Effects of Various Silvicultural Systems on Regeneration in Mixed Hardwood Stands of the Southern Appalachians

This study investigated the effects of clear-cutting and several other commonly used silvicultural systems on regeneration at seven sites in the Appalachian Mountains of Virginia and West Virginia. These even-aged oak dominated stands ranged in age from 63 to 100 yr and were located on medium quality oak sites (site indices from 18 to 23 m, base age 50). The treatments evaluated included a clear-cut, commercial harvest, shelterwood, leave-tree, group selection, preharvest herbicide, and control.

Mixed model ANOVA was used to analyze treatment response in five species groups: (a) oak (Quercus spp.); (b) maple (Acer spp.); (c) black cherry (Prunus serotina Ehrh.), and yellow-poplar (Liriodendron tulipifera L.); (d) miscellaneous overstory hardwoods; and (e) midstory species that typically do not occupy main canopy positions in mature stands. Response variables included stem density, importance value, average height for all regeneration, and the tallest 365 stems ha^?1. Comparisons were made among treatments, species groups, and between regeneration of sprout and seedling origin.

Alternative systems with residual trees reduced the regenerations overall mean height growth compared to the clear-cut by 0.34 to 0.74 m. Current conditions indicate oak will be a lesser component of the future stand, represented mostly through stump sprouting, and maple will likely increase in proportion among all treatments.     

Long-term effects of single prescribed fires on hardwood regeneration in oak shelterwood stands

One of the arguments against using prescribed fire to regenerate oak (Quercus spp.) forests is that the improvement in species composition of the hardwood regeneration pool is temporary and multiple burns are necessary to achieve and maintain oak dominance. To explore this concern, I re-inventoried a prescribed fire study conducted in the mid-1990s to determine the longevity of the effects of a single prescribed fire on hardwood regeneration. The initial study was conducted in three oak shelterwood stands in central Virginia, USA. In 1994, each stand was divided into four treatments (spring, summer, and winter burns and a control) and the hardwood regeneration was inventoried before the fires. During the burns, fire intensity was measured and categorized in each regeneration sampling plot. Second-year postfire data showed marked differences in species mortality rates, depending on season-of-burn and fire intensity: oak and hickory (Carya spp.) regeneration dominated areas burned by medium- to high-intensity fire during the spring and summer while yellow-poplar (Liriodendron tulipifera) and red maple (Acer rubrum) seedlings dominated unburned areas and all areas treated with low-intensity fire regardless of season-of-burn. The treatments were re-inventoried in 2006 and 2007 to determine whether these fire effects were still present. The new data show that the species distributions by season-of-burn and fire intensity found in 1996 still existed 11 years after the treatments. The fact that fire effects in oak shelterwood stands can last at least a decade has important management implications for resource professionals interested in sustaining oak forests in the eastern United States.     

The bottomland hardwood forest of the southern United States

Bottomland hardwood forests are valued for timber production, water storage, enhanced water quality, nutrient cycling, erosion control and wildlife habitat. However, the majority of southern bottomland stands, 90% of which are in private ownership, are occupied by a degraded mixture of tree species, caused largely by repeated, incomplete harvests. They can be naturally regenerated to a stand of favorable species composition by removing the residual stand of merchantable and non-merchantable trees. For timber production, these systems respond best to even-aged management such as clearcutting, shelterwood cutting and patch clearcutting. Plant succession under such systems allows shade intolerant species to occupy the site, followed by species of increasing shade tolerance. Uneven-aged systems, such as individual-tree selection and group selection, are also viable regeneration methods, but they require great attention to detail and frequent stand entry. In areas of high sensitivity to timber harvesting, a two-aged system such as a leave-tree is recommended. Stand disturbance, either planned or unplanned, is needed to keep southern hardwood forest stands viable.     

