Native Hardwood Research Articles

Long-Term Suppression of Hardwood Regeneration by Chinese Privet (Ligustrum sinense)

Native hardwood regeneration in the southeast United States is hindered by repeat disturbance events and the presence of invasive species. Our study aimed to determine the ability of native species in an unmanaged urban forest fragment to persist following high winds from hurricane Gustav in 2008 and subsequent salvage logging. In 2009, researchers estimated the density and composition of the regeneration and overstory trees as well as percent crown cover of invasive Chinese privet. Percent Chinese privet cover was visibly high, leading them to believe it may be inhibiting native hardwood establishment. Ten years later in 2019, we returned to the plots to take repeat measurements. Forest composition remains the same and privet crown cover remains high. There has been no increase in regenerating individuals, and overstory trees per hectare and basal area remains low. These results confirm that the heavy Chinese privet presence is persistent long term and will require management to promote reproduction of native overstory tree species.

Surface Functionalization of Spruce‐Derived Cellulose Scaffold for Glycoprotein Separation

AbstractProtein immobilization on a stationary phase, such as nanocelluloses, is widely used in biodiagnostic, biocatalytic, and bioseparation applications. With the top‐down approach which utilizes the native hardwood honeycomb structure, mesoporous cellulose scaffolds can be fabricated without the need for energy‐consuming production and bottom‐up assembly of nanocelluloses. However, this approach is difficult for preparing softwood‐based cellulose scaffolds due to the disintegration of wood cells after complete delignification. Herein, for the first time the use of spruce softwood with a homogenous cellular structure of longitudinally positioned and top‐to‐bottom joined tracheids is explored as a scaffold for protein immobilization. 1,4‐butanediol diglycidyl ether is utilized to crosslink cell wall polysaccharides before the delignification step, thus improving the adhesion between tracheids. The native cellular structure of spruce is well preserved after the complete removal of lignin, enabling the successful production of a highly mesoporous and mechanically robust spruce‐derived cellulose scaffold with exceptionally high specific surface area (219 m2 g−1). Further amination of the cellulose scaffold allows covalent immobilization of functional biomolecules, such as a lectin protein concanavalin A (Con A) and biotin, on the lumen surfaces and inside the porous cell wall. The Con A immobilized scaffold demonstrates native glycoprotein‐binding activity and possible glycoprotein separation application.

Improving the hardness of Endospermum medullosum (Vanuatu whitewood)

ABSTRACT Having almost exhausted its native forest wood supply, Vanuatu has sought to rebuild by establishing forest plantations. Whitewood (Endopsermum medulosum) has been identified as a native hardwood suitable as a plantation species: it has good growth, is resistant to high winds and produces finegrained white timber. However, whitewood has low wood density and comparatively poor mechanical properties. In particular, the soft timber does not perform well where good hardness is required, such as in flooring. Several wood modification techniques were tested with the primary aim of improving whitewood hardness. The methods tested were selected as simple treatments with low environmental impact and which, consequently, may be implemented safely in Vanuatu. Of the treatments tested, impregnation with methyl methacrylate polymer provided the greatest increase in hardness. Values commensurate with use as flooring were obtained (about 6000 N) that were three times greater than untreated controls. With treatment using methyl methacrylate bulking, the hardness of whitewood can be improved, expanding utilisation opportunities to include markets for flooring timbers, domestically and internationally. This, in turn, will improve investment security in whitewood production and the living standards of small rural landholders.

