Physiological response of mid-canopy sweetgum trees to overstory loblolly pine mortality
Increasing water use patterns were more spatially restricted than increased nitrogen in leaves and litterfall in mid-canopy sweetgum trees of varying proximity to overstory pines undergoing mortality.
Ecosystem changes following selective mortality of individual trees can be difficult to predict and depend on the response of surviving trees in the ecosystem. In the southeastern United States, southern pine beetle (Dendroctonus frontalis Zimmermann) selectively attacks and kills southern pines, particularly loblolly pine (Pinus taeda L.) which is prevalent throughout the region. Loss of loblolly pine should alter water and nutrient cycling unless co-occurring species are able to compensate for this lost functioning. The goals of this study were to determine changes in water and nutrient uptake of sweetgum trees (Liquidambar styraciflua L.) adjacent to loblolly pines experiencing mortality from girdling. We found that sweetgums near girdled pines initially used significantly less water, then similar amounts of water, then more water than sweetgums near control pines as pines experienced mortality. Relationships between daily sapflow and the natural log of vapor pressure deficit also differed significantly across years in sweetgums near girdled pines but not sweetgums near control pines. For sweetgum trees in both locations, both leaf and litterfall nitrogen content were significantly higher in the pine mortality year compared with the previous pine girdling year. Together, these results suggest that changes in water use are more spatially restricted to the region near dying pines whereas sweetgums, regardless of location, benefited from the extra available nitrogen in the ecosystem.
KeywordsDisturbance Sapflow Pinus taeda Nutrient cycling Succession
The authors thank J. Beard, T. Ciaramitaro, Z. Kassahun, K. Limpert, J. Riggins, S. Roberts, R. Rousseau, J. Tang for fieldwork assistance and use of equipment. This publication is a contribution of the Forest and Wildlife Research Center, Mississippi State University.
This work was funded by the National Institute of Food and Agriculture, U.S. Department of Agriculture, McIntire-Stennis projects (MISZ-399080 to HJR, MISZ-069390 to CMS).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Arguez A, Durre I, Applequist S, Squires M, Vose R, Yin X, Bilotta R (2010) NOAA’s US climate normals (1981–2010) NOAA National Centers for Environmental Information. https://doi.org/10.7289/V5PN93JP
- Blanche CA, Nebeker TE, Schmitt JJ, Hodges JD (1984) Techniques for distinguishing the sapwood-heartwood boundary in living loblolly pine (Pinus taeda L.). For Sci 30:756–760Google Scholar
- Coleman TW, Clarke SR, Meeker JR, Rieske LK (2008) Forest composition following overstory mortality from southern pine beetle and associated treatments Can. J For Res 38:1406–1418Google Scholar
- Costilow KC, Knight KS, Flower CE (2017) Disturbance severity and canopy position control the radial growth response of maple trees (Acer spp.) in forests of northwest Ohio impacted by emerald ash borer (Agrilus planipennis) Ann For Sci. https://doi.org/10.1007/s13595-13016-10602-13591 Google Scholar
- Daley MJ, Phillips NG, Pettijohn JC, Hadley JL (2007) Water use by eastern hemlock (Tsuga canadensis) and black birch (Betula lenta): implications of effects of the hemlock woolly adelgid Can. J For Res 37:2031–2040Google Scholar
- Filer TH, Toole ER (1966) Sweetgum mycorrhizae and some associated fungi. For Sci 12:432–437Google Scholar
- Goff JA, Gratch S (1946) Low-pressure properties of water from – 160 to 212 °F Transactions of the American Society of Heating and Ventilating Engineers 95–122Google Scholar
- Groemping U, Matthias L (2013) relaimpo: Relative importance of regressors in linear models R package version 31–118. http://CRAN.R-project.org/package=nlme
- Hornslein N (2017) Changes in water use, nitrogen uptake, and carbon assimilation during mortality of loblolly pine and succession to sweetgum. MS thesis. Mississippi State UniversityGoogle Scholar
- Jenkins JC, Aber JD, Canham CD (1999) Hemlock woolly adelgid impacts on community structure and N cycling rates in eastern hemlock forests Can. J For Res 29:630–645Google Scholar
- Johnsen KH et al (2001) Meeting global policy commitments: Carbon sequestration and southern pine forests. J For 99:14–21Google Scholar
- Kormanik PP (1990) Liquidambar styraciflua L. sweetgum. In: Burns RM, Honkala BH (eds) Silvics of North America, vol 2. USDA Forest Service, Washington, pp 400–405Google Scholar
- Pinheiro J, Bates D, DebRoy S, Sarkar D (2014) nlme: Linear and nonlinear mixed effects models. R package version 3.1–118, http://CRAN.R-project.org/package=nlme
- R Core Team (2014) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. URL http://www.R-project.org/
- Safranyik L, Carroll AL (2006) The biology and epidemiology of the mountain pine beetle in lodgepole pine forests. In: Safranyik L, Wilson WR (eds) The mountain pine beetle: a synthesis of biology, management, and impacts on lodgepole pine. Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre, Victoria, pp 3–66Google Scholar
- Siegert CM et al. (2018) Biogeochemical hotspots around bark-beetle killed trees: carbon sinks or carbon sources? In: Proceedings of the 19th Biennial Southern Silvicultural Research Conference. U.S. Department of Agriculture Forest Service, Southern Research Station, Asheville, NC, USAGoogle Scholar
- Wells OO, Switzer GL, Schmidtling RC (1991) Geographic variation in Mississippi loblolly pine and sweetgum. Silvae Genet 40:105–119Google Scholar