Comments Synchronic large-scale disturbances and red spruce growth decline

1995 ◽  
Vol 25 (5) ◽  
pp. 851-858 ◽  
Author(s):  
A.H. Johnson ◽  
E.R. Cook ◽  
T.G. Siccama ◽  
J.J. Battles ◽  
S.B. McLaughlin ◽  
...  
Keyword(s):  
Large Scale ◽  
Red Spruce ◽  
Growth Decline

not available

Synchronie large-scale disturbances and red spruce growth decline

1993 ◽  
Vol 23 (7) ◽  
pp. 1361-1374 ◽  
Author(s):  
Gregory A. Reams ◽  
Paul C. Van Deusen
Keyword(s):  
Tree Ring ◽  
Radial Growth ◽  
Large Scale ◽  
Red Spruce ◽  
Southern Appalachians ◽  
Time Interval ◽  
Growth Reduction ◽  
Usda Forest Service ◽  
Tree Ring Data ◽  
Growth Decline

Tree-ring data from the USDA Forest Service Forest Inventory & Analysis and other independent sources were used to study coincidence of changes in growth and large-scale disturbances. Numerous studies report that mean radial growth of red spruce (Picearubens Sarg.) declined synchronously throughout its range in the early 1960s. We use red spruce tree-ring data from most of the major studies to show that the synchronicity of red spruce growth decline is likely the outcome of the large-scale disturbances that occurred throughout the northeastern red spruce ecosystem in the late 1930s to early 1950s. Large-scale disturbances are either not detectable or not present in the same time interval in the southern Appalachians. This appears to correspond to an absence of a 1960s radial growth reduction in this region.

Synchronic large-scale disturbances and red spruce growth decline

1995 ◽  
Vol 25 (5) ◽  
pp. 859-869 ◽  
Author(s):  
Gregory A. Reams ◽  
Paul C. Van Deusen
Keyword(s):  
Large Scale ◽  
Red Spruce ◽  
Growth Decline

not available

Red spruce decline on Whiteface Mountain, New York. II. Relationships between apical and radial growth decline

1990 ◽  
Vol 20 (9) ◽  
pp. 1415-1421 ◽  
Author(s):  
David C. LeBlanc ◽  
Dudley J. Raynal
Keyword(s):  
New York ◽  
Radial Growth ◽  
Red Spruce ◽  
Northeastern United States ◽  
Spruce Decline ◽  
Growth Decline ◽  
Whiteface Mountain ◽  
The 1960S ◽  
Crown Dieback ◽  
The Relationship

Understanding the relationship between apical and radial growth decline can contribute toward the evaluation of hypotheses regarding causal mechanisms of red spruce decline. The etiology of red spruce decline in montane spruce-fir forests of the northeastern United States includes loss of foliage at branch apices, crown dieback, and unreversed radial growth decline since the 1960s. Demographic analyses of crown damage and radial growth decline for red spruce on Whiteface Mountain, New York, indicate that large, canopy-emergent trees with exposed crowns exhibit greater decline than codominant trees within an intact canopy. In this paper, radial growth decline is shown to have been coincident with decreased apical growth and increased incidence of injury to terminal leaders. Incidence of leader mortality is greatest for canopy-emergent red spruce or trees with exposed crowns, similar to patterns described for radial growth. This relationship suggests that the post-1960 decline of red spruce on Whiteface Mountain is caused, at least in part, by stresses that act directly on the crown.

Growth Decline in Red Spruce and Balsam Fir Relative to Natural Processes

1986 ◽  
pp. 1479-1484
Author(s):  
J. W. Hornbeck ◽  
R. B. Smith ◽  
C. A. Federer
Keyword(s):  
Red Spruce ◽  
Balsam Fir ◽  
Natural Processes ◽  
Growth Decline

Prevalence of individual-tree growth decline in red spruce populations of the southern Appalachian Mountains

1992 ◽  
Vol 22 (6) ◽  
pp. 905-914 ◽  
Author(s):  
David C. LeBlanc ◽  
N.S. Nicholas ◽  
S.M. Zedaker
Keyword(s):  
Tree Growth ◽  
Stand Density ◽  
Red Spruce ◽  
Slope Aspect ◽  
Individual Tree ◽  
Great Smoky Mountains ◽  
Individual Tree Growth ◽  
Growth Decline ◽  
Recreation Area ◽  
A Site

