They are:
Percival Cho,
Shanelly Carrillo,
Lewis Usher and
Rudy Balan
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Percival Cho, Belizean forests, Impacts of natural and antropogenic disturbances of Belizean forests carbon cycle.
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Great work. Nice to see the pictures. Can someone remind me of the names of the Belizean researchers? (I know Lewis...)
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Fantastic! congratulations! Good report of the work you're doing. Abrazos xx Cc
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Hi, we used non Fix-all silicon used for glass in a couple of plots in Manaos, Brazil and some plots of Peru. This silicon worked very well filling the leaks between the collar and the tree stem. The only problem is that with the time the silicon loses his capability of attaching. We tried with several kinds of silicons (for wood, plastic, glass, and have the same results. I do not know if Fix-all one mantain the tube attached all the time (as it is showed by GEM manual) but what I suggest is using something for extra-attaching like square pieces of inner tube plus strapping band and springs (as used by dendrometers). This extra thing does not affect the measurement and give you long-term attaching. Hope this helps.
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Hi Erika, Have you found a solution? Would you like us to send you some Soudal fix all sealant? x Cc
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Soil depth profile, Vianet Mihindou, Fidèle EVOUNA ONDO, Dr. Stephen Adu-Bredu, Ankasa National Park, Mondah Forest Reserve, Lopé National Park, Bobiri, Ivindo National Park, Kogyae Strict Wildlife Reserve, West African Forests
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Brill! Thanks a lot, Cécile!
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That's right, we are just using flux data from the spreadsheets. You can find the code we use to convert from raw EGM data to flux data on github:
https://github.com/OxfordEcosystemsLab/GEMcarbon.R It is called "EGM_raw_to_flux_option1" (or option 2, depending on your experimental layout - see RAINFOR-GEM manual for descriptions of options).
Let me know if you need help, Cécile
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Toby Marthews, Carbon dynamics of representative ecosystems in nortwestern Peruvian Amazon, Soil respiration
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Happy new year to you!
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Hear the fan is a good option, we did not realize it, but we will take this into account.
No, I do not have access to another one. In fact we have another “old/recycled one” which was used in Allpahuayo plots and stopped working in 2013. It would be great to send it to you in Oxford. Maybe people of PP Systems can do something with it. Is that possible? We bought the EGM we are using in at the end of 2013 and it had been working very well before this problem. The soda lime is still green so it is ok. I think the problem is solved, hence thank you for your help.
We have the problem of NV in partitioning respiration experiment data of Allpahuayo. If we ran the analysis (data collected in 2011) without the NV data some values are negative and we are bricking against the wall with that. We did not know that it was needed to collect the NV, so we will collect it and look what happens next.
Thanks for the analysis.
Best,
Jhon -
Hi Jhon - Happy New Year!
As far as I'm aware, the high pitched sound has no other purpose other than to indicate that the chamber is flushing, hold in air. More important is that you can here the fan in the SRC whirring, indicating that it is working and indeed mixing the air inside the SRC.
Do you have access to another EGM and SRC unit? If so, it would be nice to take repeat measurements and check for agreement. If not, do you know when the EGM was last serviced/re-calibrated? Have you troubleshooted everything else (p73 of manual) such as checking if the soda lime needs replacing? It should be replaced if 2/3's of it in the tube is turning brown. It's hard to know if what you are seeing is the machine or indeed real measurements, but if you suspect it to be faulty, you can send it back to Oxford and we can get it fully serviced by PP Systems for you.
For the control experiment in order to calculate NV or pre-existing spatial variation, I don't think it matters too much that you are measuring this at a later date - we can assume that the spatial variation is the same now as it was then - perhaps just try to carry out the measurements in a similar time of year so that soil moisture levels are similar.
As for the analysis, I will try to find out where this is described in detail and get back to you.
Cheers,
Sam -
Hi Sam,
Sorry for the slow feedback.
