Forestry Experiment Research Articles

Integration effects of soil amendments and cover crops on dryland no‐till corn

AbstractA field study was carried out at the Mississippi Agricultural and Forestry Experiment Station near Pontotoc to evaluate the synergistic impacts of broiler litter (BL) and inorganic fertilizer nitrogen (N) with flue gas desulfurization (FGD) gypsum and lignite in the presence of winter cover crops (WCCs) on dryland no‐till corn (Zea mays L.) in Falkner silt loam soil. The experimental design was a split‐plot randomized complete block design with three replications. The main plots were WCC and winter fallow (WF), and the subplots were fertilization treatments. Fertilization treatments included BL, inorganic fertilizer N, FGD gypsum and lignite with BL, FGD gypsum and lignite with inorganic fertilizer N, and an unfertilized control. BL, FGD gypsum, and lignite were applied at the rates of 13.4, 3.4, and 3.4 Mg ha−1, respectively. Inorganic fertilizer N was applied to corn at 168 kg N ha−1. BL increased soil carbon (C), soil infiltration, and resulted in higher corn grain yield compared to both inorganic fertilizer N and unfertilized control in 2020 and 2022. Averaged across fertilization treatments, WCC improved soil moisture, soil C, and soil infiltration by 16%, 19%, and 25% at the 0‐ to 15‐cm depth, respectively, and increased corn grain yield by 25% as compared to WF in 2022. Cover crops boosted corn grain yield during drier years. The combination of FGD gypsum and lignite with BL increased corn grain yield by 15% in 2020 and 13% in 2022 compared to BL alone. This approach can be considered to promote the sustainability of agroecosystems.

Forestry impacts on stream flows and temperatures: A quantitative synthesis of paired catchment studies across the Pacific salmon range

Abstract Forestry is pervasive across temperate North America and may influence aquatic environmental conditions such as flows and temperatures, as well as important species such as Pacific salmon (Oncorhynchus spp.). While there have been many large‐scale forestry experiments using paired catchment designs, these studies have yet to be quantitatively synthesized. Thus, it remains unclear whether forestry impacts are consistent, context‐dependent or unpredictable. This study aims to quantitatively synthesize forestry impacts on streamflow and temperature, through a systematic review and synthesis of paired catchment studies across the range of Pacific salmon. Specifically, we investigated whether generalizable relationships exist between forestry intensity (percent watershed harvested) and impacts to streamflow and temperature. We also examined whether watershed features (climate, hydrology and lithology) and harvest method mediated forestry impacts. We extracted information from 35 unique paired‐catchments from California to Alaska. Forestry had strong impacts on peak and low flows and maximum summer water temperatures, but responses were quite variable. Across all catchments, forestry elevated peak flows ~20% (n = 31 catchments), reduced low flows ~25% (n = 13 catchments) and increased maximum summer temperatures ~15% (n = 35 catchments) on average. However, these impacts were variable and were not predictable based on forestry intensity, thus broader stressor–response relationships were not supported. Forestry impacts on peak flows and maximum summer temperatures varied spatially. Peak flow impacts increased with northward latitude and temperature impacts decreased with eastward longitude. However, the magnitude of impacts were unrelated to other watershed attributes, which included climate (precipitation and aridity), rain versus snow hydrology, elevation and bedrock lithology. Harvest method and riparian buffer presence also had no detected effects on forestry impacts across studies and statistical models explained a low proportion of variation overall. Collectively, our results indicate that forestry can have substantial impacts on key environmental conditions; however, the magnitude of impact was variable and could not be clearly linked to easily measured watershed characteristics. This implies that forestry impacts may not be broadly predictable. Probabilistic risk models based on distributions of potential impacts may therefore be more useful for watershed management in data‐poor situations.

Registration of ‘Espresso’ lowland switchgrass

Abstract‘Espresso’ (Reg. no. CV‐293, PI 687202) is a lowland ecotype (Gulf sub‐population) of switchgrass (Panicum virgatum L.) developed and released by Mississippi State University and the Mississippi Agricultural and Forestry Experiment Station. Espresso was developed from seven cycles of phenotypic recurrent selection for rapid seed germination without stratification. All cycles of selection were made using seed harvested from open‐pollinated isolation blocks containing approximately 100 mother plants. Germination was assessed in laboratory conditions for 15 years, culminating in 2 years of field‐based germination and emergence evaluation at five locations across Mississippi. Over a 2‐year period, germination and emergence of Espresso was significantly greater (P < 0.05) than seed from ‘Alamo’ and ‘Kanlow’. Field testing revealed Espresso as having significantly (P < 0.05) greater establishment success (mean number of seedlings per linear 30 cm) when compared to Alamo. Espresso was released based on the need for southeastern US‐adapted germplasm that possesses enhanced germination characteristics.