The prevalence of individual-tree growth decline was determined for red spruce (Picearubens Sarg.) populations at three locations in the southern Appalachians: Mount Rogers National Recreation Area, the Black Mountains, and Great Smoky Mountain National Park. An index of annual stemwood volume increment (AVI) was computed from dendrochronological data and a site-specific DBH–height regression equation. Individual-tree AVI time series were analyzed to identify changes in 20-year periodic mean AVI and AVI trend. The proportion of red spruce that exhibited decreasing mean AVI or negative AVI trend was determined for the most recent 20-year period, and this was compared with the estimated historical prevalence of these indications of growth decline. Also, the prevalence of growth decline was compared among subpopulations that differed with regard to various tree, stand, and site characteristics. Of 263 red spruce sampled, 25% exhibited a decrease in mean AVI during the period 1967–1986, 8% exhibited a negative AVI trend without a reduction in mean AVI, and 17% exhibited a reduction in the slope of the AVI curve. The proportion of trees that exhibited decreasing or slowed growth after 1967 was substantially greater among trees growing at 1980 m than in populations at lower elevations; no relationship was found between elevation and growth decline below 1980 m. No difference was found in prevalence of growth decline between subpopulations that differed with regard to age, DBH, competitive status, stand density, slope aspect, or site exposure. The prevalence of individual-tree growth decline for the most recent 20-year period did not exceed estimated levels for historical periods of decline in the Great Smoky Mountains population.

Private Coffee Plantations in Ethiopia

2019 ◽  
pp. 520-536
Author(s):  
Florian T. Schäfer
Keyword(s):  
Large Scale ◽  
World Market ◽  
Regulatory Regime ◽  
Coffee Plantations ◽  
Rural Employment ◽  
Growth Decline ◽  
Private Entrepreneurs ◽  
Coffee Sector ◽  
Historical Antecedents ◽  
Unique Dataset

This chapter charts the growth, decline, and rebirth of private large-scale coffee plantations in Ethiopia, and examines the roles of the state, the market, and private entrepreneurs in their development. Contemporary large-scale private plantations are shown to have had important historical antecedents. The re-emergence of these farms is the result of a long and complex interplay of domestic and international factors. Changes in the regulatory regime in the coffee sector interacted with developments in the world market for coffee to create conditions under which private large-scale plantations could thrive. Private plantations came to cover large areas of land and have become important sources of rural employment. The chapter uses a unique dataset to show that these plantations are among the most efficient and sophisticated coffee producers in Ethiopia.

Forest dynamics and the growth decline of red spruce and sugar maple on Bolton Mountain, Vermont: a comparison of modeling methods

2008 ◽  
Vol 38 (10) ◽  
pp. 2635-2649 ◽  
Author(s):  
Daniel G. Gavin ◽  
Brian Beckage ◽  
Benjamin Osborne
Keyword(s):  
Tree Ring ◽  
Acer Saccharum ◽  
Sugar Maple ◽  
Low Frequency ◽  
Growth Patterns ◽  
Red Spruce ◽  
Forest Plot ◽  
Progressive Decline ◽  
Growth Decline ◽  
Branch Dieback

Montane forests in the northeastern United States have experienced symptoms of declining vigor, such as branch dieback and increased mortality, over the last half-century. These declines have been attributed to the cumulative impacts of acid deposition, but reconstructing these declines from tree-ring records has proved difficult because of confounding factors that affect low-frequency growth patterns, including climate and natural growth trajectories following disturbance. We obtained tree-ring records of red spruce ( Picea rubens Sarg.) and sugar maple ( Acer saccharum L.) from three elevations on Bolton Mountain, Vermont, and applied traditional dendroclimatological analyses that revealed a profound declining growth–climate correlation since ca. 1970 for sugar maple but much less so for red spruce. We then applied a new multifaceted statistical approach that conservatively detrends tree-ring records by minimizing the influences of tree size, age, and canopy disturbances on radial growth. In contrast with the traditional analysis, this approach yielded chronologies that were consistently correlated with climate but with important exceptions. Low-elevation sugar maple suffered distinct episodes of slow growth, likely because of insect defoliators, and also a progressive decline since ca. 1988. Red spruce experienced subdecadal episodes of decline that may be related to freeze–thaw events known to injure foliage but showed no evidence of a progressive decline. This analysis was supported by a forest plot resurvey that indicated major declines in these species.

Spatial and temporal variation in the prevalence of growth decline in red spruce populations of the northeastern United States

1992 ◽  
Vol 22 (9) ◽  
pp. 1351-1363 ◽  
Author(s):  
David C. LeBlanc
Keyword(s):  
United States ◽  
Tree Size ◽  
Red Spruce ◽  
Tree Age ◽  
Spatial And Temporal Variation ◽  
Northeastern United States ◽  
Data Bases ◽  
Growth Decline ◽  
Individual Trees ◽  
Historical Levels

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.

Growth decline in red spruce and balsam fir relative to natural processes

1986 ◽  
Vol 31 (1-2) ◽  
pp. 425-430 ◽  
Author(s):  
J. W. Hornbeck ◽  
R. B. Smith ◽  
C. A. Federer
Keyword(s):  
Red Spruce ◽  
Balsam Fir ◽  
Natural Processes ◽  
Growth Decline
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