The only way to measure what is sequestered by plants is measure the biomass of the plants. This can be done through estimating allometric relationships between something that is easily measured non-destructively (basal diameter of stem, etc.) and the biomass of the plant. You will need to destructively sample a few plants along a range of masses to do this. You can measure photosynthesis with and IRGA but this not sequestration, only net photosynthesis. Likewise, measuring net ecosystem exchange of carbon (NEE, aka net carbon balance of the ecosystem) is possible using eddy co-variance techniques BUT this includes soil decomposition, not just plant sequestration. I hope this helps, feel free to ask more if needed.

I don't think this can be done non-destructively or very easily unfortunately. Carbon labelling is a good method but on a field scale is a big project by itself!

You may want to read this nice introductory paper by Dennis Baldocchi on the challenging and promising world of micrometeorological measurements: Baldocchi, D. (2008). "'Breathing' of the terrestrial biosphere: lessons learned from a global network of carbon dioxide flux measurement systems." Australian Journal of Botany 56(1): 1-26

Best,

Andrea

How about an Infra-red gas analyser (IRGA) widely used to measure net CO2 uptake usually on individual leaves?

You may be better to measure carbohydrate,about measureing method seek for plant phsyiology

Hello!! I dont understand what you want to do? you want to measure the total carbon used by plants? the phtosynthetic rate measurement is a good parameter to estimate the carbon sequestering by plants. You can also install the device in a little representative portion of the field and extrapolate to the rest of it.

http://www.adc.co.uk/Plant

The only way to measure what is sequestered by plants is measure the biomass of the plants. This can be done through estimating allometric relationships between something that is easily measured non-destructively (basal diameter of stem, etc.) and the biomass of the plant. You will need to destructively sample a few plants along a range of masses to do this. You can measure photosynthesis with and IRGA but this not sequestration, only net photosynthesis. Likewise, measuring net ecosystem exchange of carbon (NEE, aka net carbon balance of the ecosystem) is possible using eddy co-variance techniques BUT this includes soil decomposition, not just plant sequestration. I hope this helps, feel free to ask more if needed.

Jonathan's answer is right on track. Biomass sampling can give you good results, but can be time consuming. Allometric relationships can be used to avoid the destructive measurements. You will need to know (or develop) a relationship between diameter and biomass. This may require destructive sampling to build this…although you may find some of this in the literature. If only ‘above-ground’ biomass relationships are known, you may need to know the 'root-to-shoot' ratio, to get an idea how much carbon is being stored below ground.

So it depends on what exactly you want to measure. As Jonathan mentions, you can also get snapshots for estimating the sequestration through flux measurements. For example, if you are interested in instruments for flux measurements, LI-COR has several options for instrumentation: photosynthesis systems for leaf-level, soil flux systems for the soil, and eddy covariance systems for the NEE, carbon balance.

Well, one can try and see the relationship between C sequestration and LAI. I have got a high and significant relationship between the two. This too is time consuming but once developed LAI will give you fairly accurate estimates of carbon sequestered by the forest

Thanks a lot everybody. Dr. Jonathan has given best suggestions and opinion. Currently I am using the biomass measurement method through no-destructive way and Allometric relationship. However, it is time consuming; even LAI has same problem.

Dr. Jonathan, can you elaborate on measuring net ecosystem exchange of carbon (NEE)?

There are two ways to determine the net balance of carbon in ecosystems. The first being the use of allometrics, annual measurements of plant growth, estimates of belowground biomass change and turnover, and decomposition. This is rather complex but it is commonly done and can be quite accurate at annual scales or at scales that mirror the frequency of all of the measurements. The goal being to quantify how much plants store and how much the rest of ecosystem consumes and respires.

A second method is to talk to Dave Johnson from LICOR (see above) and give him your credit card:) LICOR has systems that measure wind turbulence paired with very accurate atmospheric CO2 measurements to infer ecosystem uptake by measuring atmospheric subtraction of CO2. This method is also commonly used and has many benefits over the first method. Mainly being the high temporal frequency of the measurements. However, this method requires flat terrain, large homogeneous footprints, and arm of smart people, and lots of money:) See some of the recent publication on my page for some great work on both methods, mostly from my very talented co-authors. LICOR also has some wonderful publications and videos on their website.

I hope this helps.

Mahajan: I believe you should try to better define your problem, especially in terms of spatial (and time) scales. It is quite different to attack this problem -say- for a pot of a couple of wheat plants, or for a field crop, or a (natural?) forest system. In your original question, you spoke about "monthly or annual basis". I fear that any biometrical/allometrical method will fail at this time scale (but, I admit, I have forestry/agroforesty systems in my mind). It is quite difficult to develop reliable relationships for root/shoot ratios in a variable environment. In this respect, you should also clarify to yourself and to anybody is willing to help you a precision threshold you want to reach.

Also, a better definition of what you mean with "sequestration" is mandatory. You probably know that most of the "sequestered" C is below gound, either in alive or dead biomass. You actually asked for help on "plant sequestration", but do you really want to forget the destiny of the C released by plant into the soil? "Plant" sequestration is only part of the picture.

At the (eco)system scale, all these processes merge in the concept of NEE, and micrometeorological methods become the (only?) way to assess C fluxes on hourly-to-yearly basis, at a ecologically representative, "realistic" field plot scale (thosands-to-tenofthousands of square meters). There are many introductory papers on this topic, I have just suggested one of the most introductory (and clearly written).

Best,

Andrea

What you mean " sequestered by plants" ?

Plant biomass?

The total amount of C-CO2 converted by plant into other substances?

