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

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.

2003 ◽  
Vol 33 (4) ◽  
pp. 635-652 ◽  
Author(s):  
Philip M Wargo ◽  
Kristiina Vogt ◽  
Daniel Vogt ◽  
Quintaniay Holifield ◽  
Joel Tilley ◽  
...  

Number of living root tips per branch, percent dead roots, percent mycorrhizae and mycorrhizal morphotype, response of woody roots to wounding and colonization by fungi, and concentrations of starch, soluble sugars, phenols, percent C and N and C/N ratio, and Al, Ca, Fe, K, Mg, Mn, and P were measured for 2 consecutive years in roots of red spruce (Picea rubens Sarg.) in stands in the northeastern United States (nine in 1993 and two additional in 1994) dominated by red spruce and with a gradient of forest floor exchangeable Al/Ca ratios. Root vitality was measured for nonwoody and coarse woody roots; chemical variables were measured for nonwoody (<1 mm), fine woody (1 to <2 mm), and coarse woody (2 to <5 mm) roots. There were significant differences among sites for all variables, particularly in 1993, although few were related to the Al/Ca ratio gradient. Percent mycorrhizae decreased, while some morphotypes increased or decreased as the Al/Ca ratio increased. In nonwoody roots, N increased as the Al/Ca ratio increased. Most sampled trees appeared to be in good or fair health, suggesting that an adverse response of these root variables to high Al concentrations may be apparent only after a significant change in crown health.


1992 ◽  
Vol 22 (9) ◽  
pp. 1351-1363 ◽  
Author(s):  
David C. LeBlanc

An analysis of the prevalence of individual-tree growth decline, based on reconstructed annual stemwood volume increment (AVI), was implemented on three data bases that have been used in past dendrochronological analyses of red spruce (Picearubens Sarg.) decline in the northeastern United States. This analysis focused on the proportion of individual trees that exhibited a decrease in periodic mean AVI, a decrease in the linear trend of AVI, and (or) a negative AVI trend during the most recent 20-year period. Various subpopulations within the data bases were identified by site location, elevation, and aspect, and tree size, age, and competitive status, and the proportion of individual trees exhibiting growth decline was compared among these subpopulations. Also, the prevalence of growth decline after 1960 was compared with historical levels of growth decline. Differences in prevalence of growth decline were found among the three data bases and among locations within data bases. The proportion of red spruce that exhibited growth decline after 1960 exceeded historical levels of decline for populations in New York, Vermont, and New Hampshire, but not in the northern Maine population. Weak positive associations were found between prevalence of growth decline and tree size (DBH) and elevation. No consistent relationship was found between growth decline and tree age, competitive status, or stand density. Contrary to a previous report, growth decline was not more common among trees that exhibited evidence of competitive release in the 1940s than among unreleased trees.


1990 ◽  
Vol 20 (6) ◽  
pp. 743-749 ◽  
Author(s):  
Paul C. Van Deusen

The red spruce (Picearubens Sarg.) growth decline in the northeastern United States does not appear to be ubiquitous. Some selected tree-ring data sets are compared graphically and with two models that tend to support the notion that differences exist between stands as to the presence and degree of decline. It appears that the degree of post-1960 decline is related to the proportion of trees showing a pre-1950 growth increase, and stratifying the data into as few as two classes can improve model fit substantially. The models used in the comparisons are of interest in themselves, because they are capable of exhibiting the mathematical phenomenon of chaos.


1977 ◽  
Vol 7 (3) ◽  
pp. 447-461 ◽  
Author(s):  
David R. Houston ◽  
Harry T. Valentine

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.


1991 ◽  
Vol 118 (2) ◽  
pp. 331-338 ◽  
Author(s):  
NAGESWARA R. MADAMANCHI ◽  
A. HAUSLADEN ◽  
RUTH G. ALSCHER ◽  
R. G. AMUNDSON ◽  
S. FELLOWS

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