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Abstract
Phenology is an important indicator of forest health in relation to energy/nutrient cycles and species interactions. Accurate characterization of forest understory phenology is a crucial part of forest phenology observation. In this study, ground plots set up in a temperate mixed forest in Wisconsin were observed with a visible-light digital camera during spring 2007. High-frequency microclimatic data were collected concurrently. A green pixel extraction technique was used to derive phenological patterns from digital photos. Correlations were examined between derived phenology signals and climatic variables. Results indicate that though understory phenology was generally correlated with spring warmth accumulation, its daily change rate was significantly correlated with air moisture variability rather than with temperature-based weather fluctuations. We inferred that understory flush regime during springtime in a mesic temperate forest could depend more on precipitation than on temperature, due to the presumably shallower root systems. Furthermore, the study suggests that visible-light digital photography is an effective, easy-to-implement method for observing understory phenology and for other forest monitoring tasks.
Parent Publication
Citation
Liang, Liang; Schwartz, Mark D.; Fei, Songlin. 2011. Examining spring phenology of forest understory using digital photography. In: Fei, Songlin; Lhotka, John M.; Stringer, Jeffrey W.; Gottschalk, Kurt W.; Miller, Gary W., eds. Proceedings, 17th central hardwood forest conference; 2010 April 5-7; Lexington, KY; Gen. Tech. Rep. NRS-P-78. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station: 51-57.