Structured Decision Making to Prioritize Regional Bird Monitoring Needs

Conservation planning for large ecosystems has multiple benefits but is often challenging to implement because of the multiple jurisdictions, species, and habitats involved. In addition, decision making at large spatial scales can be hampered because many approaches do not explicitly incorporate potentially competing values and concerns of stakeholders. After the Deepwater Horizon oil spill, establishing baselines was challenging because of (1) variation in study designs, (2) inconsistent use of explicit objectives and hypotheses, (3) inconsistent use of standardized monitoring protocols, and (4) variation in spatial and temporal scope associated with avian monitoring projects before the spill. Herein, we show how the Gulf of Mexico Avian Monitoring Network members used structured decision making to identify bird monitoring priorities. We used multiple tools and techniques to clearly define the problem and stakeholder objectives and to identify bird monitoring priorities at the scale of the entire northern Gulf of Mexico region. Although our example is specific to the northern Gulf of Mexico, this approach provides an example of how stakeholder values can be incorporated into the coordination process of broad-scale monitoring programs to address management, restoration, and scientific questions in other ecosystems and for other taxa. History: This paper was refereed. This paper was accepted for the Special Issue of INFORMS Journal on Applied Analytics—Decision Analysis. Funding: Thanks to the National Fish and Wildlife Foundation [Grant 324423], which supported A. Fournier as a postdoctoral research associate at Mississippi State University. M. Woodrey was supported by the U.S. Department of Agriculture, National Institute of Food and Agriculture, Hatch Project funds, the Mississippi Agricultural and Forestry Experiment Station, National Oceanographic and Atmospheric Administration [Grant NA16NOS4200088 to the Mississippi Department of Marine Resources’ Grand Bay National Estuarine Research Reserve], and the Mississippi Department of Marine Resources [Grant 8200025414]. This publication is a contribution of the Mississippi Agricultural and Forestry Experiment Station. T. Zenzal was supported by the National Oceanic and Atmospheric Administration RESTORE Act Science Program [Grant NA17NOS4510092].

Registration of ‘MSB‐264’ and ‘MSB‐285’ bermudagrasses

Abstract‘MSB‐264’ (Reg. no. CV‐47, PI 699313) and ‘MSB‐285’ (Reg. no. CV‐48, PI 699314) are fine‐textured, high‐quality interspecific bermudagrasses (Cynodon dactylon × Cynodon transvaalensis) developed at Mississippi State University. These two grasses were released on 25 Aug. 2021 from the Mississippi Agricultural and Forestry Experiment Station. Compared with Tifgreen‐derived bermudagrass cultivars, MSB‐264 and MSB‐285 were bred from a much different genetic background. Through the 2013 National Turfgrass Evaluation Program warm‐season putting green test, data were collected for 4 yr across 11 locations in the United States. Compared with the commercial cultivars (‘Sunday’, ‘TifEagle’, ‘Tifdwarf’, and ‘Mini‐Verde’) and other experimental lines, both MSB‐264 and MSB‐285 exhibited superior turf quality, leaf texture, density, genetic color, fall and winter color retention, spring green‐up speed, and percent ground living cover. MSB‐264 and MSB‐285 also have a more upright leaf orientation than traditional bermudagrass putting green cultivars. Although MSB‐264 and MSB‐285 had higher seedhead production compared with the commercial cultivars and other experimental lines, regular mowing could effectively remove seedheads. MSB‐264 and MSB‐285 have demonstrated positive performance data and are the first hybrid bermudagrass cultivars used for golf greens that are not related to Tifgreen.

