Dendrochronology and wood anatomy

• Changing climatic conditions: Identifying short- or long-term relationships between radial growth and climate factors (primarily temperature and precipitation) helps to understand long-term growth patterns and tree responses to weather conditions.
• Growth response to natural and anthropogenic disturbances: Analysis of tree rings helps to understand how trees respond to natural disturbances (such as floods and insect outbreaks) and anthropogenic disturbances, including air pollution, wildfires, forest management activities (e.g., various types of logging), changes in water regimes (e.g., drainage), and the impact of deforestation on radial tree growth (in areas such as oil shale quarries).
• Species or genetic (provenance) suitability in the hemiboreal climatic zone: Studying tree rings (based on annual growth increments) allows the assessment of a species' suitability for specific site types and environmental conditions.
• Competition and environmental changes: Dendrochronological studies help assess tree responses to competition and environmental changes, including the effects of different management practices.
• Tree health, mortality indicators: Radial growth patterns provide information on tree health and mortality and allow precise dating of tree damage and death to the calendar year.
• Wood anatomy and xylogenesis research: This helps explain in great detail how climate change affects tree growth functions and wood quality.
• Wood formation research: This research improves understanding of the effects of year-round factors on wood formation and quality. It can help assess how trees and forests adapt to climate change, including through modeling.
• Remote sensing: Remote sensing data (e.g., NDVI) combined with tree ring series can be used to assess stand productivity, biomass, and carbon stocks.
• Annual growth monitoring using dendrometers: Continuous monitoring of changes in tree diameter to describe annual radial growth variations.

A) A sample of Scots pine prepared for measuring tree ring widths (cross-section). The tree rings display distinguishable earlywood (lighter portion) and latewood (darker portion). This pine tree grew in a drained area, where narrower tree rings characterize the period before the establishment of the drainage system. The change in tree ring width reveals the impact of drainage on pine growth (see C). At the time of drainage, the tree was 108 years old, with an average radial growth of 0.7 mm per year. During the post-drainage period, over the course of 61 years, the tree's breast height diameter increased by nearly 3 mm per year on average.

B) Heartwood and primary or juvenile wood. Heartwood is the dense tissue located at the center of the tree trunk, running longitudinally and tapering off at the top where the buds are. Juvenile wood typically consists of the first 10-20 (inner) tree rings. The cells in juvenile wood are short and thin-walled, with wide tree rings, a very small proportion of latewood, and low wood density.

C) Coniferous trees form cells with thin walls (spring or earlywood) at the beginning of the growing season, through which the necessary fluids for tree growth are transported. Towards the end of the summer, growth slows down, and thick-walled cells (summer or latewood) are formed, providing the trunk with strength.

The heartwood consists of thin-walled cells that store nutrient reserves. The heartwood can be round or polygonal in shape, and its form can serve as an additional feature in determining the tree species.

A frost ring in the earlywood of Scots pine (see the third ring from the heartwood). A frost ring forms as a result of cold damage during the growing season and appears as a zone of anomalously, irregularly developed cells within the annual rings (deformed cells and twisted rays of the heartwood).

Blue ring anomaly in the latewood of Scots pine (see the second ring from the heartwood). The image shows a cross-section of a wood sample, 12 μm thick, cut using a microtome and treated with dyes. In wood anatomy studies, Astra Blue and safranin are commonly used to stain samples. Astra Blue stains cellulose-rich areas blue, while safranin stains lignified cells red. Lignification is the final stage of the cell formation process. When this process is interrupted (e.g., if the temperature drops sharply at the end of the growing season), and the cells (tracheids in conifers) do not fully lignify, they appear blue under microscopic examination after staining.

Laboratory Visit

Reservations can be made for smaller groups, schoolchildren, and others. 

Planning Laboratory Work (for students of the EMÜ Forestry curricula)

Laboratory equipment can only be used with proper training and by booking a time slot in advance!

As per best practices, a primary or co-supervisor who is a member of the dendrochronology group will guide students in the laboratory.

Bachelor's Theses

• Jaan Markus Järva, 2023. 

• Laura Reimann, 2023. 

• Gert Lõhmus, 2023. 

• Kaira Kurvits, 2022. 

• Raimond Press, 2021. 

• Joel Arujõe, 2021. 

• Siim Laur, 2020. 

• Kaisa Paulson, 2019. 

• Maaris Varrik, 2017. 

• Sandra Kaasiku, 2017. Raiete mõju männipuude radiaalkasvule Järvselja harvendusraie katseala andmeil. 

• Olga Nikolenko, 2017. Lehiste radiaalkasvu analüüs Järvselja Õppe- ja Katsemetskonna puistutes. 

