bluuebunny/crossref_metadata_2025_split huggingface dataset:
Understory plant responses to uneven-aged forestry alternatives in northern hardwood–conifer forests
Authors: Smith Kimberly J. , Keeton William S. , Twery Mark J. , Tobi Donald R. 
Published: June 2008

The understory layer encompasses the majority of plant species diversity in forested ecosystems and may be sensitive to timber harvest disturbance. We hypothesize that (i) uneven-aged, low-intensity silvicultural systems can maintain understory plant diversity and support late-successional species following harvest disturbance; (ii) retaining and enhancing stand structural complexity can increase understory plant diversity in northern hardwood–conifer forests; and (iii) plant responses are influenced by interactions among canopy structure, soils, and climate processes. Experimental treatments include single-tree selection and group selection, both modified to increase structural retention, and a third technique designed to promote late-successional forest structure and function, structural complexity enhancement. Four replications of each treatment were applied to 2 ha units in Vermont and New York, USA. Understory vegetation was monitored 2 years pre- and 4 years post-treatment. Results show that over time, understory responses were strongly affected by overstory treatment and less influenced by soils and drought. All treatments succeeded at maintaining overall composition and diversity. However, late-successional diversity increased significantly in structural complexity enhancement units compared with group selection units. These results indicate that while conventional uneven-aged systems can maintain understory plant diversity, variations that retain or enhance structural complexity may be more effective at retaining late-successional species.
Natural durability of black locust (Robinia pseudoacaciaL.) wood grown in Wallonia, Belgium
Authors: Pollet Caroline , Jourez Benoit , Hébert Jacques 
Published: June 2008

The decay resistance of black locust ( Robinia pseudoacacia L.) heartwood was evaluated on standardized test specimens taken from mature and juvenile wood in 25 trees distributed over five sites in Wallonia, Belgium. The percentage mass losses caused by the wood-destroying fungi Coriolus versicolor CTB 863 A and Coniophora puteana BAM Ebw.15 were evaluated according to Cen/ts 15083-1 (Cen/ts 15083-1. 2005. Durability of wood and wood-based products — determination of the natural durability of solid wood against wood-destroying fungi, test methods — Part 1: Basidiomycetes. European Comm. for Standardization, Brussels). Black locust is classified as a “very durable” wood (class 1), while the juvenile heartwood (located near the pith) is classified in classes 1 to 2. The statistical analysis does not reveal any significant differences among the sites, suggesting that the growth environment of the trees has no effect on their natural durability. However, statistical analysis shows very highly significant differences among trees and between the two radial positions in the tree, with mature wood being more resistant than juvenile wood. Using such a naturally very durable species could reduce reliance on preservative treatment and the use of tropical species generally recommended for outdoor woodwork.
Impacts of a regional drought on the productivity, dieback, and biomass of western Canadian aspen forests
Authors: Hogg E. H. (Ted) , Brandt J. P. , Michaelian M. 
Published: June 2008

We examined the impacts of a severe, regional drought (2001–2002) on trembling aspen ( Populus tremuloides Michx.) forests in the western Canadian interior. A total of 150 plots were established in 25 study areas as part of a regional-scale study (CIPHA). Aspen health and mortality were assessed annually during 2000–2005, and changes in stem biomass were estimated using tree-ring analysis and plot-based measurements. Net mean increment in living biomass for all plots was 2.2 t·ha–1·year–1 during 2000–2002 but subsequently decreased to near zero. This collapse was driven by a more than two-fold increase in stem mortality and a 30% decrease in regional stem growth during and following the drought. The analysis showed that spatial variation in aspen productivity and biomass across the region was positively related to multiyear mean values of a climate moisture index and mineral soil silt content but was negatively related to levels of insect defoliation and wood-boring insects. In contrast, mortality and dieback was best correlated with minimum annual climate moisture index, which provided a measure of short-term drought severity. The results support previous studies showing that aspen forests are moisture limited in this region, which poses concerns for the future under a changing climate.
Response of trembling aspen to partial cutting and subsequent forest tent caterpillar defoliation in a boreal mixedwood stand in northeastern Ontario, Canada
Authors: Man Rongzhou , Kayahara Gordon J. , Rice James A. , MacDonald G. Blake 
Published: June 2008

