Apparent gene flow and genetic structure of Acer saccharum subpopulations in forest fragments

1994 ◽  
Vol 72 (9) ◽  
pp. 1311-1315 ◽  
Author(s):  
Sandhya R. Ballal ◽  
Stephanie A. Foré ◽  
Sheldon I. Guttman

Genetic data were collected for glucose-6-phosphate isomerase locus 2 from a sample of the Acer saccharum Marsh. (sugar maple) embryo subpopulations of four forested patches in southwest Ohio and compared with the juvenile (1st-year seedlings to individuals ≤ 1.0 cm in basal area) and canopy (≥ 30 cm in diameter at breast height) subpopulations. Apparent gene flow into each patch was observed as certain alleles found in the embryo subpopulation were not observed in the canopy subpopulation. Genotype frequency data indicated that at least some of the gene flow could be attributed to seed dispersal. Although in some patches, the embryo subpopulation had lower genetic diversity than other subpopulations and was genetically differentiated, it is unlikely that these observed differences represent a change in the genetic diversity of future juvenile subpopulations. Key words: sugar maple, gene flow, genetic diversity, allozyme, forest fragmentation, seed dispersal.

1992 ◽  
Vol 70 (8) ◽  
pp. 1659-1668 ◽  
Author(s):  
Stephanie A. Foré ◽  
R. James Hickey ◽  
John L. Vankat ◽  
Sheldon I. Guttman ◽  
Robert L. Schaefer

Fragmentation of large expanses of forests into small stands has isolated local populations of organisms. Sugar maple (Acer saccharum) was used to determine if the degree of forest fragment isolation affects genetic diversity and structure of local populations. Genetic data were collected from canopy (prefragmentation) and juvenile (postfragmentation) individuals in 15 woodlots. Genotypes were inferred from phenotypic enzyme patterns of seven enzymes representing eight loci extracted from cambium and resolved with starch gel electrophoresis. Analyses of allelic data indicated that genetic diversity was not significantly different between juvenile or canopy subdivisions, or between woodlots with low and high degrees of isolation. Genetic differentiation among woodlots was significantly greater for the canopy than for the juvenile subdivision. Estimates of gene flow indicate that postfragmentation gene flow rates are higher than prefragmentation rates. Apparently, sugar maple's high potential for long-distance gene flow is enhanced by altered wind flux across a fragmented landscape. The results also show that forest fragmentation does not always result in greater isolation of local populations. Key words: sugar maple, gene flow, conservation, isolation, allozymes.


2009 ◽  
Vol 39 (12) ◽  
pp. 2273-2282 ◽  
Author(s):  
Louis Duchesne ◽  
Rock Ouimet

Recently, sugar maple ( Acer saccharum Marsh.) decline in northeastern North America has been regarded as a major factor structuring hardwood forests by favouring American beech ( Fagus grandifolia Ehrh.) in the understory of maple-dominated stands. To determine whether soil fertility differences associated with sugar maple decline may have promoted the expansion of American beech, we explored the relationships between the soil base status and the sapling and tree strata density and composition, using data from 426 permanent sample plots distributed throughout Quebec. Our results indicate that American beech is currently expanding in the sugar maple range of Quebec. The abundance and proportion of American beech in the sapling stratum are mainly associated with the proportion of American beech in the tree stratum, the relative basal area of dead sugar maple trees, and the base status of soils. In accordance with the many studies reporting on the high sensitivity of sugar maple to the acid–base status of soils and the decline of the sugar maple population, this study supports the hypothesis that soil base cation depletion, caused in part by atmospheric acid deposition, is among the main factors involved in the present-day expansion of American beech over a large area in Quebec.


2011 ◽  
Vol 41 (6) ◽  
pp. 1295-1307 ◽  
Author(s):  
Robert P. Long ◽  
Stephen B. Horsley ◽  
Thomas J. Hall

Sugar maple (Acer saccharum Marsh.) is a keystone species in the northern hardwood forest, and decline episodes have negatively affected the growth and health of sugar maple in portions of its range over the past 50+ years. Crown health, growth, survival, and flower and seed production of sugar maple were negatively affected by a widespread decline event in the mid-1980s on the unglaciated Allegheny Plateau in northern Pennsylvania. A long-term liming study was initiated in 1985 to evaluate responses to a one-time application of 22.4 Mg·ha–1 of dolomitic limestone in four northern hardwood stands. Over the 23-year period ending in 2008, sugar maple basal area increment (BAINC) increased significantly (P ≤ 0.05) in limed plots from 1995 through 2008, whereas American beech (Fagus grandifolia Ehrh.) BAINC was unaffected. For black cherry (Prunus serotina Ehrh.), the third principal overstory species, BAINC and survival were reduced in limed plots compared with unlimed plots. Foliar Ca and Mg remained significantly higher in sugar maple foliage sampled 21 years after lime application, showing persistence of the lime effect. These results show long-term species-specific responses to lime application.


