bluuebunny/crossref_metadata_2025 huggingface dataset:
The GL4 Rapoport–Zink Space
Authors: Fox Maria
Published: August 2019

We give a description of the $\textrm{GL}_4$ Rapoport–Zink space, including the connected components, irreducible components, intersection behavior of the irreducible components, and Ekedahl–Oort stratification. As an application of this, we also give a description of the supersingular locus of the Shimura variety for the group $\textrm{GU}(2,2)$ over a prime split in the relevant imaginary quadratic field.
Measuring Situational Anxiety Related to Information Retrieval on the Web Among English-Speaking Internet Users
Authors: Rodon Carole , Congard Anne
Published: August 2019

Searching for information on the web is regarded as a complex problem-solving activity involving a range of cognitive and affective processes. Anxiety is a key affective factor. In this article, we describe the construction and initial validation stages of the Information Retrieval on the Web Anxiety Rate (IROWAR) scale. The final structure of this inventory was validated with a sample of 183 English-speaking Internet users. Reliability analyses indicated that the factors were internally consistent (Cronbach’s alpha: 0.92). When we checked divergent validity, we found negative correlations with both self-efficacy and positive attitude towards the Internet. There were no effects of either sex or age on the total IROWAR score, but the Internet search anxiety sum score decreased with the length of use. This scale will be useful in several domains, including research on the determinants of web anxiety, individuals’ experience of web anxiety and ways of supporting them and Internet learning.
Influence of the tree prior and sampling scale on Bayesian phylogenetic estimates of the origin times of language families
Authors: Ritchie Andrew M , Ho Simon Y W
Published: August 2019

Bayesian phylogenetic methods derived from evolutionary biology can be used to reconstruct the history of human languages using databases of cognate words. These analyses have produced exciting results regarding the origins and dispersal of linguistic and cultural groups through prehistory. Bayesian lexical dating requires the specification of priors on all model parameters. This includes the use of a prior on divergence times, often combined with a prior on tree topology and referred to as a tree prior. Violation of the underlying assumptions of the tree prior can lead to an erroneous estimate of the timescale of language evolution. To investigate these impacts, we tested the sensitivity of Bayesian dating to the tree prior in analyses of four lexical data sets. Our results show that estimates of the origin times of language families are robust to the choice of tree prior for lexical data, though less so than when Bayesian phylogenetic methods are used to analyse genetic data sets. We also used the relative fit of speciation and coalescent tree priors to determine the ability of speciation models to describe language diversification at four different taxonomic levels. We found that speciation priors were preferred over a constant-size coalescent prior regardless of taxonomic scale. However, data sets with narrower taxonomic and geographic sampling exhibited a poorer fit to ideal birth–death model expectations. Our results encourage further investigation into the nature of language diversification at different sampling scales.
Tracing black hole and galaxy co-evolution in the Romulus simulations
Authors: Ricarte Angelo , Tremmel Michael , Natarajan Priyamvada , Quinn Thomas
Published: August 2019

We study the link between supermassive black hole growth and the stellar mass assembly of their host galaxies in the state-of-the-art Romulus suite of simulations. The cosmological simulations Romulus25 and RomulusC employ innovative recipes for the seeding, accretion, and dynamics of black holes in the field and cluster environments, respectively. We find that the black hole accretion rate traces the star formation rate among star-forming galaxies. This result holds for stellar masses between 108 and 1012 solar masses, with a very weak dependence on host halo mass or redshift. The inferred relation between accretion rate and star formation rate does not appear to depend on environment, as no difference is seen in the cluster/proto-cluster volume compared to the field. A model including the star formation rate, the black hole-to-stellar mass ratio, and the cold gas fraction can explain about 70 per cent of all variations in the black hole accretion rate among star-forming galaxies. Finally, bearing in mind the limited volume and resolution of these cosmological simulations, we find no evidence for a connection between black hole growth and galaxy mergers, on any time-scale and at any redshift. Black holes and their galaxies assemble in tandem in these simulations, regardless of the larger scale intergalactic environment, suggesting that black hole growth simply follows star formation on galactic scales.
Quantifying the impact of variable BLR diffuse continuum contributions on measured continuum interband delays
Authors: Korista K T , Goad M R
Published: August 2019