Assessment of sound quality: Australian native hardwood species for guitar fretboard production

Rosewood species are used around the world in musical instrument component manufacture, most commonly for the use as the guitar fretboard. Due to the overuse of these species, rosewood has been declared an endangered wood necessitating alternatives to be sourced with similar desirable characteristics. Dynamic testing was performed on Australian high-density hardwood species with a density range of 480–943 kg/m3; the results were used for comparison with commercial Indian rosewood (IRW), used in guitar manufacturing for fretboard production. The anatomical features of the tested species were determined using microscopic imaging while dynamic testing was conducted using non-destructive, acoustic analysis. The anatomical features determined showed that certain Australian hardwood species have a strong correlation with the commercial species used for wooden instrument manufacture including frame board and soundboard production. The majority of species tested had solitary or multiple vessel type, vasicentric parenchyma and uniform ray types. The internal friction versus the specific dynamic modulus for the species tested were in a similar range of the IRW samples. The quality factor versus temporal damping of species tested showed potential similarities between the species IRW, with red siris (RSI), and red tea tree (RTT). From the study conducted, four species including: RTT, RSI, Queensland walnut (QLW) and Calophyllum (PTG) have been selected for further testing and fretboard prototyping; the selected species will be tested for quality of sound and strength in the manufactured prototypes.

Physical, mechanical, and decay resistance properties of heat-treated wood by Besson® process of three European hardwood species

Description of the subject. In Europe, the heat treatment of native wood species is gradually becoming an industrial reality. It provides a promising alternative to both the use of naturally durable, essentially tropical woods and the use of chemical preservative treatments based on biocides. Objectives. The aim of this study is to quantify the effect of heat treatment on the physico-mechanical and decay resistance properties of three native hardwood species (oak, ash, beech + steamed beech). Method. The wood was heat-treated in accordance with the Besson® process. The standard physical and mechanical tests including hardness, modulus of elasticity in static bending, static bending, axial compression, splitting and impact bending strengths, have been performed on 15 treated and 15 control associated samples for each species. The standard durability test on fungi exposed 60 treated and 60 control samples to each fungus. Results. The results show a decrease in the equilibrium moisture content and an increase in dimensional stability of heat-treated wood for the three species studied. The modulus of elasticity, hardness and axial compression strength increase slightly after the heat treatment, while static and impact bending strength and splitting strength may considerably decrease. The fungal durability of oak heartwood and ash increased until class 1, beech and steamed beech until class 3. Conclusions. The global approach of this study allows a complete and precise characterization of the technological properties of three native hardwood species after heat treatment. New uses of these native species can thus be explored.

Caracterização da madeira de Hovenia dulcis para a fabricação de pisos

Este trabalho teve como objetivo caracterizar a madeira de Hovenia dulcis Thunberg, visando sua utilização na fabricação de pisos. Para a caracterização tecnológica, foram utilizadas cinco árvores obtidas em Floresta Ombrófila Mista. As toras foram mensuradas, para a determinação do seu volume. Posteriormente, foi realizado o desdobro das mesmas em tábuas e blocos, para a determinação da massa específica básica, dureza Janka (tora da base) e ensaios de simulação de piso em serviço (toras do meio e topo). As tábuas e os blocos foram secos, para posterior preparação dos corpos de prova. Esses foram confeccionados separando-se a madeira constituída com 100% de cerne daquela que apresentava cerne e alburno. A madeira de H. dulcis caracterizou-se como de média massa específica (0,54 g cm-³), com média resistência (5.851,99 N). Em todos os testes de simulação de piso em serviço, a madeira de H. dulcis proporcionou resistência superior ou semelhante a outras espécies exóticas e inferior a espécies folhosas nativas encontradas na literatura. Concluiu-se que a madeira em estudo apresenta baixa resistência para esforços máximos, podendo ser utilizada em pisos para trânsito leve ou em locais em que as cargas são baixas.

Determining acoustic and mechanical properties of Australian native hardwood species for guitar fretboard production

