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In late October, members of the lab traveled 4 hours south to Tucson, where the 2025 AmeriFlux meeting was being held at the University of Arizona. Oscar presented his work on near-surface remote sensing in pinyon-juniper woodlands; Yujie presented her analysis of the continuity between paired NEON and AmeriFlux sites, and Andrew gave an update from the AmeriFlux Science Steering Committee and the PhenoCam Network. The meeting included a field trip to the amazing Arizona – Sonora Desert Museum, as well as a delicious conference dinner, and many stimulating talks and posters. It was a great opportunity to catch up with colleagues from across the US, and the Americas more generally.

The pictures below include the standard workshop photo, as well as snapshots from the tours to collaborator Russ Scott’s Santa Rita sites, and the U of A Laboratory of Tree Ring Research. Local host Dave Moore did a fantastic job of keeping meeting participants entertained and well fed (for some, karaoke after the first night’s dinner was a highlight).

In mid-October, Yujie and Mostafa participated in the NEON Convergence Summit 2025: Advancing Continental-Scale Biology, hosted by the NSF-funded National Ecological Observatory Network (NEON) in Boulder, CO.

The in-person facilitated summit brought together NEON staff, NEON Ambassadors (including Yujie), and researchers from across the country. Participants gathered to explore innovative and interdisciplinary ways to use NEON data, samples, and infrastructure to advance continental-scale biology.

A key outcome of the summit was the formation of enthusiastic and motivated working groups, who will collaborate on impactful outputs including writing proposals and white papers, and developing new resources for the community.

The photo shows Yujie on a pre-workshop field trip to the Central Plains Experimental Range (CPER) NEON site, 75 km to the northeast of Boulder.

Already in Arizona to visit colleagues in Tucson, Brazilian forest engineer Izabela Aleixo, newly hired as a researcher at the National Institute for Amazonian Research (INPA), traveled to Flagstaff in early October. She presented her research in a seminar titled “Tropical Forests and Environmental Change: Insights from Long-Term Phenology and Large-Scale Experiments in the Central Amazon.”  Izabela’s work focuses on tree phenology, mortality, and forest dynamics in relation to climate change, and recently she is participating in several large-scale experiments.  In her talk, Izabela showed exciting preliminary data from the AmazonFACE experiment. These results provide early evidence of the potential effects of elevated CO₂ on plant physiology and forest functioning. The full-scale experiment is still being installed. 

During her brief visit, Izabela had dinner with students at Delhi Palace, enjoyed a happy hour at Mother Road, saw the impressively shiny MICADAS AMS for radiocarbon analysis, and visited Sunset Crater. 

Hard to believe, but it’s been 20 years since a webcam was first put atop the Bartlett Experimental Forest AmeriFlux tower! The pictures from the Axis 211 weren’t great (the first recorded image, just before noon on October 4 2005 is shown below), but they were good enough. The data led to a 2007 paper in Oecologia that concluded “A network of cameras could offer a novel opportunity to implement a regional or national phenology monitoring program.” It turns out, that was a pretty good idea! This review paper in Agricultural and Forest Meteorology provides a more complete history of the PhenoCam network.

This week, core members of the PhenoCam team met up at Dark Sky Brewing to celebrate the recent acceptance in Earth System Science Data of the paper documenting V3 of the PhenoCam dataset. The dataset covers through the end of 2023 and contains almost 5000 site years of data. The data curation team did a super job vetting the phenological time series for each PhenoCam site included in the paper, but ultimately it was Keith’s wizardry with server and filesystem management, ability to dig in and resolve obscure edge-cases and bugs, and tenacity when it came to delivering approximately 40 TB of data and imagery to the ORNL DAAC, that was essential to the successful completion of this effort. For his invaluable contributions to the PhenoCam V3.0 dataset, Keith was awarded the coveted Golden PhenoCam. Thank you for all your efforts, Keith.

