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Eastern Hemlock

Latin name:
Tsuga canadensis

Extracted from a waterfront pier near Wilmington, Delaware, the tree used to make this portion of the pier
actually came from a forest located in central Pennsylvania. The outermost tree ring dates to the late 1830s.

Giant Sequoia

Latin name:
Sequoiadendron giganteum

A close up of numerous fire scars on a giant sequoia cross section from Sequoia National Park in California, dating back well prior to A.D. 1000. Look closely! Can you find the sad bearded face cradled by his hands, as if he was crying?

Douglas-fir

Latin name:
Pseudotsuga menziesii

This photo shows the tree rings from a beam extracted many years ago from a pueblo in northeastern Arizona. The section shows many false rings and many micro-rings, suggesting this tree may have been growing in a marginal environment.

Ponderosa Pine

Latin name:
Pinus ponderosa

Close up of tree rings of a ponderosa pine collected at El Malpais National Monument in New Mexico, USA, showing tree rings centered around A.D. 1400. Notice the variability in ring widths indicative of sensitivity to year-to-year variation in precipitation.

Douglas-fir

Latin name:
Pseudotsuga menziesii

Perhaps my most requested image of tree rings, obtained from a small Douglas-fir growing in the Zuni Mountains of west-central New Mexico by my colleagues Rex Adams and Chris Baisan. Not very old, but has some of the most beautiful rings of all my displays!

White Oak

Latin name:
Quercus alba

Oak cores from the Hoskins House in Greensboro, North Carolina, site of a famous battle during the Revolutionary War. The house was built from trees cut in 1811 to 1813, not cut and built in the 1780s as the historical agency had hoped.

Ponderosa Pine

Latin name:
Pinus ponderosa

This ponderosa pine once grew at El Morro National Monument in New Mexico, USA, and was cut many years ago. Once you get up close to the stump, you can see a very old scar from a fire many hundreds of years ago that scarred the tree when it only about 12 years old!

Bahamian Pine

Latin name:
Pinus caribaea var. bahamensis

We collected many cross sections of Bahamian pines that had been cut for an industrial park on the island of Abaco, but the rings are very difficult to date! Many false rings, and the pine appears to terminate tree growth during the dry season.

Longleaf Pine

Latin name:
Pinus palustris

This cross section was one of many that came from an old crib dam across a creek that was exposed after a modern dam broke in Hope Mills, North Carolina in 2003. Such sections from old-growth longleaf pines are very rare and provide information on climate back to AD 1500!

White Oak

Latin name:
Quercus alba

Sometimes you don't have to look far to find beauty in wood, and sometimes it may not be a living tree! After an oak tree was cut a year or two before this section was obtained, decay fungi had already set in, beginning to break the wood down to its basic elements.

Southwestern White Pine

Latin name:
Pinus strobiformis

I collected this fire-scarred pine on Mt. Graham in southern Arizona in fall 1991, and it remains one of the best examples of how we can determine the season of fire by looking at the position of the scar within the ring.

Bristlecone Pine

Latin name:
Pinus longaeva

Bristlecone pines have become one of the best proxy records for those who study the history of volcanic eruptions because the cool temperatures caused by these eruptions create "frost rings" that form when the cells implode from the cold.

Eastern Redcedar

Latin name:
Juniperus virginiana

Many well-preserved eastern redcedar sections have been recovered from prehistoric sites in eastern Tennessee, and they have more than enough rings to date, but we don't have a long enough living-tree reference chronology to overlap with them!

Red Oak

Latin name:
Quercus rubra

Oak is by far the most common genus we find in the many historic structures we date using tree rings in the Southeastern U.S. The genus has good ring variability and rarely has problem rings. This section came from a historic tavern in Lexington, Virginia.

Sugar Maple

Latin name:
Acer saccharum

Maple, birch, beech, and basswood are all examples of hardwood species that form diffuse porous wood, meaning that the ring contains many small-diameter vessels all through the ring. Identifying the ring boundary on this wood type is a challenge to tree-ring scientists.

Live Oak

Latin name:
Quercus virginiana

Live oak is an example of an evergreen oak, which is not common within this genus. As such, the wood is semi-ring porous and the rings are very difficult to see and date. Ring growth is also very erratic, not forming the concentric around the tree that we require.

