Size- and age-class distributions of Fraser fir following balsam woolly adelgid infestation

2000 ◽  
Vol 30 (6) ◽  
pp. 948-957 ◽  
Author(s):  
George F Smith ◽  
N S Nicholas
Keyword(s):  
Permanent Plots ◽  
Seedling Mortality ◽  
Regeneration Potential ◽  
Abies Fraseri ◽  
Great Smoky Mountains ◽  
Fraser Fir ◽  
Advance Regeneration ◽  
Size And Age Structure ◽  
Smoky Mountains ◽  
Balsam Woolly Adelgid

Fraser fir (Abies fraseri (Pursh) Poir.) has suffered catastrophic mortality throughout most of its native range from an exotic insect, the balsam woolly adelgid (Adelges piceae Ratz.). To assess the regeneration potential and viability of fir populations, overstory and understory Fraser fir size and age structure were analyzed. The data were collected from thirty-six 400-m2 permanent plots, stratified into four stand canopy composition types, established near the summits of five mountains in the Great Smoky Mountains. We found that, where canopy mortality was severe, fir advance regeneration was re-entering the overstory. In seriously impacted stands, mortality of large fir and increased recruitment have produced distributions characterized by few large fir and relatively high densities of small fir. Densities of 0- to 10-year-old fir seedlings and fir seedlings [Formula: see text]0.25 m tall were much lower in stands dominated by dead fir than in mostly intact fir stands. While the lack of reproducing adults appears to be the main cause, competition with invasive species and higher seedling mortality from environmental factors probably contribute. These results lead to a hypothesis that Fraser fir will undergo a regeneration-mortality cycle with a decrease in the numbers of each successive generation.

scholarly journals Recovery trends and predictions of Fraser fir (Abies fraseri) dynamics in the Southern Appalachian Mountains

2017 ◽  
Vol 47 (1) ◽  
pp. 125-133 ◽  
Author(s):  
S. Douglas Kaylor ◽  
M. Joseph Hughes ◽  
Jennifer A. Franklin
Keyword(s):  
Census Data ◽  
Population Data ◽  
Abies Fraseri ◽  
Great Smoky Mountains ◽  
Fraser Fir ◽  
Balsam Woolly Adelgid ◽  
Hierarchical Bayesian Inference ◽  
Local Extirpation ◽  
Term Monitoring

The endemic Fraser fir (Abies fraseri (Pursh) Poir.) is found in only seven montane regions in the southern Appalachians above ca. 1500 m elevation. Due to widespread insect-caused mortality from the invasive balsam woolly adelgid (Adelges piceae Ratzeburg), as well as possible impacts from climate change and atmospheric pollution, the future of Fraser fir populations remains uncertain. Long-term monitoring programs have been in place since the 1980s, and here we present the first predictive population models for endemic Fraser fir populations using the inventory data from Great Smoky Mountains National Park, which contains 74% of extant Fraser fir forests. Using two kinds of population data (understory density counts and overstory census data), we model Fraser fir population dynamics on five different mountaintops as a stage-structured matrix model with transition parameters estimated using hierarchical Bayesian inference. We predict robust recovery over the next several decades for some Fraser fir populations, particularly where mature overstory fir has persisted throughout the last two decades, and continued decline for populations at the lowest elevations. Fraser fir densities are already low at these lower elevations, suggesting that this population is vulnerable to local extirpation.

Gradient analysis of old spruce – fir forests of the Great Smoky Mountains circa 1935

1993 ◽  
Vol 71 (7) ◽  
pp. 951-958 ◽  
Author(s):  
R.T. Busing ◽  
P.S. White ◽  
M.D. MacKenzie
Keyword(s):  
Solar Radiation ◽  
Gradient Analysis ◽  
Deciduous Forest ◽  
Basal Area ◽  
Slope Aspect ◽  
Old Growth ◽  
Abies Fraseri ◽  
Great Smoky Mountains ◽  
Old Growth Forest ◽  
Smoky Mountains

The response of old-growth spruce – fir vegetation to environmental gradients was investigated using 1930s plot data from the Great Smoky Mountains. Gradients related to forest composition and position of the ecotone with the deciduous forest were identified using canonical correspondence analysis (CCA) and their role in vegetation response to climate change was considered. The data were subsequently stratified into three elevation classes and ordinated separately using CCA to identify gradients at various elevations. The effect of elevation on tree stratum composition and structure was profound. Secondary gradients influencing the tree stratum included slope aspect, potential solar radiation, and topographic position. Abies fraseri basal area and density were high above 1800 m elevation. Comparable basal area levels of Picea rubens were attained at elevations ranging from 1400 to 1900 m. Total stand basal area and density increased with elevation. The importance of topographic position increased with elevation, while that of slope aspect and potential solar radiation decreased. Presumably, the increasing incidence of cloud cover with elevation diminished the effect of slope aspect and potential solar radiation at higher elevations. The transition from deciduous forest occurred in the 1300 – 1600 m elevation range. A substantial proportion (24%) of plots had mixed composition (30 – 70% spruce – fir by basal area), suggesting that the ecotone is not abrupt in old-growth forest. Environmental variables other than elevation did not have a strong effect on ecotone position. Attempts to infer long-term ecotone dynamics along the elevation gradient based on species size-class data were inconclusive. Key words: Abies fraseri, gradient analysis, Great Smoky Mountains, old-growth forest, Picea rubens, spruce – fir forest.