• Kärolin Kiis, 2016. Lehise radiaalkasvude varieeruvuse analüüs tüve erinevatel kõrgustel. 

• Katariin Keerd, 2016. Piusa koobaste looduskaitseala puistute metsahäiringute tuvastamine 

• Indrek Niidu, 2015. Arukase, hariliku kuuse ja hariliku männi radiaalse juurdekasvu ja kliima mõju analüüs laanemetsade andmeil. 

• Doris Silm, 2015. Kliima mõju analüüs arukase, hariliku kuuse ja hariliku männi radiaalkasvule loometsades. 

• Lehar Savikink, 2014. Hariliku kuuse radiaalse juurdekasvu võrdlus jänesekapsa ja sinilille kasvukohatüübis. 

• Aleksei Potapov, 2014. Hüdromelioratsiooni mõju hariliku männi (Pinus sylvestris L.) radiaalsele juurdekasvule sõltuvalt kuivenduskraavi kaugusest. 

• Taavi Kannimäe, 2013. Hariliku männi erinevate kasvuaastate aastasisese vara- ja hilispuidu varieeruvuse analüüs  

• Henri Kivimaa, 2013. Häiringute mõju puude radiaalsele juurdekasvule Põhja-Eesti männikutes. 

• Helen Vaikre, 2013. Hariliku männi radiaalse juurdekasvu ja kliima võrdlus erinevates kasvukohatüüpides Hiiumaal. 

• Marietta Pruuli, 2012. Dendroökoloogiline uurimustöö Käsmu poolsaarel. 

• Evar Dubolazov, 2012. Ilmastiku mõju kase radiaalsele juurdekasvule naadi kasvukohatüübis. 

• Heiki Valdaru, 2012. Kliima mõju puude radiaalsele juurdekasvule Järvselja harvendusraie proovialal. 

• Jüri Promet, 2012 

• Sander Pikkur, 2011. Hariliku kuuse (Picea abies (L.) Kast) radiaaljuurdekasvu sõltuvus kliimamuutujatest 

Master's Theses

• Virkeli Viiberg, 2023. Põua mõju hariliku kuuse (Picea abies) ja arukase (Betula pendula) juurdekasvule puht- ja segapuistutes. 

• Neeme Lõhmus, 2018. Harvendusraie mõju puude jämeduskasvule ning süsinikuvarudele ja -voogudele palumännikus. 

• Indrek Niidu, 2017. Lehiste juurdekasvude analüüs Järvselja Õppe- ja Katsemetskonna kahe erivanuselise puistu andmetel. 

• Aleksei Potapov, 2016. Kuivendussüsteemi rajamise ja rekonstrueerimise mõju puude radiaalsele juurdekasvule. 

• Lehar Savikink, 2016. Kase, kuuse, männi- ja haavapuude rinnasdiameetri sesoonne kasv dendromeetrite andmeil. 

• Taavi Kannimäe, 2015. Kliima mõju analüüs Järvselja lehisepuistutes. 

• Henri Kivimaa, 2015. Radiaalse juurdekasvu analüüs endise Sagadi metskonna männikutes. 

• Taavi Krusenvald, 2015. Hariliku kuuse rinnasdiameetri juurdekasvu modelleerimine jänesekapsa kasvukohatüübis. 

• Marietta Pruuli, 2014. Hariliku männi kasv ja häiringute mõju analüüs Käsmu poolsaarel. 

• Evar Dubolazov, 2014. Lehiste kasvu analüüs Sirgala tasandatud põlevkivikarjääri puistangul. 

• Taavi Kajaste, 2013. Siberi lehise (Larix sibirica Ledeb.) kasvukäik Aidu karjääris ja kliima analüüs. 

Doctoral Theses

Sandra Metslaid, Doctoral degree, 2017 (supervisors: Andres Kiviste, Ahto Kangur)link opens in new page
Title: Assessment of climate effects on Scots pine (Pinus sylvestris L.) growth in Estonialink opens in new page
Institution: Estonian University of Life Sciences (Eesti Maaülikool), Institute of Forestry and Rural Engineering, Department of Forest Managementlink opens in new page

Maris Hordo, Doctoral degree, 2011 (supervisors: Andres Kiviste, Helena Henttonen, Samuli Helama)link opens in new page
Title: Application of dendroclimatological methods for forest growth modellinglink opens in new page
Institution: Estonian University of Life Sciences (Eesti Maaülikool)link opens in new page

Supervised Creative and Research Works

Karl-Martin Vahejõe, 2016. Study of Tree Ring Growth. Tartu Kivilinna School, 8th Grade.