1. When I select the plot number, appears a message: “CHAMBER FLUSHING, HOLD IN AIR". At the same time, the chamber should sound for around 15 seconds but it had not been sounding. I just opened the SRC chamber and cleaned it inside and now it is sounding again. There was some dust in it. Something curious: this device is a “new one”. When I was working at Allpahuayo plots I had used a recycled one and never heard that sound, so I do not know if that is normal. The data looks a bit lower than usual but I am not sure if that is due to machine or it is a real measurement.
2. In the last manual, there is a proportion of ambient (NV) or pre-existing spatial variation. This is measured before collar installation, so what should I do if I do not have this data. Shall I do the procedure beside the already-installed tubes and consider them as initial measurements?
3. One last question is how to analyze the data of partitioning experiment using the protocol 2. The manual omits this chapter. I am going to set up these tubes and the protocol 2 looks interesting.
Thanks
Jhon -
Hi Jhon,
I'm sat next to Toby and he asked me to try and answer this for you as I've been using them far more recently than he has.
Firstly, when you say it sounds during pre-measurement, are you referring to the high pitched tone, or the sound of the fan flushing the chamber? I've never experienced not hearing the high pitched tone before, but I think so long as you can hear the fan flushing the chamber, that is the most important part of pre-measurement calibration and it should be OK and if the results look reasonable, then this is encouraging.
Secondly, it sounds as though you are implementing partitioning experiment protocol 1 (with 4 sets of 9 tubes)? I'm not absolutely clear what your question is, but essentially, if you have removed litter before taking an initial emission measurement, you can replace the litter that was removed (same amount) from the tube, wait for some time and take another measurement, which will include the flux from the litter. Then you can remove the litter again, wait some time, and take another measurement. The difference between these two measurements is attributable to the litter.
I hope this helps, but please tell me if it wasn't what you were asking for and I'll get back to you again.
All best from Oxford,
Sam
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Thanks, Sam! You are completely right!
I guess I was just shocked to see a trap almost as tall as me! -
Hi Erika - I just checked the manual (sorry, I should have done this before) and I think you might be mis-reading it - basically, the legs need to be cut 1.5 m long, so that 0.5 m can be stuck into the ground, resulting in the litter trap tray standing at 1.0 m height. Does that make sense?
Cheers,
Sam -
Hi Sam,
Thanks a lot! Yadvinder has commented that traps used to be 1m tall and not 1.50m. Any idea if this is a typo in the manual? Toby, do you know?
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Hi Erika - just had a quick chat with Toby and we can't see any reason why you shouldn't reduce it to 1.20 m. Some of my litter traps in places with high elephant population densities are placed on the ground to prevent them being knocked over - each site has its own obstacles!
Cheers,
Sam
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Hi Jhon,
Sorry for the delay in responding to you - the reason for this is that we are currently undergoing a review of how we analyse hemispherical photos. Essentially, for all the reasons you mention above regarding 'optical centre', 'angular resolution' etc...and moreover the calibration process that is now required in CAN-EYE, we are moving to a different, freely downloadable software analysis program called Hemisfer (http://www.wsl.ch/dienstleistungen/produkte/software/hemisfer/download_EN) - the free version is fully functional (as well as far more intuitive than CAN-EYE), the only limitation being it's resolution limits. We are in the process of purchasing a number of licenses which give us access to the limit-free resolution version and can share this with you in time. In the meantime, may I suggest that you follow the link above and try running some of your photos through the free version to get accustomed to the software? For peace of mind, you can even compare some of the results from Hemisfer with CAN-EYE - we have also done this and there is good agreement (even with the free version). Let me know how you get on.
All best from Oxford,
Sam and the GEM team
Is there any source where I can find this project function? or do I have to use any default settings? I am using a Nikon Coolpix 4500 and a Nikon Fisheye FC-E8. The version of CAN_EYE is V6313
Hi again,
I followed all the steps: Open CAN-EYE, Hemispherical Images/RGB Images/upward and I had to stop in the next step which asks to specify a project function. I have read something about it and is related to camera+lens caracteristics. There are also other required caracteristics that I do not know how to fill up: Image size, optical centre, Sub-sampling, angular resolution, fapar computation. So how should I set them up? How do I interpretate the results?.
Thanks
Jhon