Fieldwork notes, July 21-August 3, 2023
Summer fieldwork for our project, “Clarifying Linkages Between Canopy Solar Induced Fluorescence (SIF) and Physiological Function for High Latitude Vegetation,” once again took our team from University of Maryland Baltimore County north to the boreal forests of central Alaska. We visited this area in the spring to collect data during the very start of the growing season, and now we are returning to collect data during the peak of summer.
This project is part of the NASA Terrestrial Ecology program’s Arctic-Boreal Vulnerability Experiment (ABoVE). The goal of ABoVE is to improve our understanding of high latitude ecosystems, how these ecosystems respond to climate change, and how satellite data can provide information to describe ecosystem processes and aid management decisions.
Our study focuses on measuring light emitted by plants called solar induced fluorescence. Green leaves absorb light, and through photosynthesis take in carbon dioxide and water and produce oxygen and sugars. Fluorescence occurs during photosynthesis as some of the absorbed light energy is radiated out from the plant. The amount of light fluoresced is only a very small fraction of what is absorbed, which is why our eyes don’t see plants glowing. In our study, we use sensitive instruments that can detect this fluorescence. Our goal is to better understand the sources of fluoresced light and how to use this information to describe productivity in boreal forests and tundra.
Our study site is at the Caribou Creek flux tower run by the National Science Foundation’s National Ecological Observatory Network (NEON). In spring, we deployed automated instruments at the NEON tower site that continuously collect data. On this trip, we are checking on how they have been working.
In July there was a big change from our previous visit in April. In April, the area had a deep snow cover with temperatures dropping below 0°F, while during this visit the daytime temperatures were in the 80s F and the ground was now all green (images below).
On the top of the tower we have an instrument called a FLoX (Fluorescence Box). The FLoX views a patch of forest from above, and every few minutes during the day it measures the reflected light and solar induced chlorophyll fluorescence. This provides us with a description of plant activity at different times of the day through the growing season (images below).
Also at the site we have monitoring PAM (MoniPAM) instruments attached to shoots of the spruce trees. The MoniPAM probes shine pulses of light at individual spruce shoots to measure fluorescence and photosynthetic processes at the leaf level (images below). We put blankets over the probes for a while to dark-adapt the shoots to measure their response when unstressed. In the spring, we put the MoniPAM probes in easy-to-reach places when there was a lot of snow on the ground. On this trip, when we returned to check them in the summer, we found we had to really reach up to get them without the snow to stand on.
From the ground, we collected reflectance and fluorescence measurements (similar to the data collected by the FLoX) of individual plants in the FLoX field of view and a variety of representative plants in the larger area surrounding the tower. These measurements will help us understand the local variability (images below).
A lot of the ground cover was cotton grass (Eriophorum spp.) that forms tussocks, which are tight clumps of grasses. The tussocks made walking through the area difficult, like walking on half-buried basketballs, so it was easy to twist an ankle, especially with a heavy backpack spectrometer on your back.
We collected branch samples to make measurements of leaves and needles that we will use to parameterize models of vegetation fluorescence and productivity (images below).
We took a little time off to visit some other places in the area. We saw musk ox, which are animals of the tundra but raised in captivity at the University of Alaska Fairbanks’ Large Animal Research Station. Their thick, shaggy coat keeps them warm through the frigid arctic winters. Under the long guard hairs is a soft wool called qiviut that musk oxen shed in the spring. Qiviut can be spun into a very warm and soft yarn. Small balls of qiviut yarn can sell for over $100.
On our last day in Alaska we visited the Cold Regions Research and Engineering Laboratory (CRREL) Permafrost Tunnel Research Facility (images below). Permafrost refers to soil that has been frozen continuously for more than two years. The permafrost around Fairbanks, Alaska, is considered ‘warm’ (at a temperature of -0.3oC/-0.4oC) as compared to the permafrost in our other study site in the North Slope of Alaska at Utqiagvik (e.g., a temperature -3oC/-4 oC). This warm permafrost is very sensitive to the changes in soil temperatures that can result from fires, rain events, and other disruptions that can cause permafrost thawing. Thawing permafrost can result in damage to roads and buildings and cause disturbance in forests.
The permafrost tunnel is dug into a hillside through earth that has been frozen for thousands of years. The tunnel reveals bones of extinct ice age animals, plants preserved since the ice age, and large ice wedges that can take hundreds to thousands of years to form. The ice wedges cause the formation of polygonal patterned ground, where the ground surface is covered with a pattern of shapes of slightly higher or lower ground. Our study site in Utqiagvik was in an area of high centered polygons, so it was interesting to be able to actually see the shapes of the underground ice that formed that unique landscape.