Survival and development of Liaodong oak stump sprouts in the Huanglong Mountains of China six years after three partial harvests

The survival and development of Liaodong oak (Quercus liaotungensis Koidz) stump sprouts were studied for 6 years under leave-tree, as well as 60 and 75% crown closure uniform shelterwood in the Huanglong Mountains of China. Stump sprout survival rate, number of sprouts, and sprout height under the three partial harvests during the first year post-harvest did not differ. Six years post-harvest, 78.32% of the stumps had living sprouts. No variation in sprout survival was found among the treatments throughout the study period. The number of living sprouts per stump was 13.77 ± 0.50 in the first growing season after harvest, and dropped to 6.49 ± 0.22 after 6 years. This result indicated the occurrence of self-thinning within the sprout clumps. Moreover, the height of dominant sprout increased from 52.88 ± 1.62 cm (in the first year) to 132.82 ± 2.35 cm (in the sixth year) post-harvest. Sprout height in the leave-tree harvest type was higher than those in the two shelterwoods in the fifth and sixth years after logging. Annual height growth was approximately 8–96 cm during the first growing season, and then decreased at a rate of 1–44 cm per year in the following years. A negative relationship was found between sprout height and the number of sprouts per stump. This result indicated a trade-off between the number of sprouts and height growth. The number of sprouts per stump decreased by about 0.2 stem for each 1 m²/ha increased in residual basal area. Therefore, sprouting may play an important role in the restoration of the secondary forest after harvesting.     

伞伐更新法对赫卡尼亚(Hyrcanian)森林系统中森林再生和林分结构的影响

研究伞伐更新法对赫卡尼亚森林系统中森林再生和林分结构的影响。在伊朗北部优势种为山毛榉（Fagus orientalisLipsky）的硬木林,采取伞伐更新法和非伞伐更新法方法设计实验区。结果表明,在山毛榉（F orientalis Lipsky）林中采用伞伐更新法处理,明显影响林下草本植物种的频度和密度。伞伐更新法处理后,林堇菜（Viola silvestris Lam.）、车叶草（Asperula odorata L.）、苔草（Carex spp.）和悬钩子（Rubushyrcanus Juz）的种频度明显增加。在对照区,树种的胸高直径（57.50±2.15cm）大于被处理区（50.67±1.88cm）的树种的胸高直径（50.67±1.88 cm）,但对照区和处理区的树种的高度值相似。在1995-2005年间,波斯铁木（Parrotia persica）苗木数量增加到13.2%,而山毛榉（F orientalis）和欧洲鹅耳枥（Carpinus betulus）的苗木数量却明显减少。总之,应该利用其它育林方法,如,带状择伐作业,而不是伞伐更新法培育赫卡尼亚森林中山毛榉林。     

Silvicultural systems for southern bottomland hardwood forests

Silvicultural systems integrate both regeneration and intermediate operations in an orderly process for managing forest stands. The clearcutting method of regeneration favors the development of species that are moderately intolerant to intolerant of shade. In fact, clearcutting is the most proven and widely used method of successfully regenerating bottomland oak species in the South. The seed-tree method of regeneration favors the establishment of light-seeded species. Mechanical soil scarification may be necessary if the desired species requires bare mineral soil for establishment. The shelterwood method of regeneration can provide for the development of heavy-seeded species, but has produced highly variable results with southern bottomland oaks. The single-tree selection method of regeneration favors the development of shade-tolerant species. When single-tree selection is applied repeatedly to stands containing commercially valuable shade-intolerant species, composition will gradually shift to less-valuable, more-tolerant species. Consequently, the single-tree selection method of regeneration is not recommended for any commercially valuable bottomland hardwood tree species. Group selection, in its strictest application, creates only small openings that usually fail to allow sufficient light to the forest floor for satisfactory establishment and development of shade-intolerant bottomland species. Patch cutting, a combination of uneven-aged (group selection) and even-aged (clearcutting) silviculture, designed to create larger openings, has been successfully used to produce an uneven-aged stand that consists of many small, irregularly shaped, even-aged groups. Silvicultural systems should include a planned program of intermediate operations designed to enhance the growth and development of those species favored during the regeneration process. Improvement cutting and commercial thinning are increasingly common in southern bottomland hardwood forests. Other partial cuttings employed today in bottomland hardwood forests typically involve some form of crop-tree release. Specific recommendations for the selection of silvicultural systems are presented for the eight most important species groups found in southern bottomland hardwood forests.     