Douglas-fir

Latin name:
Pseudotsuga menziesii

These cores were collected on Mt. Graham in southern Arizona and show a major suppression event beginning in 1685 when missing rings became evident, followed by many micro-rings. This suppression was caused by a major wildfire in 1685!

Ponderosa Pine

Latin name:
Pinus ponderosa

I find it amazing what trees can record in their tree rings! Here we see a cross section of a pine that was damaged by a major flood in the year 1945 in the Chiricahua Mountains of southern Arizona. Notice the reaction wood that formed afterward.

Pignut Hickory

Latin name:
Carya glabra

Sometimes gray-scale imagery helps define tree rings when measuring. Although classified as "ring porous" species, the rather ill-defined tree rings in hickory tree species form large earlywood vessels and smaller latewoood vessels.

Subalpine Fir

Latin name:
Abies lasiocarpa

Decay has set in on the tree rings of this dead and downed subalpine fir that once grew on Apex Mountain in British Columbia, Canada, but the tree rings can still be measured and crossdated despite this!

White Fir

Latin name:
Abies concolor

We found a beautiful fire scar on this white fir that was used to build a cabin in the Valles Caldera of New Mexico. Thought to have been built in the early 1900s, we instead found the cabin was built form white fir and Douglas-fir trees cut in 1941.

Overcup Oak

Latin name:
Quercus lyrata

These oak cores were collected in northeastern Arkansas to investigate a change in the hydrologic regime of a wildlife refuge beginning in the 1990s. We found that trees at this site experienced a major disturbance event in the 1960s.

Western Juniper

Latin name:
Juniperus occidentalis

Near Frederick Butte in central Oregon, we discovered an unusual stand of western junipers that had the most unusual lobate growth forms we had ever seen. This site yielded a drought-sensitive chronology dating back to the AD 800s!

West Indies Pine

Latin name:
Pinus occidentalis

Above 3000 meters on the highest peak in the Carribean, we found an entire forest of these pines, many with fire scars, living on a steep rocky slope. The forest looked more like the dry ponderosa pine forests of the western U.S.

Whitebark Pine

Latin name:
Pinus albicaulis

Whitebark pines growing in the northern Rockies of the western U.S. can grow to be over 1,000 years old, but the species is slowly being decimated by the introduced white pine blister rust. Many of these ancient trees are now dead with ghostly white trunks.

Shagbark Hickory

Latin name:
Carya ovata

Curiously, tree-ring scientists rarely analyze some of the more common hardwood species in the eastern U.S., such as this hickory, perhaps because such forest interior trees may contain a weak climate signal necessary for crossdating.

Virginia Pine

Latin name:
Pinus virginiana

Blue stain found in many sections of dead pines (both in the western and eastern U.S.) is caused by a fungus carried by a pine beetle. The fungus spreads into the phloem and sapwood of living and dead pines, sometimes creating stunning patterns!

Pinyon Pine

Latin name:
Pinus edulis

Burned sections of pinyon pine are commonly found in archaeological sites in the southwestern U.S. These sections can be carefully broken or surfaced with a razor to reveal the ring structure inside to assist in dating the years of construction of the site.

Red Spruce

Latin name:
Picea rubens

Conifers in the highest elevations of the Appalachians of the eastern U.S., such as this red spruce, don't experience wildfires very often, but when fires do occur, they can create numerous fire scars even in this fire-intolerant species. Notice the growth release!

White Spruce

Latin name:
Picea glauca

This tree was located in the Canadian Rockies on the toe slope of an active avalanche path. The scar was created by a debris flow or snow avalanche which struck the tree, killing a section of the living tissue. The avalanche can therefore be dated to its exact year!

Engelmann Spruce

Latin name:
Picea engelmannii

I worked considerably in the spruce-fir forests of southern Arizona in my earliest years in dendrochronology, and learned that trees with limited sensitivity can provide a vast amount of information on the history of these forests.

Ponderosa Pine

Latin name:
Pinus ponderosa

The lava flows of El Malpais National Monument in New Mexico contain vast amounts of remnant wood, mostly ponderosa pines such as this sample, and the tree rings on these samples go back nearly 2000 years! Notice the year AD 1400 on this section.

