Pine-hardwood Stands Research Articles

Profiling overstory survival trends following varying thinning and burning disturbance regimes in a mixed pine-hardwood forest in the US South

Prescribed burning as a silvicultural tool may be effective for achieving various management objectives, yet some practitioners have concerns about inadvertently increasing overstory tree mortality. Using extensive data from a long-term, ongoing study in northcentral Alabama, USA, that systematically applies a variety of thinning and prescribed burning disturbances on mixed pine-hardwood stands, we assess survival trends for different groups of trees. The primary research question is whether more frequent prescribed burns adversely affects overstory survival versus infrequent or no burns; secondary questions explore whether overstory survival trends differ based on thinning level, species group, or size class. Interest is in broad groups of trees, not individual tree survival or mortality; consequently, survival analysis methods are used, including nonparametric Kaplan-Meier (KM) techniques for examining single grouping factors, and parametric accelerated failure time models for analyzing simultaneous effects of multiple covariates. Leveraging relatively recent methodological advances, the statistical techniques are adjusted for interval censored data. KM survival curves showed that more frequent prescribed fires did not result in differing survival trends. Also, trees in unthinned stands had the lowest 14-year survival compared to thinned stands, oaks had the highest survival compared to pines and the others species group, and the smallest size class of overstory trees had the lowest survival. These results support managing transitional mixed pine-hardwoods using thinning and multiple prescribed fires to restore specific species composition and structure.

Annual Fire Return Interval Influences Nutritional Carrying Capacity of White-Tailed Deer in Pine–Hardwood Forests

AbstractPrescribed fire is a cost-effective habitat management tool in pine stands to enhance the quantity and quality of forage available for white-tailed deer (Odocoileus virginianus). Management recommendations typically suggest a 3- to 5-year burn rotation in mixed pine–hardwood stands to increase quality forage production, but as fire frequency increases, forb and legume biomass increases, and woody browse decreases. A more frequent burn rotation may be a viable management option for deer managers, but there is still a lack of information regarding preferred forage and nutritional carrying capacity response to prescribed fire at these intervals. We measured the production and nutritional quality of forage within mature pine–hardwood stands after a 1- or 2-year fire-return interval during three nutritionally stressful periods for deer on a 640-acre (259-hectare) enclosure located in east-central Alabama during 2014 and 2015. These stands had previously been burned annually for over 15 years, resulting in an abundance of herbaceous vegetation. We then compared forage class biomass, nutritional carrying capacity estimates, and digestible protein between burn treatments. A 1-year fire return interval improved habitat quality to a greater degree than a 2-year fire return interval by increasing the production of forage able to support greater nutritional planes. An annual burn rotation is an effective option for managers to increase protein availability in pine–hardwood stands, but other factors such as decreased cover availability and soft mast production should also be considered.

Spatial ecology and multi-scale habitat selection of the Copperhead (Agkistrodon contortrix) in a managed forest landscape

We evaluated the spatial ecology and habitat use of the Copperhead (Agkistrodon contortrix) in managed, pine-hardwood forests in the William B. Bankhead National Forest, Alabama. We used radiotelemetry to monitor 31 snakes (23 males, 8 females [5 gravid and 3 non-gravid females]) over a period of 3years (2006–2008). Snakes were tracked for one or more seasons in a series of 18 forest stands composed of 6 treatments (Control, Burn, Light Thin, Heavy Thin, Light Thin with Burn, and Heavy Thin with Burn) replicated three times. Home-range estimates for male snakes averaged 17.8±2.3 (based on Utilization Distributions [UD]) and 12.0±1.9ha (based on 100% Minimum Convex Polygons [MCP]), whereas home-range estimates for gravid female snakes averaged 7.1±1.8ha (based on UD) and 4.1±1.1ha (based on MCP) and were significantly different between both sexes for all home-range analyses. We did not detect an effect of forest management on home-range size of male snakes. Macrohabitat use differed among male and gravid female snakes, where male snakes used edge (field and secondary road edges) and Southern Pine Beetle macrohabitats in significantly greater proportion than what was available. Gravid female snakes did not use macrohabitats differently than what was available, but tended to use thinned stands and forest stand canopy gaps for parturition sites. Microhabitat use patterns were similar between male and gravid female snakes, where both sexes tended to use microhabitat sites with relatively greater litter depth and coarse woody debris percent cover compared to random microhabitat sites. Microhabitat use patterns for male snakes tended to differ based on forest management treatment (Thin and Thin with Burn versus Control and Burn stands), where selected microhabitat sites had lower ambient and soil temperatures compared to random sites in thinned stands. Collectively, we illustrated that male A. contortrix displayed hierarchical habitat use, whereas female A. contortrix displayed preference for habitat features at the microhabitat scale only. Overall, our short-term study provides evidence that recently-thinned pine-hardwood stands are not initially used at a frequency greater than their availability, which suggests that microhabitat and microclimate conditions likely limit use immediately following management.