Predicting Forest Regeneration in the Central Appalachians Using the REGEN Expert System

REGEN is an expert system designed by David Loftis to predict the future species composition of dominant and codominant stems in forest stands at the onset of stem exclusion following a proposed harvest. REGEN predictions are generated using competitive rankings for advance reproduction along with other existing stand conditions. These parameters are contained within modular REGEN knowledge bases (RKBs). To extend REGEN coverage into hardwood stands of the Central Appalachians, RKBs were developed for four site classes (xeric, subxeric, submesic, mesic) based on literature and expert opinion. Data were collected from 48 paired stands in Virginia and West Virginia to calibrate the initial RKBs. Paired stands consisted of one mature uncut hardwood stand adjacent to a regenerating clear-cut stand with similar site characteristics that was harvested within the previous 20 yr. Data from 17 additional paired stands was collected a year later to validate the performance of REGEN. Predicted values were within 4 percentage points of measured values on average, and model error was typically less than 20 percentage points for species groups. These results confirmed the suitability of REGEN to predict the future species composition of stands regenerated using the clear-cut method in the Central Appalachians of Virginia and West Virginia.     

Oak regeneration using the shelterwood-burn technique: management options and implications for songbird conservation in the southeastern United States

Shelterwood silviculture is commonly used to regenerate oaks in upland stands. However, competition from other species such as tulip-poplar (Liriodendron tulipifera) may deter oak regeneration when these traditional shelterwood techniques are used. The shelterwood-burn technique is a relatively new tool for regenerating oak-dominated stands on some upland sites while simultaneously minimizing undesirable hardwood intrusion with prescribed fire. Once successful oak regeneration has been achieved, three options are available which will result in different vegetative structure and composition within a stand and subsequently different habitats for songbirds. These options are: complete or partial canopy retention, post-harvest prescribed burning and complete canopy removal. Canopy retention, burning and removal treatments will create, respectively, two-age stands that are likely to harbor a diverse mixture of mature forest and early successional species; park-like woodlands with open woodland species; or early-successional habitats with shrubland species. We suggest that shelterwood-burn systems and the management options associated with them offer viable alternatives for managing both songbird and timber resources where oak-dominated stands are the desired goal in upland southeastern sites.     

Effects of silvicultural disturbance on acorn infestation and removal

Oak (Quercus spp.) regeneration is an important forest management goal in the central hardwood forest region of the United States. Silvicultural methods that target oak regeneration, such as the creation of canopy openings and removal of shade-tolerant midstory trees, are complicated by the impact of pre- and post-dispersal predators of oak acorns like acorn weevils (Curculio spp.) and granivorous small mammals. Understanding the effects of forest disturbance created by silviculture on these predators is important to promote successful oak regeneration. We conducted a 6-year study of acorn production, weevil infestation, and acorn removal at 113 black (Q. velutina) and white oak (Q. alba) trees impacted by three types of silvicultural treatments: adjacent to harvest openings, midstory removal (first-stage shelterwood harvest), and control (no harvest) in south-central Indiana, USA. We observed highly variable acorn production across years, but minimal impact of silvicultural treatments. Levels of weevil infestation and acorn removal by small mammal seed predators also varied greatly, and predation pressure was highest in years when acorns were scarce. Weevil infestation was reduced following midstory removal in shelterwood harvests, but probability of acorn removal by small mammals was unchanged following harvest. Damaged, germinated, and weevil-infested acorns were less likely to be removed by seed predators, suggesting additive effects of pre- and post-dispersal predators. This study emphasizes the importance of considering acorn predators in oak regeneration silviculture, and timing harvests to follow large acorn crops in order to reduce predation pressure and generate a high number of seedlings.     

