scholarly journals Composition and Structure of Reproduction in Group Selection Openings after 20 Years in a Southern Appalachian Mixed-Hardwood Forest

2021 ◽  
Author(s):  
W Henry McNab ◽  
Theodore M Oprean
Keyword(s):  
Group Selection ◽  
Stand Structure ◽  
Acer Rubrum ◽  
Stem Density ◽  
Mature Trees ◽  
Yellow Poplar ◽  
Southern Appalachian ◽  
Tolerant Species ◽  
Early Results ◽  
Composition And Structure

Abstract Following harvests by even-aged methods in mixed-hardwood forests, desirable oak (Quercus spp. L.) reproduction can be quickly overtopped by shade-intolerant pioneer species. In a long-term, operational-scale study of uneven-aged management by group selection, we inventoried 10- and 20-year-old reproduction following two harvest entries in a mature, dry-mesic southern Appalachian upland hardwood stand. Our study objectives included evaluating the species composition and structure of reproduction in relation to opening size (0.05 ha to 0.41 ha), position in openings (center or edge), uneven-aged diameter structure, and evidence supporting the delayed oak dominance hypothesis. Opening size had no effect on reproduction from either entry. After 10 years (but not 20) yellow-poplar (Liriodendron tulipifera L.) stem density and basal area were greater in opening centers; oaks were greater at edges. Position did not affect red maple (Acer rubrum L.) or other tolerant species. Diversity significantly increased between 10 and 20 years, suggesting evidence supporting the delayed oak dominance hypothesis. Early results from this study suggest that small openings can be used to regenerate desirable midtolerant and intolerant species in Appalachian mixed-hardwood stands on intermediate quality sites where uneven-aged stand structure is important for timber management and other goals such as visual appearance and early successional habitat. Study Implications Periodic harvests of small groups (0.05 to 0.41 ha) of mature trees in dry-mesic Appalachian oak-dominated, mixed-hardwood stands, followed by site preparation and competition release treatments to control undesirable shade tolerant species, can result in openings stocked with desirable shade midtolerant and intolerant reproduction after 20 years. Centers of openings will be dominated by yellow-poplar, but oak reproduction can be most prevalent around the periphery. Group selection is a flexible method of uneven-aged management that can be used to meet regeneration objectives and related goals such as early successional habitat and visual quality.

scholarly journals Effect of gap size on composition and structure of regeneration 19 years after harvest in a southeastern bottomland forest, USA

2020 ◽  
Author(s):  
W. Henry McNab ◽  
John C. Kilgo ◽  
John I. Blake ◽  
Stanley J. Zarnoch
Keyword(s):  
Tree Regeneration ◽  
Stem Density ◽  
Pioneer Species ◽  
Gap Size ◽  
Species Dominance ◽  
Advance Regeneration ◽  
Tolerant Species ◽  
Composition And Structure ◽  
Bottomland Forest ◽  
Species Groups

Following timber harvests in bottomland mixed-oak (Quercus) stands, desirable oak advance regeneration can be overgrown by shade intolerant pioneer species. We investigated the effects of group selection opening size on composition of tree regeneration 19 years post-harvest in an oak dominated bottomland forest and compared our results with earlier findings to evaluate development trends. In response to six opening sizes (7 - 40 m radii) we evaluated regeneration density and dominance of four tree species groups: conifers, hard mast, shade intolerant and shade tolerant hardwoods. Our objective was to determine the optimum gap size for regenerating oaks and test the delayed oak dominance hypothesis, where oaks slowly gain dominance as pioneer species undergo self-thinning. Opening size influenced conifer regeneration but minimally affected hardwoods. Hard mast species density was less than either intolerant or tolerant species regardless of opening size. Future stem density trends suggest increasing intolerant species and constant mast and tolerant species. Modeled future height trends suggest increasing mast species dominance over intolerant pioneers after 30 years. Our results suggest that gap-based silviculture can be used to regenerate bottomland hardwood stands with desirable species including oaks; larger gaps favor conifers but there was no optimum size to enhance oak regeneration.