We investigate the contribution of reprocessed continuum emission (1000–10 000 Å) originating in broad-line region (BLR) gas, the diffuse continuum (DC), to the wavelength-dependent continuum delays measured in AGN disc reverberation mapping experiments. Assuming a spherical BLR geometry, we adopt a Local Optimally emitting Cloud (LOC) model for the BLR that approximately reproduces the broad emission-line strengths of the strongest UV lines (Ly α and C iv) in NGC 5548. Within this LOC framework, we explore how assumptions about the gas hydrogen density and column density distributions influence flux and delay spectra of the DC. We find that: (i) models which match well measured emission-line luminosities and time delays also produce a significant DC component, (ii) increased $\rm {\mathit{ n}_H}$ and/or $\rm {\mathit{ N}_H}$, particularly at smaller BLR radii, result in larger DC luminosities and reduced DC delays, (iii) in a given continuum band the relative importance of the DC component to the measured interband delays is proportional (though not 1:1) to its fractional contribution to the total light in that band, (iv) the measured DC delays and DC variability amplitude depend also on the variability amplitude and characteristic variability time-scale of the driving continuum, (v) the DC radial surface emissivity distributions F(r) approximate power laws in radius with indices close to −2 (≈1:1 response to variations in the driving continuum flux), thus their physics is relatively simple and less sensitive to the unknown geometry and uncertainties in radiative transfer. Finally, we provide a simple recipe for estimating the DC contribution in disc reverberation mapping experiments.
Outflowing gas in a compact ionization cone in the Seyfert 2 galaxy ESO 153-G20
Authors: Soto-Pinto Pamela , Nagar Neil M , Finlez Carolina , Ramakrishnan Venkatessh , Muñoz-Vergara Dania , Slater Roy , Humire Pedro K , Storchi-Bergmann Thaisa , Lena Davide , Kraemer Steven B , Fischer Travis C , Schmitt Henrique R , Riffel Rogemar A , Schnorr-Müller Allan , Robinson Andrew , Crenshaw D Michael , Elvis Martin S
Published: August 2019

We present two-dimensional ionized gas and stellar kinematics in the inner 1.4 × 1.9 kpc2 of the Seyfert 2 galaxy ESO 153-G20 obtained with the Gemini-South/Gemini multi-object spectrograph integral field unit (GMOS-IFU) at a spatial resolution of ~250 pc and spectral resolution of 36 km s−1. Strong [O iii], Hα, [N ii] and [S ii] emission lines are detected over the entire field of view. The stellar kinematics trace circular rotation with a projected velocity amplitude of ±96 km s−1, a kinematic major axis in position angle of 11°, and an average velocity dispersion of 123 km s−1. To analyse the gas kinematics, we used aperture spectra, position–velocity diagrams and single/double Gaussian fits to the emission lines. All lines show two clear kinematic components: a rotating component that follows the stellar kinematics, and a larger-dispersion component, close to the systemic velocity (from which most of the [O iii] emission comes), mainly detected to the south-west. We interpret this second component as gas outflowing at ∼400 km s−1 in a compact (300 pc) ionization cone with a half-opening angle ≤40°. The counter-cone is probably obscured behind a dust lane. We estimate a mass outflow rate of 1.1 M$\odot$ yr−1, 200 times larger than the estimated accretion rate on to the supermassive black hole, and a kinetic to radiative power ratio of 1.7 × 10−3. Bar-induced perturbations probably explain the remaining disturbances observed in the velocity field of the rotating gas component.
Exploring galaxy dark matter haloes across redshifts with strong quasar absorbers
Authors: Christensen L , Møller P , Rhodin N H P , Heintz K E , Fynbo J P U
Published: August 2019

Quasar lines of sight intersect intervening galaxy discs or circumgalactic environments at random impact parameters and potential well depths. Absorption line velocity widths (Δv90) are known to scale with host galaxy stellar masses, and inversely with the projected separation from the quasar line of sight. Its dependence on stellar mass can be eliminated by normalizing with the emission-line widths of the host galaxies, σem, so that absorbers with a range of Δv90 values can be compared directly. Using a sample of DLA systems at 0.2 <z < 3.2 with spectroscopically confirmed host galaxies, we find that the velocity ratio Δv90/σem decreases with projected distances from the hosts. We compare the data with expectations of line-of-sight velocity dispersions derived for different dark matter halo mass distributions, and find that models with steeper radial dark matter profiles provide a better fit to the observations, although the scatter remains large. Gas outflows from the galaxies may cause an increased scatter, or scale radii of dark matter halo models may not be representative for the galaxies. We demonstrate by computing virial velocities, that metal-rich DLAs that belong to massive galaxy haloes (Mhalo ≈ 1012 M⊙) mostly remain gravitationally bound to the haloes.
Planetary systems in a star cluster I: the Solar system scenario
Authors: Flammini Dotti Francesco , Kouwenhoven M B N , Cai Maxwell Xu , Spurzem Rainer
Published: August 2019

Young stars are mostly found in dense stellar environments, and even our own Solar system may have formed in a star cluster. Here, we numerically explore the evolution of planetary systems similar to our own Solar system in star clusters. We investigate the evolution of planetary systems in star clusters. Most stellar encounters are tidal, hyperbolic, and adiabatic. A small fraction of the planetary systems escape from the star cluster within 50 Myr; those with low escape speeds often remain intact during and after the escape process. While most planetary systems inside the star cluster remain intact, a subset is strongly perturbed during the first 50 Myr. Over the course of time, $0.3\!-\!5.3{{\ \rm per\ cent}}$ of the planets escape, sometimes up to tens of millions of years after a stellar encounter occurred. Survival rates are highest for Jupiter, while Uranus and Neptune have the highest escape rates. Unless directly affected by a stellar encounter itself, Jupiter frequently serves as a barrier that protects the terrestrial planets from perturbations in the outer planetary system. In low-density environments, Jupiter provides protection from perturbations in the outer planetary system, while in high-density environments, direct perturbations of Jupiter by neighbouring stars is disruptive to habitable-zone planets. The diversity amongst planetary systems that is present in the star clusters at 50 Myr, and amongst the escaping planetary systems, is high, which contributes to explaining the high diversity of observed exoplanet systems in star clusters and in the Galactic field.
Not so different after all: properties and spatial structure of column density peaks in the pipe and Orion A clouds
Authors: Román-Zúñiga Carlos G , Alfaro Emilio , Palau Aina , Hasenberger Birgit , Alves João F , Lombardi Marco , Sánchez G Paloma S
Published: August 2019