Australian hardwood species have potential in musical instrumentation replacing hardwood species such as Dalbergia latifolia (Indian rosewood- IRW) which is the main species used in guitar fretboard production. In this study, a detailed characterisation was conducted using dynamic and static testing to determine samples’ mechanical strength. Dynamic testing was conducted using non-destructive acoustic testing to record the sound velocity travelling through boards in the longitudinal grain direction. The elastic modulus for the tested samples was also calculated using the dynamic results. Four point bending tests were conducted in accordance with AS/NZS 4063.1 to determine the bending strength (MOR) and stiffness (MOE) to be compared with the dynamic results. The Janka hardness for each of the species was determined for reference in accordance with the Australian testing method developed by J.J. Mack. Species tested had sound radiation characteristics values close to Indian rosewood (IRW) samples tested. The internal friction of Australian samples tested and IRW were low providing indication for future applications of these species to musical instrument manufacture. Sound quality factor and speed of sound determined for tested species were similar to IRW. Mechanical strength and performance of the tested species displayed similar values to the IRW properties; indicating the potential of these species for long-term use in fretboard applications. The MOE and MOR values for Australian hardwood species were dependent on the density; the Queensland walnut (QWL), Kuranda Satin ash (KSA), Hickory ash (HKA) and Red mahogany (RMG) samples had highest mechanical strength values within the range of IRW including the Janka hardness, MOR and MOE values. The work presented here identified four Australian hardwood species with potential for fretboard production. These species will be tested for sound quality and performance prior to fretboard prototyping.

Reproduction and Control of the Invasive Polyphagous Shot Hole Borer, Euwallacea nr. fornicatus (Coleoptera: Curculionidae: Scolytinae), in Three Species of Hardwoods: Effective Sanitation Through Felling and Chipping.

The invasive ambrosia beetle polyphagous shot hole borer is one member of the cryptic species, Euwallacea nr. fornicatus (Eichhoff), and poses a great ecological and environmental threat to ornamental and native hardwood trees and agriculturally important tree crops in southern California, United States. We monitored the emergence of polyphagous shot hole borer adults from chipped and unchipped cut logs of infested boxelder, Acer negundo L. (Sapindales: Sapindaceae), California sycamore, Platanus racemosa Nutt. (Proteales: Platanaceae), coast live oak, Quercus agrifolia Née (Fagales: Fagaceae), and red willow, Salix laevigata Bebb (Malpighiales: Salicaceae), every week for 4 to 5 mo. No polyphagous shot hole borer adults emerged from chipped or unchipped coast live oak logs, suggesting this species is not a preferred reproductive host. However, following chipping, a small number of polyphagous shot hole borer adults emerged from boxelder (up to 7 wk) and from California sycamore and red willow (both up to 9 wk). A significantly greater number of polyphagous shot hole borer adults emerged from unchipped logs of boxelder (up to 14 wk) and California sycamore and red willow (both up to 5 mo). Chipping of boxelder, California sycamore, and red willow by using common commercially available chippers reduced polyphagous shot hole borer emergence by over 97%. Emerged polyphagous shot hole borer adults were strongly female-biased, regardless of host. Chipping treatments were highly effective, but for the complete elimination of polyphagous shot hole borer from woody material, other sanitation measures such as solarization in conjunction with chipping are recommended. Environmental and ecological impact of polyphagous shot hole borer is reviewed and discussed.

Thinning effects on forest evolution in Masson pine (Pinus massoniana Lamb.) conversion from pure plantations into mixed forests

Monocultural coniferous plantations have prevailed worldwide in recent decades, which supplied much of the world’s timber, but also exerted some negative effects on local ecologies and environmental systems. Continuous development has increased the various demands of human society for forests and it is necessary to balance concerns for the ecological and economic functions. Ample evidence indicates that mixed forests are an ideal option for providing more diversified ecological services and forest goods. Converting pure forests into mixed forests by introducing broad-leaved hardwood species below coniferous plantations has become an increasingly popular forest management strategy. Yet, there has been not enough research to date on suitable management methods for enhancing forest diversity and resilience in the context of forest conversion. To comprehensively examine how the intensity in Masson pine thinning influences forest evolution, seedlings of two native hardwood species were introduced below unthinned and thinned (varying intensity) Masson pine plantations. The effects of thinning on residual tree growth, seedling survival and growth, and understory vegetation development were analyzed using a generalized additive mixed model (GAMM). Monitoring results over 10 years indicate that thinning is a necessary management measure to accelerate forest succession in the conversion process; thinning exerts significant effects on the growth of residual trees, the survival and growth of seedlings, and the development of understory vegetation. Intense thinning results in more residual tree growth and enhances the richness and diversity of herbaceous species. However, excessive thinning can reduce the likelihood of seedling survival and growth as well as the richness and diversity of shrubs. Optimal thinning intensities appear to fall between 50% and 60% depending on the specific introduced species; light-demanding species may need higher overstory thinning intensity than shade-tolerant species. The biological characteristics of the introduced species must be taken into account to design an effective thinning strategy for pine plantations conversion.