The growth response and mortality of trembling aspen ( Populus tremuloides Michx.) were monitored 1, 3, 5, and 11 years after partially harvesting an aspen-dominated mature mixedwood stand in northeastern Ontario. Both diameter and height of aspen trees responded positively to harvesting. However, 3 years after harvest, the growth rates of residual aspen were severely suppressed by 3 years of moderate to severe defoliation by forest tent caterpillar ( Malacosoma disstria Hbn.). The diameter growth of surviving trees almost recovered, but due to continuous crown dieback in the 6 years after defoliation ceased, height growth did not. Over the 11 years after harvest, 70% of residual aspen died, with 80% of that mortality occurring in the 6 years after defoliation. Trees in the lower canopy and in the partial cut had higher mortality rates than those in the upper canopy and in the uncut control. Increased mortality at the individual tree level was generally associated with greater foliage loss. Aspen growth and mortality were associated with defoliation levels, particularly for trees in partial cut treatments. Partial cutting and crown class strongly influenced the response of aspen trees to insect defoliation and should be considered when selecting residual trees during harvesting.
Transient physiological responses of planting frozen root plugs of Douglas-fir seedlings
Authors: Islam M. Anisul , Jacobs Douglass F. , Apostol Kent G. , Dumroese R. Kasten 
Published: June 2008

Short-term physiological responses of planting frozen (FR) and rapidly thawed (TR) root plugs of Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) seedlings were examined through time series (0 h, 6 h, 12 h, 1 day, 3 days, and 7 days) measurements in two separate experiments: 10 °C day : 6 °C night, RH 75% and 30 °C day : 20 °C night, RH 50%, respectively. Net photosynthesis, transpiration, shoot water potential, and root hydraulic conductance were lower in FR compared with TR seedlings under both growing conditions. Magnitude of difference in root hydraulic conductance was higher under warm-dry conditions. Chlorophyll fluorescence (Fv/Fm) values were higher for TR than FR seedlings at 0 h, but similar thereafter for both growing conditions. Needle electrolyte leakage and chlorophyll content did not differ between FR and TR seedlings under both environmental regimes. Higher root O2uptake was observed in FR seedlings in warm-dry conditions and in TR seedlings under cool-moist conditions. TR seedlings planted under warm-dry conditions had more flushed buds and new roots than FR seedlings, while no buds flushed for both FR and TR seedlings under cool-moist conditions. Comparatively higher photosynthesic rates in TR seedlings planted under warm-dry conditions likely contributed toward more new roots, which could be advantageous for survival and early growth.
Analysis of cellulose microfibril angle using a linear mixed model in Pinus taeda clones
Authors: Isik Fikret , Gumpertz Marcia , Li Bailian , Goldfarb Barry , Sun Xuan 
Published: June 2008

Variation in microfibril angle (MFA) (degrees) among loblolly pine ( Pinus taeda L.) full-sib families and clones was investigated using 43 clones from nine full-sib crosses tested at two locations. When the experiments were 12 years old, a total of 316 trees were drilled and 12 mm thick wood increment cores were collected. MFA for each growth ring in the wood core was measured using the SilviScan-2 tool. A quadratic mixed model was fitted to evaluate the MFA variation over different rings. Among the error covariance structures tested in the model, autoregressive order 1 was the best model for producing MFA estimates with the smallest errors. Estimated MFA was about 33° in the pith (ring 1) of the trees and decreased to 18° in the outer wood (ring 11). Full-sib crosses and clones within crosses explained about 12.5% of the total phenotypic variation. Repeatability of full-sib family means (H2f = 0.46) was moderate but repeatability of clone means was high (H2c = 0.79). Although it is possible to improve (decrease) MFA with recurrent selection in tree improvement programs to improve lumber quality, cost efficient and rapid methods for measuring MFA are needed.
Short-day treatment alters Douglas-fir seedling dehardening and transplant root proliferation at varying rhizosphere temperatures
Authors: Jacobs Douglass F. , Davis Anthony S. , Wilson Barrett C. , Dumroese R. Kasten , Goodman Rosa C. , Salifu K. Francis 
Published: June 2008