We present a comparative study of the physical properties and the spatial distribution of column density peaks in two giant molecular clouds (GMCs), the Pipe Nebula and Orion A, which exemplify opposite cases of star cluster formation stages. The density peaks were extracted from dust extinction maps constructed from Herschel/SPIRE far-infrared images. We compare the distribution functions for dust temperature, mass, equivalent radius, and mean volume density of peaks in both clouds, and made a more fair comparison by isolating the less active Tail region in Orion A and by convolving the Pipe Nebula map to simulate placing it at a distance similar to that of the Orion Complex. The peak mass distributions for Orion A, the Tail, and the convolved Pipe have similar ranges, sharing a maximum near 5 M⊙ and a similar power-law drop above 10 M⊙. Despite the clearly distinct evolutive stage of the clouds, there are very important similarities in the physical and spatial distribution properties of the column density peaks, pointing to a scenario where they form as a result of uniform fragmentation of filamentary structures across the various scales of the cloud, with density being the parameter leading the fragmentation, and with clustering being a direct result of thermal fragmentation at different spatial scales. Our work strongly supports the idea that the formation of clusters in GMC could be the result of the primordial organization of pre-stellar material.
“Dynamic Dualism”: Kurth and Riemann on Music Theory and the Mind
Authors: Tan Daphne
Published: August 2019

This article examines Ernst Kurth’s critical engagement with the ideas of Hugo Riemann and his eventual reformulation of harmonic dualism in dynamic terms. The principle of “dynamic dualism” appears most cogently in Musikpsychologie ([1931] 1947). After discussing the broader psychological movement within which this book emerged, I outline the aims and audience of Musikpsychologie and provide a detailed discussion of the dynamic dualism Kurth articulates therein. I then return to the origin of Kurth’s fascination with dualism, namely to Riemann, tracing points of intersection between the two figures across several decades. I suggest that Kurth’s displeasure with Riemann’s theories is symptomatic of a broader philosophical disagreement over the explanatory power of music theory and its relation to psychology at the time.
Six-Year Response of Northern Hardwoods to the Selection System
Authors: Mader Stephen F. , Nyland Ralph D.
Published: August 2019

During 6 years following selection cutting, three northern hardwood stands grew 2.8 to 3.3 square feet in basal area and 316 to 332 board feet (Int.) per acre per year. Over two-thirds of the volume accrued on trees at least 16 inches dbh. Individual trees grew most rapidly at lowest residual basal areas, with growth of small trees most sensitive to differences in stand density. Irregularities in the diameter distribution became less distinct during the 6 years. About 60 to 70% of the regeneration was of commercial species, and more than 316 seedlings per acre grew to heights of at least 6 feet. Most plots with 6-foot regeneration had advance seedlings at least 1 foot tall at the time of cutting. Results confirm the validity of the selection system, and indicate that uneven-aged northern hardwood stands with a reasonably well-balanced diameter distribution can be repeatedly cut at 12- to 15-year intervals to a constant, optimum diameter distribution. North. J. Appl. For. 1:87-91, Dec. 1984.
Volume and Value Growth of Hardwood Trees in Wisconsin
Authors: Buongiorno Joseph , Hseu Jiing-Shyang
Published: August 2019

The volume of healthy trees of commercial size in the maple-birch forest type measured during the last two Forest Inventory Analysis surveys of Wisconsin grew at 2 to 3%/yr for sawtimber, and 3 to 4% for poletimber, with substantial differences among species. However, from 1967 to 1989, the real price of logs decreased or remained constant for most grades and species. The decrease was especially large for high grade logs. The only exceptions were red oak and elm, whose prices increased at 1 to 2%/yr, for all grades. As a result, the average value growth rate of the trees that did not improve in grade was a modest 2%/yr, and not different from zero at a 5% significance level. Holding high grade trees led to substantial losses. Red oak and elm provided good returns because of favorable price trends, and quaking aspen because of its fast volume growth. Among the worst financial performers were hard and soft maple and yellow birch, the most numerous trees in the sample. A simple equation was derived to predict volume growth rates as a function of tree diameter, site index, crown ratio, stand basal area, crown dominance, and tree species. Although these variables did influence volume growth, suggesting that silvicultural practices could be beneficial, they explained only a small part of volume growth, and less of value growth. The future of commercial forestry in Wisconsin depends at least as much on policies that will develop markets and obtain good prices as on improved silviculture. North. J. Appl. For. 10(2): 63-69.
Response of Suppressed White Pine Saplings to Release During Shelterwood Cutting
Authors: Kelty Matthew J. , Entcheva Petya K.
Published: August 2019