Biobased Epoxy Thermoset Polymers from Depolymerized Native Hardwood Lignin.

Biobased epoxy thermoset polymers were prepared from lignin hydrogenolysis oils produced from native hardwood lignin. Native lignin in Eucalyptus nitens and Eucalyptus saligna wood was reacted in situ under Pd-catalyzed mild hydrogenolysis conditions to give depolymerized lignin oils in yields up to 98 wt %. Reacting these lignin oils with epichlorohydrin produced biobased epoxy resins. Blending these resins with nonrenewable bisphenol A diglycidyl ether (BADGE) in different proportions, and curing with diethylenetriamine, produced a series of epoxy thermoset polymers with varying biobased content. Up to 67% of the BADGE could be replaced with hardwood lignin-derived epoxy resins while achieving superior or equivalent mechanical properties to the BADGE control polymer. Comparing the performance of lignin-based epoxy polymers from eucalyptus and pine wood provided insights into the advantages and disadvantages of using hardwood versus softwood native lignins in the quest for high performance biobased thermoset polymers.

Ability to Glue Portuguese Eucalyptus Elements

Portuguese forests have changed in recent years. These changes were mainly boosted by the wildfires that affected a significant percentage of the softwood area. Eucalyptus is actually the dominant wood species in Portuguese forests. This is not a native hardwood, but is being planted mainly for pulp and paper production, and its availability and mechanical performance have made it very present in timber construction in the last 50 years. Within the discussion to substitute imported raw materials, mainly from softwoods, with local hardwoods for the production of engineered wood products, the study of the ability to glue eucalyptus has become a necessity. This paper presents experimental works aimed to assess the ability to glue eucalyptus elements for the production of glued laminated timber (GLT) and cross-laminated timber (CLT). Since this wood species has been known for being difficult to dry, a preliminary study on the dimensional stability under moisture content variation was performed. Then, shear strength tests were made in accordance with ASTM D143. The objective was to correlate those results with the tests performed in the following research step. In this further stage, shear strength tests of the bond line were performed following EN 14080 and EN 16351. The results obtained in all the experiments show that eucalyptus has the potential to be glued and therefore the production of GLT and/or CLT using this local undervalued wood species is potentially of high industrial interest.

Restoration of Shortleaf Pine (Pinus echinata)-Hardwood Mixtures in Low Quality Mixed Upland Hardwood Stands Using Cluster Planting and Natural Regeneration

Cluster planting of shortleaf pine, along with various site preparation and release treatments, were tested to restore mixed shortleaf pine (Pinus echinata Mill.)–hardwood stands in areas where the shortleaf pine has diminished in recent years. Shortleaf pine–hardwood mixtures were once a common forest type throughout the Cumberland Mountains and Plateau physiographic regions of the southeastern United States. Knowledge of how to restore shortleaf pine–hardwood mixtures is limited throughout shortleaf pine’s large native range. The objectives of this study were to compare planted shortleaf pine and natural hardwood regeneration survival, growth, and composition following various site preparation and early release treatments. Cluster planting and partial timber harvesting were used to reintroduce shortleaf pine and create two-aged stands in the Cumberland Mountains of Tennessee, USA. Results indicated that shortleaf pine survival, basal diameter, and height growth did not differ following four growing seasons among treatments. Natural regeneration stem densities and heights within shortleaf pine clusters did not differ significantly by treatment. Natural regeneration stem densities differed by species group and height class across the site, while the treatment × species interaction term was also significant. At this early stage of stand development, the brown-and-burn treatment appears poised for greater shortleaf pine growth rates than the other treatments. The herbicide treatment had the fewest regenerating hardwoods per hectare and the most desirable hardwood species composition.

