scholarly journals The Composition and Height of Saplings Capturing Silvicultural Gaps at Two Long-Term Experiments in Managed Northern Hardwood Forests

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 855 ◽  
Author(s):  
Knapp ◽  
Webster ◽  
Kern
Keyword(s):  
Group Selection ◽  
Northern Hardwoods ◽  
Northern Hardwood Forests ◽  
Northern Hardwood ◽  
Advance Regeneration ◽  
Second Growth ◽  
Selection Experiments ◽  
Tree Retention ◽  
Present Group

Managing forests for mixtures of canopy species promotes future resilience and mitigates risks of catastrophic resource loss. This study describes the compositions, heights, and locations within openings of gap-capturing saplings in two long-term group-selection experiments in managed northern hardwoods. We expected opening size to affect the composition of gap-capturing saplings and that composition would match advance regeneration where relatively large stems remained following harvest. We also expected sapling height to respond positively to opening size, but plateau in gap areas above 200 m2, and legacy-tree retention to negatively affect sapling height. In two group-selection experiments, we found that the composition of gap-capturing saplings was not affected by opening size at 15 and 23 years post-harvest, respectively, and that composition matched advance regeneration only when larger stems (>2.5 cm breast height, dbh) were removed during harvest. Gap-capturing sapling composition did not match the surrounding canopy in either study site. Sapling height was positively correlated with gap area, but, as we expected, plateaued in larger openings. In openings without legacy-retention, gap area did not significantly predict sapling height in openings larger than 100–200 m2, whereas this threshold was between 300–400 m2 in openings with single legacy-tree retention. Sapling height was negatively associated with distance into openings when legacy-trees were present. Group selection appears to recruit modestly higher proportions of shade-midtolerant and intolerant species to the canopy compared to adjacent unmanaged second-growth or managed, uneven-aged northern hardwoods.

Cavity trees and coarse woody debris in old-growth and managed northern hardwood forests in Wisconsin and Michigan

1998 ◽  
Vol 28 (3) ◽  
pp. 427-438 ◽  
Author(s):  
John M Goodburn ◽  
Craig G Lorimer
Keyword(s):  
Coarse Woody Debris ◽  
Woody Debris ◽  
Large Diameter ◽  
Hardwood Forests ◽  
Northern Hardwoods ◽  
Old Growth ◽  
Northern Hardwood Forests ◽  
Northern Hardwood ◽  
Tree Retention ◽  
Cavity Tree

The effects of uneven-aged management on the availability of coarse woody debris habitat were examined in northern hardwood forests (with and without a hemlock component) in north-central Wisconsin and adjacent western Upper Michigan. Snags, cavity trees, fallen wood, and recent tip-up mounds in 15 managed uneven-aged (selection) stands were compared with levels in 10 old-growth stands and six unmanaged even-aged second-growth stands. Amounts of coarse woody debris in selection stands were generally intermediate between old-growth and even-aged stands. Density of snags >30 cm DBH in northern hardwood selection stands averaged 12/ha, approximately double that found in even-aged northern hardwoods, but only 54% of the level in old-growth northern hardwoods. Highest densities of snags >30 cm DBH occurred in old-growth hemlock-hardwood stands, averaging over 40 snags/ha. For combined forest types, the volume of fallen wood (>10 cm in diameter) was significantly lower in selection stands (60 m3/ha) and even-aged stands (25 m3/ha) than in old-growth stands (99 m3/ha). Volume differences were even more pronounced for large-diameter debris (>40 cm). Cavity tree density in selection stands averaged 11 trees/ha, 65% of the mean number in old-growth stands. Densities of snags (>30 cm DBH) and large-diameter cavity trees (>45 cm) present in selection stands exceeded current guidelines for wildlife tree retention on public forests.

Elevated mortality of residual trees following single-tree felling in northern hardwood forests

2006 ◽  
Vol 36 (5) ◽  
pp. 1255-1265 ◽  
Author(s):  
John P Caspersen
Keyword(s):  
Tree Mortality ◽  
Community Dynamics ◽  
Stand Structure ◽  
Hardwood Forests ◽  
Natural Mortality ◽  
Northern Hardwood Forests ◽  
Substantial Impact ◽  
Northern Hardwood ◽  
Single Tree

In this paper, I examine tree mortality in northern hardwood forests subjected to single-tree felling. Mortality risk was estimated as a function of growth prior to harvest and time since harvest. This allowed me to separately quantify mortality due to (1) natural processes, (2) intentional felling, and (3) stress and (or) felling damage (postcut mortality). The long-term rate of mortality due to natural causes was 1.5% per year. The intentional felling of trees increased the average mortality to 3.1%, and postcut mortality of residual trees increased the average an additional 0.2%–3.3% (the latter reflects both the direct negative effects of harvesting and the indirect positive effect of releasing residual trees from suppression). Thus, from a population-level perspective, the increased mortality caused by stress and (or) felling damage to residual trees was small compared to that caused by both natural mortality and tree felling. However, the long-term population average obscures more dramatic (though transient) effects of felling on small trees (DBH <10 cm), for which mortality rates increased by as much as 5% immediately after felling. This increase is several times greater than the natural mortality rate for small trees and may therefore have a substantial impact on stand structure and community dynamics.