The need for herbicide control of hardwood understories is widely recognized for successful regeneration of white pine, because of the slow height growth of pine seedlings; however, it is often not carried out in the low-investment silviculture frequently practiced in New England. This study examined the ability of suppressed white pine saplings to respond to release following a shelterwood establishment cut where no hardwood control was done. Measurements of regeneration were made 11 yr after cutting in a mature pine-oak stand on a till soil in central Massachusetts. Pine seedlings established after the cut were surpassed in height by hardwood seedling and sprout growth. Older suppressed pine saplings which predated the establishment cut (10 to 38 yr old at the time of the cut, with mean heights of 0.4 to 2.0 m) quickly responded to release and grew to mean heights of 3.8 to 5.1 m 11 yr after cutting; these were within 1.5 m of the height of the tallest hardwoods. Retention of older pine saplings during shelterwood establishment cutting may provide a way of maintaining a white pine component in newly regenerated stands, particularly where herbicide control of hardwood competition is not planned. North. J. Appl. For. 11(1):166-169.
Performance of Japanese and Hybrid Larch Progenies in Pennsylvania
Authors: Zaczek James J. , Steiner Kim C. , Shipman R. D.
Published: August 2019

Two series of larch progeny tests were established at three locations in Pennsylvania in the spring of 1984. The Penn Orchard series contained progenies of 24 "plus-tree" Japanese larch clones growing in a seed orchard in Pennsylvania, two production seedlots of Japanese larch, and two lots of Japanese x European larch hybrids. The Westvaco test contained 5 hybrid seedlots and 15 seedlots of Japanese larch originating from 9 seed orchards (including Penn "A" Orchard), 5 plantations, and one natural stand. After 7 yr, only one site was clearly ideal for Japanese larch, having produced both rapid growth (0.83 and 0.99 m/yr) and high survival. Survival or growth was considerably lower at the other two sites, probably because of both seasonally excessive and deficient soil moisture. Hybrid lots were significantly shorter than others at the best site; they tended to survive significantly better than Japanese larch at the other two sites, but they did not necessarily grow taller. Progenies from seed orchards were not significantly faster growing than those from plantations or natural stands (Westvaco test); and progenies from select trees in the Penn Orchard test were not significantly faster growing than production lots. Although genetic effects on 7 yr height were significant in most individual plantations, few seedlots could be statistically distinguished as superior or inferior in growth rate. Seedlot pedigree had much less influence on growth rate or survival than did choice of site. North. J. Appl. For. 11(2):53-57.
Three Basal Area Level Harvest Trials in Uneven-Aged Northern Hardwoods
Authors: Orr Blair D. , Reed David D. , Mroz Glenn D.
Published: August 2019

Beginning in 1958, northern hardwood stands with initial basal areas ranging from 93 to 106 ft²/ac were harvested to residual basal areas of 70, 55, and 40 ft²/ac. Subsequent harvests of the stands over a 32-yr period illustrated potential treatments available to absentee owners of similar stands in small woodlots. In all cases stand quality improved and stand structure became more balanced, with a decrease in the number of trees greater than 20 in. dbh. At discount rates of 2% to 4%, economic returns were greatest for the 70 ft² treatment with a 10 yr cutting cycle. At discount rates of 6, 8, and 10%, the 55 and 40 ft² treatments with 18-and 22-yr cutting cycles, respectively, outperformed the 70 ft² treatment due to greater volume removed during the first (1958) harvest. North. J. Appl. For. 11(4):117-123.
The Effects of Full-Tree and Tree-Length Harvests on Natural Regeneration
Authors: McInnis Bryce G. , Roberts Mark R.
Published: August 2019

Changes in density and stocking of natural regeneration were analyzed for paired full-tree (delimbed off-site) and tree-length (delimbed on-site) clearcuts applied side by side in three mixed stands. No special effort was made to preserve advance regeneration. Three-stand means indicated larger advance softwood regeneration losses on the tree-length sites during harvests, suggesting greater direct mechanical damage, but larger softwood losses occurred on the full-tree sites during the first summer after harvests, suggesting a more stressful postharvest environment. After 1 yr, losses of advance spruce and fir did not differ significantly between treatments within stands. Recruitment of intolerant and intermediate hardwoods was greater after the full-tree harvests, probably because of higher levels of solar radiation. Results indicate (a) significantly greater densities of intolerant and intermediate hardwoods after full-tree harvests of mixed stands, and (b) that with care taken to preserve advance growth during harvests, advance softwood survival is better when slash is left on cutovers. North. J. Appl. For. 11(4): 131-137.
Shoot and Root Growth of Northern Red Oak Planted in Forest Openings and Protected by Treeshelters
Authors: Ponder Felix
Published: August 2019