Establishment and Early Development of Even-Age Shortleaf Pine–Hardwood Mixtures Using Artificially Regenerated Shortleaf Pine and Various Site Preparation and Release Treatments

Abstract Shortleaf pine (Pinus echinata)–hardwood mixtures were once a common forest type on upland sites throughout the southeastern United States. These forest types have declined throughout much of shortleaf pine’s native range. Information on restoring shortleaf pine–hardwood types when a shortleaf pine seed source is not present is lacking. The objectives of this study were to investigate the effects of four site-preparation and release treatments (control, burn, herbicide, and herbicide and burn) on the development of even-aged mixtures of planted shortleaf pine and natural hardwoods located on the Highland Rim physiographic province of Tennessee, USA. Three years after study establishment, statistical differences among treatments occurred for shortleaf pine survival and basal diameter. Survival was greatest in the herbicide-only treatment. Height and basal diameter growth were greatest in the herbicide and burn treatment. Stem densities were greater in treatments that did not include a herbicide release than those where herbicide was used alone or combined with prescribed burning. The herbicide and burn treatment had the greatest potential after 3 years for developing into a balanced, mixed shortleaf pine–hardwood stand, whereas most treatments had an influx of exotic, invasive species such as Chinese privet (Ligustrum sinense) and callery pear (Pyrus calleryana).

Urban tree specific gravity and ash content: A case study from Baltimore, Maryland USA

Interest in conducting urban tree inventories and quantifying the associated wood resource has accelerated at a pace faster than supporting research needs can be identified and accomplished. For example, it is common to apply allometric models and wood properties values developed from studies of rural forest-grown trees to urban trees, despite unknown degrees of inaccuracy that may exist. To examine potential differences in wood properties between trees grown in forest and urban settings, wood samples were collected from stumps of recently felled trees for nine native hardwood species in the city of Baltimore, MD USA. The samples were analyzed for basic specific gravity (SG) and ash content (AC). The results from urban trees were compared with published values from studies based on forest-grown trees. There was no general trend in the results for SG; however, urban Acer rubrum L., Fraxinus spp., and Quercus rubra L. appeared to have higher SG, with Quercus palustris Münchh. having lower SG, than their forested counterparts. Based on these results, the use of existing forest-based SG data may produce weight estimates of urban woody biomass that are 5–10% too low. Conversely, most of the species studied exhibited higher AC than their forested counterparts, although some results were mixed depending on the basis of comparison. Further work is needed on a wider range of species and geographic locations to refine the results and better support the analysis of urban tree inventories, which are increasingly used for carbon accounting and assessing feedstocks for biofuel use.

Structural Imaging of Native Cryo-Preserved Secondary Cell Walls Reveals the Presence of Macrofibrils and Their Formation Requires Normal Cellulose, Lignin and Xylan Biosynthesis

The woody secondary cell walls of plants are the largest repository of renewable carbon biopolymers on the planet. These walls are made principally from cellulose and hemicelluloses and are impregnated with lignin. Despite their importance as the main load bearing structure for plant growth, as well as their industrial importance as both a material and energy source, the precise arrangement of these constituents within the cell wall is not yet fully understood. We have adapted low temperature scanning electron microscopy (cryo-SEM) for imaging the nanoscale architecture of angiosperm and gymnosperm cell walls in their native hydrated state. Our work confirms that cell wall macrofibrils, cylindrical structures with a diameter exceeding 10 nm, are a common feature of the native hardwood and softwood samples. We have observed these same structures in Arabidopsis thaliana secondary cell walls, enabling macrofibrils to be compared between mutant lines that are perturbed in cellulose, hemicellulose, and lignin formation. Our analysis indicates that the macrofibrils in Arabidopsis cell walls are dependent upon the proper biosynthesis, or composed, of cellulose, xylan, and lignin. This study establishes that cryo-SEM is a useful additional approach for investigating the native nanoscale architecture and composition of hardwood and softwood secondary cell walls and demonstrates the applicability of Arabidopsis genetic resources to relate fibril structure with wall composition and biosynthesis.

