Science Communication and Outreach Events

Poster Presentations - 04/16/2026 & 04/23/2026

Title: “Edge effects and methane flux dynamics in a temperate forest.”

Abstract:

Methane, a potent greenhouse gas, contributes substantially to climate warming and continues to increase in atmospheric concentration. Methane cycling is microbially-mediated and strongly regulated by temperature and moisture, making it sensitive to environmental changes expected in temperate forests of the northeastern United States. Well-drained forest soils represent a major global methane sink, where methanotrophic communities offset a portion of natural and anthropogenic emissions.

Global change is expected to alter both forest structure and hydrology, particularly through increased fragmentation and shifts in precipitation regimes. Because methane cycling is tightly coupled to moisture and redox conditions, these changes may significantly influence the strength and stability of the forest methane sink. To assess methane flux responses to interacting global change drivers, we measured soil and tree stem methane fluxes at the Climate Interactions with Forest Fragmentation (CLIFF) experiment at Harvard Forest. Methane fluxes were quantified using a LI-7810 Trace Gas Analyzer across soil collars (n=84) and tree stem collars (n=60) spanning six experimental plots: control, precipitation exclusion (simulating drought via 90% throughfall reduction), and irrigation (1:1 redistribution). Measurements were conducted throughout the 2025 growing season and fall.

These data provide a foundation for evaluating spatial variation in methane flux across forest edge gradients, precipitation manipulations, and ecosystem components (soil vs. stems), and for developing an initial methane budget for this fragmented temperate forest system.

Check out the poster!

STEM & the Environment Green Career Panel Discussion (November 2025)

I had the pleasure of speaking on a panel with Bay Area high school students, where I shared my experiences as someone who works in STEM and environmental science.

Our conversation covered a wide range of topics: our paths into STEM majors, what a typical day looks like for those working in STEM and environmental fields, how STEM training shapes the way we perceive the environment, and advice for students pursuing STEM careers. We also offered honest advice about navigating the challenges that come throughout a STEM educational journey.

Sharing my perspective on the power of science, from understanding our environment to informing climate litigation, policy, and economic decisions, felt like a meaningful reminder of why I value this work so highly.

Read more about CANOPY's work on their website

Read more about the Green Career Series

Oral Talk - 04/19/2024 (1:00 - 2:30pm Session)

Title: “Interannual growth-climate relationships of western larch after wildfire in the northwest United States”

Abstract:

Montane and mixed-mesic conifer forests in the northwestern United States are burning at rates greater than any time in recent decades, due to the combined impacts of global warming and historical and contemporary land use and land management. Western larch (Larix occidentalis) is a tree of high regional significance, exhibiting a variety of traits that make it resistant and resilient to fire. Because seedlings are generally more sensitive to environmental stressors than adults, the impacts of climate change are expected to be detectable first in juvenile trees. Recent research shows that the natural regeneration of western larch after wildfires has not been significantly impacted by recent climate change (Vieira, 2023), although the prolonged vitality of these seedlings is of question.

To understand how seedlings naturally regenerating after wildfire respond to interannual variations in climate, I studied the influence of seasonal measures of moisture and energy inputs on the annual radial growth of western larch juveniles. The study calls on > 1600 destructively sampled western larch seedlings that were regenerating in post-fire ecosystems across the geographic range the species in the US (i.e., Montana, Idaho, Washington, Oregon). From 53 sites sampled within 30 wildfires that burned between 2000 and 2015, dendrochronological techniques were used to determine the establishment year of each seedling. Image analysis was used to then measure annual growth rings for each seedling.

I analyzed the data with a variety of statistical techniques. Using a simple correlation analysis, I assess the correlation between multiple measures of seasonal climate and radial growth of seedlings at both the plot and individual tree level. Findings reveal complex relationships between climate and radial growth, with variability in both magnitude and direction of correlations within and among sites. I then modeled climate-growth relationships using a continuous mixed effects linear regression model to infer how annual growth varies based on different climatic factors, as well as site-specific and fire-related factors (e.g., fire severity). Understanding how climate influences the annual growth of western larch seedlings is crucial for understanding, predicting, and effectively managing the future composition and structure of montane and mixed-mesic conifer forests.

References

Vieira, Spencer T., "IMPACTS OF CLIMATE AND WILDFIRE ON WESTERN LARCH REGENERATION" (2023). Graduate Student Theses, Dissertations, & Professional Papers. 12238. https://scholarworks.umt.edu/etd/12238

Mentor(s): Dr. Philip Higuera (Professor of Fire Ecology), Dr. Kimberly Davis (USFS Research Ecologist), Spencer Vieira (MS, Systems Ecology)

Oral Talk - 04/19/2024 (1:00 - 2:30pm Session)

Title: “Spatial and temporal patterns of methane efflux in a controlled flooded forest inside Biosphere 2”

Abstract:

Due to its greater radiative forcing potency compared to carbon dioxide, gaseous methane plays a key role in our climate system. Wetland ecosystems constitute a significant portion of the global methane cycle, with one major source of emissions being from annually flooded forests in the Amazon basin. Recent research has shown that tree stems can significantly contribute to the methane flux from waterlogged ecosystems (Pangala et al. 2013, 2017). However, to fully assess the influence of tree stem fluxes on flooded forest methane emissions and the global budget, we need to better understand the spatial and temporal variability of the fluxes.

