Native Hardwood Research Articles

Detritus Quality and Locality Determines Survival and Mass, but Not Export, of Wood Frogs at Metamorphosis.

Single-site experiments have demonstrated detritus quality in wetlands can have strongly negative, neutral, and even positive influences on wildlife. However, an examination of the influence of detritus quality across several regions is lacking and can provide information on whether impacts from variation in detritus quality are consistent across species with wide ranges. To address this gap in regional studies we examined effects of emergent and allochthonous detritus of different nutrient qualities on amphibians and assessed a mechanism that may contribute to potential impacts. We used aquatic mesocosms to raise wood frogs (Rana sylvatica) from two regions of the United States with whole plants from purple loosestrife (Lythrum salicaria), leaf litter from native hardwood trees, and a mixture of both. We examined several metrics of amphibian fitness and life history, including survival, number of days to metamorphosis, and size at metamorphosis. Further, we quantified whether the effects of detritus type could translate to variation in anuran biomass or standing stock of nitrogen or phosphorus export. Our results show detritus with high nutrient quality (purple loosestrife) negatively influenced survival of wood frogs, but increased size of metamorphic individuals in two different regions of the United States. Despite the decrease in survival, the increase in size of post-metamorphic anurans raised with high quality detritus resulted in anuran biomass and standing stock of N and P export being similar across treatments at both locations. These results further demonstrate the role of plant quality in shaping wetland ecosystem dynamics, and represent the first demonstration that effects are consistent within species across ecoregional boundaries.

Effects of paclobutrazol on leaf anatomy and gas exchange of Toona ciliata clones

ABSTRACTInterest in Australian cedar (Toona ciliata M. Roemer var. australis) has increased due to its economic potential as an alternative to the use of native hardwood, and because of its resistance to the Hypsipyla grandella moth, which affects native cedars. The use of growth regulators such as paclobutrazol (PBZ) in the planting of T. ciliata is aimed mostly at obtaining seedlings with greater resistance to H. grandella and a desirable height for handling. However, this growth regulator tends to induce modifications to both leaf anatomy and photosynthetic potential. The present study aimed to evaluate the effect of increasing concentrations of PBZ on the leaf anatomy and gas exchange pattern in different T. ciliata clones. Seedlings from four T. ciliata clones (BV1110, BV1321, BV1120 and BV1151) were propagated by rooting cuttings and exposed to four concentrations of PBZ (0 μM, 0.5 μM, 1.0 μM and 2.0 μM), then the anatomy of the leaf blade and midrib vascular bundles and parameters related to gas exchange were analysed. Clones were significantly different for most of the characteristics studied. PBZ showed an effect only on the thickness of the palisade and spongy parenchyma. There was no effect of PBZ on gas exchange, but higher concentrations of PBZ induced thicker leaflets with scleromorphic characteristics.

Influence of tree species, tree diameter and soil types on wood density and its radial variation in a mid-altitude rainforest in Madagascar

In a tropical rainforest of Madagascar, tree species differed in average wood density depending on their light requirements and on the soil type. Tree diameter had no effect. None of these factors influenced the variation of density related to the distance to the pith. Wood density (WD) is an important wood property as it correlates with several functional tree traits and mechanical wood properties. Furthermore, wood density is often used in forest biomass and carbon stock estimates. The variation in wood density depends on a range of intrinsic or environmental factors. This study investigated the effect of species, tree diameter, soil types and the distance from the pith on wood density in native hardwood species from a natural, mid-elevation rainforest in Madagascar. We extracted pith-to-bark core samples from the trunk of 204 trees from 23 species. Each wood core was sectioned into 1 cm-long segments on which measures of volume and weight were performed. Within-tree and between-tree variations of wood density were analysed. Average wood density was higher on shade-tolerant than on light-demanding species. It was higher on poor ferralitic than on fertile lowland soils. Tree diameter had no influence on average wood density. Regarding within-tree variation, wood density does not vary from pith to bark. These results help fill the gaps in wood properties database for tree forest species in Madagascar.