An assessment of native forests in Queensland for the potential supply of small-diameter, peeler logs for spindleless lathe rotary-veneer processing

Spindleless lathes have shown great potential for the efficient conversion of small native forest logs in Australia. However, a major impediment to the further commercial adoption of this processing approach for native forest small-diameter logs is the absence of reliable and available data on the quantities of logs possibly available and suitable for this purpose. This study undertaken in hardwood and white cypress pine (Callitris glaucophylla) native forests and at sawmills in Queensland, Australia, demonstrated that there are potentially substantial quantities (up to 10.5 m3 per hectare of Crown native hardwood, 14 m3 per hectare of private forest hardwood and 75,000 m3 per year of Crown white cypress pine) logs suitable for spindleless lathe rotary veneer processing. However, access to and utilization of these logs will depend on many factors including accommodating Government policies and log supply agreements; potential alterations in the code of practice for native forest harvesting, silviculture, tree marking and sales practices; diversion of logs from other uses; and development of appropriate log specifications.

Behavior of Concrete-Filled Single and Double-Skin uPVC Tubular Columns Under Axial Compression Loads

Background:There is an increased demand for high-performance materials in the construction industry due to the high cost, the difficulty of sourcing and shortcomings of the existing construction materials. Some of the deficiencies are corrosion of steel, brittle failure and rapid deterioration of reinforced concrete structures in a harsh environment. Nowadays, there is also a move from one material to another due to the difficulty of sourcingi.e.timber electric poles to concrete poles due to the difficulty of sourcing native hardwood. These situations have triggered the interest to develop an alternative structural system.Objective:This paper presents the behavior of unconfined concrete, Concrete-Filled Single Skin uPVC Tubular (CFSUT) and concrete-filled double skin uPVC tubular (CFDUT) members under axial compression loads.Method:The unconfined concrete cylinders, CFSUT and CFDUT specimens were prepared from a concrete class of C25 and tested using a UTM machine at a rate of 0.2MPa/s. The parameters considered where thickness to diameter ratio (2t/D), aspect ratio (h/D) and hollow ratio (d/D). Also, a model was developed to predict the peak strength of CFSUT and CFDUT specimens.Results:The result shows that both CFSUT and CFDUT specimens exhibited improved strength, ductility, and energy absorption capacity. For CFSUT and CFSUT specimens, the strength, ductility, and energy absorption capacity increased by more than 1.32, 3.75 and 14.75 times compared to the unconfined concrete specimens, respectively. It is found that the strength decreased as the h/D and d/D ratios increased. The result also shows that the strain of CFSUT and CFDUT at the peak strength increased by more than 3.16 times compared to the unconfined concrete specimens. The proposed model accurately predicted the peak strength with AAE of 2.13%.Conclusion:The uPVC confinement provided a remarkable improvement on the strength, ductility and energy absorption of concrete. Therefore, uPVC tubes can be used as confining material for bridge piers, piles, electric poles, and building columns to increase the strength, ductility and energy absorption of concrete structures.

Estimation of Coating Materials Contribution to the TVOCs Emissions of Wood Flooring in Indoor Environment

