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

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.

1993 ◽  
Vol 23 (4) ◽  
pp. 760-765 ◽  
Author(s):  
R.T. Busing ◽  
E.E.C. Clebsch ◽  
P.S. White

Aboveground biomass and aboveground net primary production (ANPP) were determined for leaf, branch, and bole compartments of cove forests in the Great Smoky Mountains, Tennessee. The sample plots included young stands (42-63 years following agricultural abandonment) and old stands with no history of logging or catastrophic fire. Tree species, diameter at breast height (DBH), and 10-year radial growth increment data were collected on plots of 0.4–1.0 ha. Biomass was estimated with species-specific allometric equations for the Great Smoky Mountains and eastern Tennessee. ANPP was estimated using diameter growth measurements to determine biomass accumulation over the preceding 10-year interval. Biomass estimates for the predominantly deciduous old-growth stands ranged from 326 to 394 Mg•ha−1 on plots ≥ 0.4 ha. These were consistently greater than the corresponding estimates of 216–277 Mg•ha−1 for young stands. The old Tsuga-dominated stands had the highest biomass estimates of 415–471 Mg•ha−1 for 1.0-ha plots. Annual ANPP estimates were high (11.7–13.1 Mg•ha−1) among the young stands. These stands had particularly high bolewood production. ANPP of the old-growth plots ≥ 0.4 ha ranged from 6.3 to 8.6 Mg•ha−1•year−1 for the deciduous stands and 8.0–10.1 Mg•ha−1•year−1 for the coniferous–deciduous stands. Previous biomass estimates for primeval cove forests were well above temperate forest means of 300–350 Mg•ha−1. Our estimates based on larger plots were lower than previous estimates of 500–610 Mg•ha−1, but they still exceeded temperate forest means. Our deciduous values were 26–94 Mg•ha−1 above the temperate deciduous forest mean of 300 Mg•ha−1, and our Tsuga–deciduous values were 65–121 Mg•ha−1 above the temperate coniferous forest mean of 350 Mg•ha−1.


1991 ◽  
Vol 21 (11) ◽  
pp. 1567-1572 ◽  
Author(s):  
Robert N. Muller ◽  
Yan Liu

Volume and mass of coarse woody debris (> 20 cm diameter) in an old-growth forest on the Cumberland Plateau in southeastern Kentucky averaged 66.3 m3/ha and 21.8 Mg/ha, respectively. Coarse woody debris was patchily distributed among 80 sample plots (0.04 ha each), with 10 plots containing 39% of the total mass. Coarse woody debris mass was inversely, although not strongly, related to plot basal area. While 23 species contributed to the accumulation of coarse woody debris, five accounted for 72% of the total mass. These included Quercusprinus L. (25% of the total), Fagusgrandifolia L. (16%), Quercusalba L. (12%), Castaneadentata (Marsh.) Borkh. (11%), and Quercusvelutina Lam. (9%). The few studies of coarse woody debris in old-growth deciduous forests of North America suggest a regional pattern of accumulation correlated with temperature. In warmer regions, old-growth deciduous forests accumulate a mass in the range of 22–32 Mg/ha, while in cooler ecosystems, coarse woody debris ranges from 34 to 49 Mg/ha.


1994 ◽  
Vol 24 (7) ◽  
pp. 1354-1368 ◽  
Author(s):  
Franco Biondi ◽  
Donald E. Myers ◽  
Charles C. Avery

Geostatistics provides tools to model, estimate, map, and eventually predict spatial patterns of tree size and growth. Variogram models and kriged maps were used to study spatial dependence of stem diameter (DBH), basal area (BA), and 10-year periodic basal area increment (BAI) in an old-growth forest stand. Temporal variation of spatial patterns was evaluated by fitting spatial stochastic models at 10-year intervals, from 1920 to 1990. The study area was a naturally seeded stand of southwestern ponderosa pine (Pinusponderosa Dougl. ex Laws. var. scopulorum) where total BA and tree density have steadily increased over the last decades. Our objective was to determine if increased stand density simply reduced individual growth rates or if it also altered spatial interactions among trees. Despite increased crowding, stem size maintained the same type of spatial dependence from 1920 to 1990. An isotropic Gaussian variogram was the model of choice to represent spatial dependence at all times. Stem size was spatially autocorrelated over distances no greater than 30 m, a measure of average patch diameter in this forest ecosystem. Because patch diameter remained constant through time, tree density increased by increasing the number of pine groups, not their horizontal dimension. Spatial dependence of stem size (DBH and BA) was always much greater and decreased less through time than that of stem increment (BAI). Spatial dependence of BAI was close to zero in the most recent decade, indicating that growth rates in 1980–1990 varied regardless of mutual tree position. Increased tree crowding corresponded not only to lower average and variance of individual growth rates, but also to reduced spatial dependence of BAI. Because growth variation was less affected by intertree distance with greater local crowding, prediction of individual growth rates benefits from information on horizontal stand structure only if tree density does not exceed threshold values. Simulation models and area estimates of tree performance in old-growth forests may be improved by including geostatistical components to summarize ecological spatial dependence.