Chestnut Oak

Latin name:
Quercus montana

In the southeastern U.S., hardwood species are often scarred by wildfire. Most often, this also will cause considerable decay in the sample, but this oak had several well preserved fire scars, suggesting fire was common in these drier, lower elevation sites.

Ponderosa Pine

Latin name:
Pinus ponderosa

I originally sampled this stump in 1991 for its fire scars, located in El Malpais National Monument of New Mexico. I found it again 20 years later and was happy you could still see the tree rings and fire scars clearly! It had originally been logged in the 1930s!

Lodgepole Pine

Latin name:
Pinus contorta

This pine is found at higher elevations in the Rocky Mountains of the western U.S. At this site in Montana, we had thought we found fire scars on these pines, but it turns out that these are scars caused by bark beetles stripping away portions of the bark.

Douglas-fir

Latin name:
Pseudotsuga menziesii

These cores illustrate the level of sensitivity to climate fluctuations in Douglas-fir trees growing in El Malpais National Monument in New Mexico. These rings show the common pattern of narrow marker rings between 1800 (on the left) and 1860 (on the right).

Douglas-fir

Latin name:
Pseudotsuga menziesii

This photo shows a close-up of the rings in the previous image. The very wide tree ring is the year 1816, the "Year Without a Summer." Cooler temperatures meant more soil water for the malpais Douglas-firs, causing a wide ring for that year!

Ponderosa Pine

Latin name:
Pinus ponderosa

Dating fire scars found in the annual rings is a major application of tree-ring dating. This photo shows two scars. Notice the wider rings that formed after the upper scar, perhaps caused by removal of competing vegetation or added nutrients.

Longleaf Pine

Latin name:
Pinus palustris

Longleaf pines have the greatest ages of all the eastern pines. They grow slowly in sandy soils of the Atlantic Coastal Plain, and have proven ideal for learning about past climate and disturbance events, if old-growth stands can be located!

Rocky Mountain Juniper

Latin name:
Juniperus scopulorum

The juniper species of the western U.S. have proven a challenge in tree-ring dating, but Rocky Mountain juniper has tree rings that are easily identified and can be crossdated. Just watch out for false rings and expanded latewood!

Douglas-fir

Latin name:
Pseudotsuga menziesii

A close-up photo of tree rings in Douglas-fir reveals the individual wood cells that make up the xylem. These are called "tracheids." Notice the change in cell wall thickness from the earlywood cells to the latewood cells along a radial file of cells.

Douglas-fir

Latin name:
Pseudotsuga menziesii

The best trees for learning about past climate will be those that grow to great ages and are particularly sensitive to year to year changes in climate. This Douglas-fir began growing around the year 200 BC and lived for nearly 1000 years!

Mesquite

Latin name:
Prosopis glandulosa

Some desert species from the mid-latitudes do form annual rings, but these diffuse-porous species have rings that are difficult to see. You can use black marker and white chalk dust to help bring out the rings! The dust fills the small vessels and the rings appear!

Norway Spruce

Latin name:
Picea abies

Spruce is the preferred genus for making high-quality wooden bodies on musical instruments. This photo shows the tree rings on the outer edge of the "Messiah" violin. Analysis of its tree rings helped show that the violin was contemporary with Stradivari!

Black Locust

Latin name:
Robinia pseudoacacia

In the eastern U.S., this common hardwood species has beautiful tree rings that demonstrate the ring porous wood type. The tree species, however, has some of the densest wood found in North America and is extremely difficult to core!

White Oak

Latin name:
Quercus alba

Oak is a major genus used to build log structures in the eastern U.S. Sometimes, however, we find that the individual trees experienced some major disturbances that caused very aberrant rings, making crossdating all but impossible.

Palo Verde

Latin name:
Parkinsonia florida

A common tree species in the American Southwest, palo verde is a diffuse porous species that forms very indistinct tree rings. As a result, little tree-ring research has been performed on this genus. Best to use complete cross sections, when available.

Ponderosa Pine

Latin name:
Pinus ponderosa

A major application of tree-ring research is learning about insect populations. For example, pandora moth defoliated the needles on this tree, causing some narrow rings to be produced. We can use this pattern to learn about insect populations over many centuries!