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.

scholarly journals Understory Vegetation Responses to 15 Years of Repeated Fuel Reduction Treatments in the Southern Appalachian Mountains, USA

Forests ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 350 ◽  
Author(s):  
Emily C. Oakman ◽  
Donald L. Hagan ◽  
Thomas A. Waldrop ◽  
Kyle Barrett
Keyword(s):  
Mechanical Treatment ◽  
Prescribed Burning ◽  
Appalachian Mountains ◽  
Understory Vegetation ◽  
Stem Density ◽  
Fuel Reduction ◽  
Importance Value ◽  
Yellow Poplar ◽  
Southern Appalachian Mountains ◽  
Southern Appalachian

Decades of fire exclusion in the Southern Appalachian Mountains led to fuel accumulation and conversion from open oak-pine woodlands to closed-canopy mesic forests dominated by shade-tolerant hardwoods and shrubs that often do not support a diverse understory. Southern Appalachian forest managers and scientists recognize this and are implementing silvicultural treatments such as prescribed burning, mechanical treatments or a combination of these to restore forest structure. In this study, conducted at the Southern Appalachian Fire and Fire Surrogate Study site in Green River Game Land, North Carolina, we assessed the effects of four fuel reduction methods: burned 4x (B), mechanical treatment 2x (M), mechanical treatment 2x + burned 4x (MB), and control (C) on the changes in understory vegetation guilds from pretreatment to post-treatment years (2001–2016). The MB treatment was most effective at meeting the restoration objectives, as it resulted in increases in oak (ΔMB = 23,400 stems/ha) and pine (ΔMB = 900 stems/ha) stem density, importance value - calculated as the sum of relative cover and frequency - for graminoids (ΔMB = 26.0), and density of oak stems >50 cm in height (ΔMB = 7133 stems/ha). The B and M treatments were generally less effective, but nonetheless met a subset of the restoration objectives. The B treatment reduced ericaceous shrub cover (ΔB = −1.2%) and increased oak stems 10–50 cm in height (ΔB = 10,017 stems/ha), while the M treatment resulted in only modest increases of mesic hardwoods, specifically for yellow-poplar (ΔM = 200 stems/ha) and blackgum (ΔM = 200 stems/ha) as compared with other treatments, but significantly increased mountain laurel and rhododendron cover (ΔM = 10.0%). Overall, these fire and fire surrogate treatments had some success in restoring understory structure, but our findings suggest a slow response in understory herbaceous vegetation.

Development of a Southern Appalachian Hardwood Stand After Clearcutting

1986 ◽  
Vol 10 (3) ◽  
pp. 168-172 ◽  
Author(s):  
Donald E. Beck ◽  
Ralph M. Hooper
Keyword(s):  
Black Locust ◽  
Robinia Pseudoacacia ◽  
Acer Rubrum ◽  
Southern Appalachians ◽  
Red Maple ◽  
Yellow Poplar ◽  
Southern Appalachian ◽  
Quercus Spp ◽  
Robinia Pseudoacacia L ◽  
A Minor

Abstract A mixed hardwood stand composed of 53% oak (Quercus spp.), 33% yellow-poplar (Liriodendron tulipifera L.), and 14% other species, was clearcut in 1963. Twenty years later a developing, even-aged stand of predominantly sprout origin is dominated by yellow-poplar, black locust (Robinia pseudoacacia L.), red maple (Acer rubrum L.), and sweet birch (Betula lenta L.). The oaks are a minor and decreasing component. This and other studies suggest that clearcuts on good sites in the Southern Appalachians will be dominated by aggressive intolerant species—mainly yellow-poplar. If a larger oak component is desired, measures to ensure strong advance reproduction and lessen competition from prolific sprouters such as red maple will be necessary. South. J. Appl. For. 10:168-72. Aug. 1986.

Did early logging or changes in disturbance regimes promote high tree densities in river red gum forests?

2016 ◽  
Vol 64 (6) ◽  
pp. 530 ◽  
Author(s):  
Hugh W. McGregor ◽  
Matthew J. Colloff ◽  
Ian D. Lunt
Keyword(s):  
Stand Structure ◽  
Root Zone ◽  
Canopy Cover ◽  
Basal Area ◽  
Stem Density ◽  
Mature Trees ◽  
Large Trees ◽  
Zone Of Influence ◽  
Disturbance Recovery ◽  
River Red Gum