Artificial regeneration has been suggested as one way to increase the oak component of harvested forest in the Central Hardwood Region. Openings in forest stands on the Mark Twain National Forest in southern Missouri were planted to northern red oak seedlings with and without treeshelters. Three years after planting, stem growth, survival, the number of branches, and stem and leaf dry weights were significantly greater for seedlings with treeshelters than for seedlings without them. Root parameters for sheltered seedlings, including root length and total and tap root dry weights, were significantly greater than for unsheltered seedlings. There were no significant differences in diameter growth between treatments. Both temperature and humidity were significantly higher inside shelters than outside. Foliar levels of phosphorus, calcium, manganese, and boron were significantly higher in leaves from sheltered seedlings than in leaves from seedlings without shelters. The use of treeshelters could aid in increasing the oak component of newly regenerated hardwood stands. North. J. Appl. For. 12(1): 36-42.
Harvesting Method Affects Survival of Black Spruce Advance Growth
Authors: Groot Arthur
Published: August 2019

Careful harvesting to preserve advance growth is an attractive regeneration option for many peatland black spruce stands. Success of this option depends on enough well-distributed trees surviving harvesting. This study examines the fate of black spruce advance growth following overstory harvesting by three methods. About 80% of the original advance growth stocking remained after winter harvesting, 70% after summer harvesting using wide-tired skidders, and 60% after summer harvesting using narrow-tired skidders. Mortality of advance growth occurred mainly during harvesting and in the first growing season after harvesting. North. J. Appl. For. 12(1):8-11.
Preliminary Site Index Equations for Three Planted Species in Northern Ontario
Authors: Payandeh Bijan , Wang Yonghe
Published: August 2019

Stem analysis data from plantations of black spruce, white spruce, and jack pine from northern Ontario were fitted to base-age specific and base-age invariant site index models. The resulting equations and their respective parameters were compared via nonlinear analysis of covariance. The base-age specific models produced a somewhat better fit to the data than their base-age invariant counterparts, although the latter are considered theoretically more elegant. Graphical comparison of plantation and natural stand site index curves for the three species showed both similarities and differences. North. J. Appl. For. 12(2):57-63.
Growth and Morphology of Black Spruce, Jack Pine, and White Spruce Container Seedlings in Northern Ontario
Authors: Jalkanen Anneli
Published: August 2019

The development of morphological attributes of containerized seedlings during the growing season was studied in eight crops from three nurseries in Northern Ontario, including four black spruce crops, three jack pine crops, and one white spruce crop. The variability was proportionally largest in root and shoot dry mass, followed by height and diameter. During seedling growth, proportionally the variability of size did not seem to increase. In absolute scale, however, differences between individual seedlings increased more than differences between seedling trays, possibly due to competition between individuals. Height and shoot growth were greater in the beginning of the growing season, and diameter and root growth were greater toward the end. In comparison to standards, the balance between morphological attributes (height/diameter, shoot/root) was usually acceptable, and usually independent of seedling size. The easiest way of monitoring crop development is to take seedling samples at regular intervals and to construct a growth progression curve for seedling height, if diameter growth reaches acceptable level. Care should be taken that the height of seedlings does not increase too much at the expense of diameter and root development in the larger crops. To monitor this, height-diameter ratios and shoot-root ratios might be measured a couple of times during the growing season to take corrective action if necessary. North. J. Appl. For. 12(2):69-74.
Growth of Multipot Black Spruce Seedlings Planted After Site Preparation with Liquid and Dry-Flowable Hexazinone
Authors: Reynolds Phillip E. , Roden Michael J.
Published: August 2019

Liquid (VELPAR L) and dry-flowable (VELPAR ULW) hexazinone (2 kg ai/ha) were aerially applied to a northern New Brunswick clearcut to reduce raspberry competition. Treatments were applied in June 1987; planting with containerized (multipot) black spruce was conducted 2 and 14 months after treatment in August 1987 and August 1988, respectively. Seedling survival and growth were measured yearly through August 1991. Five growing seasons after treatment, raspberry competition was generally less in treated plots than in controls. Hexazinone formulation did not affect raspberry control, seedling survival, or growth. Seedlings planted 14 months after hexazinone treatment grew poorly compared with those planted 2 months after herbicide treatment. Both height and stem diameter of seedlings planted 2 months after hexazinone treatment remained greater than that of control seedlings through 1991. Diameter of treated seedlings exceeded that of control seedlings in the first growing season after planting; height of treated seedlings exceeded control seedlings 3 growing seasons after planting. Fourth-year stem diameter of seedlings planted 2 months after hexazinone treatment was correlated with raspberry cover (r² = 0.383) and with raspberry height (r² = 0.379). As raspberry competition increased, black spruce growth decreased. North. J. Appl. For. 12(2):75-79.
Ecological Aspects of Forest Management Planning: A Northern Hardwood Forest Case Study
Authors: Tritton Louise M. , Sendak Paul E.
Published: August 2019

