Habitat Diversity in Uneven-aged Northern Hardwood Stands: A Case Study (original) (raw)
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Northern Journal of Applied Forestry, 1996
Five Central New York northern hardwood stands were regenerated by clearcutting method, and followed through 20 yr of development. Observations from permanent remeasured plots indicate that a closed canopy formed and completely shaded the ground by 10-15 yr. Data gathered before that time did provide general information about features like the proportion of area stocked with trees and the stem density. After canopy closure, no new species entered the stand. Yet the actual species composition continued to change throughout the 20 yr period. Additional changes will occur as relatively short-lived species like striped maple, pin cherry, and aspen die. For other species, the change of importance will continue to depend on differences in their growth rates and tolerance to shading. Collectively, these dynamics will likely prolong the relatively rapid shifting of species composition for at least one-third to one-half of a century. Such findings suggest that the onset of canopy closure mar...
Structure and spatial patterns of trees in old-growth northern hardwood and mixed forests of norther
2001
Stand structure including spatial patterns was studied in northern hardwood and mixed forest types in the 2000-ha old-growth Big Reed Forest Reserve in northern Maine using complete stem mapping, dendrochronology, and spatial analyses on ϳ 0.5 ha plots. The inclusion of saplings, dead wood, age distributions, spatial pattern, and interactions provided some idea of underlying processes and temporal change. Structural characteristics were most comparable to spruce-northern hardwood forests of northern New England and New York, and most characteristics matched expected patterns for old-growth forests of the region. Results indicated smaller maximum-tree sizes, lower basal areas (26-34 m 2 /ha) and downed-wood volumes (29-64 m 3 /ha), higher densities (475-649 stems/ha), but similar species longevities compared to other mesic old-growth forests further south and in the Lake States. The stands were dominated by very shade-tolerant tree species, including Fagus grandifolia Ehrh., Acer saccharum Marsh., Picea rubens Sarg. and Abies balsamea (L.) Mill, with each species found in many crown positions and age and size classes. The sapling layer was dominated by Fagus grandifolia followed by Picea rubens. Most species had reverse-J shaped diameter distributions, but age distributions were indicative of synchronous, episodic recruitment. In most plots, Acer saccharum diameter distributions were skewed towards the mid-larger size classes. Lack of young and small Acer saccharum stems suggested change in forest composition towards Fagus grandifolia dominance. Most species formed small-scale clusters (р 15 m) perhaps in response to small gap disturbances. Snags were the dominant dead wood type and were randomly to regularly distributed in most plots. Logfall directions were unrelated to hurricane paths. Recent small-scale disturbance events and topographic position appear to be important in explaining current structure and dynamics of the hardwood and mixed forests of Big Reed Forest Reserve in northern Maine. The continued effects of beech bark disease had a greater effect on hardwood plots, whereas a recent spruce budworm outbreak had a greater effect on plots with higher conifer density. The dominance of very shade tolerant tree species in small-scale clusters, and randomly distributed snags rather than clustered uproots were indicative of the prevalence of small scale gap disturbance regimes in the hardwood and mixed forests of Big Reed Forest Reserve in northern Maine. Varying topographic position may allow for slight changes in disturbance regime leading to consequent variation in structure and dynamics. H1, a more open plot on upper exposed slopes, had distinctly different characteristics such as lower live and dead tree and sapling densities than the other plots, but more uprooted trees and Acer saccharum saplings. Such small scale gap disturbance regimes operating on an episodic basis, and effects of slight variations in this regime on stand composition and structure have significant implications for silvicultural interventions and management of these forest types.
Forest Ecology and Management, 1999
The pattern of stand development was studied in two mixed-species single-aged stands that originated after true clearcutting at the Great Mountain Forest in northwestern Connecticut. One stand was located on a mesic swale-till site and the other on a more xeric thin-till site. At the time of cutting all sprout growth and advanced regeneration was eradicated, except for 1-yearold red oak (Quercus rubra) seedlings. Twenty-eight years after the stands originated trees were strati®ed by shade tolerance such that the canopies were dominated by the intolerant species (paper birch Betula papyrifera, gray birch B. populifolia, pin cherry Prunus pensylvanica) with mid-tolerant species (black birch B. lenta, black cherry P. serotina) becoming prevalent. The number of stems was decreasing but the basal area was steadily increasing. The pattern in species-speci®c growth rates and crown position were common to both sites; but there were also differences between the sites in the sizes of trees and positioning of the mid-tolerant trees in the canopy. At age 28 the more mesic swale-till site had fewer, taller trees, with pioneer species more typical of northern hardwood climates. On this site red oak was doing poorly, all gray birch and eastern white pine (Pinus strobus) had died, black birch and black cherry were beginning to dominate the canopy of the stand, and a signi®cant understory of beech (Fagus grandifolia) had developed through the encroachment of root suckers from the stand edge. Sugar maple (Acer saccharum), white ash (Fraxinus americana) and eastern hemlock (Tsuga canadensis), all signi®cant components of the swale-till site before clearcutting, were noticeably absent. On the thin-till site red oak had not attained the canopy of the stand but was still a signi®cant component of the mid-story with red maple (A. rubrum). However, black birch was self-thinning more rapidly on the thin-till site than that of the swale-till suggesting that red oak and red maple might well dominate the canopy within another 20 years. In general, the diameter growth rate of the thin-till site currently lags behind the swale-till by approximately 10 years.