Ecosystem accounting for measuring total income in private and public agroforestry farms

We develop an ecosystem accounting system to estimate individual products' biophysical and total income indicators. The ecosystem products are grouped into private and public activities and measured consistently with the principle of exchange value of the standard national accounts. Private products comprise timber, cork, firewood, conservation forestry, grazing, livestock, hunting, crops and private amenity, while the public ones comprise mushrooms, carbon, water, public recreation, landscape and threatened biodiversity services. Our accounting approach revises and extends the standard agricultural and forestry sector income accounts by incorporating intermediate products, natural growth, private amenity, carbon sequestration and capital gain. Furthermore, our approach extends the standard government sector income accounts by including the economic value of the consumption of public final products delivered by ecosystems on the basis of simulating prices for non-market products. We apply the agroforestry accounting system to a group of 39 agroforestry farm case studies in Andalusia, Spain. We provide results for two agroforestry farm groups: publicly owned coniferous forest and privately owned native hardwood forest (dehesa). Total income attained, on average, €140 per hectare in coniferous forests and €352 per hectare in dehesas. Cork natural growth and private amenity are the main products explaining private income in dehesa farms. Forestry activity products, particularly timber natural growth and the intermediate products of conservation forestry, are the main sources of private income in the coniferous forests. Public incomes from non-market products are the main contributors of total income in dehesas and forests.

小兴安岭森林恢复期不同植被区域蛾类组成及其多样性

PDF HTML阅读 XML下载 导出引用 引用提醒 小兴安岭森林恢复期不同植被区域蛾类组成及其多样性 DOI: 10.5846/stxb201501140116 作者: 作者单位: 东北林业大学,东北林业大学,东北林业大学,东北林业大学,东北林业大学,东北林业大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家科技部国家科技支撑计划课题（2012BCA01B00）；东北林业大学学术名师项目；国家自然科学基金项目（30870394）；中央高校基本科研业务费专项资金项目（2572014BA06） Diversity and species composition of moths in different forests types at different stages of restoration on Xiaoxing'an Mountain, Northeast China Author: Affiliation: Northeast Forestry University,Northeast Forestry University,Northeast Forestry University,Northeast Forestry University,Northeast Forestry University,Northeast Forestry University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为了研究小兴安岭地区不同植被类型的森林恢复区域和原始林区域的蛾类群落结构和多样性，对位于凉水自然保护区的4个典型区域的蛾类群落进行了系统调查。共采集蛾类标本56079号，隶属于28科598种，其中夜蛾科、尺蛾科为优势类群，豆卷叶野螟、头橙荷苔蛾、一色兜夜蛾等为小兴安岭地区优势种。对蛾类群落的种-多度关系分析得知，4个区域均符合对数正态分布假说。多样性指数分析表明，多样性和均匀度均为Ⅳ > Ⅲ > Ⅱ > Ⅰ；优势集中性指数为Ⅰ > Ⅲ > Ⅱ > Ⅳ。相似性分析和群落排序结果表明各植被恢复区域与原始林蛾类群落均存在差异，但差异不大。研究认为小兴安岭地区蛾类赖以生存的生态系统稳定，环境条件良好。 Abstract:We determined moth community structure and diversity in different forest types, including both restoration areas and primeval forests, in the Xiaoxing'an Mountains. We systematically investigated the moth communities in four typical forest types (natural mixed conifer-hardwood forest, planted and secondary growth forest, natural hardwood forest, and virgin Korean pine [Pinus koraiensis] forest) in the Liangshui Natural Reserve. We collected 56,079 specimens of 598 species, belonging to 28 families of Lepidoptera. Noctuidae, Geometridae, Pyralidae, Notodontidae, and Tortricidae were the dominant families, and Pleuroptya ruralis (Scopoli), Ghoria gigantea (Oberthür), Cosmia unicolor (Staudinger), Hydrillodes funeralis Warren, and Yponomeuta evonymellus (Linnaeus) were the dominant species. Xiaoxing'an Mountains and Changbai Mountains had similar forest habitats and accordingly, the dominant moth groups were similar. Noctuidae, Geometridae, Pyralidae and Notodontidae were the dominant families in both of these mountains, and all 27 families of moths found in Changbai Mountains, except Oecophoridae, were collected during our survey. Furthermore, we collected more than 100 individuals for most of the dominant species in the Changbai Mountains, including Hypomecis punctinalis conferenda (Butler), Deileptenia ribeata (Clerck), Clostera albosigma curtuloides Erschoff, Tethea ampliata (Butler), Diarsia canescens (Butler), and Anaplectoides virens (Butler). The Changbai Mountains, however, was host to the largest number of individuals of Geometridae and there were differences in the dominant species between the two places. The species-abundance analysis for moth communities depicted a curve in accordance with the log-normal hypothesis and goodness of fit was strong (R2>0.9240). We used common indices of diversity for the moth community. The individual number was Ⅱ >Ⅰ> Ⅲ > Ⅳ, the diversity index and the evenness index were Ⅳ > Ⅲ > Ⅱ > Ⅰ, and the dominant concentration index was Ⅰ > ⅢI > Ⅱ > Ⅳ. The diversity index was significantly correlated with the dominant concentration index (r=-0.7——0.974, P < 0.05), but it was not significantly correlated with the evenness index (r=0.173-0.471, P > 0.05). Polar ordination and community similarity analysis indicated that the moth community structure of all forest restoration areas differed little from that of the primeval forest area. We concluded that the environmental conditions the moths depend on in the Xiaoxing'an Mountains are stable and that the ecological and environmental quality has been well preserved. There were, however, differences in the insect community structure and natural environment between different forest restoration areas and the primeval forest. Compared with the primeval forest, the restoration areas had more individuals and more dominant species. Therefore, it is necessary to focus on pest monitoring of Pleuroptya ruralis (Scopoli), Ghoria gigantea (Oberthür), Cosmia unicolor (Staudinger), Hydrillodes funeralis Warren, Yponomeuta evonymellus (Linnaeus). The natural mixed conifer-hardwood stands had the greatest abundance of dominant species (i.e., lowest evenness) and the lowest diversity of the moth communities surveyed, which might be a consequence of the low diversity of vegetation. 参考文献 相似文献 引证文献

