Carbohydrate Observatory


The Carbohydrate Observatory uses a citizen science approach, the citizens being almond, pistachio and walnut growers who send us monthly wood and bark samples from their orchards to be analyzed for sugars and starch. The results are made available through a website that each grower has access to. Growers then track the carbohydrate levels of their nut trees throughout the year while pairing it with climate, management or pheneological events such as dormancy, pollination, bud break, flowering, fruiting, harvest and leaf drop. The goal is to build a better biological understanding of the role carbohydrates and to use this massive data set as a tool to predict yield and understand environmental stresses such as lack of chilling hours and drought.

Our goal is to:

1) Understand how annual patterns of starch and soluble sugars (NSC – nonstructural carbohydrates) concentration in orchard trees differ throughout the Central Valley, which will aid in the improvement of spring/fall management practices and our understanding of chilling requirements.
2) To develop a novel tool that uses NSC levels as a predictor of yield for the following year and to understand variable crop yields.
3) Create an easy interactive NSC data sharing online platform.

Carbohydrate Observatory NEWS

10/01/2018 -- We have submitted first manuscript that uses data from the Observatory. In manuscript we describe first attempt to provide mechanistic understanding of winter temperature influence on bloom time.

10/01/2018 -- We received CDFA support for the Carbohydrate Observatory

09/20/2017 -- We launched new interactive graphs to see NSC concentration of specific farms in the content of all Central Valley, CA

07/07/2017 -- We reached first milestone - 250 sites

We are in the news -Western Farm Press

02/16/2017 -- Maciej and Anna are preparing CDFA Specialty Crop proposal to support scientific effort of the Carbohydrate Observatory, do not hesitate to let CDFA know you support it too.

Anna Davidson got stack in mud while collecting samples in rain near Fresno 01/17/2017. Ask her for a picture

Liquid handler arrived !!! Be first to get naming rights. It made its first plate on 01/16/2017.

Liquid handler will arrive in mid-January. It should increase precision of the carbohydrates analysis

Anna Davidson presented poster about Carbohydrate Observatory at the Almond Conference in Sacramento (2017). The interest among growers was overwhelming.

We bought small grinder to keep us afloat - $2550

Small setback - our grinder (~$6000) broke - all new measurements are on hold till we get it repaired or get a new one.

Our map interface (beta version) is life-online - now you can track changes in concentration of carbohydrates in twigs of almond, pistachio and walnut in CA

Over 50 participating farms and growers - Ask Anna how to join our Citizen science research project

Anna drove over 2000 miles in October

We are getting new liquid handler to increase precision starch analysis

---- Link to graphical Carbohydrate Observatory data
Really cool way to compare your farm with range of geographical and tree specific parameters ----

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NEW - Bloom time prediction tool for tree crops

Trees in seasonal climates gauge winter progression to assure vital and productive blooming. However, how dormant plants asses environmental conditions remains obscure. We postulated that it involves the energetic reserves required for bloom, and therefore studied winter carbohydrate metabolism in deciduous trees.
We quantified non-structural carbohydrates throughout winter in almond, peach, and pistachio trees in California and Israel and characterized winter metabolism. We constructed a carbohydrate-temperature (C–T) model that projects changes in starch and soluble carbohydrate concentrations by temperature mediated kinetics. Then, we tested the C–T model projections of bloom times by 20 years of temperature and phenology records from California.
The C–T model attributes winter carbohydrate regulation in dormant trees to continuous updates of metabolic pathways. The model projects a surge in starch synthesis at the end of winter, and critically low concentrations of soluble carbohydrates, that trigger bloom. This is supported by field measurements of starch accumulation at the end of winter (˜50 mg g−1 DW in almonds) that preceded bloom by ˜10 days.
The C–T model provides a physiological framework for bloom forecasts in deciduous orchards. It integrates contrasting notions of chill and heat and elucidates why abnormal winter temperatures may compromise bloom in deciduous orchards.

(CLICK HERE) link to bloom time prediction tool for almonds

Understanding the seasonal trend of tree non-structural carbohydrate budget

Graphical interface:


provides near real time information on sugars and starch content in twigs of orchards participating in the citizen science project. This information is being used to conduct research on the role of carbohydrates in plant phenology, carbohydrate response to climate change, winter temperature, etc.