Soil physical and hydrological properties as affected by a five‐year history of poultry litter applied to a cotton–corn–soybean rotation system

AbstractFew studies were conducted to ascertain poultry litter (PL) and its residual influence on soil physical and hydrological properties. A field study was conducted on a sandy loam soil for 8 yr in corn (Zea mays L.), cotton (Gossypium hirsutum L.), and soybean [Glycine max (L.) Merr.] rotations at Mississippi Agricultural and Forestry Experiment Station in Verona, MS. Poultry litter treatment was applied to the three crops at an average of 7.6 Mg ha–1 yr–1 in the first 5 yr. The inorganic fertilizer treatment was 224 and 100 kg ha–1 yr–1 for corn and cotton. Inorganic P and K fertilizers applied were based on soil analysis, but no synthetic N was applied to soybean. Soil properties and yields were measured in the first year (2015) and third years (2017) after stopping PL application and planting all plots with soybean. Applying PL for 5 yr significantly improved soil aggregate stability by 17%. Infiltration rate and saturated hydraulic conductivity was two to three times greater in soil amended with PL than with inorganic fertilizer. Poultry litter addition significantly increased field capacity and plant available water content by 20%. Those soil properties were not affected by the rotation treatments. Total soil C did not differ between PL and fertilizer treatment. Soybean yield was continuously increased by 8% in 2015 and 11% in 2017 after stopping PL application. Poultry litter application is capable of improving soil physical and hydrological properties, and its residual could sustain soybean yield for 3 yr after stopping applications.

Effects of various cutting treatments and topographic factors on microclimatic conditions in Dinaric fir-beech forests

Forest microclimate is strongly affected by local topography and management activities, as these directly alter overstory structure. In the present work we analysed the dependence of observed patterns of spatio-temporal microclimatic variations on topographic, canopy- and management-related factors. A forestry experiment was conducted in managed fir-beech forests in the Dinaric Mountains (Slovenia), which are characterized by rugged karstic terrain with numerous sinkholes. In 2012, cutting treatments representing a range in the intensity of overstory removal were performed: uncut controls (CON), 50% cut of stand growing stock (intermediate management intensity – IMI) and 100% cut (high management intensity – HMI) creating 0.4 ha canopy gaps. Fine-scale variation in aspect and slope and its effects on microclimate was assessed by comparing central, south-facing and north-facing within-sinkhole positions. We measured microclimatic variables (air temperature – T, relative humidity – RH) 0.5 m above the ground over three consecutive post-treatment growing seasons. Microclimatic variables showed an increase (T and vapour pressure deficit – VPD) or decrease (RH) with management intensity. Daily Tmax and VPDmax in HMI treatment were up to 5.9°C (on average 3.5°C) and up to 1.4 kPa (on average 0.6 kPa) higher than those in CON treatment, respectively, whereas daily RHmin was up to 22.7 (on average 13.0) percentage points lower. Regarding intra-seasonal patterns, microclimatic differences between treatments were largest during the summer. South-facing plots in the HMI treatment overall exhibited the most extreme conditions, i.e. the highest Tmax and lowest RHmin. Differences in microclimate between treatments were strongly modulated by canopy cover. The results also suggest that overstory removal increases topography-mediated variation in microclimate, as evidenced by significant differences in T, RH and VPD along the fine-scale topographic gradient within the created canopy gaps.

Assessing the Relationship Between a Single Nucleotide Polymorphism in PKD2L1, Dietary Intake, and Body Composition in Young Adults (P15-012-19)

ObjectivesSingle nucleotide polymorphisms (SNPs) in taste receptor genes have previously been linked to outcomes such as differences in taste thresholds, food liking, and body mass index. Contrary to bitter, sweet, salty, fat, and umami taste, the sour taste receptor has remained elusive and knowledge on individual variability in sour taste is minimal. This study aimed to assess whether a SNP in PKD2L1, a gene proposed to be involved in sour taste transduction, is associated with differences in dietary intake or body composition in a sample of young adults. MethodsDNA was extracted from saliva samples, and genotyping was conducted using qPCR and Taqman reagents. Dietary intake was assessed via the NIH Diet History Questionnaire II. Body composition was measured with a Tanita bioelectrical impedance scale. ResultsSubjects (n = 501) were primarily female (n = 414, 83%) and Caucasian (n = 346, 72%), with a mean age of 20.46 ± 2.92 years. The minor allele “A” was associated with a significantly lower caffeine and alcohol intake (P = 0.011, P = 0.048), and a higher poultry intake (P = 0.031) compared to homozygous GG subjects. The dietary variables most closely associated with sour taste (vitamin C, citrus fruit) were significantly associated with race (P < 0.001), but not genotype. Regarding body composition, genotype was significantly associated with BMI, but not body fat percentage or fat free mass. ConclusionsFuture research will be needed to confirm and explain these findings, starting with an assessment of if there are differences in sour taste threshold levels based on rs603424 genotype. Sour-bitter confusion, and the influence of PTC/PROP taster status on sour taste perception should also be explored further in light of these findings. Funding SourcesMississippi Agricultural and Forestry Experiment Station, Mississippi State University.