A financial analysis of rain forest silviculture in southwestern Sri Lanka

We examine the financial aspects of three silvicultural systems to encourage the sustainability of valuable hardwood species in mixed-dipterocarp forests of southwest Sri Lanka. We compare the net present value (NPV) of the current forest management approach (diameter limit harvests) with shelterwood harvests that promote light hardwood timber species. In this analysis, we also consider the potential of enrichment planting various precious timber (Diospyros quaesita — calamander), and non-timber forest product (NTFP) species (Caryota urens — fishtail palm; Elettaria cardamomum var. major — cardamom; Calamus zeylanicus — rattan) in conjunction with timber harvests. Two real (inflation adjusted) discount rates were used, 4 and 6%, respectively. Results show that when real discount rates are low (4%), and advance regeneration is present, NPV is highest for the one-cut shelterwood (US $9983 ha⁻¹). At a high discount rate (6%), reflecting the current short-term concession system and unstable rights to harvest, and where no advance regeneration was present, the diameter limit system (US $7173 ha⁻¹) was the optimum. On sites with advanced regeneration, the one-cut shelterwood system is clearly preferable. For all but rattan, shelterwood treatments provide higher NPVs for NTFPs than diameter limit cuttings primarily because of the higher light regimes and more growing space made available early in the rotation. The value for tea cultivation (US $26,000 ha⁻¹) far exceeds the value of managing these lands for timber alone, explaining the dramatic expansion in tea plantations on private lands. However, our results suggest that managing these lands for a combination of timber and enrichment plantings of NTFPs (US $23,000 ha⁻¹) can be comparable to tea plantations. By managing for NTFPs and timber, forest managers have new opportunities to solve the old problems of high-grading and land-use conversion.     

Can the impact of deer browsing on tree regeneration be mitigated by shelterwood cutting and strip clearcutting?

Silvicultural treatments creating large canopy openings failed to restore regeneration of balsam fir (Abies balsamea (L.) Mill.) due to browsing pressure from white-tailed deer (Odocoileus virginianus Zimmermann). Consequently, we tested two alternative silvicultural treatments aimed at improving balsam fir establishment on Anticosti Island (Québec, Canada). In 1998 and 1999, we set up shelterwood seed cutting using three harvest intensities (0, 25 and 40% of basal area) and strip clearcutting with scarification using three different strip widths (15, 30 and 45 m), both with fenced and unfenced regeneration plots, in balsam fir stands. After 8 years, shelterwood seed cutting did not allow the establishment of new balsam fir seedlings, nor the development of unbrowsed balsam fir seedlings. In the strip clearcutting, deer browsing suppressed growth of palatable species in all strip widths. This favoured the development of unpalatable species, especially white spruce (Picea glauca (Moench) Voss). Our study demonstrates that the use of silvicultural treatments alone is unlikely to restore balsam fir regeneration on Anticosti Island, as long as the deer population remains higher than 20 deer/km².     

Early regeneration of Fraxinus rhynchophylla in the understorey of Larix kaempferi stands in response to thinning

The effects of thinning were investigated on naturally regeneratedFraxinus rhynchophylla Hance (Korean ash) grown in the understoreyof a Larix kaempferi (Lamb.) Carr. plantation, established ona site that previously supported old growth hardwood forests.The regeneration characteristics were evaluated after thinningof the plantation (about 60 per cent of relative density wasremoved). In the naturally regenerated and mixed stands, Quercusmongolica Fisch. was the most abundant tree species in the overstorey,but the understorey of the thinned plantations was dominatedby F. rhynchophylla with six other minor tree species. Fraxinusrhynchophylla was regenerated by four propagation types includingnatural seedling, stump sprout, root sprout and layering. Beforethinning, the difference of average height growth for each regenerationtype was insignificant. One year after thinning, the stump sproutsshowed the fastest growth among the regeneration types. Heightgrowth of advance regeneration was slow in the year followingthinning but then increased rapidly surpassing the other regenerationtypes 5 years after thinning. Thinning had an effect on thecomposition of regenerated trees also by seedling, stump sprout,root sprout and layering in the understorey. Advance regenerationsoccupied the upper understorey at 5 years after thinning. Alarge number of stump sprouts emerged in the plots 1 year afterthinning, while at 5 years after thinning the occupation ofstump sprouts decreased. Root sprouts and layers faded away.Considering the early growth and the composition of understoreyF. rhynchophylla, its advance regeneration has a high potentialto develop into overstorey trees at this site.     