In a stand managed for timber production, increased crown dieback and mortality of trees generally signal a need for reevaluating site conditions, management objectives, and harvesting practices. In this paper, we describe a case study of a northern hardwood forest stand intended for timber production but showing crown dieback and mortality. Plans for a diameter-limit cut were confounded by the presence of diseased and poor quality trees (especially sugar maples), a history of high-grading, and fair to poor site characteristics for sugar maple growth over much of the area. After evaluating the site, we suggested a revised management plan including a shelterwood cut favoring regeneration of both yellow birch and sugar maple. Forest management decisions based on ecological and economic considerations can promote both the long-term health and productivity of forest stands. However, management for long-term health and productivity are not likely to be accomplished under current market conditions in much of New England. North. J. Appl. For. 12(3):121-126.
Adequacy of Advance Tree-Seedling Regeneration in Pennsylvania's Forests
Authors: McWilliams William H. , Stout Susan L. , Bowersox Todd W. , McCormick Larry H.
Published: August 2019

Measurement of tree seedlings and herbaceous vegetation from 499 sample locations across Pennsylvania revealed that advance tree-seedling regeneration is inadequate for new stand establishment across most of the State. The samples were located in stands from 40% to 75% stocked to focus on stands with ample light and growing space for establishment of abundant advance regeneration. A range of regeneration adequacy criteria was applied to the measurements. Using the least stringent criterion, a low density of stems of any tree species, resulted in 40% of the sample locations being adequately stocked. Applying the most stringent criterion, a high density of stems of desirable species, resulted in only 4% of the sample locations being adequately stocked. With the exception of forest-type group, no significant relationship was found between the adequacy of regeneration and other variables tested at the broad level of geographic scale of this study. Levels of fern and grass sufficient to hamper tree-seedling development were found at 54% of the sample locations. Fern species that propagate primarily by spreading rhizomes accounted for 70% of the total fern sample. North. J. Appl. For. 12(4):187-191.
Rehabilitating a Young Northern Red Oak Planting with Tree Shelters
Authors: Gillespie Andrew R. , Rathfon Ronald , Myers Richard K.
Published: August 2019

Methods for deer browse protection are becoming a necessary aspect of hardwood silviculture, particularly with practices such as artificial regeneration of oaks. This study tested the effectiveness of two types of deer protection for aiding the rehabilitation of a failed northern red oak planting in southern Indiana. Tree shelters, bar soap repellent, and no protection (control) treatments were applied to 1 yr old, coppice-origin oak shoots arising from 8 yr old root-stocks of an unsuccessful 1980 old-field research planting. Oaks in tree shelters exhibited significantly greater early shoot growth than did unsheltered oaks. This height advantage was maintained, but not increased once tree crowns emerged from the shelter environment. After 5 growing seasons, oaks receiving the soap repellent treatment began to increase their rate of height growth. Continuation of this trend could negate early growth advantages of tree shelters. The use of tree shelters may improve the success of attempts to regenerate preferred browse species such as oaks, but concerns of practicality and economics remain. North. J. Appl. For. 13(1):24-29.
Short-Term Performance of Three Hexazinone Formulations: Efficacy, Seedling Survival, and Growth
Authors: Reynolds Phillip E. , Roden Michael J.
Published: August 2019

Granular (PRONONE 10G and 5G) and liquid (VELPAR L) hexazinone (1 to 4 kg ai/ha) were applied to a northern New Brunswick clearcut (loams, silt loams, and clay loams) to reduce raspberry competition. Treatment, using skidder-mounted herbicide application equipment, occurred in May and September 1986, with planting of 2+2, bareroot, black spruce seedlings in June 1986 and in June 1987. Seedling survival and growth were measured yearly for 5 growing seasons after planting. By August 1991, hexazinone formulation did not affect raspberry control, seedling survival, or growth. Raspberry cover for the 4 kg ai/ha treatment and for fall treatments remained less than that for controls. Survival of seedlings planted approximately 1 month after spring treatment was less than controls, but seedling stem volume was greater than that of control seedlings for most treatments. Survival and stem volume of seedlings planted approximately 1 yr after spring treatment or 9 months after fall treatment were greater than that of control seedlings for most treatments. Best survival and growth occurred for seedlings planted 1 yr after spring treatment. Fifth-year stem volume for these seedlings was correlated with raspberry cover (r2 = 0.35), decreasing as raspberry cover increased. We conclude that the use of the PRONONE 10G formulation offers operational advantages over the liquid formulation. North. J. Appl. For. 13(1):41-45.
The Korean Market for Temperate Hardwoods: A Comparison of Trade Statistics
Authors: Blatner Keith A. , Lee Sang-Min , Chapman Roger C. , Hansen Bruce
Published: August 2019

The Republic of Korea (Korea) is the second largest Asian market for temperate hardwood log and lumber exports from the United States and the subject of intense interest by exporters. The following paper summarizes recent trends in the Korean temperate hardwood market and explores the major problems encountered in attempting to reconcile Korean and U.S. trade statistics for these products. Major problems identified include: known reporting errors, apparent recording errors, shipping time, misclassification and aggregation errors, and the possible resale of log and lumber products on the high seas. Discrepancies in Korean/Canadian trade statistics for temperate hardwoods are also presented and discussed. North. J. Appl. For. 13(1):59-67.
Importance of Tree Cavities as Natal Dens for Fishers
Authors: Paragi Thomas F. , Arthur Stephen M. , Krohn William B.
Published: August 2019

