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In late June 2026, Cara and Perry (both natives of Philadelphia) attended PhysFest 5 at the University of Pennsylvania, the fifth installment of a hands-on plant physiology workshop designed to train roughly 40 grad students in key ecophysiology measurements. The workshop offered four full days of lectures and instruction on instruments related to plant water relations, thermal and hyperspectral imaging, environmental sensors, and gas exchange and fluorescence. In the final two days of the workshop, Cara and Perry teamed up with five other PhysFest attendees from Columbia, Oregon State, University of Florida, and University of Utah to craft a project idea that would be carried out in the nearby Woodlands Cemetery. Perry thought it could be interesting to use the instruments at PhysFest to assess how nighttime light pollution might affect leaf physiology. To test this, the group chose to put the Specim IQ Hyperspectral Camera and the LICOR LI-6800 gas exchange system to work in the cemetery. Given the ghostly slant to their sampling environment and the use of leaf spectral data, the group aptly named themselves the Woodlands Cemetery SPECtres. The group got to work looking for the right tree to sample, and found a beech tree with the characteristics they were looking for: one portion of the canopy directly next to a streetlight illuminated throughout the night, another portion away from the streetlight and shaded during the day, and another portion away from the streetlight but fully sunlit during the day. After collecting measurements on the three leaf types, the SPECtres found that the near-infrared (NIR) reflectance of both daytime-shaded leaves was about twice that of the sunlit leaf, but there was little difference in NIR reflectance between the daytime-shade/nighttime-lit and daytime-shade/nighttime-shade leaves. They then made photosynthetic light response curves for all leaves. As expected, the sun-adapted leaf had the highest saturation rate of CO₂ assimilation. The daytime-shade/nighttime-lit leaf, however, had the lowest assimilation rate across light conditions, and the daytime-shade/nighttime-shade had intermediate assimilation, meaning exposure to nighttime artificial light could potentially decrease photosynthetic efficiency. Each of the six groups presented their projects at the end of the course to a panel of judges (the PhysFest instructors) in founding-father-esque powdered wigs. After a long week of learning, Perry and Cara led most of the cohort on a Philly tourist sightsee and bar crawl. They felt good being back in Philadelphia and were grateful to take new skills and friendships away from it.

In early September, after a relatively wet two-week period, lab members Perry, Oscar, Yujie, and Cara (+1 for her friend Nicky, visiting from UC Davis) drove up to Schultz Pass to go foraging for lobster mushrooms. The lobster mushroom is fascinating in that it is not a single organism but rather a combination of a parasitic sac fungus (Hypomyces lactifluorum) and a host mushroom, usually a species of Russula or Lactarius. Good specimens are relatively tasty, with a firm texture and a flavor that is somewhat reminiscent of the Maine lobster, Homarus americanus. While it may not have been peak foraging season, the ‘shrooms were abundant and it was a great way to spend a beautiful Friday afternoon.

Top: The team, heading out in search of prize booty; lobster mushrooms, cooking in butter; the team, displaying their prize finds.

Two projects in which the Richardson Lab is involved have recently received some media attention, at NAU and nationally:

1. Darby’s paper, “Increasing Respiration Weakens the Carbon Sink Over Two Decades in a Temperate Deciduous Forest”, was highlighted in an NAU Review article titled “Nature’s most important climate change defenders are in peril“, and also received coverage in an article in the Concord (NH) Monitor titled “In New Hampshire, the lungs of the planet are coughing“. The paper, which documents a changing carbon cycle at Bartlett Experimental Forest since 2004, was profiled in a lab blog post a couple of weeks earlier.
2. Camelia Mosor’s work on fog in redwoods, also profiled in a blog post, was the subject of an NAU Review article titled “What AI can tell us about California redwoods and fog.”

Congratulations to Darby and Camelia!

It’s 698 miles (1123 km) from Carmel Valley, CA, to Flagstaff, and it’s a drive that Andrew and George Koch have done more than a few times for their redwoods projects; west of Carmel Valley in the Santa Lucia Preserve lie some fog-shrouded canyons where redwoods grow at the southern end of their range.

Highlights of the drive back to Flagstaff include the larger-than-life cutout figures near Salinas by local artist John Cerney , lunch at Taco Bros in Bakersfield, the Railroad Loop (not visible from the highway) at Tehachapi Pass, beautiful Barstow, the vast expanse of the Mojave Desert, the crossing of the Colorado River at Needles, CA—Topock, AZ, and the slow climb back up to the Colorado Plateau around Kingman .

On a recent trip back from Santa Lucia Preserve, topics of discussion included: (1) what is the impact of a large solar farm on net radiation and partitioning the surface energy balance? (2) how does a wind farm affect local climate? (3) how is heat from a data center dissipated, and could it be used for domestic heating? and, driving through Barstow, (4) how hot will it be at the low point on the drive, crossing the Colorado River at an elevation of 429 ft (129 m)?

Question 4, in particular, led to some passenger-seat science! South of Mojave National Preserve, I-40 reaches a maximum elevation of about 3300 ft (1000 m) before dropping down to the Colorado. Using the ambient temperature sensor in George’s Ford Maverick (reporting integer values in °F) and the My Altitude app on Andrew’s iPhone, data on air temperature and elevation were recorded every 200 ft from just over 2500 ft down to about 500 ft, and then entered into Gemini for analysis and plotting.

The calculated lapse rate of 0.95 ± 0.14 °C per 100 m compares quite favorably with textbook values for the dry adiabatic lapse rate, typically accepted as 0.98 °C per 100 m elevation. The temperature crossing the Colorado? 117 °F, or 47 °C.

Bored on your next long drive? Think science!

