The main was to try LICOR 6400 XT to measure photosynthesis and stomatal conductance in this field trip. Before going to the field, I read the manual book, and replaced opaque conifer chamber with broad-leave chamber at my lab by myself. It was not easy, but I was really a handywoman.  hhhhh~  :‑D

              Fig. 1 I assembled opaque connifer chamber

I fully tested this machine with new chamber at my lab, with a cut branch of Ponderosa pine from the university campus. The machine worked well, so I decided to test it in the field.

At August, 26, 2016, Adam, Antonio, Guang and I went to the field. Adam assisted me by carry it, while Antonio and Guang checked the condition of other equipment at other plots.

Adam and I chose a east-faced, healthy branch of the tree in front of climate station at the T2 plot in Block 1 at 1.7 m height. There were some sparse branches below it, but seemed to be not very healthy. According to data from climate stations in three plots, the most significant difference of environmental variables in three plots was the solar radiation. So I hypothesized that differences in solar radiation contributed the most to contrast sap flow rates among three plots. Besides, I wanted to establish a model giving photosynthesis rate and stomatal conductance under different light intensities, in case there would be not enough field measurement data. Therefore, I measure light-response curve of branches as a preliminary experiment to see how photosynthesis and stomatal conductance response to light.

However, the battery of 6400 died soon, only after I measured four needle clusters (around 20 minutes). Adam was so worried about it, and told to me that if the problem came from the battery or machine, then we’d better send back them to the maintenance department as soon as possible.  But I felt embarrassed somehow, because I realized that I might not charge battery in a correct way, as the charger required to choose correct voltage and pressed fitted fuse into it, otherwise it always showed that battery was fully charged. I followed the guidebook carefully, but it still might be wrong.

I told to Adam about my speculation and sorry, and promised to him that I would check the problem and fix it as soon as possible. Adam gave his understanding, and suggested me to contact with Dr. Duan. Since batteries were dead, we disassembled the 6400 and put it back to the case.

Antonio and Guang also finished their works of checking the other equipment. I downloaded the data. Since there were nothing else we could do, we went back home before lunch.