Plant Ecology, 2001
Stand structure including spatial patterns was studied in northern hardwood and mixed forest types in the 2000-ha old-growth Big Reed Forest Reserve in northern Maine using complete stem mapping, dendrochronology, and spatial analyses on ϳ 0.5 ha plots. The inclusion of saplings, dead wood, age distributions, spatial pattern, and interactions provided some idea of underlying processes and temporal change. Structural characteristics were most comparable to spruce-northern hardwood forests of northern New England and New York, and most characteristics matched expected patterns for old-growth forests of the region. Results indicated smaller maximum-tree sizes, lower basal areas (26-34 m 2 /ha) and downed-wood volumes (29-64 m 3 /ha), higher densities (475-649 stems/ha), but similar species longevities compared to other mesic old-growth forests further south and in the Lake States. The stands were dominated by very shade-tolerant tree species, including Fagus grandifolia Ehrh., Acer saccharum Marsh., Picea rubens Sarg. and Abies balsamea (L.) Mill, with each species found in many crown positions and age and size classes. The sapling layer was dominated by Fagus grandifolia followed by Picea rubens. Most species had reverse-J shaped diameter distributions, but age distributions were indicative of synchronous, episodic recruitment. In most plots, Acer saccharum diameter distributions were skewed towards the mid-larger size classes. Lack of young and small Acer saccharum stems suggested change in forest composition towards Fagus grandifolia dominance. Most species formed small-scale clusters (р 15 m) perhaps in response to small gap disturbances. Snags were the dominant dead wood type and were randomly to regularly distributed in most plots. Logfall directions were unrelated to hurricane paths. Recent small-scale disturbance events and topographic position appear to be important in explaining current structure and dynamics of the hardwood and mixed forests of Big Reed Forest Reserve in northern Maine. The continued effects of beech bark disease had a greater effect on hardwood plots, whereas a recent spruce budworm outbreak had a greater effect on plots with higher conifer density. The dominance of very shade tolerant tree species in small-scale clusters, and randomly distributed snags rather than clustered uproots were indicative of the prevalence of small scale gap disturbance regimes in the hardwood and mixed forests of Big Reed Forest Reserve in northern Maine. Varying topographic position may allow for slight changes in disturbance regime leading to consequent variation in structure and dynamics. H1, a more open plot on upper exposed slopes, had distinctly different characteristics such as lower live and dead tree and sapling densities than the other plots, but more uprooted trees and Acer saccharum saplings. Such small scale gap disturbance regimes operating on an episodic basis, and effects of slight variations in this regime on stand composition and structure have significant implications for silvicultural interventions and management of these forest types.
Stand dynamics in Connecticut hardwood forests : the old series plots (1927-1997) /
1999
The Old-Series plots chronicle 70 years of natural change in unmanaged central Connecticut forests. The plots were established in 1926-27 in four stands typical of that period: they had originated around 1900, had a prior history of repeated cutting and agricultural use, and were predominately hardwood in composition. One period of disturbance has had a large influence on changes in these plots. During the 1960s the plots were repeatedly defoliated by gypsy moth and canker worm during an extended period of drought. There were shorter periods of defoliation during the 1970s and 1980s. This Bulletin reports on natural changes between 1927-1997 on the 10.5 acres that have not been disturbed by man. All trees with a diameter of at least 0.5 inch have been mapped and measured at 10-year intervals, except during the 1940s, using 16.5 foot wide strips transversing the forests. We now have records on 43,357 stems distributed on nearly 60 tree and shrub species.
Tree species richness increased by clearcutting of northern hardwoods in central New York
Forest Ecology and Management, 1993
Data collected by periodic remeasurement of permanent plots within five northern hardwood stands in central New York describe changes in species composition of natural regeneration during a 20-year period following clearcutting. Regeneration developed from the upgrowth of advance seedlings, the emergence of new germinants, and stump sprouts. Findings indicate that the species composition of the stand prior to cutting, and of the forest around the site, influenced the relative importance of each source and species. As the regeneration developed, its composition changed to reflect characteristics of each source, and the different species' growth rates. Advance seedlings and stump sprouts helped to maintain shade-tolerant species, and new germinants influenced the proportions of shade-intolerant and intermediate species. The latter groups persisted due to better rates of height growth at the light levels created by clearcutting.