Life cycle assessment of ACQ-treated Veneer Based Composite (VBC) hollow utility poles from hardwood plantation mid-thinning

Hardwood plantations are slow to mature with low financial returns in the early stage. Veneer Based Composite (VBC) products developed from mid-thinning may improve the industry’s profitability and win new markets. Due to the increasing demand for utility poles and the banning of native forests logging in Australia, VBC poles may become viable alternative to native hardwood poles. Alkaline copper quaternary (ACQ) preservative treated VBC pole was assessed using life cycle assessment (LCA) methodology. The manufacturing processes considered were based on the current technologies in Queensland. VBC pole life cycle stages assessed include mid-thinning, manufacturing, service-life, and disposal. Three end-of-life scenarios were considered: landfilling, incineration for energy recovery and recycling as particleboard. The functional unit used in this assessment is 1-metre-length pole with 115-mm internal-diameter and 15-mm wall-thickness. Global Warming Potential (GWP100), Fossil Depletion Potential (FDP), Acidification Potential (AP), Eutrophication Potential (EP), and Ecological Toxicity Potential (ETP) were quantified. Results indicated that landfilling and incineration outperform the recycling option. Incineration scenario performed slightly better under the GWP100 (0.3659kg-CO2-Eq), AP (2.12g-SO2-Eq), FDP (0.360kg-Oil-Eq) and EP (3.81g-PO4-Eq). Meanwhile, landfilling scenario had slightly less impact in ETP (12.32-CTUe). Despite generating valuable products, the burdens caused by secondary manufacturing and transportation overweighed credits earned from recycling. ACQ treatment, Phenol-formaldehyde (PF) resins production and transportation distances were identified as significant parameters affecting the final result. Sensitivity analysis indicated that EP was sensitive to change in ACQ consumption; ETP was affected by PF resin use while changing distances of transporting product affected GWP100, AP and FDP.