Table Mountain Pine

Latin name:
Pinus pungens

The analysis of fire scars in tree rings can also be applied to pine species growing in the eastern U.S. Table Mountain pine has proven to be the best species in the Appalachian Mountains for learning about past wildfires!

Subalpine Fir

Latin name:
Abies lasiocarpa

Subalpine fir grows in the highest elevations of the southern Rocky Mountains and forms fairly compacent ring series. Sometime between 1979 and 1980, this tree was stripped almost completely of its bark by a black bear, but it still survived in one small area!

Florida Torreya

Latin name:
Torreya taxifolia

Perhaps the rarest conifer in the U.S., this species is on the brink of extinction because its habitat is facing mounting pressure from rapid changes in its native environment. It forms very nice tree rings, but few adult individuals are left to analyze.

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get in touch

Positions in Dendrochronology

The dendrochronological community is a small one relative to other scientific disciplines. This makes making connections difficult, especially in the job market. I hope to fill this gap by providing information on jobs available and of interest to the tree-ring community. If you would like to post an announcement on this page for a job position, send a message to me using the email address at the top of this page. If we all participate, we'll all benefit!


Assistantships for Master's Students
Oklahoma State University

Multiple opportunities for graduate study in plant ecology (including dendroecology) and evolutionary biology are available for Fall 2018 in the Department of Plant Biology, Ecology and Evolution at Oklahoma State University.  Teaching assistantships are available for study towards an MS in Plant Biology or a PhD in Plant Science.  Potential areas of research could include:

Trade-offs in drought tolerance among tree species at the forest-prairie ecotone

The roles of drought stress, fungal pathogens, and insects in tree mortality

Tree-ring growth response to climate among species at the forest-prairie ecotone

The role of anthropogenic change in shaping plant-pollinator interactions and plant reproductive output

The role of ecological interactions in plant mating system evolution

Comparative plant genomics, evolution, and systematics

Evolution of milkweed-insect interactions

Plant taxonomy and biogeography

Assistantships include tuition waivers and health insurance. Learn more about the OSU Department of Plant Biology, Ecology, and Evolution at http://plantbio.okstate.edu/.  Contact Dr. Henry Adams (henry.adams@okstate.edu, www.henrydadams.com), Dr. Janette Steets (janette.steets@okstate.edu), or Dr. Mark Fishbein (mark.fishbein@okstate.edu) for more information.  In your email, please include brief description of your research interests, experience, and career goals, and attach a CV or resume. Applications are due to the OSU graduate college by 2/28/18, but early application is strongly advised for full consideration and support.



Postdoctoral Researcher
Czech University of Life Sciences in Prague

We are seeking a postdoctoral researcher to join our team within the Forest Dynamics Lab of the Department of Forest Ecology, Faculty of Forestry and Wood Sciences in Prague, Czech Republic. The project is titled “Disturbance regimes as drivers of structural variability, carbon dynamics and biodiversity at the stand and landscape levels in primary mountain forests in central and eastern Europe."

 Disturbance plays a dominant role in shaping the structure and function of forest ecosystems, but quantification of disturbance effects is typically limited by missing information on a location’s history and a region’s disturbance regime. Our lab uses tree-ring data to reconstruct site histories, providing insight into how forest characteristics recover from disturbances of variable severity. We are particularly interested in linking patterns in the severity and frequencies of disturbance to variation in tree size structure, carbon dynamics and biodiversity.

The Carpathian forest region is ecologically unique in maintaining two co- mingling monospecific forest types broadly distributed across gradients of external drivers. The project will link biomass and biodiversity indicators to disturbance histories in primary forests that permit such direct contrasts of endogenous and exogenous drivers. The project will therefore provide novel insights on whether the predictions of present biomass and forest biodiversity indicators can be improved by more accurately partitioning the relative importance of exogenous and endogenous drivers. At the same time, this project will be the first to reconstruct biomass trends in large patches of primary forests in central and eastern Europe, while most other studies tend to be based on national forest inventories in managed forests, which greatly limits the ability to infer the long term dynamics of forest development. The proposed project will be organized into interlinked work packages subdivided into research questions focusing on quantification of the main drivers of forest dynamics and biomass and biodiversity indicators responses.

