Complete Granier System
The whole system is schematised in the picture on the left (click on the image on the left and then maximize the window view to get a better view). It includes sensor probes, heat-averaging tubes, 4- cores data cable, power supply unit, datalogger and external battery or solar panel.
The Granier sap flow sensor includes two probes inserted in the stem with one probe 10-15cm above the other.The upper probe is heated by applying a constant current across a coiled heating element, giving a constant power. The lower probe is not heated and measures ambient tissue temperature.
The temperature difference between the probes is measured with T-type thermocouples junctions embodied in each probe. Heat dissipation due to sap movement reduces the temperature difference. The temperature difference is found to be closely related to the sap flux density and their relationship is found to be independent of tree species or wood anatomy (Granier 1987; Lu et al, 2004).
Applications in Major Projects
(2016-10-01) Recently, PlantSensors was honored to be the selected supplier of a large number of Granier sap flow systems to the "Next-Generation Ecosystem Experiments–Tropics (NGEE-Tropics)" project that is a DOE-funded, multi-institutional project led by Lawrence Berkeley National Laboratory.
PlantSensors won this significant contract thanks to its higher product quality than its competitors' and demonstrated high reliability in hot and humide tropics.
Since 2010 we have repeatedly supplied sap flow systems to Oak Ridge National Laboratory and Los Alamos National Laboratory, and this was the first time we directly supply to Lawrence Berkeley National Laboratory.
NGEE-Tropics is a DOE-funded, multi-institutional project led by Berkeley Lab, focused on how tropical forests interact with Earth’s climate. Tropical forests cycle more CO2 and water than any other ecosystem, and play critical roles in determining Earth’s energy balance. Intact tropical forests are also estimated to be Earth’s largest carbon sink, yet the stability of this sink is susceptible to a warming climate and disturbance processes. Understanding of carbon and related water and energy exchanges between tropical forests and the atmosphere lags that of other ecosystems, and poor model representation of these processes is the most significant source of terrestrial uncertainty in projections of Earth’s future climate. Please click on the above picture for detials of the project.
(2016-10-01) PlantSensors' Sap flow systems were used in the Oak Ridge National Laboratory's "SPRUCE- Spruce and Peatland Responses Under Climatic and Environmental Change" project.
Details of the project is Here.
Clcik http://www.plantsensors.com/pdf/PS-ORNL2015.pdf to get the open access research paper. “A comprehensive data acquisition and management system for an ecosystem-scale peatland warming and elevated CO2 experiment” published in Geosci. Instrum. Method. Data Syst., 4, 203–213, 2015 www.geosci-instrum-method-data-syst.net/4/203/2015/ doi:10.5194/gi-4-203-2015 © Author(s) 2015. CC Attribution 3.0 License.
(Issued in 2011)
Our PS-TDP8 sap flow system successfully tested in hot, wet tropics
Since the launch of the new Campbell Scientific CR1000 dataloggers, PlantSensors developed PS-TDP8 Sap flow system to take advantage of the new datalogger which can measure directly 8 sensors. Meanwhile PlantSensors launched the proprietary PS-PS12 Constant Current Power Supply, which can simultaneously power 12 sensors.
The new systems have already passed the harsh field test run under conditions of high temperature, high humidity, frequent lightning and heavy rainfall in the fire-prone North Australian tropical regions . Eight sets of the sap flow systems including 64 sensors successfully monitored sap flow in eucalyptus woodland trees for 12 months without failure of any system components. Click here to download PS-TDP8 Introduction of the new system.