BRANCH DEVELOPMENT OF EUCALYPTS MANAGED FOR SAWLOGS

ABSTRACT Species of the genus Eucalyptus managed for sawlogs in fast-growing plantations show high potential for substitution for valuable native hardwoods. To obtain high quality wood, technical pruning is necessary. The objective of the study is to analyse the development of the branches for the first and second pruning lifts and to quantify the biomass of the pruned branches. For the study two stands of Eucalyptus grandis were selected (age 18 and 36 months) for evaluating a pruning lift from 0 to 3 m and 3 to 6 m. The average branch diameter and length were 18 mm and 2.1 m in the younger stand and 21 mm and 2.3 m in the older one. The relation between branch diameter and branch length could be expressed in a linear model (R² = 0.8). In both stands a higher proportion of branches were already dead. The oven-dry biomass of the pruned branches was 2.2 ton.ha-1 in the first pruning lift and 1.2 ton.ha-1 in the second. The results showed that branch development in wide spaced and early thinned eucalypt plantations is in line with the objective of high quality wood production. Pruning should take place before 18 month to avoid dead branches. The oven-dry branch biomass cut in the two pruning lifts shows a low volume making a commercial utilization difficult.

Development of ecosystem structure and function on reforested surface-mined lands in the Central Appalachian Coal Basin of the United States

Surface mining in the Appalachian Coal Basin drastically disturbs the landscape. Post-mining reforestation efforts have reached reliable tree survivability and growth; however, it is unclear whether these reforestation efforts also restore the ecological functions associated with the native forest ecosystem. The objectives of this study were to quantify the rate at which certain key ecosystem functions return to the landscape, and to relate the development of those functions to structural attributes of the ecosystem. A chronosequence of four reclaimed and reforested stands (ages 5, 11, 21 and 30 years) and unmined reference stands representing pre-mining conditions, were identified on the Appalachian Plateau in southwestern Virginia. Total soil nitrogen (N) and component (mineral soil, forest floor, root, and aboveground biomass) ecosystem carbon (C) pools were quantified. Throughout the growing season, monthly samples for soil gas fluxes [i.e., carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4)], available inorganic-N [nitrate (NO3 −) and ammonium (NH4 +)], and total and active microbial biomass were measured. As expected, soil organic C (SOC) and total ecosystem C returned to the mined landscape, although at levels still less than half of the unmined reference after 30 years. Ecosystem C accumulation was significantly correlated with soil N (r = 0.80; p = 0.0003) as well as total and active microbial biomass (r = 0.92; p = <0.0001 and r = 0.86; p = <0.0001, respectively). Surprisingly, available inorganic-N and gas fluxes of CO2 and N2O showed no significant differences among any of the mined and unmined stands; however, the reforested mined soils showed a significantly diminished capacity for CH4 uptake, where upland soils typically represent the largest global biogenic sink of atmospheric CH4. Thus, although many ecosystem components (e.g., forest and microbial biomass) and functions (e.g., N cycling), rapidly returned to the reclaimed landscape, some critical ecosystem functions (e.g., methanotrophy) exhibited a fundamentally different rate of return, if present at all. Our results indicate that reforestation of native hardwoods on reclaimed surface mined lands is largely successful at restoring many ecosystem functions, but that certain functional attributes are decoupled from the observed redevelopment of ecosystem structure. Thus, reforestation and forest ecosystem restoration are not necessarily the same thing, and a better understanding of potential disconnects between the two concepts can be critical in guiding both the science and the practice into the future.

Environmental life cycle impacts of cellulosic ethanol in the Southern U.S. produced from loblolly pine, eucalyptus, unmanaged hardwoods, forest residues, and switchgrass using a thermochemical conversion pathway

The cradle-to-grave environmental impacts of thermochemical ethanol from loblolly pine, eucalyptus, unmanaged hardwoods, forest residues, and switchgrass biomass feedstocks were determined and compared to gasoline. The Tool for the Reduction and Assessment of Chemical and Other Impacts (TRACI) method was implemented in SimaPro 7.3 to calculate midpoint environmental impacts. Two normalization value sets were used and weighting was performed to produce a single environmental score.Greenhouse gas (GHG) emission reductions of cellulosic ethanol as compared to gasoline were 65%–77%, depending on the biomass feedstock, qualifying these biofuels as cellulosic ethanol under the Renewable Fuel Standards (RFS2). Effects of direct land-use change were significant (~18%) and could increase the GHG emissions for switchgrass derived ethanol above the federal GHG reduction thresholds for cellulosic ethanol. The production and use of cellulosic ethanol reduced fossil fuel consumption by between 95% and 97% and by 81% for forest and switchgrass derived ethanol, respectively. Cellulosic ethanol, however, did not reduce all environmental impact categories (e.g., eutrophication, ozone depletion respiratory effects, acidification, and smog) compared to gasoline. The fuel scenario ranking from lowest impact to highest impact consistently remained the same for GHG emissions, fossil fuel use, and the two single weight score analysis methods and was, in ascending order, forest residues with no forest establishment burdens, forest residues with forest establishment burdens, natural hardwood, pine, switchgrass, and finally gasoline. The GHG emission reductions from the use of cellulosic ethanol at the renewable fuel standards mandated production volume of 16 billion gallons of cellulosic ethanol per year by 2020 would result in 9–10 billion metric tonnes of GHG emissions avoided.