We tested effects of shortened day length during nursery culture on Douglas-fir ( Pseudotsuga menziesii var. menziesii (Mirb.) Franco) seedling development at dormancy release. Seedlings from a 42°N source were grown either under ambient photoperiods (long-day (LD)) or with a 28 day period of 9 h light : 15 h dark photoperiods (short-day (SD)). Seedlings were periodically removed from freezer storage from January to May. Sensitivity of plant tissues to cold temperatures was investigated via electrolyte leakage at nine test temperatures ranging from 2 to –40 °C. New root growth was assessed with rhizosphere temperatures of 10, 15, 20, and 25 °C. From 2 to –13 °C, there was no difference between treatments in cold hardiness. However, at or below –18 °C, LD seedlings exhibited higher indices of damage than SD seedlings. The LT50(temperature at which 50% cell electrolyte leakage occurred) was consistently lower for SD than LD seedlings. Rhizosphere temperature differentially influenced new root proliferation: LD seedlings had greater new root production than SD seedlings at 20 °C, whereas the opposite response was detected at 10 °C. Our results confirm photoperiod sensitivity of Douglas-fir sources from relatively low (i.e., <45°N) latitudes. Increased spring cold hardiness and greater rooting at lower rhizosphere temperatures may improve field performance potential of SD-treated seedlings.
FORMULATION ON THE EMPIRICAL EQUATION OF THE CASK IMPACT FORCES BY DIMENSIONAL ANALYSIS
Authors: LEE YOUNG-SHIN , KIM YONG-JAE , CHOI YOUNG-JIN , LEE EUN-YUP 
Published: June 2008

Radioactive material is used in the various fields. The numbers of transport for radioactive material have been gradually increased in both domestic and international regions. The safety of the cask should be secured to safely transport of radioactive material. The Korean atomic law and the IAEA safety standards prescribe regulations for the safe transport of radioactive material. The cask for spent fuel is comprised of the body and the impact limiter. In this study, the empirical equation of the cask impact force was proposed based on the dimensional analysis. Using this empirical equation the characteristics of the impact limiter were analyzed. The results are also validated by comparing with the previous results of the impact area method and the finite element analysis. The present method can be used to predict the impact force of the cask.
Cretaceous characiform fishes (Teleostei: Ostariophysi) from Northern Tethys: description of new material from the Maastrichtian of Provence (Southern France) and palaeobiogeographical implications
Authors: Otero O. , Valentin X. , Garcia G. 
Published: June 2008

Abstract

The order Characiformes (Teleostei: Otophysi) is one of the most diverse freshwater fish groups. It contains around 1400 living species in South and Central America and Africa. Their fossil record starts in the Cretaceous on both continents and also in Europe. Here, we describe and discuss the occurrences of new characiform fish teeth from Provence (Maastrichtian, S. France). Five morphological types are recognized. They belong to possibly three different taxa, and they are regarded as Characiformes indet. However, two of them have resemblances to alestin fishes and could be related to the African family Alestidae. The characiform fishes from Provence are among the oldest known in Europe, together with a freshwater characiform fish occurring in Romania, and the recently described marine fish
Sorbinicharax
from Italy. The biogeographical history of characiform fishes has been intensively discussed during the last three decades. The group is generally accepted to be Gondwanan and its diversification linked with the break-up of this continent, with two main scenarios depending on whether the group is archaeo- or telolimnic. Some authors also propose a Pangaean origin. The recent discoveries of
Sorbinicharax
and of the fossils from Provence change our view on the Cretaceous characiform diversity and their early ecology, and they also enable us to re-evaluate the proposed biogeographical scenarios, reinforcing the hypothesis of the telolimny of the group.
Palaeobiogeography of Cretaceous bony fishes (Actinistia, Dipnoi and Actinopterygii)
Authors: Cavin Lionel 
Published: June 2008

