Field Notes

<--2025-03-27 08:00:00 |
Other sites visited today: Vaira
Phenocam link: Searching...

Tonzi: 2025-04-10 10:00:00 (DOY 100)
Author: Joe Verfaillie
Others: Kuno, Mihkel, Housen

Summary: Housen collect first batch of GPS data, Kuno doing standard chamber fluxes, Mihkel visiting the site, removed Theta 7, nearly fully leafed out.

Tonzi
2025-04-10

Kuno, Mihkel and I arrived at about 11:00 PDT. Mihkel is Kuno's technician visiting for the week. Housen was already at the site having arrived a little before us. It was a beautiful sunny day with wispy clouds and very little breeze. The trees are close to fully leafed out and look in better health than last year. There was some rain last week that I was worried would cause damage (fungus) to the new leaves again but seems not. The grass is also super green with flowers starting. Overall probably the best week of the year. On the way through the Delta we notice some of the hill sides already turning brown.

I showed Mihkel around while Kuno started his usual chamber work. The trees are still emitting CH4 and the ground is taking up a little less than last time. From the top of the tower we could see Mount Diablo. I collected the Tower top data: flux and camera data. The wash reservoir was about a quarter low - refilled. I cleaned the radiometers.
The 7500 read: 437.7ppm CO2, 552.6mmol/m3 H2O, 23.2C, 99.7kPa, 99.7SS
The 7700 read: 2.04ppm CH4, 58.2RSSI - 86.2 after cleaning

On the ground we did the manual soil moisture readings, manual well levels, serviced the zcams, collected the FD data and read the dendrometers. I collected the Floor data: well, flux and camera data. The wash reservoir was about a quarter low - refilled.
The 7500 read: 434.4ppm CO2, 565.2mmol/m3 H2O, 23.0C, 99.8kPa, 102.8SS
The 7700 read: 1.99ppm CH4, 48.4RSSI - 75.4 after cleaning

Housen downloaded data from the GPS units he set up last time. There was about 2GB on each of the three units. He said the antenna cable had come loose from the unit on the tower top. He also showed me how to connect to the units over wifi and download the data. Housen will send me a written protocol too. I tried running the $40 GPS I got from Amazon. It was only seeing about 12 satellites when Housen's units were seeing about 30. I need to play with this more in the lab.

Towards the end Mihkel and Kuno carried the chamber stuff to the pond to do water flux and quality measurements - the pH was high 8+ and the CH4 fluxes were low. I finished up by collecting the point dendrometer data. The tree HISE 3 is attached to has died. I think I will leave it here to compare with the living trees. I also pulled Theta probe 7 sn xxx that has been reading about half of the other Theta probes.

We left at about 15:15 PDT

Field Data

No tank data

Well Depth

Date	Location	Depth (feet)
2025-04-10	TZ_floor	22.6
2025-04-10	TZ_road	30.65
2025-04-10	TZ_tower	25.9
2025-04-10	VR_well	52.4

No TZ Moisture Point data found

No VR Moisture Point data found

No TZ grass heigth found

No VR grass heigth found

Tree DBH

Date	Tag#	Reading (mm)
2025-04-10	102	8.4
2025-04-10	2	18.2
2025-04-10	245	13.6
2025-04-10	3	11.7
2025-04-10	4	15.1
2025-04-10	5	7.7
2025-04-10	6	10.4
2025-04-10	7	17.8
2025-04-10	72	5.6
2025-04-10	79	12.0