Clarifying Details on a 1930s-Era Pine—Hardwood Stand in Arkansas

Abstract Data from recently discovered daily-work logs of US Forest Service (USFS) researcher Russell R. Reynolds enabled me to clarify a study I published a decade ago on a 1930s-vintage unmanaged, second-growth Pinus (pine)—hardwood stand in southeastern Arkansas. Though still too vague to reveal every detail, Reynolds' work logs confirmed a number of assumptions in the original paper and provided me with the background information to herein describe a more precise sampling framework for this 1930s-era study plot.

Composition, Biomass, and Overstory Spatial Patterns in a Mature Pine-Hardwood Stand in Southeastern Arkansas

A 1.21-ha plot was established in a mature pine–hardwood forest (Hyatt's Woods) along a low stream terrace in southeastern Arkansas. Compositionally, this stand had considerable arboreal richness, with 26 different tree species ≥9 cm in diameter. Loblolly pine (Pinus taeda) contributed 42% of the stand's 37.1 m2/ha of basal area; the remaining fraction included baldcypress (Taxodium distichum) and 24 hardwood species (no other single taxon exceeded 12%). Only a limited volume (15.2 m3/ha) of dead wood was encountered. The large size of the dominant conifers and abundance of high wood density hardwoods at Hyatt's Woods yielded a considerable quantity of biomass—at 317 Mg/ha, few stands in the region have more. With all species combined, tree stem location exhibited a random spatial pattern, but this changed when individual species were considered. For example, loblolly pine tended to be clustered on the higher portions of this relatively flat site, while white oak (Quercus alba) was well distributed across Hyatt's Woods, and baldcypress was associated with two abandoned stream channels. Unmanaged streamside forests in southeastern Arkansas usually contain high levels of arboreal diversity and biomass, and sometimes possess biological legacies that can date back centuries. These stands retain important structural and ecosystem service components in an otherwise increasingly fragmented and intensively managed landscape.

Developing contemporary and historical live tree biomass estimates for old pine-hardwood stands of the Midsouth, USA

Calculating stand biomass potential is an increasingly important aspect of silviculture, particularly when attempting to restore forest ecosystems or determining additionality in sequestered carbon. However, the lumbering of the original forests of the Midsouth region of the United States of America, coupled with the accelerating conversion of unmanaged natural-origin stands to loblolly pine (Pinus taeda L.) plantations, make quantifying historic biomass difficult. If carefully done, it is possible to estimate presettlement biomass from past references and modern-day old pine-hardwood remnants. Pine sawtimber-only volume estimates from old reports indicated low biomass in the virgin pine-dominated forests of the Midsouth, from as little as 10–14Mg/ha up to 72Mg/ha. Given the incompleteness of these lumber yield-only data, a set of more detailed stand table-based historic descriptions were then coupled in this study with modern allometric equations to produce more complete estimates of biomass. These suggested that presettlement pine-hardwood stands of this region averaged ∼112Mg/ha in total (above- and below-ground) live tree biomass (range=54–171Mg/ha; n=6 stands). Contemporary old forests are considerably better stocked, with an estimated 224–318Mg/ha (n=6 stands). Individual loblolly pines from the historic period reached 183cm in diameter and may have had as much as 32Mg of biomass, though specimens <6Mg were considerably more common. Large individual tree values but low stand levels imply disturbance (especially fire) regulated total tree biomass in historic forests of the Midsouth. These results further indicate that extensive restoration of modern unmanaged forests to past stand structures will likely decrease regional biomass.

Tree Mortality in Mixed Pine–Hardwood Stands Defoliated by the European Gypsy Moth (Lymantria dispar L.)