Understorey plant community and light availability in conifer plantations and natural hardwood forests in Taiwan

AbstractQuestionsWhat are the effects of replacing mixed species natural forests with Cryptomeria japonica plantations on understorey plant functional and species diversity? What is the role of the understorey light environment in determining understorey diversity and community in the two types of forest?LocationSubtropical northeast Taiwan.MethodsWe examined light environments using hemispherical photography, and diversity and composition of understorey plants of a 35‐yr C. japonica plantation and an adjacent natural hardwood forest.ResultsUnderstorey plant species richness was similar in the two forests, but the communities were different; only 18 of the 91 recorded understorey plant species occurred in both forests. Relative abundance of plants among different functional groups differed between the two forests. Relative numbers of shade‐tolerant and shade‐intolerant seedling individuals were also different between the two forest types with only one shade‐intolerant seedling in the plantation compared to 23 seedlings belonging to two species in the natural forest. In the natural forest 11 species of tree seedling were found, while in the plantation only five were found, and the seedling density was only one third of that in the natural forest. Across plots in both forests, understorey plant richness and diversity were negatively correlated with direct sunlight but not indirect sunlight, possibly because direct light plays a more important role in understorey plant growth.ConclusionsWe report lower species and functional diversity and higher light availability in a natural hardwood forest than an adjacent 30‐yr C. japonica plantation, possibly due to the increased dominance of shade‐intolerant species associated with higher light availability. To maintain plant diversity, management efforts must be made to prevent localized losses of shade‐adapted understorey plants.

Environmental impacts of bioethanol using the NREL biochemical conversion route: multivariate analysis and single score results

AbstractMandated Environmental Protection Agency biofuel qualifications focused on greenhouse gas (GHG) emissions and fossil fuel use are limited in perspective and have the potential to encourage burden shifting. When a broader host of environmental impacts are examined, environmental trade‐offs often exist when biofuels are compared to gasoline. Multivariate analysis methods examining a wide variety of weighting value systems and methodology assumptions were used to determine process design options with the lowest overall environmental impact. A multivariate environmental analysis was applied to the dilute acid pre‐treatment process followed by enzymatic hydrolysis and the fermentation process for converting loblolly pine, eucalyptus, natural hardwood, switchgrass, and sweet sorghum biomass to ethanol. The influence of co‐product treatment method choices, inclusion of direct land‐use change, and electrical grid assumptions were examined using 16 different weighting methods to create a single score result. Biofuel system rankings based on GHG emissions following the Renewable Fuel Standards 2 (RFS2) methods were very sensitive to the co‐product treatment method, inclusion of land‐use change emissions, and energy grid assumptions. The multivariate analysis ranking was heavily influenced by other environmental impacts resulting from the production of process chemicals used in ethanol conversion. Weighting methods examined had no influence on the environmental preference ranking of the biofuel scenarios. Additionally, the biofuel ranking based on the RFS2 methodology was different than the ranking following the multivariate approach examining additional impacts. These findings demonstrate a robust approach to biofuel life cycle assessment (LCA) scenario analysis and suggest that the limited scope of the RFS2 environmental analysis could result in burden shifting. © 2015 Society of Chemical Industry and John Wiley &amp; Sons, Ltd

Influence of spoil type on afforestation success and natural vegetative recolonization on a surface coal mine in Appalachia, United States

