Field Notes

When: July 17, 2003 D198
Where: Tonzi/Vaira Ranches
Who: Liukang Xu, Jianwu Tang, Qi Chen
Weather Sunny, little windy, temperature 106^oF (at Sacramento). At the site temperature was 42.09^oC at 15:30 from the floor met station.

Trip Purpose: check 3 flux systems and download data, soil moisture probe reading, Soil CO2 flux measurement, install two additional soil CO2 probe, sample leaf sample at 9 locations in Mr. Tonzi’s ranch for CASI image.

Tower system: was running good, but again we are still missing lot of data. We captured only 60% of data in last 10 days, while Floor and Vaira had much higher data capturing percentage for the same period.

Percentage of data capturing for three flux systems during the period of d188.65-198.65.

Download data, after reboot pc, gillsonic outputs:

Problem: the pump for the CO2 profile was broken.

Floor system: System running good, we got more than enough solar power, PV reading 13.5, 7.5 and 2.5. All data loggers working good. Replaced battery for Nancy’s sapflow (the one near the floor tower).

Vaira site: Arrived 6:35, fence and flux system running great. But the watchdog program quit working, fortunately we didn’t miss any single data points. PV reading 12.7, 1.5 and 3.0.

Soil moisture probe reading

Jianwu’s Note

CO2 efflux measurements are averaged 2 micro mol s-1 m-2 under the tree, and 0.5 micro mol s-1m-2 in the open area. The stem respiration is about 1.5-2 micro mol s-1m-2. I installed two more CO2 sensors in soil, one in the open at 24cm, and one under the tree at 24cm. The concentrations in the open are about 350ppm (2cm), 800ppm(8cm), 1400 ppm(16cm), and 1700ppm (24cm); under trees are 1700ppm (2cm), 4300ppm(8cm), 7800 ppm(16cm), and 11200ppm (24cm), much more than those in the open.

Qi Chen’s Note

We arrived the field site at around 10:00am, and Liukang and I then began to collect the leaf samples.

As planned, we sampled two trees in nine study plots. In each trees, we got 6 leaf samples at the top, east, south, west, north and center portions of trees, respectively. The leaf samples are put in Ziplocs and stored in the cooler.

When sampling, there are several issues:
1)It is difficult to locate the plots with dense trees.
We located the study plots with GPS and IKONOS imagery. For the sparse area where there are few trees, it is easy to locate the plots; however for areas with dense trees like the north and east-north direction to the tower, it took us long time to locate the plots.

2)It is hard to get the top leaf samples for some tall trees.
Even we got a ladder, but the ladder and pruner are not tall enough to sample leaves at the top of some tall trees. Consequently, we don't have sample leaves for some tall trees.

At the same time, we measured the tree locations with GPS.

When finished, it was around 6:00pm already. Besides samples for 18 oak trees, I also sampled one gray pines.

Around 8:00pm, we arrived home.

Around 9:30pm, I began to measure the leaf reflectance for all leaf samples with ASD spectroradiometer and weighted each samples. Each leaf samples are measured for ten times. After weighting, I transfer all samples into paper bags.


7/18/2003.

In the afternoon, I helped Jianwu to measure the CO2 flux for soil samples and we finished around 7:00pm

In the evening, I began to measure the leaf area for all samples in the lab. After done, I put all leaf samples in oven to dry it.

July 24, ppt in am in Oakland and Davis. Check the ranch