Comparing and predicting forest stand susceptibility to gypsy moth

1977 ◽  
Vol 7 (3) ◽  
pp. 447-461 ◽  
Author(s):  
David R. Houston ◽  
Harry T. Valentine
Keyword(s):  
United States ◽  
Gypsy Moth ◽  
Principal Components ◽  
Food Preference ◽  
Tree Mortality ◽  
Forest Stand ◽  
Northeastern United States ◽  
Structure Feature ◽  
Oak Mortality ◽  
Components Analysis

One hundred and sixty-eight forest stands in the northeastern United States with different histories of defoliation and responses to defoliation by the gypsy moth were compared by principal-components analysis (PCA) ordinations. The ordinations were based on tree structure-feature variables. PCA ordinations separated stands into meaningful groups that historically have been either susceptible or resistant to prolonged gypsy moth infestation. The best separation of resistant and susceptible stands occurred when the structure-feature variables were measured separately for tree species in different gypsy moth food-preference classes. Tree mortality after defoliation often was greater in the resistant wet bottom and mesic slope and ridge stands than in the susceptible dry ridge and sand stands. Our ordinations suggest that some stands, as a consequence of high oak mortality, may now be more resistant than before.

Guides for Estimating Forest Stand Losses to Gypsy Moth

1984 ◽  
Vol 1 (2) ◽  
pp. 21-23 ◽  
Author(s):  
David A. Gansner ◽  
Owen W. Herrick
Keyword(s):  
Species Composition ◽  
Gypsy Moth ◽  
Tree Mortality ◽  
Cost Effective ◽  
Forest Stand ◽  
Measure Data ◽  
Effective Management ◽  
Field Plot ◽  
Crown Condition ◽  
As Species

Abstract People who have to make decisions about cost-effective management for gypsy moth need help in predicting and evaluating its effects. Field plot data collected during recent outbreaks in Pennsylvania are being used to develop guides for predicting forest stand losses to the pest Presented here are some of the more useful products of that effort to date. Easy-to-measure data for forest characteristics such as species composition and crown condition can be collected and applied in models that estimate potential stand and tree mortality and changes in timber value. North. J. Appl. For. 2:21-23, June 1984.

Cambial and internal electrical resistance of red spruce trees in eight diverse stands in the northeastern United States

1993 ◽  
Vol 23 (2) ◽  
pp. 322-326 ◽  
Author(s):  
K.T. Smith ◽  
W.D. Ostrofsky
Keyword(s):  
United States ◽  
Electrical Resistance ◽  
Direct Relationship ◽  
Anthropogenic Disturbances ◽  
Forest Stand ◽  
Red Spruce ◽  
Northeastern United States ◽  
Rating Systems ◽  
Wide Range ◽  
Tree Condition

Rating systems are being developed to determine the degree to which forests are at risk from pests, pathogens, and anthropogenic disturbances. Measurements of electrical resistance of living trees have been shown to be correlated with cambial growth and alterations of wood function in a wide range of species. A comparison was made of patterns of cambial electrical resistance and of stem internal electrical resistance for eight red spruce (Picearubens Sarg.) stands in the northeastern United States. Stands were compared by a new procedure using cambial electrical resistance profiles. The resulting groupings provided a refinement of vigor categories over other comparative methods, and the technique should prove useful for guiding management decisions. No direct relationship was found between the internal tree condition and the cambial electrical resistance, and implications of this with regard to monitoring forest stand health are discussed.

Variation in Canadian Gomphus fraternus (Odonata: Gomphidae) in relation to the recognition of subspecies manitobanus

2008 ◽  
Vol 140 (3) ◽  
pp. 327-337
Author(s):  
Paul M. Catling ◽  
Marjorie Hughes
Keyword(s):  
United States ◽  
North America ◽  
Principal Components Analysis ◽  
Principal Components ◽  
Abdominal Segment ◽  
Discrete Group ◽  
Dorsal Surface ◽  
Segment Length ◽  
Western North America ◽  
Components Analysis

AbstractSeven characters were evaluated in 146 specimens of Gomphus fraternus (Say), including both subspecies, G. f. fraternus (Say) and G. f. manitobanus Walker, to clarify their circumscription and geographic occurrence in Canada. Specimens corresponding to subspecies manitobanus were all from the Assiniboine and Red rivers and formed a discrete group in a principal components analysis, supporting their taxonomic recognition. Their distribution in Canada suggests a separation of subspecies near the boundary of the prairie ecozone in central southern Manitoba. In subspecies fraternus the extensor surfaces of the tibiae are largely black, with pale areas often lacking and rarely up to 50% of the segment length. Similarly the dorsal surface of abdominal segment 9 is largely black. If there is a pale area, it is <1 mm long. In subspecies manitobanus the extensor surfaces of the tibiae have pale markings on ≥50% of their lengths and the dorsal surface of abdominal segment 9 has a dorsal yellow spot ≥1.4 mm long. Widespread dragonflies in western North America are paler in drier climates and the increased pale colouration in the western subspecies manitobanus corresponds to this trend. Currently known only from Manitoba, subspecies manitobanus may occur in prairie habitats of the Midwestern United States, based on reports of pale individuals in that region.