Andrew and newly-retired George Koch recently traveled to Carmel Valley, CA, to remove instrumentation from six redwoods in the upper reaches of Potrero Canyon, which lies within the Santa Lucia Preserve. Instruments to measure microclimate, fog, phenology, tree growth, and water stress had been installed two years ago with the objective of determining whether trees grow more on foggy nights than clear nights. The project has been funded by the Save the Redwoods League.

With more than 25 kg of equipment in each tree (including batteries, instruments and cables, fiberglass enclosures, and solar panels), and with trees averaging about 230 ft in height, assistance from both gravity and also Steve Sillett and Marie Antoine was greatly appreciated! Also: huge thanks to Tom and Alayna Gray, who hosted the arbornauts at their beautiful home within the Preserve, and a nod of appreciation to Emma Levy, conservation ecologist with the Santa Lucia Conservancy, who both helped to coordinate our visit and trekked out to the big trees to say hello.

Top: George at the base of a big tree; Bottom left: George, Steve, and Marie; Bottom right: George and Emma.

While on a tour of the American West that included visits to the National Ecological Observatory Network (NEON) in Boulder, CO, and the USA-National Phenology Network (USA-NPN) in Tucson, AZ, 김동학 (Kim Dong-hak) and 김상준 (Kim Sang-jun), from the Korea National Arboretum  in Pocheon, Gyeonggi Province, South Korea, spent a day in Flagstaff to learn more about the PhenoCam Network. Dong-hak runs the Korean National Phenology Network, and is responsible for the K-NPN’s citizen science and phenological forecasting efforts.

Dong-hak and Sang-jun joined Oscar and Andrew on an outing to Oscar’s “Blue Chute” field site, followed by a hike into the Red Mountain cinder cone and then lunch (one XL pepperoni, red onion, and green chile pizza, a new favorite) at the downtown Fratelli Pizza. After a quick tour of the Richardson-Carbone lab space, Dong-hak and Andrew talked about PhenoCam’s evolution and growth, open science philosophy, and cyberinfrastructure.

Thank you Dong-hak and Sang-jun for your visit—we hope that it leads to many productive collaborations down the road.

Dong-hak and Sang-jun were pleased to learn that in the US, elevation is measured in feet not meters!

Inside the Red Mountain cinder cone—one of the best short hikes in the Flagstaff area.

Big congratulations to Darby—her first dissertation chapter has just been published in Global Change Biology Communications! The paper, “Increasing Respiration Weakens the Carbon Sink Over Two Decades in a Temperate Deciduous Forest,” synthesizes 20 y of flux measurements from Bartlett Experimental Forest, New Hampshire. The key result is that net ecosystem productivity (NEP) is showing a strong declining trend over the period 2004-2023. For the last three years, Bartlett has been a net source of CO₂ to the atmosphere. Darby’s analysis shows that this shift in NEP is related to warmer winters and increasing ecosystem respiration. Her paper is one of just a handful published to date with 20 y of flux measurements.

Andrew, his postdoc advisor Dave Hollinger (USDA Forest Service, retired), and Dave’s technician Bob Evans (USDA Forest Service, retired) built the tower late in 2003 and instrumented it for eddy covariance measurements in January 2024 (Darby was in first grade at the time). The AmeriFlux site been running (most of the time!) ever since, thanks to assistance from many different people over the years including Scott Ollinger, Andy Ouimette, Chris Costello, Trevor Keenan, and Don Aubrecht.

The pictures below document some of the first 10 y at Bartlett. Top row: a much younger Andrew working on the tower (2004), looking down from the top of the tower (2012), looking west from the top of the tower to Crawford Notch (2012), the instrument shed at the base of the tower (2004), and early UAV imagery (2014) from Andrew’s former PhD student Steve Klosterman (the tower is clearly visible left of center).

Postdoc Mostafa Javadian is now Professor Dr. Javadian: he is starting a tenure-track position at College of the Holy Cross in Worcester, Massachusetts. To celebrate, lab members went out to lunch at Fratelli Pizza.

Holy Cross is just 20 minutes from Harvard Forest, and Mostafa expects to conduct research there. His teaching will be in the areas of general environmental science and remote sensing.

Mostafa had been with the lab since 2023, and his warmth, kindness, and good humor will be missed. Mostafa published a number of important papers during his time in Flagstaff. In one study, he applied the PT-JPL model to estimate individual tree transpiration from thermal images. In another, he carefully documented the performance of the NetCam Live2 as a suitable camera for PhenoCam use. He also contributed to the curation and publication of the PhenoCam V3 dataset, and put together another paper (not yet published) on changes in land surface temperature.

Good luck with your new position, Mostafa!

From left: Yujie Liu, Darby Bergl, Cara Fields, Jacob Blais, Delaney Watkins, Mostafa, Perry Giambuzzi, and Ben Wiebe.

Oscar drove up to Salt Lake City to participate in the 111th annual meeting of the Ecological Society of America. He presented two posters, “Stem freeze-thaw cycles in an evergreen woodland and its control on winter water use and photosynthesis” and “Using open-access PhenoCamimagery and data for science outreach and education in elementary to university-level classrooms.” Visitors to his posters included friends and collaborators Drew Peltier and his group from UNLV, Barry Logan from Bowdoin, Marguerite Mauritz from UTEP, and Lin Meng from Vanderbilt. After the meeting, Oscar commented that “I felt more ‘at home’ than I thought I would, due to the large number of ecophys sessions.”

Next year’s ESA meeting is in Andrew’s hometown of Toronto, Canada!

To celebrate the end of the semester, Andrew and Mariah took the lab group out to lunch at Delhi Palace. You can’t go wrong with garlic naan and a big plate of rice and curry!