Patterns of seed removal of fire-sensitive tree species in floodplain and upland sites in the absence of fire

Restoring longleaf pine ( Pinus palustris Mill.) in loblolly pine ( Pinus taeda L.) stands: Effects of restoration treatments on natural loblolly pine regeneration

: Throughout the southeastern United States, upland sites that were once dominated by longleaf pine (Pinus palustris Mill.) have been widely converted to faster growing species such as loblolly pine (P. taeda L.). Consequently, existing populations of the federally endangered redcockaded woodpecker (RCW; Picoides borealis) are currently occupying mature loblolly pine stands. Reports of declining loblolly pine health in some locations raised concerns about the longevity of existing RCW habitat and underscored the need to convert upland forests back to longleaf pine. Forest managers needed protocols to restore longleaf pine on sites where canopy pines are retained. Further, because protocol suitability is likely to vary among site types based on productivity and the structure and composition of the canopy and ground layer vegetation protocol development on a range of site conditions was necessary. The need for such protocols were deemed critical at Fort Benning, Georgia, where as many as 70% of the active RCW cavities were found in loblolly pine trees. Because longleaf pine seedling growth tends to decrease as canopy cover increases, the conversion of loblolly pine stands to longleaf was expected to require a balance between canopy removal to increase the growth of planted longleaf pine seedlings and canopy retention for RCW habitat and other ecosystem services (e.g., fuel inputs from needlefall). Retaining the trees likely to live the longest would secure the most RCW habitat value through time; thus, a model for predicting tree longevity would be a valuable management tool. Additionally, an increased understanding of environmental factors associated with reduced loblolly pine health was needed to inform RCW management decisions at Fort Benning.

Economic viability of longleaf pine management in the Southeastern United States

Fusiform rust is the most devastating disease of slash pine (Pinus elliottii) and loblolly pine (Pinus taeda )i n the southeastern United States. Since the 1970s, the USDA Forest Service Forest Inventory and Analysis (FIA) Program has assessed fusiform rust incidence on its network of ground plots in 13 states across the southeastern United States. Through analysis of the FIA data, we found that current fusiform rust incidence varied by state, forest type, and stand origin and that across all stand ages, rust incidence was approximately equal in planted and natural stands of loblolly pine but was higher for planted versus natural stands of slash pine. Decreases in rust incidence over the last 30 – 40 years were evident in young planted loblolly pine stands but not in young planted slash pine stands. Results for slash pine were surprising, and the reasons remain unclear but one reason may be planting stock origin, which was unknown and may be highly variable in rust resistance. These analyses of FIA rust incidence data also were used to update the original rust disease hazard maps published by Starkey et al. (1997).

Southeastern U.S. longleaf pine savannas have been reduced to less than 5% of their original extent, giving space to fast‐growing, high‐density loblolly pine plantations. Restoring longleaf pine savannas is an alternative that has been discussed to reduce evapotranspiration and increase water yield, which is of great relevance in resource management and ecosystem restoration. Understanding the benefits of forest management and restoration requires advanced tools to better quantify the fundamental processes of energy, water, and carbon interactions at stand, landscape, and regional scales. We implement and assess the Community Land Model Version 5 (CLM5) at two long‐term research sites, one representing a typical loblolly pine ( Pinus taeda ) plantation with a high tree density and another a typical longleaf pine ( Pinus palustris ) savanna with a low tree density. We also carry out numerical experiments exploring potential differences in energy, water, and carbon balances under alternate land cover scenarios at each site. Using tailored parameterizations for loblolly and longleaf pine and an adjusted C4 grass parameterization, we found that CLM5 reasonably captured the overall observed stand structure and functions at both sites, performing substantially better than with the default parameterizations. Our numerical experiments indicated 8%–17% lower evapotranspiration and 30%–125% higher water yield for longleaf pine savanna compared to loblolly pine plantation. However, net ecosystem production (NEP) and NEP‐based water use efficiency were 60% lower for longleaf pine savanna than loblolly pine plantation. Our modeling framework could be implemented regionally in future studies to support forest management decisions and longleaf pine restoration initiatives.

A commitment to long-term forest research provides the basis and opportunity to understand developmental processes and stand dynamics over an entire rotation. The southeastern United States has undergone a significant evolution in forest management practices over the last 60 years, especially in regard to the intensification of pine plantation silviculture. However, few studies have examined production relationships for an entire rotation. This article reviews results from a rotation-length experiment that tested factorial combinations of understory competition control and sustained fertilizer additions on the productivity and stand dynamics of loblolly (Pinus taeda L.) and slash pine (Pinus elliottii var. elliottii) in north central Florida. After 25 years, fertilizer and competition control treatments increased site index (base age, 25 years) from 64 to 87 ft in loblolly pine and from 75 to 88 ft in slash pine. In addition, these cultural treatments increased total stand stem volume accumulation by 1.8–2.2-fold compared with the control treatments for slash and loblolly pine, respectively; the proportion of volume in high-value product classes such as chip-n-saw (C/S) and sawtimber was also increased in both species (e.g., 39% in C/S and sawtimber in the loblolly pine control treatment versus 74–87% in the fertilizer and/or weed control treatments). Overall, results from this study, as well as others in the region, highlight the overriding importance of soil nutrient supply on long-term productivity of southern pine stands.