In the Biosphere 2 Tropical Rainforest’s várzea, we performed controlled flooding experiments to better understand the spatial and temporal aspects of wetland methane emissions. We sought to understand patterns behind tree stem fluxes including spatial variability across the surface of a stem and temporal variability over the duration of a flood. Using manual tree stem chambers on Pterocarpus indicus and Theobroma cacao trees, and a floating diffusion/ebullition chamber, we quantified methane emissions throughout dry periods and extended floods.

Our results suggest that 1) peak stem emissions are highly variable in time between species, 2) emissions continue to increase over time without peaking, 3) stem fluxes decrease strongly with height along tree stems, 4) stem fluxes vary radially across tree stems, and 5) tree stem fluxes correlate well with sap flux rates over a 24hr diurnal period. Understanding when and where to measure tree stem emissions will help to improve the ability to quantify how significant wetland ecosystems and their trees are in the global methane and climate cycles for use in models.

References

Pangala, S. R., Enrich-Prast, A., Basso, L. S., Peixoto, R. B., Bastviken, D., Hornibrook, E. R. C., Gatti, L. V., Marotta, H., Calazans, L. S. B., Sakuragui, C. M., Bastos, W. R., Malm, O., Gloor, E., Miller, J. B., & Gauci, V. (2017). Large emissions from floodplain trees close the Amazon methane budget. Nature 552, 230–234. https://doi.org/10.1038/nature24639

Pangala, S. R., Moore, S., Hornibrook, E. R. C., & Gauci, V. (2013). Trees are major conduits for methane egress from tropical forested wetlands. New Phytologist 197, 524-531. https://doi.org/10.1111/nph.12031

Mentor(s): Dr. Joost van Haren (Franke Honors College, University of Arizona) & Jason Deleeuw (Rain Forest Research Specialist and Terrestrial Biome Manager, Biosphere 2)

See me present this research at the American Geophysical Union Conference (2023)

• Wednesday, December 13th; 8:30 AM - 12:50 PM CST

• Moscone Center, South, Poster Hall A-C

• San Francisco, California

Abstract: “Spatial and Temporal Patterns of Methane Efflux in a Controlled Flooded Forest Inside Biosphere 2 ” 

Authors: Junior Burks, Joost van Haren, Jason Deleeuw

Due to its greater radiative forcing potency compared to carbon dioxide, gaseous methane plays a key role in our climate system. Wetland ecosystems constitute a significant portion of the global methane cycle, with one major source of emissions being from annually flooded forests in the Amazon basin. Recent research has shown that tree stems can significantly contribute to the methane flux from waterlogged ecosystems (Pangala et al. 2013, 2017). However, to fully assess the influence of tree stem fluxes on flooded forest methane emissions and the global budget, we need to better understand the spatial and temporal variability of the fluxes.

In the Biosphere 2 Tropical Rainforest’s várzea, we performed controlled flooding experiments to better understand the spatial and temporal aspects of wetland methane emissions. We sought to understand patterns behind tree stem fluxes including spatial variability across the surface of a stem and temporal variability over the duration of a flood. Using manual tree stem chambers on Pterocarpus indicus and Theobroma cacao trees, and a floating diffusion/ebullition chamber, we quantified methane emissions throughout dry periods and extended floods.

Our results suggest that 1) peak stem emissions are highly variable in time between species, 2) emissions continue to increase over time without peaking, 3) stem fluxes decrease strongly with height along tree stems, 4) stem fluxes vary radially across tree stems, and 5) tree stem fluxes correlate well with sap flux rates over a 24hr diurnal period. Understanding when and where to measure tree stem emissions will help to improve the ability to quantify how significant wetland ecosystems and their trees are in the global methane and climate cycles for use in models.

References

Pangala, S. R., Enrich-Prast, A., Basso, L. S., Peixoto, R. B., Bastviken, D., Hornibrook, E. R. C., Gatti, L. V., Marotta, H., Calazans, L. S. B., Sakuragui, C. M., Bastos, W. R., Malm, O., Gloor, E., Miller, J. B., & Gauci, V. (2017). Large emissions from floodplain trees close the Amazon methane budget. Nature 552, 230–234. https://doi.org/10.1038/nature24639

Pangala, S. R., Moore, S., Hornibrook, E. R. C., & Gauci, V. (2013). Trees are major conduits for methane egress from tropical forested wetlands. New Phytologist 197, 524-531. https://doi.org/10.1111/nph.12031