provide possible explanations for ecosystem resilience. The impact (length and strength) of the pool of ecosyst...

Fire is the most important natural disturbance in boreal forests, and it has a major role regulating the carbon (C) budget of these systems. With the expected increase in fire frequency, the greenhouse gas (GHG) budget of boreal forest soils may change. In order to understand the long-term nature of the soil–atmosphere GHG exchange after fire, we e...

Disturbance regimes are changing in forests across the world in response to global climate change. Despite the profound impacts of disturbances on ecosystem services and biodiversity, assessments of disturbances at the global scale remain scarce. Here, we analyzed natural disturbances in boreal and temperate forest ecosystems for the period 2001–20...

Disturbance regimes are changing in forests across the world in response to global climate change. Despite the profound impacts of disturbances on ecosystem services and biodiversity, assessments of disturbances at the global scale remain scarce. Here, we analyzed natural disturbances in boreal and temperate forest ecosystems for the period 2001–20...

The tree diameter distribution was used to characterize the impact of forest disturbances and the ecosystem dynamics during the process of regeneration in the absence of any management 44 years after the event. In addition, the impact of salvage logging after windthrow remains unknown, especially on long-term responses. In this study, comparisons w...

A large area of Estonian hemiboreal forest is recovering from clear-cut harvesting and changing carbon (C) balance of the stands. However, there is a lack of information about C- source/sink relationships during recovery of such stands. The eddy covariance technique was used to estimate C-status through net ecosystem exchange (NEE) of CO2 in two st...

Boreal and temperate forests cover a large part of the Earth. Forest ecosystems are a key focus for research because of their role in the carbon (C) balance and cycle. Increasing atmospheric temperatures, different disturbances (fire, storm and insects) and forest management (clear-cutting) will change considerably the C status of forest ecosystems...

In Lithuania, free-ranging European bison live sedentarily in the fragmented landscape of the central part of the country. The aim of this study was to analyze the distribution and habitat selection of European bison in a semi-isolated territory. Free-ranging European bison living sedentarily have formed six groups in the mosaic landscape of centra...

The main aim of afforestation in the Baltic States until recently has been to establish commercially valuable, particularly conifer-dominated forests. Spruce (Picea spp.) and pine (Pinus spp.) plantations on abandoned farmland, however, are often plagued with root rot, and timber quality is reduced by the wide spacing of low density plantings that...

In the Baltic States region, anthropogenic disturbances at different temporal and spatial scales mostly determine dynamics and development phases of forest ecosystems. We reviewed the state and condition of hemiboreal forests of the Baltic States region and analyzed species composition of recently established and permanent forest (PF). Agricultural...

The main tenets of forest health management are to simultaneously maintain productivity and all native species over time, which will in turn maintain ecosystem services provided by the forest. Natural disturbances oppose the stable flow of materials, while removals of timber short-circuit the flow of organic materials to the deadwood pool and reduc...

Isaac Newton's approach to developing theories in his book Principia Mathematica proceeds in four steps. First, he defines various concepts, second, he formulates axioms utilising the concepts, third, he mathematically analyses the behaviour of the system defined by the concepts and axioms obtaining predictions and fourth, he tests the predictions...

The condition of forest ecosystems depends on the temporal and spatial pattern of management interventions and natural disturbances. Remnants of previous conditions persisting after disturbances, or ecosystem legacies, collectively comprise ecosystem memory. Ecosystem memory in turn contributes to resilience and possibilities of ecosystem reorganiz...

We compared the changes in aboveground biomass and initial recovery of C pools and CO2 efflux following fire disturbances in Scots pine (Pinus sylvesteris L.) stands with different time since stand-replacing fire. The study areas are located in hemiboreal vegetation zone, in north-western Estonia, in Vihterpalu. Six areas where the last fire occurr...

Establishment of the SMEAR Estonia at a hemiboreal mixed deciduous broad-leaved-evergreen needle-leaved forest at Järvselja, SouthEastern Estonia, has strongly enhanced the possibilities for national and international cooperation in the fi elds of forest ecosystem – atmosphere research and impacts of climatic changes on forest ecosystems, atmospher...

Fire is a significant agent for the development of boreal and hemiboreal forests, altering soil and light conditions, affecting seedbanks, and removing seed trees. Burned areas should be managed with care, as inappropriate techniques prolong the regeneration period and reduce the diversity and resilience of stands to disturbances. To study the effe...

Corresponding with the increasing global resource demand, harvesting now affects millions of hectares of boreal forest each year, and yet our understanding of harvesting impacts on boreal carbon (C) dynamics relative to wildfire remains unclear. We provide a direct comparison of C stocks following clearcut harvesting and fire over a 27-year chronos...

The effects after 25 years of moose browsing on Scots pine stands in Lahemaa National Park were evaluated, emphasizing economic damage. A re-evaluation in 2001 examined stands that had been evaluated in 1975–1976. Moose damage significantly affected the tree species composition which changed over time as pine dominance increased and the number of m...