2003 ◽  
Vol 33 (11) ◽  
pp. 2074-2080 ◽  
Author(s):  
Louis Duchesne ◽  
Rock Ouimet ◽  
Claude Morneau

The first tree health decline symptoms usually observed are foliar deficiency symptoms, foliage loss, and dieback. To improve the subjective nature and unspecificity of these assessments, we examined sugar maple (Acer saccharum Marsh.) radial growth and health to develop an indicator of sugar maple tree health status based on radial growth pattern. We used the basal area increment (BAI) of 328 tree-ring collections from 16 sites located in southern Quebec, throughout the sugarbush natural range, that were categorized by defoliation class. BAI of trees with decline symptoms was significantly lower than that of healthy trees in 9 of the 16 stands. BAI trends since 1955 showed an inverse relationship with tree decline class measured in 1989, irrespective of tree age. The results indicate that declining trees in these stands have not recovered based on BAI. They also suggest that the decrease in slope of BAI predated the observed symptoms of sugar maple decline by at least one decade. Results suggest that sugar maple vigor and health can be assessed by measuring tree's BAI trend, an indicator that may be useful for the diagnosis of sugar maple health and status years before the appearance of visible canopy symptoms.


1984 ◽  
Vol 62 (12) ◽  
pp. 2425-2428 ◽  
Author(s):  
Uldis Roze

Winter feeding of individual porcupines (Erethizon dorsatum L.) was studied in the northern Catskill Mountains of New York by following individual feeding trails in the snow. The study population as a whole fed primarily on beech (Fagus grandifolia) and sugar maple (Acer saccharum) and less frequently on eight other tree species. Individual porcupines limited their feeding to one or two species. An individual's primary food choice corresponded to the numerically most abundant tree species in its foraging area; its secondary food choice could not be related to relative density nor to relative basal area.


2003 ◽  
Vol 33 (5) ◽  
pp. 862-869 ◽  
Author(s):  
Jose Alexander Elvir ◽  
G Bruce Wiersma ◽  
Alan S White ◽  
Ivan J Fernandez

Responses in basal area increment (BAI) of sugar maple (Acer saccharum Marsh.) and red spruce (Picea rubens Sarg.) to chronic ammonium sulfate ((NH4)2SO4) treatment were examined at the Bear Brook Watershed in Maine. The Bear Brook Watershed is a pair-watershed forest ecosystem study with West Bear watershed treated with (NH4)2SO4 at a rate of 1800 equiv.·ha–1·year–1 since 1989, while East Bear watershed serves as a reference. Following 10 years of treatment, BAI was significantly higher for sugar maple trees growing in the treated watershed, with yearly increases relative to the reference watershed ranging from 13% in 1999 to 104% in 1996. The increase in sugar maple radial growth was attributed to a fertilization effect from the (NH4)2SO4 treatment. A reduction in BAI in sugar maple growing in the treated watershed observed in 1998 and 1999 was attributed to internal stresses and growth allocation to crown recovery after the severe 1998 ice storm. Red spruce showed no BAI growth responses to the treatment. Lower foliar Mg and Ca concentrations in red spruce in the treated watershed and lower soil responses to N enrichment in treated softwood stands compared with treated hardwood stands could explain the lack of BAI response in red spruce.


2003 ◽  
Vol 79 (5) ◽  
pp. 898-905 ◽  
Author(s):  
Steve Bédard ◽  
Zoran Majcen

Eight experimental blocks were established in the southern part of Québec to determine the growth response of sugar maple (Acer saccharum) dominated stands after single tree selection cutting. Each block contained eight control plots (no cut) and eight cut plots. The intensity of removal varied between 21% and 32% and residual basal area was between 18.2 and 21 m2/ha. Ten year net annual basal area growth rates in cut plots (0.35 ± 0.04 m2/ha) were significantly higher (p = 0.0022) than in control plots (0.14 ± 0.06 m2/ha). The treatment particularly favoured diameter growth of stems between 10 and 30 cm in dbh, whose crowns were released by removing neighbouring trees. These results show that if the same net growth rate is maintained in the next decade most of the cut plots will reach their pre-cut basal area in about 20 years after cutting. Key words: northern hardwoods, selection cutting, uneven aged silviculture, basal area growth, diameter growth


Botany ◽  
2014 ◽  
Vol 92 (8) ◽  
pp. 563-569 ◽  
Author(s):  
Justin L. Hart ◽  
Christopher M. Oswalt ◽  
Craig M. Turberville

The range of sugar maple (Acer saccharum Marsh.) is expected to shift northward in accord with changing climate. However, a pattern of increased sugar maple abundance has been reported from sites throughout the eastern US. The goal of our study was to examine the stability of the sugar maple southern range boundary by analyzing its demography through the southern extent of its distribution. We analyzed changes in sugar maple basal area, relative frequency, relative density, relative importance values, diameter distributions, and the ratio of sapling biomass to total sugar maple biomass at three spatial positions near the southern boundary of the species’ range using forest inventory data from the USDA Forest Service Forest Inventory and Analysis program over a 20 year observation period (1990–2010). We contend that the southern range boundary of sugar maple neither contracted nor expanded during this period. We speculated that biophysical changes caused by succession may provide a short-lived ameliorative barrier to a rapid southern range contraction for some species. The eclipse of some greater climate change threshold may therefore be required to realize significant range movement for mesophytic tree species.


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