WP 1. Drivers of disturbance dynamics
WP 2. Tree growth history and forest biomass
WP 3. Stand structural diversity and biodiversity indicators

The successful candidate will have access to a completed database of 20 000 tree cores collected from 1000 forest plots distributed throughout remaining patches of old-growth forest is central and eastern Europe. Plots are distributed in a hierarchical design (i.e. plots nested within stands, within landscapes throughout the Carpathian mountain range). The aim of the design is to partition the effects of disturbance effects at a variety of scales, from local variation among neighboring locations due to smaller-scale gap dynamics to more extreme events impacting entire landscapes. The selected candidate will be expected to lead projects using available tree- ring data to link tree growth, disturbances and biomass dynamics to abiotic and biotic factors. Responsibilities will predominantly be data analysis and manuscript preparation. Opportunities to visit some of our impressive field locations will be available, but the candidate is not expected to participate in data collection.

We are a young and energetic research team with close collaborations with international partners. Opportunities exist for international exchange visits and meetings. To obtain more information about our team, visit http://scholar.google.cz/citations?user=DaBJTM4AAAAJ

Applicants should have a PhD (at the time of hire) in environmental or related sciences (biology, ecology, geography, forest sciences), and excellent English communication and writing skills on the level of native speaker is essential.   Salary: 45000 –60 000 CZK based on the previous experience and performance. We offer a 2-year position. The starting monthly salary represents double of the median salary in the Czech Republic. To compare living costs see here: https://www.expatistan.com/cost-of-living In addition, there is a share increase based on the personal performance.

Applications: Please attach a CV listing skills and qualifications, a list of publications and other documents deemed important by the applicant. Applicants should provide a short statement outlining why they believe themselves to be suitable for the above position. Applicants should include contact information for two references, one being the current or most recent employer.   Send the application to the following address: Miroslav Svoboda Email: svobodam@fld.czu.cz Postal address: Czech University of Life Science, Faculty of Forestry and Wood Science, Kamycka 129, Praha 6 Suchdol, 16521, Czech Republic

 


PhD Assistantship in Riparian Forest Ecology and Tree-Ring Research
State University of New York-ESF

Project description: Linking basin-scale, stand-level, and individual tree water stress indicators for groundwater-dependent riparian forests in multiple-use river basins

Managing water resources is increasingly challenging in many river basins globally as the climate becomes warmer and drier. Human demand on water resources, particularly groundwater, is high in multiple-use river basins where significant withdrawals occur for intensive agriculture and industry. The interaction between high groundwater extraction by humans and climatic drought, such as that which is currently affecting large areas of California, can result in rapidly declining water tables with strongly negative consequences for groundwater-dependent ecosystems (GDEs). Riparian forests, which are hotspots of biodiversity and support key functions and habitats within many GDEs, are particularly sensitive to water table dynamics. Rapid and sustained declines in groundwater tables typically induce reduced growth, vigor, and physiological function in drought-intolerant riparian trees. These conditions, if they persist, lead to riparian forest decline, with substantial risks to the ecosystems they support and the services they provide to society. This NSF-funded project will use a suite of interdisciplinary methods to measure water stress in riparian forests that are linked to changes in groundwater availability. The study will take place in the Santa Clara River basin in Southern California, where as in many water-limited regions of the world, interactions between climate and water withdrawals for agriculture threaten the integrity of GDEs and their component species. The interdisciplinary project team from SUNY-ESF and UC Santa Barbara will couple high-resolution remote sensing with field-based tree-ring research and groundwater well data to develop water stress indicators across a range of geographic scales from individual trees to forest stands to an entire riparian corridor. The ultimate goal of the project is to identify trends and thresholds in forest response to groundwater decline that can be used to develop sustainable groundwater management approaches for protecting GDEs in multiple-use river basins.