Surface mining has altered a vast land area in the Appalachian Region, threatening highly biodiverse native forest, contributing to habitat fragmentation, and generating severely disturbed sites that are unsuitable for succession to native ecosystems. Although there are many factors that influence species colonization and establishment on these sites, selection of topsoil substitutes suitable for native species is of particular concern. A series of experimental plots was installed in 2005 on a reclaimed mine site in eastern Kentucky, United States, to examine the suitability of three spoil types (unweathered GRAY sandstone, weathered BROWN sandstone, and MIXED sandstone/shale) as topsoil substitutes. Bareroot 1:0 seedlings of four native hardwood species (Fraxinus pennsylvanica, Quercus rubra, Q. alba, and Liriodendron tulipifera) were planted in the spoil. Seed required for ground cover was not applied so that natural colonization could be evaluated. Two years after installation, researchers concluded that tree growth was highest on BROWN; in addition, species richness and ground cover of volunteer vegetation were higher on BROWN. In 2013, tree volume was over 50 times higher in BROWN than GRAY. In addition to planted hardwoods, naturally colonizing vegetation provided nearly 100% cover on BROWN compared to 20% on MIXED and less than 10% on GRAY plots. Species richness of volunteer vegetation continued to be higher on BROWN (41) than GRAY (30) or MIXED (30), with native species comprising 65–70% of total species richness on all plots. Findings suggest that when topsoil substitutes are used, weathered spoils are more favorable to reforestation than unweathered spoil.

A taxonomic monograph of Nearctic Scolytus Geoffroy (Coleoptera, Curculionidae, Scolytinae).

The Nearctic bark beetle genus Scolytus Geoffroy was revised based in part on a molecular and morphological phylogeny. Monophyly of the native species was tested using mitochondrial (COI) and nuclear (28S, CAD, ArgK) genes and 43 morphological characters in parsimony and Bayesian phylogenetic analyses. Parsimony analyses of molecular and combined datasets provided mixed results while Bayesian analysis recovered most nodes with posterior probabilities >90%. Native hardwood- and conifer-feeding Scolytus species were recovered as paraphyletic. Native Nearctic species were recovered as paraphyletic with hardwood-feeding species sister to Palearctic hardwood-feeding species rather than to native conifer-feeding species. The Nearctic conifer-feeding species were monophyletic. Twenty-five species were recognized. Four new synonyms were discovered: Scolytus praeceps LeConte, 1868 (= Scolytus abietis Blackman, 1934; = Scolytus opacus Blackman, 1934), Scolytus reflexus Blackman, 1934 (= Scolytus virgatus Bright, 1972; = Scolytus wickhami Blackman, 1934). Two species were reinstated: Scolytus fiskei Blackman, 1934 and Scolytus silvaticus Bright, 1972. A diagnosis, description, distribution, host records and images were provided for each species and a key is presented to all species.

English

Surface mining for coal has contributed to wide-scale deforestation and forest fragmentation in the eastern United States. Over the last thirty years, mine reclamation practices involving heavy compaction and introduction of nonnative vegetation have produced large areas of reclaimed land, which exist in a state of arrested natural succession, termed legacy sites. These sites were reclaimed to standards of the day, which usually involved compaction of the surface material and seeding an aggressive ground cover to control erosion. These sites are typically dominated by non-native grasses and legumes (e.g., tall fescue and lespedeza) and are often colonized by invasive and undesirable woody shrubs (e.g., autumn olive). Interest in restoring native hardwood forest on these sites has grown over the past decade. The development of techniques to mitigate the unfavorable soil and vegetative conditions on these legacy sites is essential to forest restoration in Appalachia. In addition to representing a good opportunity for native hardwood reforestation in Appalachia, legacy sites present a unique opportunity to reintroduce improved blight resistant American chestnut across much of its native range. This study investigated the impacts of tree shelters and weed mats on the growth and survival of planted American chestnuts on legacy mine sites in eastern Kentucky. Shelters significantly reduced browse pressure from deer and therefore improved growth and survival in most instances. Weed mats did not significantly influence tree growth or survival and were unpredictable in their effect on herbaceous biomass. This study demonstrates that properly prepared legacy mine sites can support the establishment of improved American chestnuts.