Density of woody plants is thought to have increased in many ecosystems in Australia since European colonisation. Globally, there has been much debate as to whether this phenomenon is driven by the process of post-disturbance recovery – whereby historical logging resulted in the replacement of large, mature trees with smaller, younger trees – or by the process of encroachment – whereby cessation of disturbance events reduced the mortality of seedlings and saplings. We examined the extent to which historical changes in forest structure are compatible with each of these models. The study was conducted in river red gum Eucalyptus camaldulensis Dehnh. floodplain forest on the River Murray at Millewa Forest, southern New South Wales. We compared ‘historical’ (~1860s) stand structure to ‘current’ structure in 45 one-hectare quadrants randomly stratified between three forest productivity classes. Historical trees were determined by stumps or stags likely to have been cut during the late 1800s. Size and position of each historical and current tree was recorded, and used to calculate stem density, basal area, canopy cover and the area of the ‘zone of influence’ (the peripheral extent of the root zone). Current stand structure was vastly different from historical structure. Stem density has increased 9-fold, from a mean of 17 (historical) to 147 (current) trees ha–1. However, basal area increased only slightly, from 13.0 to 15.3 m2 ha–1. Canopy cover increased substantially from 22.1 to 33.5% cover, as did zone of influence, from 55 to 81% cover. Evidence for both the post-disturbance recovery and encroachment hypotheses was found. The 9-fold increase in stem density between historical and current stands was attributable largely to the replacement of large trees with small trees, because basal area had increased only slightly (by 18%). However, the increase in basal area was associated with a substantial increase in canopy cover and area of the zone of influence, supporting the encroachment hypothesis. Regardless, the post-disturbance recovery hypothesis accounts for the bulk of changes in this river red gum forest.

Occupancy of two forest specialist birds in the Southern Mistbelt Forests of KwaZulu-Natal and Eastern Cape, South Africa

2020 ◽  
pp. 1-16
Author(s):  
S. THOBEKA GUMEDE ◽  
DAVID A. EHLERS SMITH ◽  
YVETTE C. EHLERS SMITH ◽  
SAMUKELISIWE P. NGCOBO ◽  
MBALENHLE T. SOSIBO ◽  
...  
Keyword(s):  
South Africa ◽  
Camera Trap ◽  
Habitat Requirements ◽  
Stem Density ◽  
Grass Cover ◽  
Eastern Cape ◽  
Wet Season ◽  
Mature Trees ◽  
Natural Habitats ◽  
Kwazulu Natal

Summary Establishing the specific habitat requirements of forest specialists in fragmented natural habitats is vital for their conservation. We used camera-trap surveys and microhabitat-scale covariates to assess the habitat requirements, probability of occupancy and detection of two terrestrial forest specialist species, the Orange Ground-thrush Geokichla gurneyi and the Lemon Dove Aplopelia larvata during the breeding and non-breeding seasons of 2018–2019 in selected Southern Mistbelt Forests of KwaZulu-Natal and the Eastern Cape, South Africa. A series of camera-trap surveys over 21 days were conducted in conjunction with surveys of microhabitat structural covariates. During the wet season, percentage of leaf litter cover, short grass cover, short herb cover, tall herb cover and saplings 0–2 m, stem density of trees 6–10 m and trees 16–20 m were significant structural covariates for influencing Lemon Dove occupancy. In the dry season, stem density of 2–5 m and 10–15 m trees, percentage tall herb cover, short herb cover and 0–2 m saplings were significant covariates influencing Lemon Dove occupancy. Stem density of trees 2–5 m and 11–15 m, percentage of short grass cover and short herb cover were important site covariates influencing Orange Ground-thrush occupancy in the wet season. Our study highlighted the importance of a diverse habitat structure for both forest species. A high density of tall/mature trees was an essential microhabitat covariate, particularly for sufficient cover and food for these ground-dwelling birds. Avian forest specialists play a vital role in providing ecosystem services perpetuating forest habitat functioning. Conservation of the natural heterogeneity of their habitat is integral to management plans to prevent the decline of such species.

scholarly journals Thinning Response and Potential Basal Area in a Mixed Sub-humid Low-elevation Oak-Hornbeam Forest

2021 ◽  
Author(s):  
Mathias Neumann ◽  
Hubert Hasenauer
Keyword(s):  
Stand Structure ◽  
Basal Area ◽  
Climatic Conditions ◽  
Diameter Distribution ◽  
Stem Density ◽  
Growing Stock ◽  
A Site ◽  
Water Nutrients ◽  
Related Mortality