Political Independence in America, Part II: Towards a Theory

1988 ◽  
Vol 18 (2) ◽  
pp. 197-219 ◽  
Author(s):  
Jack Dennis
Keyword(s):  
United States ◽  
Political Parties ◽  
Principal Components ◽  
Four Dimensions ◽  
Positive Identification ◽  
Political Independence ◽  
Components Analysis ◽  
Party Differences ◽  
Contemporary United States ◽  
Negative Feelings

This second article asks what it means to be independent in the contemporary United States. Four different meanings are hypothesized: (1) negative feelings about major political parties and partisanship; (2) positive identification with ideals of independence, especially individualistic autonomy; (3) neutrality or indifference because of no detectable party differences of significance; (4) a self-perceived pattern of variability in partisan behaviour. These four attitudinal dimensions are supported empirically via principal components analysis using both national and Wisconsin data. The four dimensions of independence attitudes show varied patterns of association with general indices of Independence self-classification, relevant political attitudes and behaviours, and various antecedents such as age and education.

Flavonoids and affinities of some North American lupines

1983 ◽  
Vol 61 (3) ◽  
pp. 708-730 ◽  
Author(s):  
K. W. Nicholls ◽  
B. A. Bohm
Keyword(s):  
United States ◽  
North America ◽  
Principal Components Analysis ◽  
Principal Components ◽  
North American ◽  
Southeastern United States ◽  
Flavonoid Glycosides ◽  
Structural Modifications ◽  
Components Analysis

Seventy-three taxa of the genus Lupinus in North America have been studied for their flavonoid constituents. In all, 56 compounds were isolated and either partially or totally characterized. Flavonoid types encountered were flavones, C-glycoflavones, isoflavones, flavonols, and, tentatively, flavanones. Further structural modifications seen were O-methylation, O-glycosylation at a variety of positions and acylation of several of the flavonoid glycosides. Principal-components analysis was performed on (i) presence–absence data of individual compounds with consideration given to relative concentrations and (ii) presence–absence of the types of flavonoid structures. Several groupings of taxa emerged from these analyses based upon the presence of unique compounds or combinations of compounds. In a number of these groups the chemical affinities paralleled morphological affinities closely. In all, 10 groupings were seen. Lupinus diffusus, a simple-leaved taxon from southeastern United States, stood apart from all groups.

Severe red spruce winter injury in 2003 creates unusual ecological event in the northeastern United States

2004 ◽  
Vol 34 (8) ◽  
pp. 1784-1788 ◽  
Author(s):  
Brynne E Lazarus ◽  
Paul G Schaberg ◽  
Donald H DeHayes ◽  
Gary J Hawley
Keyword(s):  
United States ◽  
New Hampshire ◽  
Tree Mortality ◽  
Picea Rubens ◽  
Red Spruce ◽  
Late Winter ◽  
Foliar Injury ◽  
Northeastern United States ◽  
Injury Event ◽  
Ecological Event

Abundant winter injury to the current-year (2002) foliage of red spruce (Picea rubens Sarg.) became apparent in the northeastern United States in late winter of 2003. To assess the severity and extent of this damage, we measured foliar winter injury at 28 locations in Vermont and surrounding states and bud mortality at a subset of these sites. Ninety percent of all trees assessed showed some winter injury, and trees lost an average of 46% of all current-year foliage. An average of 32% of buds formed in 2002 were killed in association with winter injury. Both foliar and bud mortality increased with elevation and with crown dominance, and bud mortality increased with greater foliar injury. Foliar injury in 2003 at a plantation near Colebrook, New Hampshire, was more than five times the typical levels for 9 previous years of measurement and more than twice that measured for another high-injury year. Plantation data also indicated that bud mortality in 2003 was greater than previously documented and that persistent winter injury was associated with increased tree mortality. Comparisons of our data with past studies for two sites with native red spruce also indicated that damage in 2003 was greater than other recently reported, high-injury years. Because heavy foliar and bud losses can severely disrupt the carbon economies of trees, the 2003 winter injury event could lead to further spruce decline and mortality, particularly among dominant trees at higher elevations.

Diagnoses Generated by Numerical Taxonomic Methods Applied to Standard Blood Variables

1980 ◽  
Vol 19 (04) ◽  
pp. 205-209
Author(s):  
L. A. Abbott ◽  
J. B. Mitton
Keyword(s):  
Liver Cirrhosis ◽  
Renal Disease ◽  
Principal Components Analysis ◽  
Discriminant Function ◽  
Principal Components ◽  
Discriminant Function Analysis ◽  
Chronic Renal Disease ◽  
Function Analysis ◽  
Infectious Hepatitis ◽  
Components Analysis

Data taken from the blood of 262 patients diagnosed for malabsorption, elective cholecystectomy, acute cholecystitis, infectious hepatitis, liver cirrhosis, or chronic renal disease were analyzed with three numerical taxonomy (NT) methods : cluster analysis, principal components analysis, and discriminant function analysis. Principal components analysis revealed discrete clusters of patients suffering from chronic renal disease, liver cirrhosis, and infectious hepatitis, which could be displayed by NT clustering as well as by plotting, but other disease groups were poorly defined. Sharper resolution of the same disease groups was attained by discriminant function analysis.

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