Abstract Defoliation by the European gypsy moth (Lymantria dispar L.) and subsequent tree mortality have been well documented in the northeastern United States. In this study we evaluate tree mortality after initial defoliation in mixed pine–hardwood stands in the southeastern United States as the range of European gypsy moth expands. In 1993, 46 mature pine–oak and pine–sweetgum stands were selected on the coastal plain in Maryland and Virginia along the advancing gypsy moth front. Initial stand conditions, defoliation, and tree mortality after a single defoliation outbreak were monitored for 4 years. Susceptible oaks and sweetgum were defoliated at the greatest intensities. After defoliation, mortality in attacked stands was 4.4 m2/ha higher in pine–oak stands and 1.7 m2/ha higher in pine–sweetgum stands, representing 13 and 3% of the total basal area, respectively. Mortality of pines was observed mainly among suppressed and intermediate trees. Logistic regressions were derived to correlate individual tree mortality to stand and tree factors associated with gypsy moth attack. On the basis of these models, susceptible understory species with degraded crowns in pine–oak stands were at the greatest risk of mortality. Dominant overstory pines in pine–hardwood stands appear to be at low risk.

Effect of Time and Barred Owl Playback on Winter Detection of Woodpeckers in East-Central Mississippi

Broadcast vocalizations have been used to augment winter point counts. We investigated the effects of time and Strix varia (Barred Owl) playback on woodpecker detection. Habitats were classified as upland pine, bottomland hard- wood, and mixed pine-hardwood stands. Ten unlimited-radius, silent point counts of 3-min and 10-min duration were conducted in each habitat type on alternating weeks. During alternate weeks, silent counts followed by Barred Owl playback and post- playback counts were conducted. Detection was significantly greater during 10-min silent counts than during 3-min silent counts. We detected more woodpeckers after Barred Owl playback than during 3-min silent counts prior to playback. Species diversity was highest in mixed pine-hardwood stands, although abundance was lower than in hardwood stands. Mixed stands may not be able to support high woodpecker densities as well as bottomland hardwood forests.

Comparison of Sandhills and Mixed Pine-hardwood Communities at Fort Benning, Georgia

Abstract Fall Line sandhills vegetation occurs on dry, sandy ridgetops and supports a suite of rare or uncommon plant species (TES). We surveyed nine sandhills sites and 32 “matrix” mixed pine-hardwood stands at Fort Benning to characterize canopy and groundlayer vegetation patterns and determine the extent of sandhills vegetation, including characteristic dominant species and TES, over the upland landscape. The relative abundance of Pinus palustris (longleaf pine), P. taeda (loblolly pine), and P. echinata (shortleaf pine) and sandhills oaks contributed to canopy composition differences among sites. The sandhills communities support a unique set of groundlayer species, including state-listed Chrysoma pauciflosculosa. Although there is some species overlap, especially in overstory composition, characteristic sandhills vegetation is not widely distributed in mixed pine-hardwood stands at Fort Benning and conservation might best be achieved by maintaining existing sites.

Soil chemistry and nutrient regimes following 17–21 years of shortleaf pine-bluestem restoration in the Ouachita Mountains of Arkansas

Harvesting and repeated burning are frequently used to restore shortleaf pine-bluestem ecosystems within the Ouachita Mountains of Oklahoma and Arkansas, USA. These practices have been shown to adequately restore much of the habitat for bird and mammal species that utilize this ecosystem. However, there have been only limited studies to quantify the impact of restoration activities on soil chemistry and nutrient availability in this region. We compared soil chemistry and foliar nutrient concentrations for a 3-year period in three shortleaf pine-hardwood stands that had restoration activities for at least 17 years with soil chemistry and foliar nutrient concentrations in three stands that have had no restoration activities. Mineralizable N, total N, C, Ca, and pH of the surface soil were higher in the restored stands than in the stands without restoration activities. The magnitude of the increases in nutrient concentrations and pH appeared to reflect the combined impacts of harvesting and prescribed burning in the restored stands. Foliar concentrations of N, P, K, and Ca were significantly higher in the restored stands for at least 1 year following the most recent prescribed fire. However, only K concentrations were greater in the restored stands during the entire 3 year study. An increase in nutrient availability within the restored stands suggests that surface soil fertility and productivity may have increased with shortleaf pine-bluestem restoration activities.