Metabolism of trees, ground vegetation and microbes generate carbon and nitrogen fluxes in forest ecosystems. Carbon flows through the system, and nitrogen circulates between vegetation and soil. Trees synthesise sugars in photosynthesis and take nitrogen from soil. The biochemical regulation system allocates the annual amounts of synthesised sugar...

Background/Question/Methods Storm events increase heterogeneity in the range of potential tree establishment sites. This heterogeneity does not, however, guarantee survival. Many studies on post-disturbance stand development are limited to only the first few years after disturbance. In this investigation, we analyse regeneration height and mortali...

Background/Question/Methods Changes in regional or global biological diversity or spatial distribution reflect the reactions of organisms in these ecological systems to modified environment conditions. Changes in the behavior of any single species, taxon or geographic region have a number of possible explanations including not only climate change...

Aboveground deadwood, consisting of downed woody debris (DWD), snags, and stumps, is an important component of boreal forest ecosystem structure. Accurate deadwood density estimates are essential for evaluating ecosystem biomass and carbon stocks. The objective of this study was to examine the relationships between deadwood density, tree species, a...

The damage caused by large herbivores feeding on forest trees is considerable. This study was carried out to determine the reaction of Scots pine (Pinus sylvestris L.) trees to mechanical bark stripping that imitates the damage to tree stems caused by moose (Alces alces L.). There was a significant difference between the height increment of control...

During two measurement campaigns, from August to September 2008 and 2009, we quantified the major ecosystem fluxes in a hemiboreal forest ecosystem in Järvselja, Estonia. The main aim of this study was to separate the ecosystem flux components and gain insight into the performance of a multi-species multi-layered tree stand. Carbon dioxide and wate...

Boreal forest carbon (C) storage and seques-tration is a critical element for global C management and is largely disturbance driven. The disturbance regime can be natural or anthropogenic with varying intensity and fre-quency that differ temporally and spatially the boreal for-est. The objective of this review was to synthesize the literature on C...

We reviewed studies dealing with regeneration under variable conditions in boreal and hemiboreal forests as affected by different microsite types by tree species functional groups. Generally, the importance of storm-induced microsites for regeneration dynamics in boreal forests depends on several factors: (1) distribution and type of microsites (ge...

There is strong evidence that climate change alters tree growth in boreal forests. In Estonia, the analysis of ring measurements has been a common method to study growth changes. In this study, annual height growth data from dominant or co-dominant Scots pine (Pinus sylvestris L.) trees were used to develop a growth model for three forest generatio...

Natural regeneration of windthrow areas is an important issue when planning forestry measures after forest disturbances. Seedling recruitment was investigated in storm-damaged hemiboreal mixed forests in eastern Estonia. The establishment and growth of seedlings from natural regeneration was registered for tree species in soil pits and in mounds of...

Long-term sample plots have been used to study pathways of succession, and its mechanisms and causes. These observations are relevant not only to communities protected from human interference, but also to managed forests, where the objective is to explain response patterns following specific harvesting operations. The establishment and maintenance...

Köster, K., Voolma, K., Jõgiste, K., Metslaid, M., Laarmann, D. 2009: Assessment of tree mortal-ity after windthrow using photo-derived data. — Ann. Bot. Fennici 46 (4): 291-298. We used sequential surface photography and photo-derived data to evaluate tree mor-tality in a windthrow area in eastern Estonia, where a storm occurred in 2001. The study...

Disturbances are a natural part of all ecosystems and they are important for the maintenance of biodiversity in forest ecosystems (Attiwill 1994). Periodicity and intensity of disturbances shape the structural characteristics and dynamics of forest landscape mosaics (Turner et al. 2001). Natural disturbances increase habitat availability and divers...

• This review summarizes early stand-scale studies of pristine forest structures, disturbance regimes and successional patterns carried out in boreal Eurasia. We attempt to reveal, characterize and classify stand dynamic types that can be used as templates for nature-based forest management. • The studies reviewed demonstrate multiple successional...

Coarse woody debris (CWD). represented by logs and snags (>10 cm in diameter and >1.3 m in length/height), were sampled from two Eastern Estonian windthrow events (Tudu and Halliku), where storm occurred in the summers of 2001 and 2002. CWD was sampled to identify factors that affect early wood decomposition and changes in wood density. Tree specie...

As fire is inherent to boreal forest, sustainable forest management should consider emulating this disturbance type, taking into account the natural fire regime and the historical impact of humans. Fire often removes the dominant species and reveals mineral soil, which allows new species to spread on burned areas. Variable conditions provide habita...

Modern forestry has been evolving towards multiple-use of forests and maintenance of biodiversity. Interest in integrating natural forest dynamics into management planning and silvicultural practices has increased as a result of concerns related to biodiversity values and maintaining ecological functions in managed forests. Taking advantage of natu...