We determined characteristics of natal dens used by radio-collared fishers in southcentral Maine. Twelve adult (≥2 yr old) females were monitored for periods of 1-5 yr each during 1984-1989. Estimated whelping dates of 12 litters were March 3-April 1, and females used 1-5 natal dens each until denning ended in early June. All 33 natal dens were in tree cavities on upland sites. Hardwoods composed 94% of the den trees, with aspens accounting for 52%. We recommend that forestry practices allow for a continued supply of mature and decadent hardwoods > 40 cm dbh to replace cavity trees that fall. Where cavity trees must be removed, cutting should be done outside the March-June denning period to avoid disturbance or mortality of fisher litters. North. J. Appl. For. 13(2): 79-83.
Mapping Shifts in the Relative Stocking of Tree Species
Authors: Gansner David A. , King Susan L. , Arner Stanford L. , Drake David A.
Published: August 2019

Baseline standards for measuring the "health" of our forests do not exist. But, one factor that can be considered when making judgments about the health of a particular forest tree species is change in the relative stocking of that species, that is, the extent to which the species isgaining or losing ground in its ecosystem. The forest survey unit at the Northeastern Forest Experiment Station used remeasured forest inventory plot data to estimate current average annual change in the relative stocking of common forest tree species in Pennsylvania. Spatial shifts in therelative stocking of individual species were mapped. The procedure can be readily extended to other species in other regions. Information on shifts in relative stocking can provide a symptomatic guide to recognizing problems of forest health, and it gives us a better understanding of the complexworkings of a dynamic ecosystem. North. J. Appl. For. 13(2):92-95.
Decreasing Woodlot Size and the Future of Timber Sales in Massachusetts: When Is an Operation Too Small?
Authors: Kittredge David B. , Mauri Michael J. , McGuire Edward J.
Published: August 2019

The heavily forested landscape of Massachusetts is dominated by nonindustrial private ownerships. Statistics indicate that parcel size has decreased to a most recent average of 10.6 ac. Professional loggers were queried to determine if there was a timber sale size (expressed in eithervolume or area) below which they would not bid. Respondents indicated that they had operated on a timber sale as small as an average of 7.8 ac and 20.4 mbf, and would purchase one as small as an average of 5.3 ac and 17.1 mbf. The single most important factor in deciding to bid on a smallsale was the quality and value of the timber. In the future, small parcels with a preponderance of low-quality timber resulting from high-grading may be deemed inoperable by loggers. The importance of high quality timber on small parcels emphasizes the need for stand improvement measures toensure small parcels are feasible to commercially operate in the future. North. J. Appl. For. 13(2):00-00.
Forestry-Related Educational Needs of Innovative Ohio Sawmill Operators
Authors: Bratkovich Stephen M. , Floyd Donald W. , Miller Larry E.
Published: August 2019

Thirty-two innovative Ohio sawmill operators were surveyed to assess perceived "job importance" and their "current knowledge" of 67 job-related skills divided into 6 subject areas. The discrepancy or gap between importance and knowledge scores was used to compute perceived educational need scores for the skills, 21 of which are highlighted in this paper. Although the subject area of "sawmill production" was ranked first by sawmill operators in both importance and knowledge, the areas of "environmental awareness" and "forest product marketing" had the highest perceived educational need. Seventy-five percent of the forests-related skills received "high" importance scores; however, with the exception of "maintaining an adequate log supply," forestry-related skills ranked in or near the bottom-half of all skills in perceived educational need. Sawmillers rated their knowledge of forestry-related skills such as "understanding the benefits of TSI" higher than their knowledge level of skills such as "exporting lumber" and "developing new wood products." Recommendations are given for field foresters to assist them in initiating a meaningful dialogue with sawmill operators to help bridge the often-encountered communication gap between sawmiller, forester, and NIPF landowner. North. J. Appl. For. 13(3):135-139.
Financial Performance of Maple-Birch Stands in Wisconsin: Value Growth Rate Versus Equivalent Annual Income
Authors: Hseu Jiing-Shyang , Buongiorno Joseph
Published: August 2019

The value growth rate and equivalent annual income per acre were computed for the maple-birch plots measured at the last two Wisconsin forest inventories. The computations reflected stand growth as well as real price changes between the two inventories. The equivalent annual income averaged $13/ac/yr on industrial forests, and $8.50/ac/yr on public and other private lands. Stand value growth rates, in percent per year, suggested much higher returns, but they are misleading because many of the stands that grew fast were understocked and gave low returns per acre. At the other extreme, some of the best stocked stands (highest basal area) also were poor financial performers. A regression equation showed that the stands of highest equivalent annual income were on better sites, had a basal area of about 80 ft²/ac, a large number of smaller poles ready to become sawtimber, large proportions of oak, elm, ash, and cherry trees, and few aspen or softwoods. No single variable had a major effect by itself, but within the range of the data, by changing all of them together, the annual income on land of average site index could double. North. J. Appl. For. 14(2):59-66.
Optimal Management of Shortleaf Pine Plantations in the Central United States
Authors: Pelkki Matthew H.
Published: August 2019