Composition and Structure of a 1930s-Era Pine-Hardwood Stand in Arkansas

This paper describes an unmanaged 1930s-era pine-hardwood stand on a minor stream terrace in Ashley County, AR. Probably inventoried as a part of an early growth and yield study, the sample plot was approximately 3.2 ha in size and contained at least 21 tree species. Loblolly pine comprised 39.1% of all stems, followed by willow oak (12.7%), winged elm (9.6%), sweetgum (7.8%), water oak (6.7%), white oak (6.2%), red oak (4.9%), and hickory (4.6%). Pine, sweetgum, and oak dominated the midcanopy and overstory, with few late successional species. Stand basal area averaged 32 m2/ha, with 409 live trees/ha. The dominance of shade intolerant species, the lack of very big trees, and a scarcity of snags suggested that this stand was second-growth and likely arose from a disturbance in the mid-19th Century. Because this forest was sampled in the 1930s, its composition and structure should better reflect mature presettlement pine-hardwoods on minor stream terrace sites than modern examples.

Initial Effects of Reproduction Cutting Treatments on Residual Hard Mast Production in the Ouachita Mountains

Abstract We compared indices of total hard mast production (oak and hickory combined) in 20, second-growth, pine-hardwood stands under five treatments to determine the effects of different reproduction treatments on mast production in the Ouachita Mountains. We evaluated mast production in mature unharvested controls and stands under four reproduction cutting methods (single-tree selection, group selection, shelterwood, and clearcut with wildlife tree retention) during the first 6 yr after initial harvest. Mean Whitehead mast production indices were greater in shelterwoods and clearcuts with wildlife tree retention than in unharvested stands 5 of the 6 yr of study, indicating individual trees in these stands produced greater amounts of hard mast. Stand production values for the 6 yr combined indicated group selections generally produced the greatest amounts of total hard mast, probably because competing pines in the matrix were thinned and hard mast-producing tree densities were unchanged after harvest. However, wide variation in residual density of mast trees existed among stands of the same treatment. Our results indicate hard mast production can be affected by different silvicultural treatments and managers should consider the importance of residual mast production along with other objectives when determining silvicultural treatments to apply. South. J. Appl. For. 27(4):253–258.

Understory development in canopy gaps of pine and pine-hardwood forests of the upper Coastal Plain of Virginia

Canopygaps are important in establishing a pool of natural regeneration in manytemperate forest ecosystems. Information on the role of gaps in loblolly pine(Pinus taeda L.) and pine-hardwood foreststands in the southeastern Coastal Plain of the United States is lacking.Accordingly, 12 small canopy gaps in mature pine and pine-hardwood standsin Petersburg National Battlefield, Virginia, were studied. Loblolly pineregeneration was significantly more abundant in canopy gaps as compared to theadjacent forest in both forest cover types. In four stands dominated by loblollypine, there were 750 saplings/ha in the gaps compared to only 125saplings/ha in the adjacent forest. Pine saplings dominated the regenerationspectrum in the gaps in the pine stands, while red maple (Acerrubrum L.) was more important in the adjacent forest. In fourpine-hardwood stands, regeneration in both the gaps and adjacent forestwas dominated by sweetgum (Liquidambar styracifluaL.) with importance values of 27% and 28%, respectively.There were no loblolly pine seedlings in the adjacent forest, but an average 313per ha in the gaps of the pine-hardwood stands. Within thegaps in both cover types, loblolly pine saplings were lower in stature thancompeting hardwood stems, leading to the conclusion that the gaps may form atemporary pool of pine regeneration. Without further stand disturbance, theprocess of gap closure may reduce the pine component to a secondary status, orperhaps eliminate it altogether.

Impacts of intensive forestry on early rotation trends in site carbon pools in the southeastern US