White-tailed deer herbivory and timber harvesting rates: Implications for regeneration success

Herbivory by white-tailed deer (Odocoileus virginianus) can affect forest regeneration. Typical measures to ensure forest regeneration have included physical barriers or direct manipulation of deer densities. However, altering silvicultural practices to provide abundant deer forage has not been tested thoroughly. We examined browse species preferences and changes in herbivory rates in 1–6 year old regeneration areas from 2001 to 2004 in the central Appalachians on the MeadWestvaco Wildlife and Ecosystem Research Forest in West Virginia. Woody vegetation reached the maximum plot coverage by the 4th growing season. However, the establishment of less abundant woody species, such as northern red oak (Quercus rubra), may be inhibited when browsed greater than or proportionally to occurrence. Herbivory rates declined precipitously as the amount of early successional habitat increased on our study site. We conclude that providing approximately 14% of an area in well-distributed, even-aged managed forests can have substantial impacts on reducing herbivory rates. However, management practices also should consider harvesting effects on hard mast production, habitat requirements of other species, and hardwood lumber marketability.     

Influence of browsing damage and overstory cover on regeneration of American beech and sugar maple nine years following understory herbicide release in central Maine

Northern hardwood stands, notably those with American beech (Fagus grandifolia Ehrh), sugar maple (Acer saccharum Marsh.), and yellow birch (Betula alleghaniensis Britton), are abundant across the forested landscapes of northeastern USA and southeastern Canada. Recent studies have reported an increasing dominance of American beech in the understory and midstory of these forests. Beech is a commercially less desirable tree species due to its association with beech-bark disease, and because it commonly interferes with the regeneration of other more desirable tree species. We examined hardwood regeneration characteristics nine years after application of a 3 × 4 factorial combination of glyphosate herbicide (0.56, 1.12, and 1.68 kg ha^?1) and surfactant concentrations (0.0, 0.25, 0.5, and 1.0% v v^?1) to release sugar maple regeneration from beech-dominated understories using three stands that received shelterwood seed cutting in central Maine. Measurements nine years after treatment showed that glyphosate rate increased both absolute (AD) and relative density (RD) of sugar maple regeneration, but not its height (HT). In contrast, beech AD, RD, and HT were all significantly reduced with increasing glyphosate rate. Post-release browsing by ungulates and a high residual overstory basal area resulted in reduced sugar maple HT. Our results indicated that glyphosate herbicide applied in stands that have been recently shelterwood seed cut can significantly increase the abundance of sugar maple regeneration. However, subsequent browsing damage combined with the negative influence of the residual overstory cover can limit the longer-term benefit of understory herbicide treatments. Subsequent removal of the overstory and browsing-control measures may be needed to promote sugar maple regeneration over beech in similar northern hardwood stands.     