Measuring instrument is used ADC LCA-4 and millimeter block paper. LCA-4 is used to measure the CO2 absorption and millimeter block is used to measure the area of the leaf blade. Measurement results using the LCA-4 in laboratotorium silviculture, flattened and formed a graph the rate of photosynthesis. From the graph obtained rate equation parameters of each type of plant photosynthesis. Furthermore, by considering the basic data about the estimated daily light intensity into the equation, then the rate of photosynthesis obtained an average of of plants in site. Photosynthetic rate of plants is still in units of micro moles per square meter per second. The unit then converted to kilograms per hectare per day. Micro mol converted into kilograms with the consideration of the relative factors of CO2 molecules. Units per hectare is obtained by multiplying the area of ​​one leaf, number of leaves per tree and number of trees per hectare of any kind. Seconds that turned into consideration long day with an average irradiation in site.

Dear Dr. Mahajan, Please follow Jonathan Martin suggestions. I am agree 100% . You can measure by allometry as well as LI-Cor Instruments specially Eddy-covariance. May i know where are you working India or out side. If you are working in India it would be great to introduce Eddy-covariance.

For those interested in learning more about Eddy Covariance, you can find an educational guidebook to the measurement method at the link below. Download a free copy if you would like.

www.licor.com/ec-book

Thanks Abhishek and Dave. This information will be of great help for me.

I am working in Pune (India), especially on urban green spaces/plantations as well as the natural areas around Pune with my students.

Thanks.

For India, allometric relationships of major plant species is documented by Forest Survey of India. You may visit their website and download a recent report on State of Forest Carbon which provides these equations. Again, as Mr. Pitacco discussed earlier that understanding of scope of estimation in spatial and temporal scale may be required for providing specific inputs.

yes it is made by a company: Licor in Franklin, NE, USA.

Sir in the case of Azolla, how can I measure the carbon sequestration? is Biometrical/allometrical method applicable also? or any suggestion from the experts? thank you very much.

For some tree species, particularly, loblolly pine stand-level allometry has been estimated for different treatments/sites/. When we build allometric relationships with trees, we carefully excavate pits surrounding the tree down to a depth appropriate for the age of the tree/soils. It takes some initial deep excavations to determine that depth. We then remove any remaining taproot using a backhoe. For between the pits we will also dig pits to get at the lateral coarse roots. Cores, even big ones, don’t do a good job for estimating these coarse roots as they are very spatially heterogeneous. This is very labor intensive. Then, of course, you need to analyze the various plant tissues for C concentration although 0.5 is often the used as a default value. We have developed the use of ground penetrating radar (GPR) for estimating lateral coarse roots and on many soils, and if it isn’t too wet, this works great. GPR lets you greatly increase the space you sample. Check out my ResearchGate page for papers on this, the first author on these is John Butnor (he has a page also) who is probably the world expert on using GPR to estimate root biomass.

Analysis of leaf photosynthetic CO2 uptake - the rate of leaf photosynthesis was measured on fully expanded leaves using a closed glass exchange portable Infrared Gas Analyzer (IRGA) (LICOR, USA). The photosynthetic CO2 uptake was expressed as  moles CO2 sec -1 m -2.

Hi D.M.,

A lot of tracks to sequestration of plants have been mentioned already in response to your question, by the colleagues here above me. Johnathan Martin gets very close. But since you said plants, and not trees, allometric approaches are not always the road to follow, but plausible for forests evidently. Sequestration is indeed as some have pertinently remarked a time dependent process. Does a one year herb significantly sequester carbon on the long-term? No it does not. It is like the leaves of trees, they fall off, and are taken out of the carbon sequestration loop by bacterial and fungal consumption. The same happens with one year herbs. Even multi-yearly herbs do not sequester carbon in the same time horizon as trees do. So one has to define the time boundaries of sequestration quite well. For a natural forest, this goes up to a century or so. Sometimes longer. But that's the longest you will find for plants.

For man-made forests the sequestration time horizon is much shorter, because these forests are managed for the production of wood. In Europe there are no natural forests (left). Even worse, scientist are looking to shorten forest rotation times as much as possible to produce fuel wood or chips and wood pellets with it. Lunacy!!! If this wood is burned, out of the loop your carbon goes.

If wood is not burned, but used to produce paper, the same happens as with burning unless this paper is recycled a few cycles. The most durable application of wood is when it is used for building houses or furniture and the like. This may lead to carbon sequestered during decades. Hence all depends (as always) on the premises you start out from.

One should not forget that lots of carbon in ecosystems is sequestered in soils as well. The poorest soils in that respect are agricultural soils (evidently). The richest soils with respect to carbon content are those of (natural) forests and Northern highland moors (peat you know).

So it is not enough to measure carbon sequestration in plants if you want to quantify the complete bookkeeping of carbon sequestration for a certain ecosystem. Moreover some fraction of an ecosystems carbon leaves the system by the rivers of the watershed(s) where your ecosystem with its plants (or trees and mostly both) are growing. The carbon in the rivers of a watershed will ultimately end up somewhere in a sea or ocean, unless the river ends up in a desert, which happens once and a while as well.

Hence D.M., brace yourself for a pretty complex exercise trying to keep track of all those sequestration pathways. For each of them you will have to apply other techniques to quantify them and to estimate the half-life of carbon storage when carbon is sequestered in trees, plants, soils, watersheds, houses, paper etc etc....

I certainly don't want to discourage you, but the exercise is more complex than one would expect at first glance. But since you are scientist, you must be used to that I figger.

Our politicians (a bit like children) ask lots of simple questions about the carbon cycle. Scientists are confronted with these questions (funding you know) and the fact is that much less simple answers are for the taking when trying to answer honestly. But that's life as it is, I guess you know that too.

Cheers,

Frank

Sir in the case of Azolla, how can I measure the carbon dioxide sequestration? any suggestion from the experts? thank you very much in advance.