The effects of different silvicultural practices on site, especially soil, carbon (C) pools are still poorly known. We studied changes in site C pools during the first 5 years following harvesting and conversion of two extensively managed pine-hardwood stands to intensively managed loblolly pine plantations. One study site was located on the lower Atlantic Coastal Plain in North Carolina (NC) and another on the Gulf Coastal Plain in Louisiana (La). Four different harvesting-disturbance regimes were applied: stem only harvest (SO), whole tree harvest (WT), whole tree harvest with forest floor removal (WTFF), and full amelioration, i.e. whole tree harvest, disking, bedding and fertilization (FA; only in NC). Each harvesting-disturbance regime plot was split and one-half received annual herbicide treatments while the other half received no herbicide treatments. In NC, soil C decreased slightly with WT, and increased with FA, otherwise no significant changes were detected. In La, there was a consistent decrease in soil C content from the pre-harvest value in all cases where herbicides were applied. All treatments caused a reduction in the forest floor C pool in NC. In La, the most intensive treatments also resulted in a decrease in the forest floor C, but to a smaller extent. In contrast, there was no net change in forest floor C with the SO and WT treatments, even though significant amounts of logging slash were added to the forest floor at harvest in the SO plots and not in the WT. Herbicide treatment clearly decreased the C pool of hardwoods and understory, and more than doubled that of planted pines. Carbon accumulation in the planted pines was similar for trees growing in the SO, WT, and WTFF treatments on both the LA and NC sites. The full amelioration treatment (only applied at the NC site) led to a significant increase in C sequestration by the planted pine component. Due to a large amount of voluntary pines, total 5-year pine C pool was highest on the non-herbicided intensive management plots on the NC site, however. The differing response patterns of soil and forest floor C pools between the two sites may be due to their differing drainage-summer rainfall regimes. Our results suggest that while poor drainage-wet summer conditions may be impeding carbon loss from the soil component it may be accelerating the rate of decomposition of the forest floor and slash on the soil surface.

Tree-roost Characteristics of Subadult and Female Adult Evening Bats (Nycticeius humeralis) in the Upper Coastal Plain of South Carolina

Abstract We radio-tracked 4 solitary subadult (2 male and 2 females) and 3 adult female evening bats (Nycticeius humeralis) to 7 and 14 roost trees, respectively, during the summer of 1997 on the Upper Coastal Plain of South Carolina. Roosts for both age-classes were located in cavities and under exfoliating bark in live trees and dead snags. Based on nightly exit counts, adult female evening bats roosted communally. Some roosts were presumed to be active maternity colonies. Five of six subadult roosts and one adult female roost were located under exfoliating bark on dead snags in beaver (Castor canadensis) ponds. Thirteen of 14 adult female evening bat roosts were located in cavities in live longleaf pines (Pinus palustris) in stands of relatively mature, park-like, pine plantations. One subadult roost was located under exfoliating bark in a live longleaf pine. No evening bats roosted in the more densely canopied, nearby bottomland hardwood stands, mixed pine-hardwood stands or loblolly pine (P. taeda) s...

Characteristics of Roost Sites of Adult Wild Turkey Females

Little research has examined roost-site selection processes by eastern wild turkeys (Meleagris gallopavo silvestris). Additionally, few studies have quantified selection of roost sites relative to availability of habitats within the home range and female movements prior to roosting. Hence, we examined selection of roost sites relative to availability of habitats within the home range and assessed the relationship between selected landscape metrics and location of roost sites. We obtained 638 triangulated roost locations on 34 adult female wild turkeys during 1996-97 on a study area composed of different landowners in central Mississippi. Roosting habitat use differed (P < 0.01) from availability within home ranges, with females preferring to roost in sawtimber pine (Pious spp.) and pine-hardwood stands. Distance to nearest creek and stand age frequently differed (P < 0.05) between roost and random sites. Roost sites were closer to creeks and in older aged stands than random sites. Females did not appear to increase movements prior to roosting, suggesting that roosting may influence female movements throughout the day, allowing females to be at preferred roosting sites at dusk. Alternatively, females may simply roost in the nearest suitable habitat at the end of the day. We suggest managers and biologists consider importance of stand age and landscape metrics to roost site selection when managing for eastern wild turkeys.

Three Methods for Low-cost Regeneration of Pine—Hardwood Stands in the Gulf Coastal Plain

Abstract Seedtree, clearcut-and-plant, and fell-burn-and-plant methods were applied to three mature, mixed loblolly pine (Pinus taeda L.)-upland hardwood stands at the Dixon Forestry Education Center in southern Alabama. One to two years after treatment, all methods resulted in adequate stocking (&gt; 100 trees/ac) of loblolly pine, laurel oak (Quercus hemisphaerica Batr. Ex Wild.) and other oak species. Clearcut-and-plant resulted in more laurel oaks than loblolly pines while fell-burn-and-plant had the opposite effect. Relatively high densities of both species occurred in the seed tree. In the first two years after harvest, fell-burn-and-plant had the lowest litter cover. All treatments had greater rates of surface soil movement than untreated controls. Six-to-seven years after methods were applied, loblolly pine and laurel oak maintained their dominance in all treatments, although loblolly pine had greater mean height and a greater proportion of stems in larger size classes. Density of oaks more than 4.5 feet tall 6 to 7 yr after harvest were predictable from pre-harvest surveys of total oak density. If adequate densities of pine seed and advance oak regeneration are in place at time of harvest, any of these low cost methods can provide successful regeneration of mixed pine-oak stands on Coastal Plain uplands. South. J. Appl. For. 24(1):37-44.