The PhD position and how to apply:

We seek a Ph.D. student at the State University of New York College of Environmental Science and Forestry (SUNY-ESF) working with Dr. John Stella and interdisciplinary collaborators at UC Santa Barbara and The Nature Conservancy. The position will start in summer 2017. Research questions will focus on riparian ecosystem response to drought and methods will include field sampling to inventory riparian forest structure and health, collecting and analyzing tree rings for growth trends and annual water use efficiency using carbon isotopes, and assessing critical thresholds for riparian forest decline. Field studies will occur in the Santa Clara River basin in Southern California with lab work at SUNY-ESF and at the University of Utah. Ideal candidates will have an MS in ecology, environmental science, or a related field; a strong quantitative and statistical background; the ability to work in remote field settings; and interest in riparian forest ecology and tree ecophysiology in dryland regions. The position is funded for a minimum of three years and provides a competitive stipend, tuition and benefits. Interested candidates should send a CV/resume (with GPA and GRE scores), a description of research interests and experience, and names and contact information for 3 references to stella@esf.edu. For more information on how to apply, see http://www.esf.edu/fnrm/stella/opportunities.html

About SUNY-ESF

Founded in 1911, SUNY-ESF is the nation's oldest school dedicated to the study of the environment, developing renewable technologies and building a sustainable future. The ESF main campus is in Syracuse, NY and has regional campuses throughout Central New York and the Adirondack Park. Providing a small-college atmosphere with a low student/faculty ratio that allows for personal attention and mentoring for students, ESF is one of nine Ph.D. degree granting campuses within the SUNY system, and is designated a Carnegie RU/H (Research University/High Activity) school. Integration of research and teaching is emphasized and the college has a strong undergraduate research program where advanced undergraduate students regularly work with graduate students and faculty. ESF has nine regional campuses/field stations and maintains nearly 25,000 acres in college properties offering unrivaled opportunities for field-based research. On ESF's main campus, access to chemical instrumentation, advanced electron microscopy, computing clusters and growth chambers is available. In addition, the ESF campus is contiguous with that of Syracuse University and in close proximity to SUNY Upstate Medical University, giving students and faculty the added resources of a larger institution of higher education, including a wide array of courses, computer and library facilities. The City of Syracuse is uniquely situated between the Finger Lakes Region, Lake Ontario, and the Adirondacks, providing abundant opportunities for outdoor recreation.

 


Groupleader Dendro Sciences
WSL, Birmensdorf, Switzerland

As a researcher with long-term experience and international reputation, you will manage the group and the tree-ring laboratories. You will promote and coordinate the research of the Dendro Sciences Group and perform your own projects. Furthermore, you will procure third party funding for research projects and encourage cooperation with other research groups of WSL, other institutes and organizations at both national and international level.

You will have a PhD in a natural science or related fields, an excellent international record in tree-ring research and are experienced in managing teams and projects. Additionally, you will have an integrative personality with good negotiating skills and are willing to coordinate and support the Dendro Sciences Group across a broad range of topics. You are fluent in English, and a good knowledge of one of the Swiss national languages will be advantageous.

Please send your complete application online to Sabine Hirt, Human Resources WSL. PD Dr. Matthias Bürgi, Tel. +41 (0)44 739 23 54, will be happy to answer further questions. The WSL strives to increase the proportion of women in its employment, which is why qualified women are particularly called upon to apply for this position.

Application page is here.


Postdoctoral Position
Czech University of Life Sciences

Dendroecological perspectives on temperate mountain forest dynamics of Central and Eastern Europe

Type of employment: Temporary position – until the end of 2019 (with possibility to extend to permanent positon)
Working hours: Full time
First day of employment: summer 2017
Number of positions: 1
City: Prague
Country: Czech Republic

Czech University of Life Sciences in Prague, Faculty of Forestry and Wood Sciences

We are seeking a postdoctoral researcher to join our team within the Forest Dynamics Lab of the Department of Forest Ecology, Faculty of Forestry and Wood Sciences in Prague, Czech Republic. The project is titled “Disturbance regimes as drivers of structural variability, carbon dynamics and biodiversity at the stand and landscape levels in primary mountain forests in central and eastern Europe.”

Disturbance plays a dominant role in shaping the structure and function of forest ecosystems, but quantification of disturbance effects is typically limited by missing information on a location’s history and a region’s disturbance regime. Our lab uses tree-ring data to reconstruct site histories, providing insight into how forest characteristics recover from disturbances of variable severity. We are particularly interested in linking patterns in the severity and frequencies of disturbance to variation in tree size structure, carbon dynamics and biodiversity.

