The Solar Thermal Unit Concept in Problems Related to Plant Development and Potential Evapotranspiration

  • Joseph. M. Caprio
Part of the Ecological Studies book series (ECOLSTUD, volume 8)


Since 1735, when Reaumur first attempted to relate temperature to plant development, the degree-day or heat-unit concept has been applied to problems of plant-climate relations. This paper is a contribution to the discussion of this problem. It describes our solar thermal unit concept, which attempts to explain why different quantities of heat units are sometimes required in different locations and seasons for a given stage of plant development to occur.


Phenology evapotranspiration radiation temperature lilac bloom flower ecotype solar thermal unit North America 


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Copyright information

© Springer Science+Business Media New York 1974

Authors and Affiliations

  • Joseph. M. Caprio
    • 1
  1. 1.Plant and Soil Science DepartmentMontana State UniversityBozemanUSA

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