Regional frequencies of tree species associated with anthropogenic disturbances in three forest types

We used a probability-based sampling scheme to survey the forested lands of Georgia and Alabama, two adjacent states in southeastern USA. Using a nationally consistent plot design and field methods, we evaluated the presence/absence of tree species at 123 1/15 ha plots for individuals having a diameter at breast height >2.5 cm. Three forest cover types were considered: loblolly-shortleaf pine, oak-hickory, and oak-pine. Visually evident anthropogenic disturbances (e.g. artificial regeneration, logging, and prescribed burning), if any, were recorded on each plot. We classified plots with visually evident anthropogenic disturbance as `disturbed'. The remaining plots were classified as `undisturbed'. For each of the three forest types considered, mean species richness of trees was significantly greater in undisturbed plots. Of 61 species forest type combinations, eight (13.1%) had significantly different frequencies in undisturbed than in disturbed areas. In the loblolly-shortleaf pine type, five of the 18 species (27.8%) considered occurred significantly more frequently on undisturbed plots. In the oak-hickory type, two of the 21 species considered (9.5%) occurred more frequently on undisturbed plots and one species, loblolly pine, occurred more frequently on disturbed plots. Species occurring more frequently on undisturbed areas in these forest types included occupants of both the mid and upper canopy. Loblolly pine is not a common associate in the undisturbed oak-hickory forest. These results and those from other studies strongly suggest that anthropogenic disturbance, particularly clearcutting and subsequent planting of pine plantations, is having profound effect on the structure and composition of the forested area of the region. Because the three forest cover types we considered account for approximately 71% of the total forested area of the region, these results should be useful for forest management and conservation planning in the states. Management implications of mixed pine-hardwood stands vs. pine plantations in the south-east are discussed.

Habitat Use of Eastern Wild Turkeys in Central Mississippi

Most past studies of wild turkey (Meleagris gallopavo) habitat use were limited to 1 spatial scale. were of short duration, and had not simultaneously examined habitat use by both sexes. We used compositional analysis to describe habitat use of an castern wild turkey (M. g silvestris) population in central Mississippi at 3 spatial scales (study area, home range, within home range). We conducted the study on the 14,410-ha Tallahala Wildlife Management Area (TWMA), which was composed of hardwood, pine, and pine-hardwood stands of various ages. Overall, turkevs of both sexes preferred pine and hardwood sawtimber most, and poletimber stands least Throughout the vear, females primarily used hardwood sawtimber stands, but males tended to use pine sawtimber. Habital use by females during preincubation may have influenced subsequent nest success. Habitat use at 3 spatial scales was similar and was reflective of the adaptable nature of wild turkeys and the high degree of habitat heterogencity on the study area.

Four Site-Preparation Techniques for Regenerating Pine-Hardwood Mixtures in the Piedmont

Abstract Four variations of the fell-and-burn technique, a system developed to produce mixed pine-hardwood stands in the Southern Appalachian Mountains, were compared in the Piedmont region. All variations of this technique successfully improved the commercial value of low-quality hardwood stands by introducing a pine component. After six growing seasons, loblolly pine (Pinus taeda L.) occupied the dominant crown position and oaks the codominant position in fell-and-burn treated stands on poor to medium quality sites. The precise timing of felling residual stems, as prescribed by the fell-and-burn technique, may be flexible because winter and spring felling produced similar results. Although summer site preparation burns reduced hardwood height growth by reducing the length of the first growing season, they did not improve pine survival or growth. Pines were as tall as hardwoods within four growing seasons in burned plots and within six growing seasons in unburned plots. Additional research is needed to determine the level or intensity of site preparation needed to establish pine-hardwood mixtures over a range of site conditions. South. J. Appl. For. 21(3):116-122.