Int J Biometeorol (2005) 49:325–331 DOI 10.1007/s00484-004-0245-z ORIGINAL ARTICLE Delphis F. Levia · William C Bollinger · Robert A. Hrabik Evaporation of intercepted precipitation from fruit litter of Liquidambar styraciflua L. (sweetgum) in a clearing as a function of meteorological conditions Received: 2 July 2004 / Revised: 26 October 2004 / Accepted: 8 November 2004 / Published online: 3 December 2004  ISB 2004 Abstract Interception of precipitation by fruit litter is a poorly understood component of the hydrologic cycle in forested ecosystems. Even less well understood is the effect of meteorological conditions on the evaporation of precipitation intercepted by forest litter. This study sought to examine the influence of meteorological conditions on the evaporation of intercepted precipitation by fruit litter from Liquidambar styraciflua L. (sweetgum) by deriving and calibrating a regression model to estimate evapora- tion from the fruit litter that may be of potential use to forest and watershed managers. Data on evaporative losses from the fruit litter used to derive and calibrate the statistical model were acquired through a larger field experiment conducted from mid November 2002 through April 2003. Results from the forward stepwise least squares multiple regression model demonstrated that evaporative losses from the fruit litter were estimated with a high degree of accuracy based on the amount of water stored, solar radiation inputs, and vapor pressure deficit (adjusted R 2 =0.836, F=82.28, P<0.00001). The amount of water stored in the fruit litter explained the highest proportion of variance in the regression model. Storm to storm comparisons also highlighted the impor- tance of solar radiation and wind speed in determining evaporation from the fruit litter. The regression model potentially may be used in conjunction with a canopy interception model to predict interception losses from L. styraciflua dominated forests and plantations. Keywords Water storage capacity · Evaporation · Litter interception · Fruit litter · Liquidambar styraciflua L. Introduction Water storage capacity of forest litter was the focus of intense study from the mid 1950s through the late 1960s throughout much of the USA (e.g., Blow 1955; Metz 1958; Bernard 1963; Helvey 1964; Helvey and Patric 1965; Mader and Lull 1968; Clary and Ffolliott 1969). These studies examined the water storage capacity of the bulk litter layer on the forest floor in both deciduous and coniferous forests, finding that the amount of water de- tained by the litter was considerable, exceeding 200% of the oven-dried weight. These early litter studies made no attempt, however, to separate forest litter into its various components (e.g., foliar, woody, and fruit matter) and quantify water storage capacity or interception of indi- vidual components. Leaf litter interception has been found to account for 47% of the interception storage ca- pacity of native eucalypt forests and Pinus radiata D. Don (Monterey pine) plantations in Australia (Putuhena and Cordery 1996). More recent research has examined (1) litter interception as a percentage of annual evapotran- spiration (Waterloo et al. 1999); and (2) litter interception as a function of deforestation (Ataroff and Rada 2000). No known research has investigated the interception of fruit litter. Levia et al. (2004) investigated the water storage capacity of and interception by fruit litter of Liquidambar styraciflua L. (sweetgum) that constitutes a substantial proportion of the litter layer in L. styraciflua dominated forests and plantations in late winter and early spring. The mean water storage capacity of fruit litter of L. styraciflua was 399% of their oven-dried weight, with interception values measured in a clearing ranging from approximately 3% to 215% of the incident gross precip- itation (Levia et al. 2004). D. F. Levia Jr ( ) ) Department of Geography & Center for Climatic Research, University of Delaware, Newark, DE, 19716-2541, USA e-mail: dlevia@udel.edu Tel.: +1-302-8313218 Fax: +1-302-8316654 W. C. Bollinger III Department of Geography, Southern Illinois University, Carbondale, IL 62901-4514, USA R. A. Hrabik Jr. National Park Service, Yosemite National Park, CA, 95389, USA