Development and Evaluation of a Higher Education Food Security Toolkit to Provide Ideas of Initiatives for Student Wellbeing: WISH4Campus (P04-049-19)

ObjectivesMany universities are starting initiatives on campus to support food insecure students in receiving nutritious food. However, there is no comprehensive resource of these initiatives to help guide universities in starting a program on campus. The objective of this study is to describe the development and evaluation of a toolkit that can assist higher education institutions in promoting a campus environment, providing adequate resources for food insecure students. MethodsThe toolkit development was guided by the basis of the Normalization Process Theory (NPT) to evaluate factors that could facilitate or inhibit initiative success on campus. A review of literature was undertaken by two independent reviewers to gather all peer reviewed and grey literature on food insecurity programs currently available on college campuses in the United States. Findings were compiled into a toolkit that contained six initiative chapters: food pantries, campus gardens, farmers markets, dining and recovery programs, mobile applications, and policy initiatives. The toolkit was evaluated by experts from land-grant universities who work with food insecurity issues (n = 126). Experts completed a 27-question survey to determine demographics, perceptions of food insecurity and evaluation of specific toolkit components. Descriptive statistics and frequency analyses were performed on quantitative data and content analysis was used to analyze qualitative data. ResultsThirty experts (23.8% response rate) completed the evaluation survey. Evaluation feedback covered four main topics: layout, overall content, initiatives, and application. Eight themes emerged from the coding and categorization of responses. They were visual appeal, organization, value, provoking, comprehensive, barriers, collaboration, and efficiency. Corrections and recommendations were provided for each topic. ConclusionsThe themes derived from expert feedback encompassed the initial objective of the toolkit. This toolkit serves as a comprehensive resource that can be utilized by student leaders, clubs or organizations, campus stakeholders or administrators to begin a food security initiative on campus to promote student well-being. Funding SourcesPrimary funding is from the West Virginia Agricultural and Forestry Experiment Station WVA00689 and WVA00721. The first author is supported by the National Institute of General Medical Sciences T32 grant (GM081741).

Green tree retention enhances negative short-term effects of clear-cutting on enchytraeid assemblages in a temperate forest

We studied the response of enchytraeid (Annelida: Oligochaeta) community structure to different forest management treatments via an open-field forestry experiment in a managed sessile oak-hornbeam forest in Hungary. The applied forestry treatments were 1) clear-cutting 2) clear cutting with a small patch of retention tree group, 3) gap-cutting, 4) preparation cutting and 5) control (closed mature stand).Our questions were: how did the selected forestry treatments influence the abundance and species richness of enchytraeids two years after the intervention, and how could the worms compensate the altered environmental conditions by vertical movements in topsoil layers (0–12 cm). The effects of the treatments on the species composition of the assemblages and species-specific responses were also analysed.Two years after the treatments, a strong response of enchytraeids was observed in clear-cutting and even more in retention tree group: in both treatments the abundance and the species richness of enchytraeids were reduced. Species did not show vertical movements into deeper layers and were not able to tolerate the altered soil conditions caused by changed microclimate. Gap-cutting and preparation cutting did not differ significantly from control plots. Our study showed that right after the interventions tree retention at the size of one tree height in diameter had no sheltering effect on this important soil decomposer animal community. These results are in contrast with earlier findings in boreal zones, where soil organic layer is considered a well buffered habitat against environmental changes. Oppositely, enchytraeid assemblages in a temperate deciduous forest are more diverse but seem more vulnerable to management-related alterations in soil conditions (soil temperate increment, reduced soil moisture).

Aerial seeding of forests in Russia: A selected literature analysis

The study is intended for international readers or those unable to read Russian. Information search was carried out in Russian-language databases (Russian libraries and ELibrary.ru) and English-language databases. . Currently, there are a large number of sites in the Russian forests that need to be restored. For many of them, reforestation by ground-based seeding or planting is inefficient or not available. Sowing forest from the air in Russia has more than half a century of history. The results of retrospective analysis show that the choice of the reforestation method depends on the site characteristics and the level of negative environmental impact. Generally, the cost of aerial seeding on such sites with unmanned aerial vehicles (UAV) is lower compared to the use of manned aerial vehicles (MAV). This study will aid in the planning of new forestry experiments to study reforestation with the assistance of natural reforestation in Russia. The study will enable correct plant propagation protocols for sustainable forest management. However, many questions remained unresolved: what types of UAV and sowing apparatus to use; how to position the UAV under a forest canopy?