2021 ◽  
Author(s):  
Leszek Bartkowicz ◽  

The aim of the study was to compare a patch-mosaic pattern in the old-growth forest stands developed in various climate and soil conditions occurring in different regions of Poland. Based on the assumption, that the patch-mosaic pattern in the forest reflect the dynamic processes taking place in it, and that each type of forest ecosystem is characterized by a specific regime of natural disturbances, the following hypotheses were formulated: (i) the patches with a complex structure in stands composed of latesuccessional, shade-tolerant tree species are more common than those composed of early-successional, light-demanding ones, (ii) the patch-mosaic pattern is more heterogeneous in optimal forest site conditions than in extreme ones, (iii) in similar site conditions differentiation of the stand structure in distinguished patches is determined by the successional status of the tree species forming a given patch, (iv) the successional trends leading to changes of species composition foster diversification of the patch structure, (v) differentiation of the stand structure is negatively related to their local basal area, especially in patches with a high level of its accumulation. Among the best-preserved old-growth forest remaining under strict protection in the Polish national parks, nineteen research plots of around 10 ha each were selected. In each plot, a grid (50 × 50 m) of circular sample subplots (with radius 12,62 m) was established. In the sample subplots, species and diameter at breast height of living trees (dbh ≥ 7 cm) were determined. Subsequently, for each sample subplot, several numerical indices were calculated: local basal area (G), dbh structure differentiation index (STR), climax index (CL) and successional index (MS). Statistical tests of Kruskal- Wallis, Levene and Generalized Additive Models (GAM) were used to verify the hypotheses. All examined forests were characterized by a large diversity of stand structure. A particularly high frequency of highly differentiated patches (STR > 0,6) was recorded in the alder swamp forest. The patch mosaic in the examined plots was different – apart from the stands with a strongly pronounced mosaic character (especially subalpine spruce forests), there were also stands with high spatial homogeneity (mainly fir forests). The stand structure in the distinguished patches was generally poorly related to the other studied features. Consequently, all hypotheses were rejected. These results indicate a very complex, mixed pattern of forest natural dynamics regardless of site conditions. In beech forests and lowland multi-species deciduous forests, small-scale disturbances of the gap dynamics type dominate, which are overlapped with less frequent medium-scale disturbances. In more difficult site conditions, large-scale catastrophic disturbances, which occasionally appear in communities formed under the influence of gap dynamics (mainly spruce forests) or cohort dynamics (mainly pine forests), gain importance.


1983 ◽  
Vol 7 (4) ◽  
pp. 208-212 ◽  
Author(s):  
Robert N. Muller

Abstract An old-growth forest and a 35-year-old, second-growth forest on the Cumberland Plateau were studied to compare species composition and structure. Species composition and total basal area of the two stands did not differ, although total stand density was 19 percent lower and basal area of commercial species was 25 percent higher in the old-growth than in the second-growth stand. Analysis of size-class distributions showed that both stands were best represented by an inverse J-shaped distribution, which best describes old-age stands. The rapid regeneration of the second-growth stand seems to be the result of minimal disturbance to accumulated nutrient pools in the soil. The importance of these accumulated nutrient pools and implications for forest management on the Cumberland Plateau are discussed.


2002 ◽  
Vol 32 (7) ◽  
pp. 1232-1243 ◽  
Author(s):  
Nathan J Poage ◽  
John C Tappeiner, II

Diameter growth and age data collected from stumps of 505 recently cut old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees at 28 sample locations in western Oregon (U.S.A.) indicated that rapid early and sustained growth of old Douglas-fir trees were extremely important in terms of attaining large diameters at ages 100–300 years. The diameters of the trees at ages 100–300 years (D100–D300) were strongly, positively, and linearly related to their diameters and basal area growth rates at age 50 years. Average periodic basal area increments (PAIBA) of all trees increased for the first 30–40 years and then plateaued, remaining relatively high and constant from age 50 to 300 years. Average PAIBA of the largest trees at ages 100–300 years were significantly greater by age 20 years than were those of smaller trees at ages 100–300 years. The site factors province, site class, slope, aspect, elevation, and establishment year accounted for little of the variation observed in basal area growth at age 50 years and D100–D300. The mean age range for old-growth Douglas-fir at the sample locations was wide (174 years). The hypothesis that large-diameter old-growth Douglas-fir developed at low stand densities was supported by these observations.


2000 ◽  
Vol 30 (6) ◽  
pp. 948-957 ◽  
Author(s):  
George F Smith ◽  
N S Nicholas

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.


1998 ◽  
Vol 15 (4) ◽  
pp. 165-168 ◽  
Author(s):  
Martin A. Spetich ◽  
George R. Parker

Abstract We examine the relationship between disturbance regime and plot size for woody biomass estimation in a midwestern old-growth deciduous forest from 1926 to 1992. Analysis was done on the core 19.6 ac of a 50.1 ac forest in which every tree 4 in. dbh and greater has been tagged and mapped since 1926. Five windows of time are compared—1926, 1976, 1981, 1986 and 1992. The most efficient plot sizes requiring measurement of the least total area range from 0.02 to 1.6 ac. A small plot size was recommended after grazing disturbance, and a large size was recommended when mortality was high and acceptable error was low. North. J. Appl. For. 15(4):165-168.


2010 ◽  
Vol 86 (5) ◽  
pp. 614-622 ◽  
Author(s):  
William C. Parker ◽  
Thomas L. Noland ◽  
Brian Brown

Seed production and seed characteristics were examined during a mast seeding year in unmanaged, old-growth eastern white pine (Pinus strobus L.) stands located in northeastern Ontario and compared with those in adjacent stands partially harvested 16 years earlier using a structural retention system. Seed yields from old-growth stands were comparable to those of mature, second growth white pine stands but seed production assessed relative to unit area (# ha-1) and pine basal area (# m-2) was lower in partially harvested stands. In both unmanaged and harvested stands, seed production rate of trees growing in localized areas of lower pine basal area was higher. Seed characteristics and seed viability did not differ between harvest treatments. Although structural retention harvesting reduced seed production, results suggest that supply and viability of seed are unlikely to limit seedling recruitment in managed or protected old-growth white pine forests. Key words: germination, old-growth forest, partial harvest, seed mass, seed production


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