My studies focus on the health of Northeastern hardwood forests. Specific projects include: relative susceptibility of forest plants to ozone; temporal and spatial trends of mercury accumulation in the forest; biocontrol of artillery fungi (Sphaerobolus spp.) using spent mushroom compost; biocontrol of tree-of-heaven (Ailanthus altissima) using Verticillium. General projects are directed towards determining the etiology of hardwood diseases, as well as understanding the temporal progression of disease using tree-ring analysis. Teaching responsibilities include the undergraduate course “Diseases of Forest and Shade Trees” and the graduate course “Diagnosis of Plant Diseases.” In 2008, the latter course was taught in Costa Rica.

Davis, D.D. and R.P. Pursell. 2008. Additions to the bryoflora of Pennsylvania: Dicranella cerviculata and Pseudoscleropodium purum. Evansia. 25:12-14.

Kline, L.J., D.D. Davis, J.M. Skelly, J.E. Savage, and J. Ferdinand. 2008. Ozone sensitivity of 28 plant sections exposed to ozone under controlled conditions. Northeastern Naturalist 15:57-66.

Orendovici, T., J.M. Skelly, D.D. Davis, J.A. Ferdinand, J.E. Savage, and R.E. Stevenson. 2007. Ozone uptake (flux) as it relates to ozone-induced foliar symptoms of Prunus serotina and Populus maximowizii x trichocarpa. Environ. Pollut. 151:79-92.

Davis, D.D. and R.P. Pursell. 2007. Update--identification of additional bryophytes on the mossy cap polypore (Oxyporus populinus). Evansia 24:49-54.

Davis, D.D. 2007. Ozone injury to plants within the Seney National Wildlife Refuge in northern Michigan. Northeastern Naturalist 14:415-424.

Davis, D.D. and R.A. Pursell. 2007. Collecting the knothole moss, Anacamptodon splachnoides. Evansia 24: 1-5.

McClenahen, J.R., D.D. Davis, and R.J. Hutnik. 2007. Macrolichens as biomonitors of air quality change in western Pennsylvania. Northeastern Naturalist 14:15-26.

Davis, D.D., J.R. McClenahen, and R.J. Hutnik. 2007. Use of the moss Dicranum montanum to evaluate recent temporal trends of mercury accumulation in oak forests of Pennsylvania. Northeastern Naturalist 14:27-34.

Davis, D.D. 2007. Ozone-induced symptoms on vegetation within the Moosehorn National Wildlife Refuge in Maine. Northeastern Naturalist 14:403-414.

Davis, D.D., M. Fromm, and M.D. Davis. 2006. Impact of the hemlock woolly adelgid on radial growth of old-growth eastern hemlock in south-central Pennsylvania, In: Proc. 15th Central Hardwood Forest Conference, Knoxville, TN, 27 Feb. – 1 Mar. 2006.

Fromm, M. and D.D. Davis. 2006. Abundance of Armillaria within old-growth eastern hemlock stand in south-central Pennsylvania infested with the hemlock wooly adelgid, In: Proc. 15th Central Hardwood Forest Conference, Knoxville, TN, 27 Feb. – 1 Mar. 2006.

Davis, D.D. and R.A. Pursell. 2006. Moss and liverworts growing on the mossy cap polypore
(Oxyporus populinus). Evansia 23:87-91.

Davis, D.D. and T. Orendovici. 2006. Incidence of ozone symptoms on vegetation within a National Wildlife Refuge in New Jersey, USA. Env. Pollut. 143:555-564.

Davis, D.D., L.J. Kuhns, and T.L. Harpster. 2006. Use of mushroom compost to suppress artillery fungi. J. Env. Hort. 24:212-215.

Geml, J., D.D. Davis, and D.M. Geiser. 2005. Systematics of the genus Sphaerobolus based on molecular and morphological data, with the description of Sphaerobolus ingoldii sp. nov. Mycologia 97:680-694.

Geml, J., D.D. Davis, and D.M. Geiser. 2005. Influence of selected fungicides on in vitro growth of artillery fungi (Sphaerobolus spp.). J. Environ. Hort. 23:63-66.