After five connecting flights—8,000+ miles and over 40 hours of traveling—our flight descended into the “Land of the Thunder Dragon.”
Our team from the SERVIR program made our way to the Himalayas to work with partners in Bhutan and demonstrate how NASA Earth observations and applied science approaches can align with the country’s unique environmental vision. Having grown up in the U.S., Bhutan certainly feels like a unique and rarified place. The legends of the towering snowy mountains, lush valleys, and unbelievably happy people are completely true. Also true are the legends of the harrowing descent into the country’s main airport. There is only one international airline that is allowed to fly into Bhutan, and I have heard tales that this measure is to ensure that only experienced Bhutanese pilots are guiding jets down through the narrow, twisting Himalayan valleys to reach the tarmac on the flat valley floor. Needless to say, I was very happy to have an experienced pilot at the yoke as we gracefully rolled and yawed down, cutting through the clouds and arriving in the amazing landscape of the Paro Valley.
The Kingdom of Bhutan is often known for its conservation and land management practices, and of course for its philosophy of “gross national happiness.” Bhutan is unique compared to other counties in that its constitution requires that 60% of the land remain forested to ensure social, economic, and environmental well-being for all. In addition, the country’s government famously follows a policy of measuring its progress not by its economic growth, but by the happiness of its citizens. This forward-leaning approach to both policy and the conservation of natural landscapes is just some of what makes Bhutan such a special place.
Since the 1970s, Bhutan has started to open its doors to foreign collaboration, and since the first democratic election in 2008, the Kingdom has made unbelievable strides to equip their next generation as regional leaders in science, technology, engineering and math (STEM), forestry, and sustainable agriculture—that’s where we align. SERVIR is a collaboration of NASA and the U.S. Agency for International Development. Our program assists communities in using geospatial science and Earth observing satellites to address and support their own environmental goals, collaborating with organizations to build tools that are demand-driven and tailored to local needs. The Department of State has been funding SERVIR to support STEM opportunities in Bhutan—but until now, that work has taken place entirely remotely through conference calls and webinars.
On paper, I was arriving halfway around the world to formally launch a new rice mapping tool and conduct capacity building trainings. But in the big picture, this visit really built the kind of connections with the Bhutanese community—university partners, NGOs, government agencies, as well as community members—that you just can’t achieve when combating an eleven-hour difference with a teleconference.
Back in early 2020, the Department of State and NASA Headquarters identified the opportunity to collaborate and support STEM opportunities in Bhutan through NASA’s Applied Sciences Program. Bhutan has never had diplomatic ties with the United States, but SERVIR and I took on the challenge to lead STEM initiatives and begin to collaborate with partners in the country to collaborate on geospatial solutions to environmental challenges. Through these efforts, we also had the opportunity to build ties between our two countries.
You know what they say about best laid plans. COVID presented a distinct challenge as we halted all in-person events, but we found ways to keep the project moving forward. In 2021, NASA’s DEVELOP program started special 10-week projects to help Bhutanese students living in the U.S. grow their geoscience and remote sensing skills while working with organizations in Bhutan (Bhutan Highlight). I was the lead science advisor on some of these projects, and it was a great opportunity to form meaningful connections with the brilliant Bhutanese students and the burgeoning geospatial community in Bhutan, even if we couldn’t yet meet face to face. NASA’s GLOBE program also got involved, helping to set up Earth science and geospatial workshops tailored to Bhutanese participants.
With SERVIR, I continued working intensively with our partners at Bhutan’s Department of Agriculture, as well as advising for more and more Bhutan DEVELOP projects connecting with over 30 Bhutanese scholars studying in the U.S.
Fast-forwarding, after two-plus years of extensive remote co-development of a geospatial crop mapping service and four virtual trainings focusing on remote sensing and applied Earth observation efforts, the conditions were finally just right for travel. SERVIR began to plot out our trip. Set for May 2023, we worked tirelessly with the State Department’s Bhutan Affairs Unit with partners from the Bhutan Foundation to plan the visit. The foundation was extraordinarily helpful, and they connected us with the Bhutan Ecological Society (BES), who aided us in designing a joint “training of trainers” workshop and did the unbelievably heavy lift of supporting our SERVIR team with logistics. Both the Bhutan Foundation and the BES not only made it possible for this trip to even be possible, but they also made us feel truly welcome.