A dynamic programming (DP) algorithm was developed for shortleaf pine in the Central United States. All thinning strategies examined (above, below, above and below, and mechanical) improved economic returns with thinning from above returning the highest soil expectation value (SEV). A planting density of 500 trees/ac maximized economic returns under all economic conditions. SEV was found to increase with site, and rotation length decreased on better sites. As sawtimber stumpage prices decreased relative to pulpwood prices, thinning was no longer economically advantageous. Finally, under conditions of uncertainty related to future prices, rotation length decreases slightly. North. J. Appl. For. 14(2):67-71.
Rate of Sawtimber Volume and Value Growth of Individual Sugar Maple Trees in Managed, Uneven-Aged Stands in the Lake States
Authors: Reed David D. , Mroz Glenn D.
Published: August 2019

While volume growth of individual sawtimber trees is dependent on changes in diameter and merchantable height, value growth is dependent on these along with changes in tree quality, the quality of logs recovered from the tree, and market prices. For sugar maple and other northern hardwood species, quality development is at least as important as biological growth in determining value growth, making development of silvicultural prescriptions and marking guidelines complex but extremely important for maximizing returns. This paper utilizes projection methods from the literature to develop expected rates of biological and value growth for sugar maple in managed, uneven-aged forests. These rates are presented by 2 in. diameter class and one-half 16 ft log merchantable height classes. Based on the models, the projected rate of biological growth increases with tree diameter and decreases with merchantable height. The rate of value growth generally increases with tree diameter and decreases with merchantable height, but the relationships with tree grade are complex. North. J. Appl. For. 14(2):78-83.
Effectiveness of Diflubenzuron and Bacillus thuringiensis Against Gypsy Moth Populations
Authors: Thorpe Kevin W. , Ridgway Richard L. , Webb Ralph E.
Published: August 2019

Aerial applications of Bacillus thuringiensis Berliner subsp. kurstaki (74.1 billion international units/ha per application; single and double applications), diflubenzuron [69 g (ai)/ha], and no treatment were evaluated. Treatment effects were estimated from frass collections, defoliation, counts of pupae under burlap, and egg-mass counts. Estimates of larval density in the canopy 20 days after treatment ranged from 318.3 to 55.5 larvae per m² in the control- and diflubenzuron-treated plots, respectively. Larval density was reduced in all treatments, and was lowest in the plots treated with diflubenzuron and two applications of B. thuringiensis. Population density rapidly declined in the control plots, and by June 20, when larvae were predominantly in the fifth and sixth instars, no significant differences in larval density were detected among the treatments. Significantly less defoliation occurred to oak trees in the treated plots, but no differences were detected among the spray treatments. Counts of pupae under burlap, postseason egg-mass counts, and percent reduction in egg-mass density did not differ significantly among treatments or versus controls. These results suggest that diflubenzuron and double B. thuringiensis treatments caused higher levels of larval mortality than occurred with a single B. thuringiensis application, but that with a naturally declining gypsy moth population the final levels of damage were the same under all treatments. North. J. Appl. 14(3):135-140.
Wildlife Responses to Thinning Red Pine
Authors: Bender Louis C. , Minnis Donna L. , Haufler Jonathan B.
Published: August 2019

Red pine is the most intensively managed conifer type in the Lake States, but its typical stand structure of a closed canopy with little understory results in poor wildlife habitat. We evaluated the effects of thinning mature red pine stands on wildlife habitat attributes and use. Red pine stands were thinned to a residual basal area of 16.1 m²/ha and 25.3 m²/ha and compared with controls (>32.1 m²/ha) in terms of understory development, small mammal use, and ungulate use. Overstory thinning resulted in increased woody shrub densities and understory productivity. Small mammal populations tended to increase with overstory thinning, but the results were inconclusive. Elk and deer use increased with overstory removal. Increased ungulate use was likely attributable to increased forage quantity and quality and increased hiding/security cover attributes of the thinned stands. We conclude that overstory thinning can be an effective means of enhancing wildlife habitat and increasing wildlife use of red pine. North. J. Appl. For. 14(3):141-146.
Modeling Impacts of Forest Roads on Recreation Opportunities
Authors: Queen LLoyd P. , Vlaming Jonathan C. , Arthaud Greg J. , Lime David W.
Published: August 2019

Transportation systems are one of the key components of forest recreation activities, yet they are often overlooked and seldom adequately considered in the planning process. This paper presents a road impact model (RIM) used to analyze transportation networks to determine their impact on recreation opportunities in an area. Four categories of opportunities are considered in this analysis: experiential recreation, physical recreation, transportation network, and aesthetics. The RIM model is demonstrated on a test area utilizing a geographic information system (GIS) to aid in spatial data handling. The case study presents and demonstrates an assessment framework based on simplified interpretations of the four identified opportunity classes. This spatially explicit approach will aid recreation planning through providing information on current recreation opportunities and on potential recreation opportunities driven by changes to the road or trail systems in an area. North. J. Appl. For. 14(4):194-201.