Abstract Competition for resources (light, water, nutrients, etc.) limits the size and abundance of alive trees a site can support. This carrying capacity determines the potential carbon sequestration in alive trees as well as the maximum growing stock. Lower stocking through thinning can change growth and mortality. We were interested in the relations between stand structure, increment and mortality using a long-unmanaged oak-hornbeam forest near Vienna, Austria, as case study. We expected lower increment for heavy thinned compared to unmanaged stands. We tested the thinning response using three permanent growth plots, whereas two were thinned (50% and 70% basal area removed) and one remained unmanaged. We calculated stand structure (basal area, stem density, diameter distribution) and increment and mortality of single trees. The heavy thinned stand had over ten years similar increment as the moderate thinned and unthinned stands. Basal area of the unthinned stand remained constant and stem density decreased due to competition-related mortality. The studied oak-hornbeam stands responded well even to late and heavy thinning suggesting a broad “plateau” of stocking and increment for these forest types. Lower stem density for thinned stands lead to much larger tree increment of single trees, compared to the unthinned reference. The findings of this study need verification for other soil and climatic conditions.

Precommercial Thinning Increases Diameter Growth of Appalachian Hardwood Stump Sprouts

1983 ◽  
Vol 7 (2) ◽  
pp. 93-97 ◽  
Author(s):  
Neil I. Lamson
Keyword(s):  
Quercus Rubra ◽  
Acer Rubrum ◽  
Height Growth ◽  
Prunus Serotina ◽  
Black Cherry ◽  
Northern Red Oak ◽  
Red Maple ◽  
Yellow Poplar ◽  
Precommercial Thinning ◽  
Stump Sprouts

Abstract In West Virginia crop trees were selected from 7- or 12-year-old yellow-poplar (Liriodendron tulipifera L.), basswood (Tilia americana L.), red maple (Acer rubrum L.), black cherry (Prunus serotina Ehrh.), and northern red oak (Quercus rubra L.) stump sprouts. Crop trees were dominant or codominant, well-formed sprouts that originated not more than 6 inches above groundline and did not fork in the lower 17 feet. Four treatments were evaluated: (1) control; (2) thinning; (3) pruning; and (4) thinning plus pruning. Five years after treatment the diameter (d.b.h.) growth of thinned sprouts was 1.5 times greater than that of control sprouts. Pruning did not cause a significant decrease in five-year d.b.h. growth. Height growth was not affected by the treatments. Most of the epicormic branches produced by pruning were dead five years after treatment. Natural pruning was reduced by thinning; the average clear bole length of thinned sprouts was about 2 feet shorter than that of the control sprouts. Survival was nearly 100 percent.

scholarly journals Tree Regeneration Response to the Group Selection Method in Southern Indiana

1997 ◽  
Vol 14 (2) ◽  
pp. 90-94 ◽  
Author(s):  
Dale R. Weigel ◽  
George R. Parker
Keyword(s):  
Group Selection ◽  
Species Group ◽  
Selection Method ◽  
Tree Regeneration ◽  
Average Height ◽  
Yellow Poplar ◽  
The North ◽  
South Central ◽  
Regeneration Response ◽  
Number Of Stems

Abstract Tree regeneration response following the use of the group selection method was studied within 36 group openings on the Naval Surface Warfare Center, Crane Division in south central Indiana. Two different aspects and three time periods since cutting were examined. The objectives were to determine whether aspect, age, species group, location within the opening, or their interactions had any influence on the number of stems or average height of the tree regeneration. Among openings up to 20 yr since cutting, yellow-poplar and dogwood were most abundant for stems greater than 2.5 cm diameter at breast height (dbh), and dogwood and cherry-ash-walnut were most abundant for stems less than 2.5 cm dbh. The location×species group interaction also influenced the number of stems greater than 2.5 cm dbh. Stems less than 2.5 cm dbh were influenced by the age×species group and aspect×species group interactions. The north aspect and the oldest openings contained the most stems per hectare less than 2.5 cm dbh. The interaction of age and species group influenced average height for stems greater than or equal to 2.5 cm dbh. Average height increased with age for stems greater than or equal to 2.5 cm dbh. North. J. Appl. For. 14(2):90-94.

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