Congratulations to Jen, who was selected as an Outstanding Graduate Student in the Steve Sanghi College of Engineering (SCE) for Fall 2025. SCE Dean Charles Chadwell summarized Jen’s exceptional accomplishments: “You were awarded the highly selective NASA FINESST fellowship to support your work, and you independently secured approximately $35,000 in funding to organize and lead an international workshop at Hat Ranch, bringing together 40 participants from 10 countries. The outcomes of this workshop were featured in AGU’s EOS news magazine, underscoring the impact of your efforts. Your scholarly contributions are already impressive, with your first paper published in Environmental Research Letters and a coauthored article in PNAS. You have also shared your research widely through oral presentations at venues such as the Flagstaff Gravity Lab, the 2024 AmeriFlux Meeting at UC Berkeley, Universidad de Sonora, the AGU Fall Meeting in Washington, DC, and the University of Plymouth in the UK. Your ability to secure funding, publish in top journals, and present internationally highlights your leadership, initiative, and the global relevance of your work.”

Great job, Jen!

With the end of September marking the end of the water year, it’s a good time to look back on this year’s summer rainfall, and compare it to previous years. While the summer monsoon season “officially” runs from June 15 to September 30, it’s not like rain in May and early June doesn’t matter. So, the graph above compares cumulative precipitation over the period from May 1 to late October. And, although well into August it looked like 2025 might be a total dud, or what some call a “non-soon,” abundant rainfall over the last six weeks turned things around. As measured by a Campbell Scientific ClimaVue all-in-one weather station located in the Forestdale neighborhood of southeast Flagstaff, the official precipitation total from May 1 to today (October 1) is a very respectable 197.4 mm, or 7.8″. Compared to the previous 5 y, it’s almost three times as much as the ultra-dry summer of 2020, but about 40% less than the epically-wet summer of 2021.

Fun fact: The final September rain in Flagstaff brought the first autumn snow to the highest summits of the San Francisco peaks, although it melted away by mid-day.

Andrew met up with PBS personality and Trail Mix’d host Kristen Keogh at 9000′ on Humphrey’s Peak for a wide-ranging interview that touched on changes in vegetation with increasing elevation, whether aspen need fire to reproduce, and what to expect with fall colors in 2025. Andrew’s bold prediction, 3 weeks out, is that aspen colors at Hart Prairie will peak between October 20 and 25, and that despite the dry summer the colors should still be “pretty good”. So far, the leaves aren’t changing much – but you can keep an eye on the changing seasons through the Hart Prairie phenocam!

On the final day of the 2025 Flagstaff Festival of Science, Andrew and other STEM professionals from NAU, USGS, and the Lowell Observatory participated in the event “Making STEM Digestible,” which was held at the USGS Astrogeology Science Center. The event was moderated by Greg Vaughan (USGS), whose research focuses on volcanic and geothermal phenomena.

To get the event rolling, Greg asked the panelists to describe the work they do first in technical and inaccessible language, and then in terms that (hopefully) the audience could understand. Andrew’s technical version: “In my research, we measure the fluxes of carbon dioxide, latent heat, and sensible heat between the land surface and the atmosphere. We do this using the eddy covariance method, which is a micrometeorological technique that uses 10 Hz measurements from a sonic anemometer and infrared gas analyzer to calculate the covariance between the vertical wind velocity and fluctuations in CO₂, water vapor, and air temperature. When we gap-fill the resulting time series using machine learning methods we can estimate daily, monthly, and annual budgets of carbon and water for the ecosystem.” Hardly understanding a word, the audience was surprised to learn that Andrew is a forest ecologist!

The easier-to-understand version? “I use fancy instruments mounted above the forest canopy to measure the rhythmic “breathing” of trees. Trees breathe through tiny pores on the surface of leaves, known as stomata, with carbon dioxide being absorbed by the leaf, and water vapor being released. From my measurements we can learn how much trees are growing and how much water they are using.” Now that’s more digestible!

The photo shows (L to R) Todd Gonzales (Lowell Observatory), Anya Metcalfe (USGS), Greg Vaughan (USGS), Angie Hodge-Zickerman (NAU), and Andrew.

During an evening of steady cold rain and eerie thunder, Jacob told a personal story about how observing the impact of dramatic weather events on the desert landscape he grew up in is what led him down a career path in science. He told his story as part of the yearly Flagstaff Festival of Science event, “Science through Story.” The event is organized by ECOSS’s own Dr. Jane Marks in partnership with Writing Class Radio. In addition to learning about the importance of studying dryland ecosystems in response to changes in climate, Jacob also revealed to the audience a bit about his careless adolescent shenanigans. In the words of Andrea and Allison of Writing Class Radio, “Everyone has a story. What’s yours?”