Karl-Martin Vahejõe, 2020. The Impact of Precipitation and Temperature on Radial Growth of Trees: A Case Study of Järvselja Nature Reserve. Research Paper, Tartu Jaan Poska Gymnasium.

Doctoral Theses

Aleksei Potapov, (juh) Maris Hordo, Modelling of tree and stand growth and yield in changing site conditions and economic analyze (Puu ja puistu kasvukäigu modelleerimine muutuvates kasvutingimustes ja majanduslik analüüs), Eesti Maaülikoollink opens in new page 

Maria Cristina Ferreira Marques, doktorant, (juh) Sandra Metslaid, Hariliku männi, hariliku kuuse ja kase puidu moodustumine seoses keskkonnatingimustega, Eesti Maaülikoollink opens in new page 

• The Formation of Stem Cracks in Spruces of Different Origins and Their Growth Response to Drought
• Growth of Different Tree Species under Changing Climatic Conditions and Their Growth Response to Drought
• The Impact of Drainage and the Reconstruction of the Drainage System on Pine Growth
• Growth and Suitability of Non-Native Species in Estonia's Climatic Conditions
• The Effectiveness of the Maintenance of Land Reclamation Systems on the Growth of Pine, Spruce, and Birch-Dominated Stands, Groundwater Level Seasonal Dynamics, and Wood Density Variabilitylink opens in new page
• Biomass Potential of Hybrid Poplar Plantations and Their Long-Term Impact on Biodiversity and the Environmentlink opens in new page

In Estonia

Department of Geography, University of Tartu: Emeritus Associate Professor Alar Läänelaid (PhD), Researcher Kristina Sohar (PhD), PhD student Kärt Erikson (PhD)

Department of Ecophysiology, University of Tartu: Associate Professor Arvo Tullus

Tartu Observatory: Vegetation Remote Sensing Researcher Jan-Peter George

International collaboration 

• Senior researcher, PhD Roberts Matisons, Latvian State Forest Research Institute “Silava”, Latvia, 2022-2023 

• Researcher/Postdoc PhD Jernej Jevšenak, Department for Forest and Landscape Planning and Monitoring, Slovenian Forestry Institute, Slovenia 

• Research Prof. Lauri Mehtätalo, Natural Resources Institute Finland (Luke), Joensuu, Finland 

• Prof. Marco Carrer, Department of Land, Environment, Agriculture and Forestry (TESAF), University of Padova, Italy 

• Prof. assoc. Marcin Klisz, Forest Research Institute, Poland, 2018-2023 

• Prof. of Wood Science Alan Crivellaro, University of Torino, Italy, 2018-2023 

• PhD student, Ciara Greaves, Department of Geography at the University of Cambridge, UK, 2022-2023 

• PhD student Karolina Janecka, Institute of Botany and Landscape Ecology, University of Greifswald, Germany, 2018-2022 

• Researcher, PhD Johannes Edvardsson, Department of Geology, Lund University, Sweden, 2018-2019 

• Senior researcher PhD. Maxim Yermokhin, Institute of Experimental Botany of the National Academy of Science of Belarus, Belarus , 2018-2019 

• TRACE 2027 link opens in new pageMay 24–29, 2027, Tartu, Estonia
• BaltDendro 2023, link opens in new pageAugust 14–18, 2023, Saaremaa, Estonia
• BaltDendro 2023: sharing knowledge and experience in the field of dendrochronology across the Baltic stateslink opens in new page
• BaltDendro 2014, August 25–28, 2014, Järvselja, Estonia

Tree-ring analysis, consultation

Tree-ring analysis, consultation.

link opens in new page

Dendrochronological methods

• Composing growth prognoses
• Dating the accurate tree age
• Estimating forest productivity
• Analyzing disturbances
• Analyzing climate effect
• Estimating the effectiveness of forest drainage
• Estimating the effect of thinning 

The variability of tree-ring width series provides information about environmental changes during the long period. By matching the pattern of wide and narrow tree rings (crossdating) it is possible to find the exact year of formation of each tree. The recovery and development of the stand due to disturbances (thinning, fire, ditching, insect outbreaks, drought, etc.) can be reconstructed using dendrochronological methods. It is possible to study the growth of coniferous and several deciduous species by using tree ring dating. Tree ring width measurement data enable to estimate the tree’s yearly increment and the stand growth. Based on stand increment data thinning and other management works of stands can be planned. It is possible to examine the growth of conifers and several deciduous trees on the basis of tree rings. Measuring the width of the tree rings allows to determine the annual increase in one tree and also calculate the growth of stand. Thinning and final cutting are planned based on the growth of stand.