Automatic Dendrometers

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Agricultural Electronics Corporation makes two types of automatic dendrometers for the measurement of growth and reaction of a plant or tree to environmental changes.

Automatic Point Dendrometers - measures changes in the radius of a branch or main stem with a rod held against the outside surface by a constant force.

Automatic Band Dendrometers - measures changes in circumference with a band wrapped around the branch or main stem and held by a constant force.

Shown below is a schematic of the Automatic Point Dendrometer

The general characteristics of the automatic recording dendrometers are shown in the table below.

In addition to the automatic recording dendrometers we also produce a highly sensitive yet inexpensive Manual Band Dendrometer. A description and technical specifications are shown in a separate table.

See the Dendrometer User Group pages for the exchanges of experiences with AEC dendrometers.

Automatic Dendrometers
Element Automatic Point Dendrometers Automatic Band Dendrometers
Resolution Two micrometers change in radius Two micrometers change in circumference.
Size and Weight Approximate size: 20 cm by 10 cm by 18 cm; Weight: 310 grams Approximate size: 11 cm by 15 cm by 6 cm; Weight: 365 grams
Methodology Sensing rod is held against outside surface of branch or main stem by a constant sensing force. As radius changes the position of sensing rod changes Band is wrapped around and held against the perimeter by a constant band tension. Change in circumference changes the length of the band relative to a fixed point.
Band Tension Principle   Constant Force Spring
Sensing Rod Force Principle Constant Force Spring  
Sensing Force and Tension Characteristics Rod Force 0.3 newtons; Rod Pressure: 0.38 newtons per square inch 0.54 newtons (Band Tension)
Readings Changes can be read automatically using a linear variable differential transformer (LVDT) for conversion from displacement to electrical voltage. See POD Package Changes can be read automatically using a linear variable differential transformer (LVDT) for conversion from displacement to electrical voltage. See POD Package
Unadjusted Range 15,000 micrometers 15,000 micrometers
Band Material Supplied   Material: Hastalloy 276 or Invar 36 as specified by the user.* Three meters length. Width: 3 mm. Thickness 75 microns.
Temperature Sensitivity   Determined by length and composition of band material. Coefficient of thermal expansion: Hastalloy 276: 11.2 micrometers/meter/degree C; Invar 36*: 1 micrometers/meter/degree C.
Adjusted Range 50,000 micrometers without mounting adjustment Depends on the amount of spare band material at the time of installation
Assembly Materials Brass, stainless steel, G10 Brass, stainless steel, nylon, G10
Mounting Assembly Three 4 mm outer diameter threaded rods (#8-32) each 17.8 cm long Two 4 mm outer diameter threaded rods (#8-32) each 17.8 cm long
*Footnote   Invar 36 can be supplied if specifically requested. However, it will corrode rapidly and will stain bark. The toxicity of this staining is presently unresolved.

Web Site Navigation Links
Welcome Page  
PHYTOGRAM™ - Applications and specifications Automatic Point and Band Dendrometers - For precise measurements of growth
POD - In-the-field solar powered data collection computer operating over extended period of time in various environmental conditions Manual Band Dendrometers - Schematic drawing and product characteristics
Equipment Cost and Support Services - Products, Services, and typical Research Packages Automatic Root Dendrometers - For measurement of diurnal cycles and growth rates of roots near the surface.
Ontogenetic Irrigation Scheduling- When to water and how much to water based on plant development over four seasons Dendrometer User Group Pages
Data Transfer Methods - Various alternatives- primarily cell phone and radio communication capabilities  
Water Content Levels of Wine Berries- for wine industry, using the Phytogram™ for indicator of hydration status and berry ripeness  
Environmental Sensors - For concurrent assays of air and ground temperature, light, and soil moisture Communicating with Agricultural Electronics Corporation - By E-mail, US Postal Service, Telephone and Fax
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