The joint effects of fire and herbivory on hardwood regeneration in central Texas woodlands

Oaks (Quercus spp.) are not regenerating in forests and woodlands in central Texas and elsewhere. This has been attributed to fire suppression. However, overabundant white-tailed deer (Odocoileus virginianus) can also limit oak regeneration. We hypothesized that both fire re-introduction and protection from deer would increase the number and growth of hardwood seedlings, saplings, and sprouts in a central Texas woodland co-dominated by Texas red oak (Quercus buckleyi) and Ashe juniper (Juniperus ashei). We measured the separate and joint effects of prescribed fire and deer herbivory on the number, size, and growth of Ashe juniper and hardwoods, tree mortality, and canopy cover. We collected data one year before and three years after deer-fence construction and a prescribed fire. Fire stimulated re-sprouting in oak and other hardwoods, but had no detectable effect on their seedlings or saplings, even three years later. Deer exclusion increased the number of seedlings transitioning to the sapling size class. Both fire and deer exclusion together were required to increase average sprout height above the browseline. The apparent adaptations of native hardwoods to fire are the strongest evidence we have for an important role for fire pre-settlement. Our results also indicate that fire suppression in central Texas and other parts of the south-central US is causing a shift, not to more mesic-adapted species as observed in the eastern US, but to juniper (Juniperus spp.), which is at least as xeric-adapted as oak. Therefore, thinking about the “oak regeneration problem” needs to be expanded beyond “mesophication” to incorporate the shift to juniper in drier regions. It is likely that deer control is necessary to allow fire to have positive effects on the regeneration of oaks and other hardwoods in this region and wherever deer are over-abundant. Moreover, the negative effects of deer herbivory on oak growth may partially account for reported failures of single fires alone to promote hardwood regeneration elsewhere.

Comparison of soil bacterial communities in a natural hardwood forest and coniferous plantations in perhumid subtropical low mountains.

BackgroundThe bacterial community of forest soils is influenced by environmental disturbance and/or meteorological temperature and precipitation. In this study, we investigated three bacterial communities in soils of a natural hardwood forest and two plantations of conifer, Calocedrus formosana and Cryptomeria japonica, in a perhumid, low mountain area. By comparison with our previous studies with similar temperature and/or precipitation, we aimed to elucidate how disturbance influences the bacterial community in forest soils and whether bacterial communities in similar forest types differ under different climate conditions.ResultsAnalysis of 16S ribosomal RNA gene clone libraries revealed that Acidobacteria and Proteobacteria were the most abundant phyla in the three forest soil communities, with similar relative abundance of various bacterial groups. However, UniFrac analysis based on phylogenetic information revealed differences of bacterial communities between natural hardwood forest and coniferous plantation soils. The diversities of bacterial communities of the replanted Calocedrus and Cryptomeria forests were higher than that in natural hardwood forest. The bacterial diversity of these three forest soil were all higher than those in the same forest types at other locations with less precipitation or with lower temperature. In addition, the distribution of some of the most abundant operational taxonomic units in the three communities differed from other forest soils, including those related to Acidobacteria, α-, β- and γ-Proteobacteria.ConclusionsReforestation could increase the bacterial diversity. Therefore, soil bacterial communities could be shaped by the forestry management practices and climate differences in warm and humid conditions.Electronic supplementary materialThe online version of this article (doi:10.1186/s40529-014-0050-x) contains supplementary material, which is available to authorized users.

Integrated conversion, financial, and risk modeling of cellulosic ethanol from woody and non‐woody biomass via dilute acid pre‐treatment