Registration of ‘MSA 2‐3‐98’ St. Augustinegrass

‘MSA 2‐3‐98’ (Reg. No. CV‐284, PI 689102) is a cold‐tolerant, high‐quality St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] developed at Mississippi State University. MSA 2‐3‐98 was released on 19 Apr. 2006 from Mississippi Agricultural and Forestry Experiment Station. MSA 2‐3‐98 offers many advantages compared with other St. Augustinegrass cultivars. Leaf length, leaf width, internode length, and internode diameter of MSA 2‐3‐98 were significantly smaller than ‘Floratam’ and ‘Raleigh’. The more diminutive morphology of MSA 2‐3‐98 allows it to establish a denser turfgrass canopy with finer leaf texture. Cold tolerance of MSA 2‐3‐98 was evaluated from spring assessments of percentage green turfgrass cover and overall plot green‐up. The cold tolerance of MSA 2‐3‐98 was similar to Raleigh but outperformed Floratam. MSA 2‐3‐98 turfgrass quality tended to be greater than ‘Delmar’, Floratam, and Raleigh. Gray leaf spot severity on MSA 2‐3‐98 was variable among locations where the disease was evaluated. MSA 2‐3‐98 has greater turfgrass quality than Raleigh, with similar cold tolerance.

Initial understory response to experimental silvicultural treatments in a temperate oak-dominated forest

In recent decades, alternative management techniques integrating conservation concerns into industrial forestry have become increasingly widespread. In order to compare the effects of various management methods on forest site and biodiversity, a systematic forestry experiment was conducted in a managed, mature oak–hornbeam forest. The present work introduces the 2-year responses of environmental variables and understory vegetation to different silvicultural treatments. These belong either to clear-cutting (clear-cutting, retention tree group), to shelterwood (preparation cutting), or to continuous cover forestry systems (gap-cutting). The experiment follows a complete block design with four replicates. Light availability was significantly higher in all the treatments than in the uncut control, with highest values in the clear-cuts. Soil moisture was highest in the gap-cuts and clear-cuts, while in the retention tree group, it did not differ from the control. Species richness, cover, and height of the understory considerably differed from the control in the clear-cuts and gap-cuts, while in the retention tree group, only species richness was higher. The establishment of ruderal, non-forest species altered the species composition in the clear-cuts. Based on these short-term responses, we conclude that as a result of the extreme environmental changes, clear-cutting in oak–hornbeam forests changes the understory vegetation considerably. Retention tree groups can maintain legacies of the understory composition for some years. Despite the experienced high vegetation cover, gap-cutting preserves the forest characteristics of the understory better than clear-cutting. These results confirm that in oak–hornbeam forests, continuous cover forestry may be more sustainable from conservational aspect than clear-cutting system.

Big Data in Agriculture: A Challenge for the Future

AbstractThis article examines the challenge and opportunities of Big Data, and concludes that these technologies will lead to relevant analysis at every stage of the agricultural value chain. Big Data is defined by several characteristics beyond size, particularly, the volume, velocity, variety, and veracity of the data. We discuss a set of analytical techniques that are increasingly relevant to our profession as one addresses these issues. Ultimately, we resolve that agricultural and applied economists are uniquely positioned to contribute to the research and outreach agenda on Big Data. We believe there are relevant policy, farm management, supply chain, consumer demand, and sustainability issues where our profession can make major contributions. The authors are thankful to the anonymous reviewers and editor Craig Gundersen for helpful comments. Support was provided by the Mississippi Agricultural and Forestry Experiment Station Special Research Initiative.