The successful candidate will have access to a completed database of 20,000 tree cores collected from 1000 forest plots distributed throughout remaining patches of old-growth forest is central and eastern Europe. Plots are distributed in a hierarchical design (i.e. plots nested within stands, within landscapes throughout the Carpathian mountain range). The aim of the design is to partition the effects of disturbance effects at a variety of scales, from local variation among neighboring locations due to smaller-scale gap dynamics to more extreme events impacting entire landscapes.

The selected candidate will be expected to lead projects using available tree-ring data to link tree growth and biomass dynamics to abiotic and biotic factors. Responsibilities will predominantly be data analysis and manuscript preparation. Opportunities to visit some of our impressive field locations will be available, but the candidate is not expected to participate in data collection.

We are a young and energetic research team with close collaborations with international partners. Opportunities exist for international exchange visits and meetings. To obtain more information about our team, visit http://scholar.google.cz/citations?user=DaBJTM4AAAAJ.

Applicants should have a PhD (at the time of hire) in environmental or related sciences (biology, ecology, geography, forest sciences), and excellent English communication and writing skills on the level of native speaker is essential.

Salary: 1300 – 1600 EUR based on the previous experience and performance We offer a 2-year position starting as soon as possible. The starting monthly salary will be around 1300-1600 Euro, which represents double of the median salary in the Czech Republic. To compare living costs see here: https://www.expatistan.com/cost-of-living In addition, there is a share increase based on the personal performance.

Applications: Please attach a CV listing skills and qualifications, a list of publications and other documents deemed important by the applicant. Applicants should provide a short statement outlining why they believe themselves to be suitable for the above position. Applicants should include contact information for two references, one being the current or most recent employer.

Send the application to the following address: Miroslav Svoboda Email: svobodam@fld.czu.cz Postal address: Czech University of Life Science, Faculty of Forestry and Wood Science, Kamycka 129, Praha 6 Suchdol, 16521, Czech Republic

 


PhD Opportunity in dendrochronology
Université du Québec en Abitibi-Témiscamingue

Effect of species mixing on long-term trends in forest productivity

Although a large body of recent research has already pointed to possible effects of a changing climate on tree growth across the boreal forest, there is still a need for better empirical data to verify some of the most fundamental assumptions adopted in this research. Climate impact studies have revealed changes in growth rates and the extent of forest decline as a result of increased evapotranspiration demand, variability in the frequency of extreme climatic and disturbance events (such as fires, insect outbreaks), and indirect effects of climate change, involving tree regeneration and competitive interactions within community. However, a vast majority of these studies has relied on a combination of short-term observations and long-term model-driven projections involving many not-so-evident assumptions. To address this knowledge gap we will conduct a study looking specifically at long-term changes in growth rates in natural pure and mixed stands of boreal Quebec. We will consider low frequency (century long) trends in growth as integral metrics of climatically-driven changes in growing conditions.

We are looking for an ambitious and highly motivated PhD student with a completed master degree in forest ecology, climatology, geography, ecosystem modelling, or mathematics. Documented experiences in dendrochronology, GIS-added analyses, work with large relational databases, modeling of biological systems and good skills in computer programming (R) will all be valued during the evaluation process. It is important that the candidate is fluent in English and has an excellent ability to formulate himself/herself both orally and in writing. Knowledge of French is an strong asset.

A past record of scientific publication and presentation is highly valued. We put great emphasis on personal characteristics of the successful applicant, solid work ethic, and in particular - the ability to independently manage a large volume of fieldwork and laboratory tasks, and meet reporting and publication deadlines.

