Author
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Feldhake, Charles |
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Submitted to: Northern Nut Growers Association Proceedings
Publication Type: Proceedings Publication Acceptance Date: 2/18/2002 Publication Date: 10/12/2002 Citation: Feldhake, C.M. 2002. Proximity to conifers minimizes frost exposure. 92nd Annual Report of the Northern Nut Growers Association. pp. 101-108. Interpretive Summary: Technical Abstract: In temperate climates, agricultural production is frequently damaged at both ends of the growing season due to episodic radiation frost. During these periods, air temperature is frequently adequate for forage and specialty crop growth. The effect of thermal radiation from conifer tree canopies on forage canopy temperature was evaluated for a silvopasture with variable tree density. A longwave-radiation-sensitive sensor for measuring temperature at the forage canopy level was designed, tested, and used to approximate night time forage canopy temperature during the autumn of 1999 and 2000 and spring of 2000. Temperature from the designed sensor correlated linearly with forage canopy temperature measured with an infrared thermometer with a slope of 1.0, a 0.9C offset, and an r2 of 0.999. The response of sensor temperature to night sky shading by trees was also linear. Under 77% tree cover, sensor temperature remained within half a degree of air temperature, however, under 7% cover averaged 11.5C below air temperature during radiation frost events. The results of this study indicate that a well designed agroforestry system with mixed conifer and crop tree species can potentially extend the growing season on both ends in regions were radiation frosts are prevalent. |