Contributions of root and stump sprouts to natural regeneration of a logged tropical dry forest in Bolivia

A major impediment to the sustainable management of tropical dry forests in Bolivia is the scarcity of natural regeneration of commercial timber tree species. Where regeneration is present, true seedlings of many species are outnumbered by vegetative sprouts from roots, broken stems, and the stumps of felled trees. This study evaluates the importance of resprouts promoted by logging operations for the regeneration of commercially important canopy tree species. The objectives of the study were: (1) to characterize stump and root sprouting behaviors of canopy tree species harvested for timber; (2) to quantify the effect of logging on relative abundances and growth rates of stump sprouts, root sprouts, and true seedlings; (3) to relate the species-specific probabilities of stump sprouting to stump diameter and stump height; and (4) to explore how sprouting varies with the ecological requirements of canopy tree species. The study was carried out 1–5 years after logging of a privately owned land in a Bolivian tropical dry forest. Twenty-seven of the 31 species monitored resprouted at least occasionally, among which Centrolobium microchaete (Leguminosae-Fabaceae) and Zeyheria tuberculosa (Bignoniaceae) were the most frequent stump sprouters, and Acosmium cardenasii (Leguminosae-Fabaceae) and C. microchaete were the most frequent root sprouters. In all species the number of sprouts declined with increasing stump diameter and stump height. The probability of stump resprouting differed among species but did not vary consistently with stump diameter, except in Z. tuberculosa in which it declined. Approximately 45% of juveniles <2 m tall of canopy tree species originated from root or stem sprouts. Light-demanding species tended to regenerate more from seeds and root sprouts than from stumps. Seedling densities were higher in microsites opened by logging, while root and stem sprouts were equally common across microsites. Given their abundance and the fact that root and stem sprouts at least initially grew faster than true seedlings, we conclude that vegetative regeneration in this tropical dry forest is an important mode of post-logging regeneration especially for species that regenerate poorly from seed. Resprout management should be considered as a potentially effective strategy for the procurement of regeneration following logging, especially for species that do not readily recruit from seed.     

Vegetation response to strip cutting young hardwood stands in West Virginia

Three 21-year-old Appalachian hardwood stands were strip cut using three cutting widths (2.4-m, 3.7-m, and 4.9-m) and allowed to resprout. One year after strip cutting, we examined the vegetation response within the harvested strips relative to non-treated control areas, focusing on the sprouting ability of young hardwood stems and the herbaceous component for wildlife habitat. Results indicate the width of the strip cutting significantly affected the amount of biomass produced from stump sprouts (p = 0.042) and influenced species composition. Shade-intolerant species accounted for more of the biomass production within the wider cut strip widths, while shade-tolerant and shade-intermediate species were more prominent within the narrower cut strips. Cut strip width did not have a significant effect on the biomass of new seedlings germinating after the cuttings. Herbaceous vegetation was greater within the 4.9-m cut strips than in the control plots (p = 0.046); however, the amount of herbaceous biomass produced did not vary among months during the first growing season. Overall, our initial results suggest that strip cutting can provide benefits to wildlife and can possibly provide for additional biomass as the regrowth is harvested in the future.     

Cherrybark oak stump sprout survival and development five years following plantation thinning in the lower Mississippi alluvial valley,USA

Cherrybark oak (Quercus pagoda Raf.) stump sprouts were studied for 5 years in a 30-year-old plantation thinned to 70–75% stocking (light thinning) and 45–50% stocking (heavy thinning). Sprouting success, survival, number of sprouts per stump, and sprout height differed little between thinning treatments throughout the 5-year study period. Pre-harvest tree d.b.h. also had no influence on sprout survival and development. A 2-year drought reduced survival and may have influenced sprout development. Sprout clump survival dropped from 90% 1 year following thinning to 46% 3 years after thinning. Although sprout height averaged 337 cm 5 years after thinning, annual sprout growth decreased from 166 cm the first year after thinning to 33 cm in each of the last 2 growing seasons. Results indicated that bottomland hardwood regeneration evaluation models may underestimate the potential of oak stump sprouts to contribute to pre-harvest regeneration assessments. Further study in the role of stump sprouts to regenerate bottomland oak species is needed. The U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged     