Registration of Six Germplasm Lines of Cotton with Resistance to the Root‐Knot and Reniform Nematodes

Six upland cotton (Gossypium hirsutum L.) germplasm lines, M Rk‐Rn 1(Reg. No. GP‐1015, PI 678938), M Rk‐Rn 2 (Reg. No. GP‐1016, PI 678939), M Rk‐Rn 3 (Reg. No. GP‐1017, PI 678940), M Rk‐Rn 4 (Reg. No. GP‐1018, PI 678941), M Rk‐Rn 5 (Reg. No. GP‐1019, PI 678942), and M Rk‐Rn 6 (Reg. No. GP‐1020, PI 78943), with resistance to root‐knot nematode [Meloidogyne incognita (Kofoid and White) Chitwood], and reniform nematode (Rotylenchulus reniformis Linford and Oliveria) were jointly released by the USDA‐ARS and the Mississippi Agricultural and Forestry Experiment Station in 2016. The source of resistance to root‐knot nematode was M‐240 RNR (PI 592511) and to reniform nematode was M713 Ren1 (PI 665928). The two lines were crossed and plants were selected using markers with subsequent crosses to ‘Sure‐Grow 747’ (PI 656375), followed by marker selection. The germplasm lines were selected using simple sequence repeat (SSR) markers CIR 316 and BNL 3661 that are linked to root‐knot resistance and GH 132, BNL 3279, and BNL 569 that are linked to reniform resistance genes. Egg production of root‐knot and reniform nematodes was suppressed significantly from the susceptible check Sure‐Grow 747 in growth chamber tests. In addition to resistance to both nematodes, these lines, which also exhibit differences for agronomic and fiber traits such as length, strength, and micronaire, should be valuable to cotton breeding programs. The successful use of these specific SSR markers further validates their use in selection of nematode‐resistant plants in segregating generations.

Characterization of Volatile and Polar Compounds of Jiaogulan Tea [Gynostemma pentaphyllum (Thunb.) Makino] by Hyphenated Analytical Techniques

Mississippi Agricultural and Forestry Experiment Station, Mississippi State University National Institute of Food and Agriculture: MIS-219060

Role of an Abscisic Acid‐Activated Protein Kinase in Drought Response in Soybean Revealed by RNA‐Seq

Glycine max (soybean) is the most important oilseed cereal crop, most widely grown in the world. It is the most important source of protein and oils for humans as well as for biodiesel production. Drought stress is the major environmental factor limiting the productivity of soybean. With the rapid growth of global population and environmental degradation, improving soybean yield is a crucial task to meet the human demand for food and energy. Soybean can survive drought stress if there is a robust and deep root system. Thus, there is a significant need for crop improvements that will increase stress tolerance. Abscisic acid is the essential hormone mediating abiotic stress responses in plants. We previously identified an abscisic acid‐activated protein kinase (AAPK) in broad bean and demonstrated that AAPK is a positive regulator that can enhance abscisic acid signaling. These results suggest that genetic engineering of the AAPK gene may have the potential to improve drought stress in crop plants. To this end, we have generated overexpression and RNAi lines of three AAPK homologous genes in soybean. We found an RNAi line of AAPK homologous gene a noticeable reduction in plant wilting in response to drought treatment. To understand the phenotype changes of this AAPK‐knockdown line, we conducted a genome‐wide transcriptomic analysis in roots of soybean at the early vegetative stage under drought stress. The analysis with an RNA‐Seq pipeline (using STAR aligner and edgeR analysis of differential gene expression) identified over 4000 gene transcripts that were differentially expressed as a response to drought stress in wild‐type samples and RNAi knockdown samples. Our ongoing study reveals the dynamic transcriptomic reconfiguration in soybean roots to acclimate drought stress and highlights the gene expression changes associated with signaling through AAPK. We expect that pathway analysis of the differentially expressed genes will reveal new signaling components associated with drought stress in soybean.Support or Funding InformationThis research was supported by MAFES (Mississippi Agricultural and Forestry Experiment Station) Special Research Initiative grants to Jiaxu Li and Vincent Klink. Saroj Sah is supported by a MAFES Director's Doctoral Fellowship awarded to Jiaxu Li and Raja Reddy. This material is based upon work that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, Hatch/Multi State project (Multistate No. NC1200; Project No. MIS‐153180) under Accession No. 232044. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the view of the U.S. Department of Agriculture.