Forest management can significantly affect both the diversity and spatial patterning of understory vegetation. However, few studies have considered both diversity and spatial patterning at a stand scale. Our objective was to evaluate the effects of forest management on understory plant communities in northern hardwood forests and assess the processes governing differences in species composition, diversity, and spatial patterns. We sampled understory vegetation (all species Ͻ2 m tall) and percentage of light transmission levels in three forest types in 12 mesic northern hardwood stands in northern Wisconsin and the Upper Peninsula of Michigan, USA: old-growth, undisturbed forests; even-aged forests resulting from clearcut logging (ϳ65-85 yr old); and uneven-aged forests with recent selective logging.
Managing Appalachian hardwood stands using four management practices: 60-year results
Forest Ecology and Management, 2017
A long-term forest management case study on the Fernow Experimental Forest in West Virginia referred to as the Cutting Practice Level study is evaluated after 60 years. Treatments include a commercial clearcut (one time application), a 39 cm diameter-limit (applied 4 times), uneven-aged management using two variations of single-tree selection (applied 7 and 8 times, respectively), and an unmanaged reference area. We examine productivity, species composition and diversity, structure, tree quality, and revenues generated related to each treatment since establishment. The diameter-limit treatment resulted in greatest average periodic annual increment (PAI) of sawtimber volume of 3.1 m 3 ha À1 yr À1 while the unmanaged reference area resulted in the least of 2.2 m 3 ha À1 yr À1 (based on the difference in standing volume from 1956 to 2008). All types of partial harvesting resulted in greater sawtimber productivity than either the commercial clearcut or the reference area. Post-harvest tree quality, as measured by proportion of grade 1 butt logs, has improved from 1988 to 2008 for all but the diameter-limit treatment, which is similar to conditions in 1968. In 2008, the proportion of grade 1 trees in the residual stand ranged from a high of 0.22 for single-tree selection to 0.15 for diameter-limit harvesting. Species composition is becoming less diverse and more dominated by shade-tolerant species in all treatment groups but the change has been the greatest in the two single-tree selection treatments. Initially, size-class distributions were somewhat unimodal and reflective of even-aged stands with shade tolerant species persisting in the understory. In 2008, the single-tree selection treatments were both characterized by a reverse-J size class distribution and it appears this structure can be maintained due to recruitment of shade-tolerant species in the smaller size classes with concomitant reductions in species diversity. The net present value for each treatment in 2008, the time of the last management intervention, ranged from 20,000haAˋ1forreferenceareatoalmost20,000 ha À1 for reference area to almost 20,000haAˋ1forreferenceareatoalmost34,000 ha À1 for the single-tree selection treatment that included management of pole-sized trees based on all revenue and the value of standing timber using an internal rate of return of 4%.
Using data collected in 1964 and 2006, we examined changes in the composition and structure of a second-growth and old-growth beech-maple forest of Crall Woods, located in Ashland County of north central Ohio. Over the 42 years, the old-growth forest (estimated to be at least 250 years old) experienced a significant shift in species composition as American beech, yellow-poplar, and red maple increased in importance while American basswood, sugar maple, and shagbark hickory all declined in importance. Similar changes were observed in the second-growth stand, except that the increases in importance were associated with shade-intolerant (e.g., yellow-poplar) and shade mid-tolerant (e.g., northern red oak) species. Despite the shifts in composition, stand structure remained fairly consistent over the 42 years and was similar between the second-growth and old-growth stand. We suggest that the old-growth stand will continue to have both shade-tolerant and intolerant species over time and that the composition of the second-growth stand will shift toward the more shade-tolerant species. These species will dominate the forest understory as they replace shade-intolerant and mid-tolerant overstory individuals that die.
Forest Science, 2004
On high quality growing sites in West Virginia, shade intolerant tree species have increased in importance in third-generation forests following clearcutting. We investi- gated the effect of tree species canopy position on the Shannon-Weiner Diversity Index (H'), Pielou's evenness index (0, and species richness (S) using a chronosequence of 13 clearcuts. Two to 26 yr after clearcutting, tree species diversity significantly decreased from 2.07 to 1.83, and evenness decreased from 0.80 to 0.71 while species richness was maintained. As the number of years since harvesting increased, the importance value of oaks (Quercus L.), hickories (Carya Nutt.), American beech (Fagus grandifolia Ehrh.), sugar maple (Acersaccha- . rum Marsh.), and black birch (Betula lenta L.) decreased while the importance of yellow-poplar (Liriodendron tulipifera L.) increased. In these mixed-species stands with stratified canopies, species importance in overstory versus understory canopy layers was the be...