People who study plant physiology have lots of experience with tree photosynthetical activity thanks to devices like Licor and Waltz.
Most of time, during the working with devices, we input some value (CO2=380, Rh=55%, PAR= 2000 etc.) to the device and we get to output value (A, E, Gs etc.).
So, in vivo and under the natural conditions and outside conditions without input of values, has anybody any experience in measuring photosynthesis parameters ( A, E, Gs, etc.) of forest trees in real-time?
Forest is a community and some of the firms for leaf gas exchange produce items for Scalars exchange, like Eddy correlation (Campbell, Licor). Remote sensing of Chlorophyll fluorescence can give some clue on quantum yield, but alla depends on application case, that can be wet or dry, natural or artificial, hilly or plane. Wood annual growth rates by trunk sizes and dry matter or weed parcels can give a good estimate to start along with diversity
Thank you Dear Boingi,
You indicated such an excellent point that effects of site index on tree growth and annual increment result of physiological activity.
It can be assessed and estimated growth ratio within very simple and basic way without using any complex machine by just measuring diameter and height of trees.
The question, may be extraordinary, is that we may use machine like gas analyser devices however is there any study done by using real outsite condition values while working with this machine...or is there any possibility?
It depends what do you know. I had made measurements of gas interchange (with a Li-6400) in mangrove and banana using environmental conditions with good results. However I also made measurements in epiphytic bromeliads in a cloud florest. Here, the problem with 6400 was the high humidy (above 80% all day) which made the stabilization of the equipment slow. But I think that is possible to do good measurements with a gas analyser if you have some patience...
Dear Sur,
Thank you for your contribution. Yes you are right, this devices work limited condition and calibration takes more times as I have experienced with Waltz device while working with extreme temp. range.
May you give some detail and results about the study you have done in mangrove and banana plants?
Shure, I made measurements in scrub mangrove (languncularia racemosa and rizhophora mangle) at Clestún, Yucatán, (southeast of México). Measurements of gas exchange was made every 3 h during light period with LI-6400 (environmental conditions was used). Cuvette of the apparatus was left for two minutes on each measured leaf before taking the measurement. We found highest CO2 asimilation at 9:00 am (around 4.5 micro mol m-2s-1) on both species. Highest transpiration was registered about 2:00 pm on both species (around 1.5 mmol m-2s-1).
For ecosystem level real time measurements of CO2 exchange between the forest or any tree crop system eddy covariance flux measurement system is more appropriate and suitable. We have experience in natural rubber ecosystem in India for the last four years.
The net ecosystem exchange of CO2 and water can be converted into half an hour average and finally net value for a day. We need to equip the system above the forest canopy beyond rough flux zone, most probably in a field standing tower.
K. Annamalainathan
Rubber Research Institute of India
Dear Annamalainathan K. ,
Thank you very much for such a valuable contribution. If you dont mind, may you share your study with us?
Article Energizing the CO2 utilization by Chemo-enzymatic approaches...
This paper is interesting and informative in the context of enhancing CO2 sequestration potential of plants/trees. Recommended.