林龄、采伐方式对大叶相思萌芽更新的影响*

在海南省琼海县进行了不同林龄、不同采伐方式对大叶相思萌芽更新影响的研究，同时比较了保留不同萌条数量的萌芽林生长表现。结果表明：（１）林龄对伐桩萌芽率没有显著影响，但对伐桩存活率及萌条的径、高生长影响显著或极显著。林龄越大，萌芽更新效果越差；（２）皆伐和隔行采伐对大叶相思伐桩的萌芽率、萌条数量和存活率均无显著影响，但对萌条的径、高生长影响极显著。试验证明对大叶相思林分施以隔行采伐通过萌芽更新建立复层     

Stand age and habitat influences on salamanders in Appalachian cove hardwood forests

We surveyed cove hardwood stands aged 15, 25, 50, and ≥85 years following clearcutting in the southern Appalachian Mountains of northern Georgia to assess the effects of stand age and stand habitat characteristics on salamander communities using drift-fence array and pitfall methodologies from May 1994 to April 1995. Over a 60,060 pitfall trapnight effort, we collected 3937 salamanders represented by Desmognathus aeneus, Desmognathus monticola, Desmognathus ocoee, Desmognathus quadramaculatus, Eurycea bislineata, Gyrinophilus porphyriticus, Pseudotriton ruber, Plethodon glutinosus, Plethodon serratus, and Notophthalmus viridescens. Analysis of covariance with pitfall array to stream distance as the covariate showed that salamander species richness and diversity measures and numbers of Desmognathus aeneus and Desmognathus ocoee were highest in stands ≥85 years. Eurycea bislineata and Plethodon glutinosus were more abundant in stands ≤50 years old than in stands ≥85 years. Within cove hardwood stands, species richness and diversity measures and relative abundances of Desmognathus spp. and Gyrinophilus porphyriticus were negatively correlated with distance to stream. Species richness and diversity were positively correlated to amounts of emergent rock. Species richness, diversity and relative abundances of Desmognathus spp. were correlated with basal area within stands and extent of connected mesic, cove hardwood habitat and amount of cove habitat within 1 km radius among stands. Eurycea bislineata was negatively correlated with landform index, a measure of surrounding landform sheltering, and Plethodon glutinosus was positively correlated with elevation in cove hardwood stands. Our research indicates stand age is an important factor in explaining the abundance and community composition of salamanders in southern Appalachian cove hardwood communities. Because southern Appalachian woodland salamander communities are slow to recover and are substantially changed following disturbances such as clearcutting, populations in small, isolated cove hardwood stands might be more vulnerable to extirpation or may require longer recovery times than those in larger coves. Managers may need to assess habitat features such as cove extent and habitat connectivity to minimize impacts on these taxa by forest management activities in southern Appalachian cove hardwood communities.     

Comparative mast seed production in unmanaged and shelterwood white pine (Pinus strobus L.) stands in central Ontario

The effect of the seed cut of the uniform shelterwood silvicultural system on white pine seed production, seed characteristics, and seed viability during 2 mast seeding events was examined in operationally harvested second growth, white pine-dominated forest stands in central Ontario. Seed traps placed along transects in unmanaged and shelterwood stands in each of 3 blocks were used to monitor seed production in 2000 and 2006 (4 and 10 years after harvesting). During these 2 mast seed years between 386,000 and 2,730,600 seed ha^?1 were produced among study stands. Total seed production expressed on a per hectare and unit pine basal area basis did not differ by harvest treatment or among blocks in either year. Variability in seed production among stands was primarily due to differences in stand structure, with seed production positively related to white pine basal area. Seed characteristics were largely similar between harvested and unmanaged stands and between seed years. Seed viability was relatively high in both years, with seed from shelterwoods germinating slightly slower than those from unmanaged stands. Seed quality, as estimated by laboratory germination performance, was higher in 2006 than 2000, likely due to improved seed development and maturation in the warmer, wetter growing season of 2006. Our results suggest that the seed cut of the uniform shelterwood system applied to second growth white pine stands is unlikely to adversely affect white pine seed production, seed quality, or potential for natural regeneration during mast seeding events.