The need for a comprehensive and mechanistic understanding of competition has never been more important as plants adapt to a changing environment and as forest management evolves to focus on maintaining and enhancing complexity. With the recent decline in shortleaf pine (Pinus echinata Mill.) land area, it is critical to determine the effects of competition on shortleaf pine and its performance against loblolly pine (Pinus taeda L.), the preferred planted replacement. We evaluate differences in shortleaf and loblolly pine 10 year mean basal area increment (BAI) and crown dimensions across a gradient of neighborhoods. Linear mixed-effects regression models were developed using BAI and several crown metrics as responses and crowding, competitor species abundance and identity, and initial size and species identity of focal tree as predictors. Crowding of focal trees negatively impacted BAI and crown size (p < 0.001, respectively). Although loblolly pine had three times higher BAI as compared to shortleaf pine within similar neighborhoods, BAI was variable, and the crowding effect did not differ between shortleaf and loblolly pine (p ranged from 0.51–0.99). Competitive impacts on focal trees did not differ by competitor identity (p ranged from 0.07–0.70). Distance-independent competition indices better explained the variation in BAI and horizontal crown metrics, while distance-dependent size ratios were more effective at evaluating vertical crown metrics. These findings highlight shortleaf pine competitive potential in mature, natural-origin stands and provide support for the restoration of pine–hardwood and hardwood–pine stratified mixtures as well as management of shortleaf pine at long rotations.

Forest ecosystems in the eastern United States are undergoing significant compositional and demographic shift. To understand these changes, we used Forest Inventory & Analysis data (2003 - 2021) to examine landscape-scale trends in the North Carolina Piedmont, focusing on forest type groups, taxonomic family, and species. We assessed metrics such as annual net primary productivity, relative density, and biodiversity, aiming to determine: i) Which forest group types are changing most, ii) Whether these changes extend to lower taxonomic units, and iii) How stability has shifted over time. Our findings reveal an increasing dominance of Pinus species, particularly naturally regenerated loblolly pine (Pinus taeda), accompanied by sweetgum (Liquidambar styraciflua). This shift corresponds to rising prevalence of pine and oak-pine forest type groups. Notably, while red maple (Acer rubrum) consistently had high seedling densities, its recruitment lagged behind species like sweetgum and yellow-poplar (Liriodendron tulipifera), defying broader regional trends. These results highlight a clear progression from species-level changes to broader taxonomic families and forest types, emphasizing a shift toward pine in the region. The study underscores the importance of multi-level analyses for capturing ecological trends and advancing understanding of forest dynamics in changing landscapes.

Glyphosate herbicide was applied to red maple, sweetgum, and loblolly pine seedlings at the end of the second growing season to evaluate the effects of application timing and water stress on glyphosate absorption, translocation, and efficacy. Although there was no difference in 14C-glyphosate absorption among species, sweetgum translocated significantly more herbicide to the roots and stem below the treated leaf than red maple and loblolly pine. These differences may explain, in part, the variability among species in susceptibility to glyphosate. Application timing and water stress had an interacting effect on red maple and loblolly pine efficacy. Increasing water stress resulted in decreased efficacy in August, but had no consistent effect in September and October, possibly due to physiological changes associated with the development of fall dormancy. Glyphosate was most phytotoxic to sweetgum, followed by loblolly pine and red maple, which corresponds to results observed in commercial pine release applications. For. Sci. 36(2):438-447.

