In Phase 1 of this study (2019-2021), we examined transpiration, interception, stem flow, and soil moisture patterns in four species of common Pacific Northwest Trees using a variety of sophisticated technologies including sapflow sensors and remotely transmitting tipping-buck rain gauges. Details on this work were presented in this final report, and this poster. These exciting new data demonstrated variable timing in tree transpiration among Douglas-fir, western redcedar, red alder, and bigleaf maple trees at four sites in the lowland areas of the Puget trough.
In 2022-2024, we have expanded our work to address two additional and important questions for scaling up our work to make estimates about the roles of trees hydrologic cycling in lowland forests and urban landscapes. First, we are sampling across tree sizes to determine how speed of water movement (sapflux velocity) in trees scales with tree size. We have two large sapflux stations set up at the Evergreen State College where we are sampling Douglas-fir and bigleaf maple trees from 4-inch diameter trees all the way up to 30-inch diameter trees! Second, we are developing a small mobile sapflux probe technology that we are using to measure trees in isolated conditions. This ground-breaking new technology is allowing us to sample individual trees in urban conditions where large and complex sapflux stations would be impossible. We have deployed trees across a series of parking lot tree islands to determine patterns of water movement in trees in urban and semi-urban spaces. Of course, we have a series of weather stations, soil moisture measurements, and additional experiments that are all supporting these efforts. Pictures and data from our ongoing work are below!
May 5th, 2023 update: In 2023, we are off and running with several deployments of our mobile units and continuous monitoring of sapflux in 20 trees since January 2023.
Here are links to our public Weather Station Data associated with this project:
The Evergreen Organic Farm Station
Our Interception Bucket Data ( rainfall under trees)
In March-May we’ve gotten some great data from our mobile probes )pictures above). The below graphs show permanent fixed station sapflux and some of our mobile station (MU) data for Douglas-fir trees which were very active in April. Check back soon to see graphs compiling all data!
Fixed Station Transpiration:
Mobile Units (note that these are smaller trees than above, and so total water-use is smaller):
