Laboratory of Forest - Atmosphere Interactions 

Tropical forest ecosystem, community & functional ecology, biosphere-atmosphere interactions, ecoclimate teleconnections, LiDAR remote sensing and high-throughput canopy ecology

View of forest in Guyana from Mt. Roraima, Dec. 30th 2010, SC Stark (click to enlarge)

Tropical forest ecosystems in a changing world

The 'big picture' features of the natural world around us -- the climate and the vegetation -- ultimately arise from biological and physical phenomena that are very localized, such as the production associated with a single leaf or the reproductive success of an individual tree.  These local phenomenon, though slight in effect individually, together give rise emergent processes that drive the natural systems of the Earth, including carbon and water cycles and the energy budget of the atmosphere.  Today these Earth systems are in historically uncharted territory.  Unprecedented levels of human activity impact ecosystems in virtually every meter cubed of the biosphere through land conversion, forest degradation, atmospheric CO2 pollution, the elimination of top predators and many other processes.  These impacts decrease local biodiversity, change patterns of dominance and distributions of species, and alter the climate.  While evidence mounts describing the extent of present day global changes, it remains extremely difficult to predict their down-stream impacts.  The following questions and many others about the future of Earth systems do no have adequate answers:  Will the climate be drastically different in the year 2100?  Will forests that have not been converted to agriculture and urban environments continue to function and harbor high levels of biodiversity? Can vegetation change in one part of the world be teleconnected to vegetation change in another?  To answer these questions requires a detailed understanding of local natural phenomena and the processes that influence how they are connected to larger scale patterns and dynamics.  

While the ocean plays the largest single role in global atmospheric dynamics, current evidence suggests that the response of the Earth's land surface to climate change creates the greatest uncertainty in the future of the climate.  The fate of the Amazon in particular acts a pivotal point in projections of future climate.  If the Amazon remains largely forested, or even increases its biomass because of a fertilization effect of increased CO2, we expect that the land surface may act as a sink for human CO2 emissions through 2100.  If, instead, increasing heat and drought in the Amazon basin lead to extensive die-off of unconverted forest, the land surface will be a significant source of CO2 emissions, exacerbating global warming significantly.     

To better understand the future of the Amazon and Earth systems at large, we must better understand the interplay between vegetation and the atmosphere -- we must understand how changes to local biological and physical phenomena on large scales in space and time influence the climate and how the climate in turn influences local phenomena. Furthermore, we must transcend the accounting of processes as they are today to, instead, understand the mechanisms that influence them, to gain insight into the possible future states.  Thus, the Big Questions in basic science -- questions about ultimate causes an fundamental mechanisms -- play a central role in the study of global change. To predict the interplay between vegetation and the climate we must understand how ecological and evolutionary processes determine forest structure and function (ecology & evolution), how surface radiation interacts with vegetation, soil and rainfall to determine the energy balance of the atmosphere (ecosystem & atmospheric sciences).           

My research addresses the interplay of the climate and vegetation by leveraging remote sensing -- primarily airborne LiDAR -- to address how the above-ground structure of the forest canopy impacts population and community processes of trees, and how canopy structure impacts, and responds to under disturbance, the atmosphere. More specifically this work is aimed at understanding the fundamental mechanisms at play by addressing the combined effects of size structure, light limitation, and physiological diversity on tropical forest dynamics and biosphere–atmosphere interactions. To achieve these goals, my work combines data from traditional forest plots, ecophysiological measurements, and LiDAR remote sensing to connect canopies with tree dynamics. Exciting new work seeks to scale this understanding up to interregional and continental dynamics using earth systems models to ask if die-off or land use change in one region can impact vegetation in another via ecoclimate teleconnections (NSF awards assessing teleconnections due to N. Am. Die-off and Amazon deforestation and potential teleconnections from vegetation change between the domains of NEON). Furthermore, I draw heavily on past experience (.) coordinating tropical forest ecological field investigations in the Amazon and Central America, (.) deploying and analyzing ground-based and airborne LiDAR systems to characterize forest structure and function, (.) manipulating and analyzing field and simulation data, primarily in the R Environment, and (.) in speaking the Portuguese for work and for fun.   



March 2017. Fantastic immersive multimedia experience produced (this is the LINK) highlighting the work of Scott Saleska from the University of Arizona in understand the breath of the Amazon forest, from the California Academy of Science. The MSU Lab of Forest - Atmosphere Interactions is an important collaborator working alongside Saleska and his team at this site in the Amazon; in fact Stark just received funding (~$150K) from NASA Earth Sciences as part of an award to Saleska to work on detailed estimation of canopy leaf light environments with LiDAR and other measurements at this site.  

Early 2017. New papers out on Ecoclimate teleconnections from NSF Funded Macrosystems Biology Research. Villegas et al 2017 Ecosphere on assessing local scale effects of forest die-off on the atmosphere rapidly. And Garcia et al 2016 PLOS ONE on assessing potential global ecoclimate teleconnections from forest loss in western North America and the Amazon. See these news pieces and press releases on Garcia et al 2016: MSU Today, Climate News Network

December 2016. Collaborative author in Science article on the determinants of the phenology of ecosystem function in the central Amazon! (Wu et al. 2016). See ScienceDaily article

October 2016. Co-author on paper led by 'mentee' Brazilian masters student Danilo Almeida in Remote Sensing, using ground LiDAR to understand the impacts and drivers of fire in seasonally flooded forests in the Amazon. (Almeida et al. 2016)  

November 2015. New collaborative conceptual paper on Ecoclimate Teleconnections is out! (Stark et al Landscape Ecology)

Early 2015. Ecology Letters article detailing a method to retrieve size distributions and light environments of size classes with compex overlapping canopies is out! (Stark et al 2015 Ecology Letters

As reported above, two NSF awards 2014 and 2015 (I am co-PI) assessing possible ecoclimate teleconnections due to North America tree die-off and Amazon deforestation and potential teleconnections from vegetation change between the domains of NEON in North America

In January 2013 I joined the Michigan State University Department of Forestry to develop a research program to address basic and applied questions in forest ecology and biosphere atmosphere interactions with a specific focus on the Amazon and the role of the Amazon in Earth systems.


Research Photos & Links

In canopy leaf gas exchange measurements.  Photo: Cédric Billod-Laillet, 2009, Tapajós National Forest, Santarém, Pará, Brazil.  
Full disclosure: I am not usually the one up in the tree!

Complex patterns of leaf irradiation in a typical Amazonian forest canopy. Photo: ML Friesen, 2011, Tambopata, Madre de Dios, Peru. 


Current lab groups:

Former lab groups and current collaborators:


Photojournals from the NSF-funded Amazon-PIRE Program, thanks to Jake Bryant

I had the pleasure of participating in 5 years of the Amazon-PIRE program at the University of Arizona, including 4 field courses (3 Brazil and 1 Peru).  What follows are photo-journals from some of those courses captured by Jake Bryant, tropical science (fashion) photographer extraordinaire. 

Here is a nice video preview of an upcoming show of photos from this program slated for display in the Biosphere2 in Arizona:

And, all the great photo galleries:


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