A race against time, my entrance to Bhutan did not exactly proceed as originally planned. I was delayed a day en route, but my colleagues were thankfully able to arrive as scheduled. They met and became fast friends with our BES colleagues, starting off the journey with a tour. Twelve hours later, I got my connection in Kathmandu and when I touched down I was ready to run because our service launch was scheduled that same day. Floored by the sights, I ran to meet a representative from the BES who helped me hightail from Paro to Thimphu. After a two hour jaw-dropping road trip on a winding two-lane road, I made it just in time for our partners from the Ministry of Agriculture and Livestock and the Department of Agriculture to kick off the launch of the Agriculture Classification and Estimation Service (ACES).
The launch of the ACES tool was a centerpiece of our visit to the capital of Thimphu. ACES was built in collaboration with the Bhutanese Department of Agriculture and provides the country with an automated system to map rice fields. At the launch event, we were lucky enough to be joined by several high-ranking members of the Department of Agriculture. I was thrilled to see the enthusiasm and excitement for what we had created together. The Department of Agriculture was so impressed that they invited other higher-ups from the local government to get involved, and our training planned for the next week hit max capacity.
We then traveled back to the city of Paro to conduct a week-long training on using Earth observations and geospatial resources like ACES to manage agriculture. On the way, we crossed paths with a group of farmers as they were walking out to the rice fields, and they were kind enough to answer our questions. With the help of our interpreters, we were able to learn about the unique challenges of local cultivation, how communities cycle their crops, and the gender dynamics that influence local agriculture. We later were able to ask the same set of questions to the local Department of Agriculture, allowing us to understand these same topics from the perspective of the government. From these opportunities, we were able to come into our training with a deeper understanding and greater appreciation for what Bhutanese communities really want and need out of a rice-mapping tool.
With the help of the Bhutan Ecological Society, we had a full week to dive into the nuance and opportunities of using remote sensing, machine learning, and resources like Collect Earth Online. Thirty-one participants—20 men and 11 women—enrolled in the training, including regional land managers, economists, academics, and even some students. The training also included sections on field data collection using GeoFairy, a mobile application developed by Liping Di, a principal investigator with SERVIR’s Applied Sciences Team.
Throughout this process, participants from all of these different backgrounds shared their knowledge with our team so we could better understand the unique landscape and agricultural practices of Bhutan—knowledge we could take back with us to help SERVIR better serve the community with ACES and other resources. The opportunity to build ties between NASA and the Bhutanese STEM community was also incredibly rewarding. We were honored to meet over 100 students and faculty who attended a lecture we gave at the Royal Thimphu College. We visited the amazing Super FabLab, which provides STEM educational resources, including geospatial and Earth observations tools. Throughout our entire trip, we heard so much enthusiasm for NASA, and we were inspired by just how many people were excited to share ideas for future collaborations.
The trip—with the ACES launch, lectures to students, and amazing week-long joint training with the Bhutan Ecological Society—was even more successful than we could have anticipated. With the connections we had newly minted between NASA and the Bhutanese STEM community, our SERVIR team left in a great position to continue to collaborate.
Four connecting flights and over 48 hours of travel time and I closed the loop to arrive back in Alabama, literally flying all the way around the world. It was an absolute pleasure and an amazing opportunity to visit the Kingdom and see the spectacular architecture and scenery. The landscape reminded me of the Columbia River Gorge, close to where I grew up in the Pacific Northwest, but with looming Himalayan mountains and rice fields as far as the eye can see. I always appreciate how much we at SERVIR have been able to accomplish by connecting virtually, but our time in Bhutan was a great reminder of just how much more we can achieve when we get the opportunity to meet our international colleagues face to face, and get a sense of their community needs. I met some amazing people as part of the trip and I cannot wait to return, as it truly felt once in a lifetime.
I’m writing this post on our last day in St. Mary’s, Alaska. This tiny village of about 560 inhabitants had its surroundings ravaged by two large tundra fires in the summer of 2022. The East Fork fire was the second largest tundra fire in Alaska in over 40 years and the biggest in Southwest Alaska. These events were historic, and I could start this post by writing about the intense and productive three weeks of work we had here. However, this whole project started much earlier.
I started this Ph.D. with plans to do field work in Siberia. However, halfway through, due to the pandemic and geopolitical issues, I saw all those plans slip through my fingers. Despite being from a country with among the greatest biodiversity in the world (Brazil), the arctic-boreal environments have always fascinated me. So in the winter of last year, when I came across these fires while analyzing satellite images, I knew this was a unique opportunity to pack my bags and finally be in the tundra. I remember showing the first satellite images and data of these fires to my supervisor, Dr. Sander Veraverbeke, and he confirmed that these fires were indeed scientifically very interesting and logistically feasible for our expedition. From then on, a long process of preparation began.