Reserve tree mortality in two expanding-gap silvicultural systems 20 years after establishment in the Acadian forest of Maine, USA

Land managers are increasingly called upon to maintain ecosystem function and restore late-successional forest structures by retaining trees (“reserves”) in harvest prescriptions. Such retention practices often result in mortality of reserve trees owing to increased exposure to wind and ‘gap shock’, thereby compromising management objectives. This study investigated the mortality of reserve trees (n=787) retained over 20years in the Acadian Forest Ecosystem Research Project (AFERP), a long-term ecological forestry experiment in central Maine, USA. Cumulative mortality across 18 species was very low (8.4%±3.3%, mean±SD) relative to similar studies throughout the world. Annualized mortality of reserve trees of the two silvicultural systems was 1.1% for the large-gap treatment and 0.4% for the small-gap treatment. Cumulative mortality of Tsuga canadensis was lowest (2%) among species with >50 individuals, while the cumulative mortality of Thuja occidentalis was highest at 19%. Over 59% of cumulative mortality was wind-related. Annualized wind-related mortality of the reserve trees was 0.6% in the large-gap treatment and 0.2% in the small-gap treatment. More vigorous trees showed lower mortality rates. Cumulative mortality and wind-related deaths were somewhat higher in large gaps, and were influenced by spatial position within gaps. The non-traditional, expanding-gap, multi-aged silvicultural systems in this study may explain the lower incidence of windthrow and gap shock experienced by reserve trees relative to the annualized mortality rates from studies of similar, though predominantly single-cohort, silvicultural systems.

Effects of Temperature on Development and Voltinism of Chaetodactylus krombeini (Acari: Chaetodactylidae): Implications for Climate Change Impacts.

Temperature plays an important role in the growth and development of arthropods, and thus the current trend of climate change will alter their biology and species distribution. We used Chaetodactylus krombeini (Acari: Chaetodactylidae), a cleptoparasitic mite associated with Osmia bees (Hymenoptera: Megachilidae), as a model organism to investigate how temperature affects the development and voltinism of C. krombeini in the eastern United States. The effects of temperature on the stage-specific development of C. krombeini were determined at seven constant temperatures (16.1, 20.2, 24.1, 27.5, 30.0, 32.4 and 37.8°C). Parameters for stage-specific development, such as threshold temperatures and thermal constant, were determined by using empirical models. Results of this study showed that C. krombeini eggs developed successfully to adult at all temperatures tested except 37.8°C. The nonlinear and linear empirical models were applied to describe quantitatively the relationship between temperature and development of each C. krombeini stage. The nonlinear Lactin model estimated optimal temperatures as 31.4, 32.9, 32.6 and 32.5°C for egg, larva, nymph, and egg to adult, respectively. In the linear model, the lower threshold temperatures were estimated to be 9.9, 14.7, 13.0 and 12.4°C for egg, larva, nymph, and egg to adult, respectively. The thermal constant for each stage completion were 61.5, 28.1, 64.8 and 171.1 degree days for egg, larva, nymph, and egg to adult, respectively. Under the future climate scenarios, the number of generations (i.e., voltinism) would increase more likely by 1.5 to 2.0 times by the year of 2100 according to simulation. The findings herein firstly provided comprehensive data on thermal development of C. krombeini and implications for the management of C. krombeini populations under global warming were discussed.*Scientific Article No. 3278 of the West Virginia Agricultural and Forestry Experiment Station, Morgantown, West Virginia

Hydrological resilience of a Canadian Rockies headwaters basin subject to changing climate, extreme weather, and forest management

AbstractMarmot Creek Research Basin in the Canadian Rockies has been the site of intensive streamflow, groundwater, snow accumulation, precipitation, and air temperature observations at multiple elevations. The basin was instrumented in 1962, subjected to forestry experiments in the mid‐1970s, and experienced extreme flooding in 2013. Climate change, forest cover change, and recent extreme weather make the basin an ideal laboratory for studying hydrological resilience. Observations show increases in low elevation air temperature, multiple day and spring precipitation, interannual variability of precipitation, and high elevation groundwater levels. Observations also show decreases in peak seasonal snow accumulation and low elevation groundwater levels. Despite these substantial hydrometeorological and groundwater changes, streamflow volume, timing of peak, and magnitude of the peak are not changing. Streamflow volumes are also insensitive to forest cover changes and teleconnections. The June 2013 flood was unprecedented in the period of record, and the basin significantly moderated the hydrological response to the extreme precipitation; the 2013 storm precipitation depth was 65% greater than the next highest storm total over 51 years; however, the 2013 peak streamflow was only 32% greater than the next highest peak flow recorded. The hydrology of Marmot Creek Research Basin displays remarkable resilience to changing climate, extreme weather, and forest cover change. Copyright © 2015 John Wiley &amp; Sons, Ltd.