Seedling input, death, and growth in uneven-aged northern hardwoods

1976 ◽  
Vol 6 (3) ◽  
pp. 368-374 ◽  
Author(s):  
William B. Leak ◽  
Raymond E. Graber
Keyword(s):  
New Hampshire ◽  
Stand Structure ◽  
Northern Hardwoods ◽  
Diameter Growth ◽  
Short Term ◽  
Northern Hardwood ◽  
Growth Equations ◽  
Constrained Behavior

Seedling input, death, and diameter growth equations, covering a broad range in stand densities, were developed from short-term remeasured plot data in northern hardwood stands in New Hampshire. Long-term simulated changes in stand structure based on these equations exhibited logical constrained behavior.

Ground-layer response to group selection with legacy-tree retention in a managed northern hardwood forest

2007 ◽  
Vol 37 (10) ◽  
pp. 1797-1807 ◽  
Author(s):  
Joshua M. Shields ◽  
Christopher R. Webster
Keyword(s):  
Group Selection ◽  
Tree Height ◽  
Rubus Idaeus ◽  
Ground Layer ◽  
Hardwood Forest ◽  
Northern Hardwood Forest ◽  
Upper Peninsula ◽  
Northern Hardwood ◽  
Tree Retention ◽  
The Matrix

We examined the effects of group selection with legacy-tree retention on ground-layer or understory diversity and composition in an uneven-aged northern hardwood forest in the Upper Peninsula of Michigan. We sampled 20 reference plots in the surrounding forest matrix and 49 openings with radii of 0.5 (n = 16), 0.75 (n = 17), and 1.0 (n = 16) times mean canopy tree height (22 m). Resultant opening areas were 321 ± 16 (mean ± SEs), 697 ± 21, and 1256 ± 39 m2, respectively. Each opening contained a centrally located legacy tree. Two years after harvesting, ground-layer diversity was significantly higher in openings than on reference plots (p < 0.05) because of an influx of early seral, wetland, and weedy exotic species. The importance of aggressive ruderals (i.e., Carex ormostachya Wieg. and Rubus idaeus subsp. strigosus (Michx.) Focke) increased significantly (p < 0.001) with increasing opening area. Although the importance and cover of several late-seral species were lower in openings compared with the forest matrix, few species found in the matrix were wholly absent from the openings. These results suggest that ground-layer plant communities in managed northern hardwood forests may display a high degree of resilience to intermediate-intensity disturbances.

Economic and tree diversity trade-offs in managed northern hardwoods

1992 ◽  
Vol 22 (11) ◽  
pp. 1807-1813 ◽  
Author(s):  
Jeffrey Neal Niese ◽  
Terry F. Strong
Keyword(s):  
Species Diversity ◽  
Tree Species ◽  
Hardwood Forests ◽  
Northern Hardwoods ◽  
Tree Species Diversity ◽  
Economic Returns ◽  
Northern Hardwood Forests ◽  
Northern Hardwood ◽  
Shannon’S Index ◽  
Trade Offs

Forest ecologists have long believed that greater tree species diversity in hardwood forests reduces biological risk, but researchers have not yet linked diversification with economic returns for managed hardwood forests. This paper shows how management of northern hardwood forests affects tree species diversity and economic returns. Shannon's index is used to measure regeneration diversity for eight even- and uneven-aged cutting methods from a 40-year study on the Argonne Experimental Forest. These indices of tree species diversity are compared with the potential economic returns for the research sites.

Long-Term Evolution of Composition and Structure after Repeated Group Selection Over Eight Decades

2020 ◽  
Author(s):  
Nicole Rogers ◽  
Anthony W. D'Amato ◽  
William Leak
Keyword(s):  
Group Selection ◽  
Stand Structure ◽  
Fagus Grandifolia ◽  
Long Term Results ◽  
Northern Hardwood Forests ◽  
Composition And Structure ◽  
Shade Tolerant Species ◽  
Bartlett Experimental Forest ◽  
Developmental Dynamics

: In northeastern North America, group selection is frequently used in northern hardwood forests to maintain uneven-aged stand structure and promote regeneration of tree species spanning a range of shade tolerances. For this study, long-term application of group selection at the Bartlett Experimental Forest, New Hampshire, USA provided a unique opportunity to address cohort and stand level progression after 80-years of treatment. Cohort-level evolution reflected successional and developmental dynamics associated with even-aged forest systems, whereas aggregate, stand-level conditions were consistent with expectations for uneven-aged systems. As cohorts aged, diameter distributions progressed towards descending monotonic forms and species composition transitioned from shade-intolerant species to shade-tolerant species. Standing deadwood and downed woody material in cohorts followed trajectories of aging even-aged stands through time. Although American beech (Fagus grandifolia Ehrh.) was a primary species across cohorts and at the stand level, stand level regeneration included a mixture of ecologically and commercially valuable species. These long-term results offer important insights into emergent cohort and stand-level conditions and processes that may affect continued recruitment of desirable compositional and structural conditions in stands managed using group selection over numerous cutting cycles.

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