Field Notes

Trip note On Oct. 7-8, and Oct. 11, 2003
Who: Jianwu Tang and Qi Chen
Weather: clear

I measured soil CO2 efflux along the transect and checked and downloaded the soil CO2 profile measurements.

CO2 efflux averaged 0.8 mmol m^-2 s^-1 under trees, while 0.3 mmol m^-2 s^-1 in the open areas.

At 9:50 am I watered two small plots (the second time watering), one mimicking 10mm rain and the other 5mm rain. Soil respiration immediately increased from 0.2 to as high as 12 mmol m^-2 s^-1, and then gradually declined until 2.4 mmol m^-2 s^-1on the late Oct. 11.

In order to see how fast the enhanced soil respiration decreases, I measured again on Oct. 11. Soil respiration dropped to 0.35 mmol m^-2 s^-1 (after 5mm rain) and 0.75 mmol m^-2 s^-1 (after 10mm rain), still above the background values 4 days after “rain”.

Soil moisture probe reading:

Qi’s log: 10/07

To collect LAI, I chosen 15 isolated trees and designed one screening plot under each trees. The edge of each screening plot is curled up for preventing leaves from blowing away. The size of each plot is 48in * 84in.

I also helped Jianwu to setup the large plot for his tree.

10/08

I got 4 leaf samples for each tree (since there are 15 trees, there are 60 leave samples). The samples are put into ziplock bags and kept in cooler for keeping fresh.

After returning to lab, I measured the leaf reflectance using ASD spectroradiometer and weighted the fresh leaves.