As this field campaign is part of my Ph.D. project, I was responsible for planning both the scientific and logistical aspects. Now, reflecting after the final day of sampling, it is incredibly rewarding to see that the planning has paid off. We sampled 11 days by boat along the Andreafsky River sampling the East Fork fire and another five days by helicopter sampling the Apoon Pass fire. Our main goal was to estimate the carbon combustion from these fires, that is, the area-normalized emissions in grams of carbon per square meter. Field measurements are the prime way to accurately quantify carbon combustion. To do it, we collected soil samples and estimated the burn depth of the soil organic layer. It is crucial to advance the quantification of tundra fire carbon combustion and understanding its environmental drivers.
In addition to carbon emissions, another key point of our expedition is to understand the effects of fires on permafrost. Previous research has shown that fires in the boreal forest increase the thaw depth of the active layer above permafrost, which can lead to permafrost degradation. We are curious to investigate this mechanism in the tundra, even more so now that we have found ice-rich permafrost during our fieldwork.
But it was not just the work that was amazing during this campaign. The tundra landscape was always breathtaking. Both from above with the helicopter and along the river from the boat. We were presented with a stunning rainbow on our first day using the helicopter. Wildlife was always around: moose, bears, beavers, eagles, geese, and countless other bird species.
Lucas Ribeiro Diaz, Max van Gerrevink, Rebecca Scholten, Sonam Wangchuk, Thomas Janssen, Thomas Hessilt, and Sander Veraverbeke were part of this field expedition. Our team is part of the Climate & Ecosystems Change research group at the Vrije Universiteit Amsterdam. However, the success of this campaign would not have been possible without the help of our boat driver, David ‘Matty’ Beans, and our helicopter pilot, Savanna Paulsen. We are also grateful to the city of St. Mary’s and its people for warmly welcoming us during these weeks. Finally, Dr. Lisa Saperstein from the U.S. Fish and Wildlife Service in Alaska has provided tremendous help when we were organizing our campaign.
45 plots, 1,383 tussocks measured, 255 soil samples, 495 thaw depth measurements—numbers like these make us believe that we have just concluded a field campaign on some of the most densely sampled tundra fires in the history of science. Now, we have three more weeks of work ahead of us at the USGS soil laboratory in Anchorage. With lots of ideas in my head, I’m excited to see the new findings this valuable data can reveal!
I have just finished writing this post and I realize that perhaps it is too personal. But it could not be otherwise. Our science often blends in with who we are, our dreams and expectations. I leave St. Mary’s feeling fulfilled, I think I have always dreamed of being here. I leave the tundra sure that moments like this are the reason I decided to embark on this journey of doing research.
This tundra fires field expedition is part of FireIce (Fire in the land of ice: climatic drivers & feedbacks). FireIce is a Consolidator project funded by the European Research Council. FireIce is affiliated with NASA ABoVE. This blog post was written by Lucas Ribeiro Diaz, a Ph.D. student at Vrije Universiteit Amsterdam, studying arctic-boreal fires by combining field and remote sensing approaches.
Just like the undulating terrain of the tussocky tundra we traverse, our days also take unexpected twists and turns. After a beautiful last day of sampling the East Fork fire scar along the Andreafsky River, where three moose visited us and delivered a personal goodbye, we were all excited for our first day of sampling the Apoon Pass fire scar via helicopter. But our spirits were momentarily dampened by news of Savanna, our pilot flying in from Nome, getting stuck in a thunderstorm on her way to our base in St. Mary’s, Alaska. Her arrival, delayed until early afternoon, was just the prelude to a challenge-laden morning.
Further issues emerged with our satellite communications device, requiring transatlantic collaboration with our colleagues in Amsterdam (many thanks to Thomas for his unwavering support!) These obstacles left us momentarily uncertain about the feasibility of flying at all that day. Miraculously, by 2 p.m., the looming cumulus of problems and bad weather began to disperse, and by 2:30 p.m., with a renewed sense of purpose, we embarked on our mission to sample the second fire of our field campaign.
The flight itself proved to be a standout experience, treating us to a breathtaking panorama over the hilly tundra that we had sampled along the Andreafsky River in the preceding days. The Apoon Pass fire scar, though not far from the East Fork fire, is geographically quite different, as it is located in very flat lowland terrain. Flying over the last crests of the hill range provided a captivating sight of the vast lowlands extending in all directions.
