Thrust fault zones in the Allegheny Plateau of north-central Pennsylvania

1979 ◽  
Author(s):  
Howard A. Pohn ◽  
Terri L. Purdy
Keyword(s):  
Thrust Fault ◽  
Fault Zones ◽  
North Central ◽  
Central Pennsylvania ◽  
Allegheny Plateau

scholarly journals Measuring changes in stress and vitality indicators in limed sugar maple on the Allegheny Plateau in north-central Pennsylvania

2002 ◽  
Vol 32 (4) ◽  
pp. 629-641 ◽  
Author(s):  
Philip M Wargo ◽  
Rakesh Minocha ◽  
Betty L Wong ◽  
Robert P Long ◽  
Stephen B Horsley ◽  
...  
Keyword(s):  
Soil Ph ◽  
Acer Saccharum ◽  
Sugar Maple ◽  
Soluble Sugars ◽  
North Central ◽  
Tree Vitality ◽  
Molar Ratios ◽  
Central Pennsylvania ◽  
Allegheny Plateau ◽  
Highly Correlated

A study established in 1985 in north-central Pennsylvania to determine effects of lime fertilization on declining sugar maple (Acer saccharum Marsh.) was evaluated in 1993 and showed that liming positively affected growth and crown vitality in sugar maple. This effect of lime on sugar maple offered an opportunity to assess other indicators of tree vitality and their response to lime additions. Foliar polyamines, starch and soluble sugars in root tissues, and cambial electrical resistance (CER) at breast height were evaluated. Foliar putrescine, soluble sugars, and CER decreased, while starch increased in lime-treated trees. Changes in these indicators were correlated with tree growth and crown vitality, which improved in limed plots. However, they were more highly correlated with lime-induced changes in foliar and soil elements and soil pH. Putrescine, soluble sugars, and CER decreased and starch increased, as Ca and Mg and molar ratios of Ca/Al and Mg/Mn increased and as Al and Mn decreased in both soil and foliage, and as soil pH increased. Results showed the beneficial effect of lime on tree vitality that was not reflected in visual assessments of crown vitality and demonstrated the potential utility of these physiological and biochemical measures as indicators of vitality in sugar maple.

Physiographic analysis of witness-tree distribution (1765–1798) and present forest cover through north central Pennsylvania

1995 ◽  
Vol 25 (4) ◽  
pp. 659-668 ◽  
Author(s):  
Marc D. Abrams ◽  
Charles M. Ruffner
Keyword(s):  
Forest Cover ◽  
Forest Composition ◽  
North Central ◽  
Tree Distribution ◽  
High Plateau ◽  
European Settlement ◽  
Central Pennsylvania ◽  
Witness Trees ◽  
Allegheny Mountains ◽  
Allegheny Plateau

This study analyzed witness-tree data recorded from 1765 to 1798 with respect to landform in four major physiographic provinces represented through north central Pennsylvania. These data were also compared with present-day forest composition to evaluate broad changes that occurred 200 years after European settlement. In the Allegheny High Plateau, Tsugacanadensis (L.) Carr. represented 40–47% of witness trees in mountain coves and stream valleys, but only 9% on plateau tops, which comprised 45% Fagusgrandifolia Ehrh. Pinusstrobus L. represented ≤4% frequency across all landforms. The original forests of the Allegheny Mountains were dominated by mixed Quercus, Acer, Castaneadentata (Marsh.) Borkh., and Pinus and had significant T. canadensis only in stream valleys. The presettlement forests of the Allegheny Front and the Ridge and Valley provinces had a similar mix of Quercus, Pinus, Castanea, and Carya, with increased P. strobus on the more mesic sites and Pinusrigida Mill, on the xeric ridges. Comparisons of presettlement with present-day forest composition indicate a dramatic reduction of T. canadensis (32% to 4%) and F. grandifolia (33% to 12%) in the High Plateau and increases in Acer (11% to 37%), Quercusrubra L. (0% to 10%), Prunusserotina Ehrh. (1% to 6%), and Betula (5% to 10%). Other units exhibited reductions in P. strobus, P. rigida, Quercusalba L., and Carya spp. and increases in Quercusprinus L., Q. rubra, Acerrubrum L., and P. serotina. Castaneadentata had its greatest abundance on higher elevation sites in each physiographic unit, and the elimination of this species this century apparently facilitated the increase in Q. prinus and Q. rubra on ridge sites. South of the Allegheny Plateau, increases in A. rubrum, P. serotina, and other mixed-mesophytic species may be in response to fire exclusion this century. The results of this study indicate the importance of landform and physiography on presettlement forest composition as well as the dramatic changes that have occurred as a result of altered disturbance regimes following European settlement.

scholarly journals First Report of Fenhexamid-Resistant Botrytis cinerea Causing Gray Mold on Heurchera in a North American Greenhouse

Plant Disease ◽  
2012 ◽  
Vol 96 (1) ◽  
pp. 147-147 ◽  
Author(s):  
G. W. Moorman ◽  
A.-S. Walker ◽  
S. May
Keyword(s):  
Botrytis Cinerea ◽  
Mode Of Action ◽  
Gray Mold ◽  
North Central ◽  
First Report ◽  
Group I ◽  
Central Pennsylvania ◽  
Commercial Operation ◽  
Penn State ◽  
Botryotinia Fuckeliana

Greenhouse-grown Heuchera plants, treated with fenhexamid (Decree, SePRO, Carmel, IN; FRAC group 17 hydroxyanilide), with active gray mold were submitted to the Penn State Plant Disease Clinic in December 2010 from a commercial operation in north-central Pennsylvania. Genetic and phenotypic analyses identified the isolate as Botrytis cinerea Pers. (teleomorph Botryotinia fuckeliana (de Bary) Whetzel), HydR3 phenotype (2) and not B. pseudocinerea (previously Botrytis group I) (4), naturally resistant to fenhexamid (phenotype HydR1) (1). While 0.2 μg of fenhexamid per ml or less is required to slow mycelial growth and germ tube elongation of sensitive isolates by 50% (EC50), the radial growth EC50 of the Heuchera isolate was approximately 2,000 μg of fenhexamid per ml in culture. Five cucumber seedlings receiving 25 μl of 0.1 M dextrose containing the label rate of Decree (1,800 μg/ml) on the growing tip were inoculated with colonized agar in the drop. Five check plants received 25 μl of 0.1 M dextrose. B. cinerea from silica gel storage since 1988 was also tested. This experiment was repeated three times. The 1988 isolate killed all fungicide-free but no fenhexamid-treated plants. The Heuchera isolate killed all fungicide-free and fenhexamid-treated plants within 4 days. To our knowledge, this is the first report of B. cinerea from a greenhouse in North America with fenhexamid resistance. Resistance occurs in U.S. fields (3). The Heuchera isolate's HydR3 resistance phenotype (2) has been detected in Germany, Japan, and France and has mutations affecting the 3-keto reductase protein, encoded by the erg27 gene, the specific target of fenhexamid and involved in Botrytis sterol biosynthesis. The Decree label states that it is to be used only twice on a crop before switching to a different mode of action. Greenhouses have resident Botrytis populations that are likely to be exposed to any fungicide applied in the structure. Growers should consider using fenhexamid only twice in a particular greenhouse, rather than on a particular crop, before switching to a different mode of action. References: (1) P. Leroux et al. Crop Prot. 18:687, 1999.(2) P. Leroux et al. Pest Manag. Sci. 58:876, 2002. (3) Z. Ma and T. J. Michailides. Plant Dis. 89:1083, 2005. (4) A.-S. Walker et al. Phytopathology 101:1433, 2011.

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