Geml, J., D.D. Davis, and D.M. Geiser. 2005. Phylogenetic analyses reveal deeply divergent species lineages in the genus Sphaerobolus (Phallales: Basidiomycota). Molecular Phylogenetics and Evolution 35:313-322.

Schaub, M., J.M. Skelly, J.W. Zhang, J.A. Ferdinand, J.E. Savage, R.E. Stevenson, K.C. Steiner, D.D. Davis, S.P. Pennypacker. 2005. Physiological and foliar symptom response in the crowns of Prunus serotina, Fraxinus americana, and Acer rubrum canopy trees to ambient ozone under forest conditions. Env. Pollut. 133:553-567.

Davis, D.D., L.J. Kuhns, K. Akina, and T.L. Harpster. 2004. Sporulation by the artillery fungus on 27 different mulches - a field study. J. Environ. Hort. 22:117-123.

Schaub, M., J.M. Skelly, K.C. Steiner, D.D. Davis, S.P. Pennypacker, J. Zhang, J.A. Ferdinand, J.E. Savage, and R.E. Stevenson. 2004. Physiological and foliar responses of Prunus serotina, Fraxinus americana, and Acer rubrum seedlings to varying soil moisture and ozone. Environ. Pollut. 124:307-320

Wei, C., J.M. Skelly, S.P. Pennypacker, J.A. Ferdinand, J.E. Savage, R.E. Stevenson and D.D. Davis. 2004. Influence of light fleck and low light on foliar injury and physiological responses of two hybrid poplar clones to ozone. Environ. Pollut. 130:215-227.

Wei, C., J.M. Skelly, S.P. Pennypacker, J.A. Ferdinand, J.E. Savage, R.E. Stevenson and D.D. Davis. 2004. Responses of hybrid clones and red maple seedlings to ambient O3 under differing light within a mixed hardwood forest. Environ. Pollut. 130:199-214.

Davis, D.D. and R.P. Long. 2003. Climate-tree growth models in relation to long-term growth trends of white oak in Pennsylvania. pp. 527-536 in: Van Sambeek, J.W.; Dawson, J.O.; Ponder, F., Jr.; Loewenstein, E.F.; Fralish, J.S. eds. Proc. 13th Central Hardwood Forest Conf.; 2002 April 1-3; Urbana , IL . Gen. Tech. Rep. NC-234. St. Paul . MN; U.S.D.A. Forest Service, Nor. Cen. Res. Sta. 565 pp.

Davis, D.D. and T.M. Frontz. 2003. Growth and mortality of bigtooth aspen trees stressed by defoliation. Pp. 538-543 in: Van Sambeek, J.W.; Dawson, J.O.; Ponder, F., Jr.; Loewenstein, E.F.; Fralish, J.S. eds. Proc. 13th Central Hardwood Forest Conf.; 2002 April 1-3; Urbana, IL. Gen. Tech. Rep. NC-234. St. Paul. MN; U.S.D.A. Forest Service, Nor. Cen. Res. Sta. 565 pp.

Taylor, M.D., J.P. Sinn, D.D. Davis, and E.J. Pell. 2002. The impact of ozone on a salt marsh cordgrass (Spartina alterniflora). Environ. Pollut. 120:701-705.

Davis, D.D., J.R. McClenahen, and R.J. Hutnik. 2002. Selection of a biomonitor to evaluate mercury levels in forests of Pennsylvania. Northeastern Naturalist 9:183-192.

Brantley, E.A., D.D. Davis, and L J. Kuhns. 2001. Biological control of the artillery fungus, Sphaerobolus stellatus, with Trichoderma harzianum and Bacillus subtilis. J. Environ. Hort. 19:21-23.

Brantley, E.A., D.D. Davis, and L.J. Kuhns. 2001. Influence of mulch characteristics on growth and sporulation of the artillery fungus Sphaerobolus stellatus. J. Environ. Hort. 19:89-95.

Davis, D.D., J.R. McClenahen, and R.J. Hutnik. 2001. Use of an epiphytic moss to biomonitor pollutant levels in southwestern Pennsylvania. Northeastern Naturalist 8:379-392.