To our surprise, we were only able to spot the difference between burned and unburned tundra when descending to a relatively low altitude. This observation, together with the satellite imagery prepared by our campaign lead Lucas, led us to an initial conjecture that fire severity would be lower than what we had previously seen.
To systematically assess fire severity and carbon emissions in our plots, we are following protocols established by Mack et al. (2011) and Moubarak et al. (2023) for tundra fires in Alaska. We use two independent methods to estimate the burn depth based on the height of tussocks and Sphagnum (peat moss) patches in our plots. For the tussock-based method, we compare the height of tussocks that survived the fire with the height of tussocks in unburned locations. This gives us an estimate how much duff and other organic material has been combusted. For the Sphagnum-based method, we connect different moss patches of similar height with a thread and measure the distance from the thread to the surface at 25-centimeter intervals. This will give us an overview of the variability in burn depth within our sampling locations.
These two measurements will allow us to quantify the amount of carbon combusted per plot, which we can relate to the satellite imagery, as well as to the thickness of the active layer we are measuring at each plot to assess how the fire is affecting the permafrost.
In the end, to our surprise, our first helicopter day turned into one of the best sampling days we had during the campaign so far. We were gifted with beautiful, sunny weather until 9 p.m., and sampled even more plots than we had initially expected. We have now become a well-oiled machine, capable of sampling a plot within a mere hour and a half. Having the helicopter with us at all times offered an invaluable advantage—the ability to swiftly transport parts of our team to nearby sampling sites. After having returned to our base, we are excited for another day in the beautiful tussock tundra of southwestern Alaska—keeping our fingers crossed for another couple of days of good weather!
In 2022, severe lightning ignited many fires in Alaska. Notably, several exceptionally large fires burned in the tundra of Southwest Alaska, an ecosystem that is traditionally less prone to fire. While our understanding of the carbon emissions of boreal forest fires in Alaska and Canada has strongly advanced in recent years thanks to the work of several teams within NASA’s Arctic-boreal Vulnerability Experiment (ABoVE), the impacts of these tundra fires on the ecosystem’s carbon balance and permafrost has remained less well known.
Our Climate and Ecosystems Change research group from the Vrije Universiteit Amsterdam in the Netherlands is currently in Southwest Alaska to fill these critical knowledge gaps. Our team received tremendous help of Dr. Lisa Saperstein from the Alaska Fish and Wildlife Service in organizing the campaign. Lisa will also start a field campaign in the same fires in the next few days and we plan to pool our datasets to maximize synergies between our efforts.
The 2022 East Fork and the Apoon Pass fires together burned more than 100,000 hectares (380 square miles) of primarily tundra landscapes in Southwest Alaska. They were among the largest tundra fires on record for the region.
Our basecamp is the village of St. Mary’s, located just west of the East Fork fire on the Andreafsky River. For the first part of our campaign, we are taking a boat upstream to access the fire scar. We are looking for burned tussock tundra sites, where we can measure the effects of the fire on the vegetation, soils, and permafrost in our plots. We are also sampling unburned tundra sites, which provide us a reference of the conditions without fire disturbance. During the last part of our campaign we will access sites in the remote Apoon Pass fire by helicopter.
The local community heavily relies on the landscape for subsistence activities, like hunting and berry picking. Our boat driver, Matty Beans, is native to the area and is extremely helpful in bringing us to the right places. A large concern of the community is how the fire has effected the abundance of berries in the burned tundra. Our preliminary observations indicate that the cloudberries, locally also called salmonberries, were abundantly present in the burned sites. However, this was not the case yet for blueberries.
So far, we have been extremely lucky with mostly dry weather and only a little bit of rain. However, the dry weather has affected the water levels in the Andreafsky River. We came across collapsed river banks and exposed sand banks in the river. Our boat driver has switched to his jet boat so that we can continue on, even in more shallow parts of the river. The weather is changing though, with rain coming in for several days. This is good for the water levels, but the colder and rainy weather may make our sampling efforts more challenging.
After seven days and 19 plots of sampling, we are now taking a well-deserved rest day. I used this rest day to write this blog and digitize some datasheets. Over the next four days, we will continue sampling along the river and then use a helicopter to access the Apoon Pass fire site for more sampling.
This field expedition is part of FireIce (Fire in the land of ice: climatic drivers & feedbacks). FireIce is a Consolidator project funded by the European Research Council. FireIce is affiliated with NASA ABoVE.