scholarly journals Variation in overstory nitrogen uptake in a small, high-elevation southern Appalachian spruce-fir watershed

2002 ◽  
Vol 32 (10) ◽  
pp. 1741-1752 ◽  
Author(s):  
M Barker ◽  
H Van Miegroet ◽  
N S Nicholas ◽  
I F Creed
Keyword(s):  
Stand Structure ◽  
N Uptake ◽  
High Elevation ◽  
N Deposition ◽  
Root Turnover ◽  
Betula Alleghaniensis ◽  
Atmospheric N Deposition ◽  
Great Smoky Mountains ◽  
Smoky Mountains ◽  
Balsam Woolly Adelgid

High-elevation red spruce (Picea rubens Sarg.) – Fraser fir (Abies fraseri (Pursh) Poir.) forests of the southern Appalachians exhibit considerable spatial heterogeneity in structure, and possibly in N uptake, because of a combination of natural disturbances and heavy fir mortality caused by infestations of the exotic balsam woolly adelgid (Adelges piceae Ratz). The objectives of this study are to determine spatial variability in tree N uptake in a small high-elevation catchment in the Great Smoky Mountains National Park, compare outcomes among calculation methods, and assess the influence of stand and landscape properties on N uptake. Tree N uptake is estimated for fifty 20 × 20 m plots in the Noland Divide Watershed (NDW). Components considered in the calculations are stem growth, foliage increment, and mortality of spruce, fir, and yellow birch (Betula alleghaniensis Britt.) from 1993 and 1998 stand inventories; throughfall N flux measured in summers 1998 and 1999; litterfall N return for 1 year in a subset of 12 plots; tissue N analyses; and atmospheric N deposition and root turnover estimates from the literature. Overstory N uptake varies spatially within NDW, with a CV of 9–41% depending on the calculation method. Variability among methods is even higher, with an almost 15-fold difference between the smallest and largest average overstory uptake estimate (5 vs. 74 kg·ha–1·year–1). Only 5 and 3 kg·ha–1·year–1 of N is sequestered in wood and foliar increment, respectively, while 36 kg·ha–1 of N returns annually as aboveground litterfall. Uptake and its components are correlated with measures of stand structure but not with elevation or aspect.

scholarly journals Diversity and density of the EM fungal community present in high elevation Fraser fir forests of Great Smoky Mountains National Park

2014 ◽  
Vol 9 (0) ◽  
pp. 1 ◽  
Author(s):  
Richard Baird ◽  
C. Elizabeth Stokes ◽  
John Frampton ◽  
Benjamin Smith ◽  
Clarence Watson ◽  
...  
Keyword(s):  
Fungal Community ◽  
National Park ◽  
High Elevation ◽  
Great Smoky Mountains ◽  
Fraser Fir ◽  
Smoky Mountains

The distribution pattern of two juvenile hormone related compounds in Fraser fir and the induced response to a balsam woolly adelgid infestation

2001 ◽  
Vol 31 (10) ◽  
pp. 1701-1707 ◽  
Author(s):  
Glenn Fowler ◽  
Jie Zhang ◽  
Fred P Hain ◽  
John F Manville
Keyword(s):  
Juvenile Hormone ◽  
Distribution Pattern ◽  
Apical Dominance ◽  
Induced Response ◽  
Abies Fraseri ◽  
Fraser Fir ◽  
Significant Difference ◽  
Attack Trees ◽  
Balsam Woolly Adelgid ◽  
Related Compounds

Two juvenile hormone related compounds (JRCs), juvabione and dehydrojuvabione, were isolated from Fraser fir, Abies fraseri (Pursh) Poirit. Both juvabione and dehydrojuvabione concentrations had large variations across the tested trees and within trees. Juvabione, but not dehydrojuvabione, was much higher in stemwood then in branchwood. There was no significant difference in either chemical in relation to high, low, or middle branch position. To determine if juvabione concentration was influenced by an infestation of balsam woolly adelgid, Adelges piceae Ratz., branches from infested and uninfested 11-year-old Abies fraseri with were sampled at the bottom, middle, and top branches of each tree. While mean juvabione concentrations for each infested fir were higher than their uninfested counterparts, only the infested middle tree sections had mean juvabione values that were substantially higher (p = 0.078) than the corresponding uninfested tree section of all the infested firs. The two infested Abies fraseri that maintained apical dominance demonstrated the highest upper branch levels of juvabione of all the infested. These results indicate that juvabione may be induced in small Abies fraseri in response to adelgid attack. Trees that produce large quantities of this compound may possess tolerance to the adelgid. Further research is needed to elucidate this possibility.

Sign in / Sign up

Export Citation Format

Share Document