In general, forests in Estonia are characterized by great variability, not only in protected areas but in commercial forests as well. The data needed for the derivation and calibration of growth models can be obtained by continuous observation of permanent growth plots (also known as longitudinal studies) or by establishing chronosequences with tem...

The regeneration patterns in wind-damaged areas are largely influenced by damage severity and varied microrelief. Regeneration was studied in Picea abies dominated stands with total and partial canopy destruction and in harvested areas in Myrtillus and Filipendula site types in Estonia 4–5 years after a storm, examining particularly the influence o...

We studied the acclimation of advance regeneration of Norway spruce after the regeneration cut. The sampling of trees was carried out on permanent sample plots in Estonia. It was developed further new method to use physiological indicators for modelling advance regeneration. Therefore portable photosynthesis system CIRAS is used to measure gas exch...

La composition en espèces et le nombre d'espèces dans la végétation au sol suite à un chablis varient selon la sévérité des dommages et les actions posées après une tempête. Cette étude avait pour but de déterminer les changements dans la composition en espèces selon la sévérité des dommages causés par la tempête. La réponse de la végétation a été...

The classification of forest plant communities has been carried out by several researchers. The classification proposed by E. Lõhmus is used as an official tool by forest survey institutions in Estonia. The research addresses the results of cluster analysis to distinguish site types using different indices of floristic similarity. The methods of tr...

This study examined the effect of release on needle properties of Norway spruce advance regeneration in a gap clearing. Needle mass is a variable revealing the acclimation capacity of understorey saplings. Correlations between several needle variables were also examined. A model of needle mass increase over time was developed. Needle mass and shoot...

Ecosystem management assumes that management practices based on natural disturbance patterns are likely to preserve both natural biodiversity and ecosystem functions. Ecosystem management thus combines traditional natural resource management and forestry practices together with classical notions of protection that are focused on sustaining a natura...

The coarse woody debris (CWD) was inventoried in two boreal Estonian conifer-dominated forest landscapes/national parks, Lahemaa and Karula, with different forestry history and management intensity. The inventoried areas in both national parks consisted of a core with a strict nature reserve (unmanaged) and the surrounding protected special and res...

Several storms have damaged Estonian forests in recent years. Individual tree properties such as diameter at breast height (dbh) and tree height affect the type of damage (stem breakage or uprooting) and influence the formation of postdisturbance forest structure. The aim of this study was to analyse how the risk of uprooting and stem breakage vari...

We developed a basal area growth model for recovery of advance growth of Norway spruce trees after clear-cutting. Stem diameter growth at ground level and needle-mass characteristics were measured on permanent sample plots in Estonia. Both tree ring analysis (destructive sampling on one sample plot) and yearly repeated measurement data (two plots)...

There has been a long discussion among ecologists, foresters and natural resource managers over the need to combine traditional natural re- source management and forestry with classical nature protection methods. Ecosystem management is widely proposed in popular and scientific literature as a new way of managing natural resources and ecosystems. T...

Summary We examined the growth of birch (Betula pendula Roth. and Betula pubescens Ehrh.) regenerated on 22 former agricultural fields in Estonia. Birch stands on half of the former fields were planted, while the other half were from natural regeneration. After 2 years of data collection, stem and crown variables were correlated with growth indices...

The aim of the present study was to examine the quantitative and qualitative status of dead wood in two Estonian national parks (Lahemaa and Karula). The volume, size and decay stage of Coarse Woody Debris (CWD) in forests of different kinds of forestry background and forest site type variability were investigated. The primary interest was to exami...

The growth of trees of spruce advance regeneration growth was measured in consecutive years on a permanent sample plot. The basic acclimation tendencies of needles are described by a dynamic model. The hypothesis on continuous needle recovery was verified. The attributes correlated to age and growth were searched. The needle mass characteristics ca...

An individual tree basal area increment model was developed for Norway spruce [Picea abies (L.) Karst] in mixed stands of spruce and birch in Estonia. Different regression equations were fitted for different combinations of variables to obtain biologically tractable interactions between growth and factors affecting it. The best fit index of the reg...

Metsade bioloogilise mitmekesisuse säilitamine - brošüür Eesti Metsakaitsealade Võrgustiku raames

Bolewood volume accumulation patterns and levels of mixed Norway spruce and birch forests in Estonia based on modelled population dynamics are discussed in this paper. Trees were divided into separate populations according to species and canopy class. Diameter growth was estimated from increment cores in ten 0.1 ha-sample plots to provide the growt...

There are different approaches to modelling the regeneration of tree stands. The regeneration phase of the stand can be seen as a causal factor in the further development of the stand. The variables selected for regeneration modelling determine the model output resolution. The present paper deals with the mechanisms and processes used for regenerat...