AbstractDilute sulfuric acid pre‐treatment followed by enzymatic hydrolysis and fermentation is a technology widely studied as a potential pathway for conversion of lignocellulosic biomass to ethanol. Six feedstocks were evaluated in process and financial simulations. The woody feedstocks include natural hardwood, Eucalyptus, and loblolly pine while the non‐woody feedstocks include corn stover, switchgrass, and sweet sorghum. Based on experimental and literature data, ethanol yields for the non‐woody biomasses range from 315 to 328 liters per bone dry metric ton (L/BDt). Sweet sorghum that is pressed and washed to remove soluble sugars prior to dilute acid processing can have an ethanol yield of approximately 470 L/BDt. Natural hardwood and Eucalyptus produce ethanol yields of 336 and 309 L/BDt, respectively. When processing 700 000 bone dry metric tons per year, the non‐woody biomasses have lower minimum ethanol revenues to achieve a 12% internal rate of return (MER@12%) than the woody biomasses. The non‐wood MER@12% ranged from $0.70 to $080/liter while the MER@12% for natural hardwood and Eucalyptus was $0.84–$0.85/liter. The impact of feedstock composition variability on the net present value at 12% (NPV@12%) discount was estimated for corn stover, switchgrass, and loblolly pine. One standard deviation in the sample carbohydrate content for corn stover, switchgrass, and loblolly pine will impact the NPV@12% by approximately $40 M, $72 M, and $24 M, respectively. If recent historical cost and revenue variability continues for the life of the project the most attractive feedstock is squeezed sweet sorghum where the probability of achieving at least a 12% internal rate of return is 64%.

Effect of heat treatment on longitudinal gas and liquid permeability of circular and square-shaped native hardwood specimens

Effects of heat-treatment on longitudinal permeability of circular and square wood specimens were studied here. Specimens were heated to 50, 75, 100, 125, 150, and 185 °C. Results showed that permeability increased at the lowest temperature due to shrinkage; then, it decreased due to irreversible hydrogen bonding and stiffness. The highest temperature increased permeability due to micro-cracks. The higher perimeter in the square specimens aggravated the effects of heat treatment.

Pest management through tropical tree conservation

Tropical trees can provide various ecological services to adjacent agricultural environments, including maintaining and amplifying the numbers of beneficial insects. In Mexico, certain tree species harbor a diverse guild of hymenopteran parasitoids that attack pest fruit flies (Diptera: Tephritidae) and are at the same time sources of valuable hardwood timber. Indigenous trees and their associated fauna are slowly disappearing due to forest clearance and the expansion of crop monocultures. Here we explore the relationship among pest and non-pest fruit flies, their fruit-hosts and parasitoids in the context of mango orchards and surrounding patches of uncultivated vegetation and propose a novel mechanism to use these associations in favor of conservation purposes and pest management. Trees of conservation biological control interest are classified as: (1) parasitoid multiplier plants, species that serve as alternate hosts for key fruit fly pests when their commercial hosts are not available, but in which they are unusually vulnerable to parasitism; (2) parasitoid reservoir plants, native or introduced trees in whose fruits non-pest fruit flies serve as hosts to generalist parasitoids that are able to attack pest tephritids in other species of commercially grown fruit; and (3) pest-based parasitoid reservoir plants, native or introduced species that are not economically important locally, but which harbor fruit flies that would be pests in other circumstances and that serve as hosts for parasitoids of the important pests in the vicinity. Protection, multiplication and dissemination of such tree species has the potential to increase the number of naturally produced fruit fly parasitoids and could assist in the management of tephritid pests in areas where destruction of forests has impoverished the historical sources of fruit fly natural enemies. Tropical forest conservation may help resource-poor farmers reduce crop losses, increase biodiversity within fruit-growing regions and conserve native forests for both conservation purposes and commercial use of native hardwoods.

Aedesspecies in treeholes and fruit husks between dry and wet seasons in southeastern Senegal

During the dry season in February, 2010 and the wet season in September, 2011 we sampled mosquito larvae and eggs from treeholes of seven native hardwood species and the husks of Saba senegalensis in 18 sites in the PK-10 forest in southeastern Senegal. Larvae were reared to adults for species identification. In the dry season, we recovered 408 Aedes mosquitoes belonging to seven species. Aedes aegypti s.l. comprised 42.4% of the collection, followed by Ae. unilineatus (39%). In contrast to reports from East Africa, both Ae. aegypti aegypti and Ae. aegypti formosus were recovered, suggesting that both subspecies survive the dry season in natural larval habitats in West Africa. In the wet season, 455 mosquitoes were collected but 310 (68.1%) were the facultatively predaceous mosquito Eretmapodites chrysogaster. The remaining 145 mosquitoes consisted of ten Aedes species. Aedes aegypti s.l. comprised 55.1% of these, followed by Ae. apicoargenteus (15.2%) and Ae. cozi (11.7%). Similar to East Africa, most (90%) of Ae. aegypti s.l. in the wet season were subspecies formosus.