Root feeding bark beetles in the genus Hylastes Hylastes breeding in loblolly pine across 3 crown (Coleoptera: Curculionidae: Scolytinae) commoncondition classes (healthy, dying, dead). Addition ly carry ophiostomatoid fungi (Ophistomatales: ally, the relationship between ophiostomatoid Ophistomataceae)and collectively contribute to species, their Hylastes species vectors, and tree root disorders of Pinus species around the world condition were investigated. (Jacobs & Wingfield 2001). One of the most damLoblolly pine stands across central Alabama aging root disorders is black-stain root disease have experienced high mortality rates, character of conifers in the Western United States, caused ized by scattered stand mortality with a distinct by the fungal species Leptographium wageneri lack of above-ground pests (Brown & McDowell Kendrick and its primary beetle vector H. nig1968). During an investigation of one stand in rinus (Mannerheim) (Witcosky et al. 1986). ReMay 2008 in central Alabama, dying trees were cently, Hylastes salebrosus Eichhoff and H. tenuis found to be infested with root-inhabiting beetles Eichhoff have been associated with loblolly pine and their associated ophiostomatoid fungi. Six (Pinus taeda L.) decline (Eckhardt et al. 2007), trees were selected based on crown condition, in which is considered an emerging forest health iseluding 2 with green, healthy crowns (healthy), sue in the southeastern United States (Eckhardt 2 with severely chlorotic and thinning crowns et al. 2010). (dying), and 2 with red crowns (dead). Two pri Loblolly pine decline (LPD) is a tree disease mary lateral roots were randomly selected and complex that is characterized by symptoms that excavated to approximately 3 meters from the include thinning tree crowns, growth reductions root collar. Roots were removed from trees and (Eckhardt et al. 2007) and premature mortality in carefully dissected. All insects, including imma localized areas (Brown and McDowell 1968). Eviture stages, were collected from roots and adult dence suggests the complex is the result of interbeetles were identified to species. Root tissue was acting abiotic (Eckhardt & Menard 2008) and biobtained from each brood gallery for the isolation otic (Eckhardt et al. 2007) stress factors. Hylastes of ophiostomatoid fungal species using methods species vector a variety of root-infecting ophiostodescribed in Eckhardt et al. (2007). Following matoid fungi (Klebzig et al. 1991, 1995; Eckhardt surface sterilization, tissue was placed on CSMA et al. 2007; Zanzot et al. 2010) which are patho(malt extract agar containing 800 mg/L of cyclo genic to loblolly pine (Matusick & Eckhardt 2010; heximide and 200 mg/1 of streptomycin sulfate) Matusick et al. 2011). Hylastes beetles and their selective nutrient agar (Jacobs & Wingfield 2001). associated fungi are thought to collectively contribEach adult insect was also rolled on CSMA to re ute to LPD by causing root damage through fungal cover ophiostomatoid fungi from insect bodies infection and insect feeding (Eckhardt et al. 2007). (Zanzot et al. 2010). Isolated ophiostomatoid fun Root and lower stem feeding beetle species (Colegal species were identified using morphological optera: Curculionidae) includingH. salebrosus and characters and established keys. Unknown iso H. tenuis are found in increased numbers within lates were sequenced and confirmed as new spe LPD-affected stands, compared to healthy stands cies by M. Wingfield (Forestry and Agricultural (Eckhardt et al. 2007, Menard 2007). A recent Biotechnology Institute, Pretoria, South Africa), study has found Hylastes to be the most common A total of 157 adult beetles (Coleoptera: Cur bark beetle genus observed in loblolly pine stands culionidae) were collected from roots, most from in central Alabama (Thompson 2011), illustrating dying trees (Table 1). A majority of the beetles col their dominance in this ecosystem. Despite their lected were Hylastes species, including a total of dominance and potential for damage in loblolly 113 H. salebrosus (all from dying trees) and 34 pine, the breeding behavior of Hylastes species in H. tenuis (31 from dying and 3 from dead trees), the southeastern United States is not well underIn addition, H. salebrosus larvae and pupae were stood. In the current study, observational methcollected from dying trees. Other adult insect spe ods were used to investigate the potential for cies collected include the black turpentine beetle

Loblolly pine outperforms slash pine in the southeastern United States – A long-term experimental comparison study

Post-fire resprouting of shortleaf pine is facilitated by a morphological trait but fire eliminates shortleaf × loblolly pine hybrid seedlings

Habitat associations of saproxylic beetles in the southeastern United States: A comparison of forest types, tree species and wood postures

Although the forests of the southeastern United States are among the most productive and diverse in North America, information needed to develop conservation guidelines for the saproxylic (i.e., dependent on dead wood) fauna endemic to the region is lacking. Particularly little is known about the habitat associations and requirements of saproxylic parasitoids even though these organisms may be even more vulnerable than their hosts. We sampled parasitoids emerging from dead wood taken from two forest types (an upland pine-dominated forest and a lowland hardwood-dominated forest), three tree species (Liquidambar styraciflua L., Pinus taeda L., and Quercus nigra L.) and two wood postures (standing dead trees (i.e., snags) and fallen logs) in South Carolina. Parasitoid abundance did not differ between forest types or among tree species, but did differ between wood postures, being higher in snags than logs. This difference may have been due to the logs being in contact with the ground or surrounding vegetation and therefore less accessible to parasitoids. Parasitoid abundance and density decreased with height on both snags and logs. Species richness did not differ between forest types, among tree species or between wood postures. According to analysis of similarities, parasitoid communities did not differ between forest types, but did differ among tree species. The wasp communities associated with the different tree species and posture combinations were distinct. In addition, communities associated with the upper boles and crowns of snags were distinct from those occurring lower on snags. These results emphasize the importance of maintaining tree diversity in managed forests as well as retaining or creating entire snags at the time of harvest.

Assessment of repeated application of poultry litter on phosphorus and nitrogen dynamics in loblolly pine: Implications for water quality