Graphical interface:


can be used to evaluate dynamic carbohydrate content in specific orchards, in comparison to general trends observed for chosen criteria that include scion, rootstock, county. It should be used only as an information tool. We do not yet recommend using this tool to make management decisions. We anticipate that information collected over next few seasons will result in transformative research progress allowing growers to refer to their orchards NSC trends for additional guidance in making decisions.

How to use interactive graphs :

The graphical interface was coded by Maciej Zwieniecki. Sugar content analysis and related research is conducted by Anna Davidson, Maciej Zwieniecki and the Z-Lab

Below is the map presenting location of participating orchards

The map interface was coded by Jessica Orozco and Maciej Zwieniecki.

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What happens to the wood and bark samples sent to Carbohydrate Observatory in the Z-Lab?

  • Each sample is ground into powder. Then a small amount (25 mg) is washed in 1 mL of water to dissolve all soluble carbohydrates.

  • Using a colorimetric method, the concentration of sugars is measured and compared to lab standards.

  • The remaining material (the pellet) is washed again several times, centrifuged, and is then prepared for the starch analysis.

  • The pellet is treated with two different enzymes that digest starch to form the soluble sugars. These are again measured in colorimeter.

  • The entire process to determine soluble sugars and starch takes three days (80 samples can be done simultaneously).

  • We acurrently process more then 10000 samples per year

    Who is who in the Observatory

    Maciej Zwieniecki
    Tree physiologist

    Katelyn Cooper

    Sydeny Kim
    Junior Specialist

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    How to participate

    Please contact Maciej Zwieniecki at
    or by phone: 530 752 9880
    and we will get you started.

    For smapling protocol (pdf file) click here

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    Big thanks to Benefactors of Carbohydrate Observatory for their finacial support

    Polysaccharide Circle (donation above $1000)

    $10,000 - Anonymous 1

    $10,000 - Anonymous 1 second year

    $8,000 - Anonymous 2

    $20,000 - Wilbur Ellis 2

    Disaccharide Circle (donation between $100 and $1000)

    David Doll

    was first to support Carbohydrate Observatory
    '...I am very interested in seeing the results from your carbohydrate mapping efforts...' D.Doll

    David Doll

    second year donation - BIG THANK YOU

    Monosaccharide Circle (donation up to $100)

    Your name here

    If you would like to contribute to the Carbhydrate Observatory Z-Lab research effort please contact Maciej Zwieniecki at (gifts to UC Davis may be tax deductible). Donations support the Carbohydrate observatory, new equipment, financial support for undergraduate students and the creation of an endowment that would enrich plant physiology research in California. Checks should be written to UC Reagents marked with memo Zwieniecki Lab - Carbohydrate Observatory. Checks can be mailed to Maciej Zwieniecki, PES 2316, One Shields Ave, UC Davis, Davis, CA 95616

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    Paticipating Farms, Growers, Farm Advisors - Sample supliers only - No finacial support

    Sierra Orchards

    Coleman Farming Co.

    Valadez Farm

    Sleeper Ranch

    Larry Boardman

    Gilbert Farm

    Mueller farm

    Ryan Garcia-Salida Ag Chem

    John Fassler

    Dan Hrdy

    Terry Prichard

    Grower's Choice

    Nickels Soil Lab

    Carl Fanucchi

    Valley Orchard Management

    Bob and Nancy Lea

    Eduardo Rojas

    Brian O’Neil and Gary Robinson

    Dr. Richard Rosecrance
    Chico State University

    Jon Parnigian


    Neil Heaton

    Robert Smith

    Terry Prichard

    Grower's Choice Orchard Services (Robert Longstreth)

    The Crums

    Kris Tollerup

    Pete Davidson

    Root Creek Farms


    Mark Battany
    Farm Advisor

    Franz Niederholzer
    Farm Advisor

    Roger Duncan
    Farm Advisor

    Joe Grant
    retired Farm Advisor

    Katherine Jarvis Sean
    Farm Advisor

    Janine Hasey
    Farm Advisor

    Mae Culumber
    Farm Advisor

    Mohammad Yaghmourr
    Farm Advisor

    Special thanks to:
    Florent Trouillas

    Special thanks to:
    Bruce Lampinen

    Special thanks to:
    Astrid Volder

    Special thanks to:
    Louise Ferguson

    Rachel Elkins
    Farm Advisor

    David Doll
    Farm Advisor

    Steve Burgess
    Farm Advisor

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