The successful candidate will join a dynamic and international team of the Forest Research Institute at the University of Quebec at Abitibi-Temiscamigue, Quebec Canada (Igor Drobyshev and Yves Bergeron). The position is offered within the framework of a three-year MITACS project Can tree species mixing improve resilience and productivity of boreal forests?, in cooperation with consortium OURANOS and  Ministère de l'Énergie et des Ressources naturelles of Quebec (Daniel Houle). It is expected that this 3-year PhD project will start in the January-February 2017.  Please direct all inquiries to igor.drobyshev@uqat.ca and yves.bergeron@uqat.ca

 


PhD position in Dendroclimatology
University of Minnesota

The Center for Dendrochronology at the University of Minnesota is accepting applications for a fully-funded PhD position to start in Fall 2017. The successful candidate will join a NSF-sponsored project studying low-frequency climate variability and the causes of widespread megadrought in North America (http://www.nsf.gov/awardsearch/showAward?AWD_ID=1602512&HistoricalAwards=false), and collaborate with paleoclimatologists, statisticians, and climate scientists at the University of Minnesota, Cornell University, and the United States Geological Survey (USGS).

Responsibilities
Under the supervision of Dr. Scott St. George (http://umn.edu/~stgeorge), the candidate will use tree-ring data, climate simulations, and biological process models to clarify how and why drought in North America may persist for one or more decades. First, the student will produce a new set of tree-ring records from the Northern Hemisphere that is optimized to recover low-frequency (decadal- to centennial-scale) environmental signals. Afterwards, the student will estimate the spatial structure of dec-cen variability in tree-ring records across North America, and outline the fingerprint of major low-frequency climate modes within the tree-ring network. Other major tasks include (i) helping to lead a pair of summer workshops on dendroclimatology for statisticians and computer scientists, and (ii) collaborating with researchers at Cornell’s Emergent Climate Risk Lab (http://ecrl.eas.cornell.edu) to test the ability of state-of-the-art climate models to simulate megadrought.

Relevance
Understanding decadal drought and multidecadal megadrought risk requires us to characterize the amplitudes and spatial patterns of climate fluctuations on these time scales. Decadal-centennial (dec-cen) variability in terrestrial climate, including ’megadroughts’, may arise due to low-frequency behavior in the oceans or may be residuals from high-frequency forcings, but instrumental climate records by themselves are not adequate to distinguish between these two frameworks. Proxy records from natural archives are able to extend our perspective on the climate system beyond the last century and a half, making these data essential for evaluating the pre-instrumental behavior of dec-cen climate variability. In terrestrial settings, records of tree-ring width and latewood density have been the dominant source of information about dec-cen behavior due to their high resolution and dating accuracy, but important questions about the ability of this archive to describe low-frequency climate variability remain unanswered. 

Qualifications
We seek to hire a highly motivated student who holds an M.Sc. or equivalent in a relevant field and has research experience in dendrochronology, climatology, or Quaternary environmental change. Undergraduate or graduate training in botany, physics, statistics, or mathematics would be an asset, as would basic programming skills in Matlab, Python, R, or equivalent.  Minimum academic qualifications include a 3.5 GPA on a 4.0 system.

Salary
$17,500 to $22,500 during the Fall/Spring academic term, depending on qualifications. Students will receive an additional stipend for summer work (up to $7,000), and be encouraged to apply for college- and university-level fellowships and research grants. Finally, if the successful applicant is a United States citizen, they will have the opportunity to apply for a USGS internship through their Graduate Student Preparedness program (https://powellcenter.usgs.gov/national-science-foundation-graduate-research-internship-program-grip). 

How to apply
Students interested in this opportunity should contact Dr. St. George by sending an inquiry to stgeorge@umn.edu. In order to evaluate your qualifications, it would be helpful to share: (i) a cover letter outlining your research experience and motivation for joining this project; (ii) an up-to-date curriculum vitae, including contact information for at least two referees; and (iii) academic transcripts for degrees completed or in-progress (either official or unofficial). 

Students will subsequently apply to either the Ph.D. program in Geography (http://cla.umn.edu/geography/graduate) or Land and Atmospheric Science (http://www.laas.umn.edu) at the University of Minnesota. Please do not submit an application to either program without contacting Dr. St. George first.

Closing date
December 15, 2017
  
Scott St. George
Associate Professor, Department of Geography
University of Minnesota
 
** In 2017 **
Humboldt Research Fellow
Johannes Gutenberg-Universität Mainz
Helmholtz-Zentrum Geesthacht
 
twitter: @scottstgeorge
email: stgeorge@umn.edu
web: http://umn.edu/~stgeorge
lab: http://umndendro.umn.edu

 

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