Based on the increasing concern about the exposure to volatile organic compounds () from indoor finishing materials, industrial companies are called to meet the growing demand for more sustainable products. Recently, most designers and consumers have more environmental considerations while selecting the finishing materials. These considerations are related to thecontent of the finishing material itself regardless of its coating layers. Nowadays, interior wood coatings are commonly applied to large surfaces (ceilings, walls, floors) and many types of furnishing, leading to a high loading factor (surface-to-volume ratio). These coatings might contribute significantly to theemissions due to repeatedly and periodically use during maintenance, remodeling, and renovation of interior spaces.The aim of this study is to estimate the wood coating materials contribution to theemissions of wood product in the indoor environment to shed light on the importance of comprehensive analysis of wood material with all treatment coatings. So, a small interior space with controlled temperature, relative humidity, and air exchange rate was simulated using IA-Quest program to investigate the influence of three wood coating materials; stain, wax, and varnish which were applied to an area of natural hardwood Oak floor. Theemission data resulted from the different coated wood floor was compared withemissions caused by the natural wood floor to find out the coating material contribution inemissions of a wood flooring material.

Conservation of Neotropical migratory birds in tropical hardwood and oil palm plantations.

Tropical forests in the Americas are undergoing rapid conversion to commercial agriculture, and many migratory bird species that use these forests have experienced corresponding populations declines. Conservation research for migratory birds in the tropics has focused overwhelmingly on shade coffee plantations and adjacent forest, but both cover types are now in decline, creating an urgent need to evaluate conservation opportunities in other agricultural systems. Here we compare how a community of 42 Neotropical migratory bird species and a subset of five conservation-priority species differ in usage and habitat associations among a secondary forest baseline and four expanding commercial plantation systems in Guatemala: African oil palm, teak, rubber, and mixed-native hardwoods. We found that mixed-native hardwood plantations supported the highest richness and diversity of all migrants and that the three hardwood plantation types generally outperformed oil palm in richness and diversity metrics. Despite this, oil palm supported high abundance of several common and widespread species also experiencing range-wide population declines and may therefore play an important role in conserving common species. Mature secondary forest hosted low abundance and diversity of the full migratory community, but high abundance and richness of conservation priority migrants along with native hardwood and teak plantations. Likewise, the percentage of forest cover on the landscape was positively associated with priority migrant abundance and richness but negatively associated with the abundance of migrants in general, highlighting how individual species within the broad group of Neotropical migratory landbirds respond differently to anthropogenic changes in land use. Across all cover types, the retention of tall overstory trees increased the abundance, richness, and diversity of all migrants, which indicates that vertical structural diversity and remnant trees are important habitat features for birds in agricultural landscapes. Our findings show that conservation opportunities exist in hardwood and oil palm plantations, though the species likely to benefit from conservation action will vary among plantation types. For the subset of conservation priority migrants, our results suggest that conservation efforts should combine strategies that retain and restore secondary forest, promote the adoption of native hardwood and teak plantations, and promote the retention of tall, remnant trees in agricultural landscapes.

Spoil Type Influences Soil Genesis and Forest Development on an Appalachian Surface Coal Mine Ten Years after Placement

Surface mining for coal (or other mineral resources) is a major driver of land-use change around the world and especially in the Appalachian region of the United States. Intentional and well-informed reclamation of surface-mined land is critical for the restoration of healthy ecosystems on these disturbed sites. In Appalachia, the pre-mining land cover is predominately mixed hardwood forest, with rich species diversity. In recent years, Appalachian mine reforestation has become an issue of concern, prompting the development of the Forestry Reclamation Approach, a series of mine reforestation recommendations. One of these recommendations is to use the best available soil substitute; however, the characteristics of the “best” soil substitute have been an issue. This study was initiated to compare the suitability of several types of mine spoil common in the Appalachian region: brown sandstone (Brown), gray sandstone (Gray), mixed spoils (Mixed), and shale (Shale). Experimental plots were established in 2007 with each spoil type replicated three times. These plots were planted with a mix of native hardwood species. Ten years after plot construction and planting, tree growth and canopy cover were highest in Brown, followed by Shale, Mixed, and Gray. Soil conditions (particularly pH) in Brown and Shale were more favorable for native tree growth than Mixed or Gray, largely explaining these differences in tree growth and canopy cover. However, soil chemistry did not clearly explain differences in tree growth between Brown and Shale. These differences were more likely related to differences in near-surface soil temperature, which is related to soil color and available shade.