scholarly journals Invasion of Winter Moth in New England: Effects of Defoliation and Site Quality on Tree Mortality

Forests ◽  
2014 ◽  
Vol 5 (10) ◽  
pp. 2440-2463 ◽  
Author(s):  
Michael Simmons ◽  
Thomas Lee ◽  
Mark Ducey ◽  
Kevin Dodds
1958 ◽  
Vol 34 (4) ◽  
pp. 405-422 ◽  
Author(s):  
J. R. Blais

The annual defoliation by spruce budworm and the progressive mortality of balsam fir trees were recorded in nine study plots in northwestern Ontario over a period of 11 years. In addition to general observations on the relationship of tree mortality to defoliation, some information was obtained on the relative vulnerability of the trees with respect to size, physiological age (flowering condition), and vigor (site quality).


1987 ◽  
Vol 4 (4) ◽  
pp. 197-201 ◽  
Author(s):  
David E. Hibbs ◽  
William R. Bentley

Abstract Physical and financial yields from investments in white pine spacing control were estimated using a simulation model sensitive to site quality and changes in spacing. Financial returns were estimated using two assumptions each for price-diameter relationships, real interest rates, and precommercial spacing costs. Management guidelines were developed on the basis of the results. Precommercial thinning was not recommended. First thinnings were suggested as average tree size reaches commercial minimums (45 to 60 yr, depending on site and utilization standards) and final harvest was recommended at 60 to 75 yr, again depending on site and standards. Comparison of pine and oak management opportunities in southern New England favored pine, even if substantial investments were required for hardwood control. North. J. Appl. For. 4:197-201, December 1987


1976 ◽  
Vol 52 (3) ◽  
pp. 137-142
Author(s):  
J. Beaubien

Since 1970 northeastern North America has experienced a spruce budworm (Choristoneura fumiferana (Clem.)) outbreak. In Quebec, at the end of 1974, some tree mortality was reported for an area of approximately 3 million acres (1,200,000 ha) of pulpwood stands while severe defoliation occurred over 33 million acres (13,300,000 ha). In an effort to improve current methods used to estimate the extent of forest insect damage over large areas, a remote sensing study was initiated with high altitude color-IR aerial photographs (scale 1:60,000) taken over the Gaspé peninsula in mid-August 1974. Cumulative past feeding was apparent at this period of the summer, as almost all current year chipped needles had fallen. Only very severe damage of one year feeding or more could be identified on the images. Colour variations due to stand characteristics such as density, age, rate of growth, prevent the detection of lighter damage on high-altitude CIR photographs. The relative importance of these factors is discussed. For instance a moderately defoliated dense stand can easily be confused with a more open healthy one. It seems that the two main stand characteristics affecting color tonality are density and length of annual shoot growth which is mainly function of age and site quality. Forest insect damage has been more successfully detected on large (up to 1:2,000) or medium (1:4,000-1:12,000) photo-scales. Normal color film may give better information on defoliation levels. As long as objectives are met, the smallest possible photo scale should be used since cost is reduced because fewer photographs have to be purchased and handled during photo-interpretation work.


2019 ◽  
Vol 65 (4) ◽  
pp. 496-507 ◽  
Author(s):  
Jianwei Zhang ◽  
Kaelyn A Finley ◽  
Nels G Johnson ◽  
Martin W Ritchie

AbstractStand density affects not only structure and growth, but also the health of forests and, subsequently, the functions of forest ecosystems. Here, we integrated dendrochronology and repeated inventories for ponderosa pine research plots to determine whether long-term growth and mortality responded to climate trends and how varying stand density influenced the responses. The plots were established prior to 1975 on existing stands throughout northern California. Although annual temperature increased consistently for the last 65 years, ring-width indices produced by eliminating age and thinning effects failed to detect radial trend regardless of site quality. However, interannual variation for the indices was substantial, reflecting a strong influence of climate on tree growth. Plot-level basal area increments were significantly affected by tree mortality. Stand density index explained most variation of mortality. Lowering stand density enhanced remaining tree growth, reduced mortality, and increased stand resiliency to disturbances and climate change. Besides higher climate moisture indices or lower vapor pressure deficits, any treatments that improve tree vigor and reduce stress will have a similar effect to reducing stand density. Although neither biotic disturbances nor abiotic conditions can be controlled, forest managers can manage stand density appropriately to enhance resilience to climate change and disturbances.


1984 ◽  
Vol 14 (6) ◽  
pp. 755-762 ◽  
Author(s):  
Donald A. Perala

The number and stem position of three endemic disease- and insect-caused injuries, shoot dieback, galls, and lesions, were monitored during the first 7 years of development of aspen (Populustremuloides Michx.) sucker stands on both a good and an excellent site. Injury frequency was significantly higher on the good site compared with the excellent site. Only shoot dieback clearly had a negative effect on height growth and tree class differentiation. Galls and lesions were related directly to bole area but not tree class. These injuries healed rapidly and most were undetectable within a few years. The apparently high incidence of insect- and disease-induced injury is normal in aspen sucker stands. Tree mortality was caused by intraspecific suppression and was not enhanced by any of these injuries. Although growth is undoubtedly diminished owing to injury, productivity of these stands should meet or exceed historical expectations. The effect of site quality, stocking density, and other stand variables on the influence of insect- and disease-induced injury needs controlled experimentation to assess their roles in affecting aspen productivity.


1995 ◽  
Vol 12 (3) ◽  
pp. 109-114
Author(s):  
Edgar K. Sewall ◽  
James H. Brown

Abstract Regeneration patterns were studied in low-site oak and oak-pine stands in southeastern New England after gypsy moth defoliations in 1981-1982. Three oak and three oak-pine stands where tree mortality was high (HM) and two oak and two oak-pine stands where tree mortality was low (LM) were used. Salvage logging had occurred in the three HM oak stands. Despite average basal area losses of 68% in HM oak and 46% in HM oak-pine stands, oaks dominated overstories in 5 of the 6 HM stands. Oaks dominated overstories in all LM oak and oak-pine stands. Combined totals of oak saplings and more vigorous forms of regeneration (stump sprouts and seedling sprouts) indicated numbers sufficient to regenerate oaks in all stands. White pine seedling and sapling totals (561/ac) in HM oak-pine and 858/ac in LM oak-pine stands should ensure the continued strong presence of pine in the oak-pine stands. Results of regeneration surveys suggest that the future composition of the oak and oak-pine stands studied is unlikely to change. North. J. Appl. For. 12(3):109-114.


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