Abstract
Dispersal and vicariant patterns have been used as opposite concepts to explain biogeographical histories of organisms. Vicariance has been preferred to dispersal: the former is said to be falsifiable while the latter is regarded as a contingent hypothesis. If included in a temporal framework, however, a sister-group relationship between two taxa could be more parsimoniously explained by a dispersal event if both taxa are not contemporaneous in time. Published phylogenies of various clades of bony fishes are compared with evolution of the palaeogeographical framework during the Cretaceous, and possible causes involved in the observed patterns, such as vicariant events, dispersal events or radiations are suggested. Most Cretaceous patterns concerns east–west events (vicariance and dispersal) rather than north–south events. This is probably because the separation of Laurasia and Gondwana is already underway in the Late Jurassic and affected Cretaceous faunas only weakly. Late Cretaceous dispersal patterns constitute a more common phenomenon than previously expected. It is suggested that the entire autoecology of the fishes is a more significant parameter affecting dispersal ability than only their allegedly capacity to tolerate salt waters.
Fossil Mooneyes (Teleostei: Hiodontiformes, Hiodontidae) from the Eocene of western North America, with a reassessment of their taxonomy
Authors: Hilton Eric J. , Grande Lance 
Published: June 2008

Abstract

The skeletal anatomy of fossil hiodontids from western North America is examined based on newly-prepared specimens, including several specimens that were prepared using the acid transfer method and some using the ‘lost fossil’ technique. This study resulted in many new interpretations and clarifications, such as the presence of a curved tubular nasal bone and a posterodorsal spine on the opercle of ‘†
Eohiodon
’, as found in extant
Hiodon
. We also further describe the variation of the caudal skeleton that has been known in both fossil and extant
Hiodon
. For instance, the neural spine of preural one is most often fully developed (as it is in a minority of extant
Hiodon
specimens), although in some specimens it is rudimentary, as it is in most specimens of living taxa. We review the characters that have been used in recent analyses of relationships of osteoglossomorph fishes. After correcting the descriptions of the fossil taxa, we could find no valid synapomorphies to separate the genus †
Eohiodon
from the genus
Hiodon
. Therefore, we conclude that †
Eohiodon
should be regarded as a synonym of
Hiodon
.
Osteoglossomorphs of the marine Lower Eocene of Denmark – with remarks on other Eocene taxa and their importance for palaeobiogeography
Authors: Bonde Niels 
Published: June 2008

Abstract

The geological, faunal and palaeoecological conditions of the marine deposits from lowermost Eocene in North Jutland are briefly reviewed as background for the descriptions of six species of osteoglossiform fishes from the Stolle Klint Clay and the overlying Mo-clay (Ølst and Fur Formations respectively). Four of these primitive teleosteans are referred to new genera and species (one based on an almost complete skeleton, three others on skull material, one very incomplete), and the two most fragmentary specimens are referred to
Brychaetus
sp. and an indeterminate osteoglossiform. The phylogenetic relationships of these fossils are evaluated in the framework of two different models of osteoglossomorph phylogeny provided earlier by Taverne and Hilton. Despite differences in both data bases, methodologies and results given by the two models (the former based on
c
. 300 characters in an intuitive, qualitative phylogenetic parsimony analysis, the latter on 72 characters in a critical, rigorous, quantitative cladistic analysis) the phylogenetic positions of four of the fossil species are very similar in the two models concerning the relations to the recent forms. The other two species, rather fragmentary, but similar in many ways to the Eocene phareodonts (paraphyletic group), end up very differently in relation to extant forms in the two models. The phylogenetic systematics of all the marine, fossil osteoglossiforms (including
Brychaetus, Opsithrissops
and Monte Bolca forms) is evaluated as background for interpretation of their (palaeo-)biogeographic significance as marine members of a group, Osteoglossomorpha (of which the recent forms are prime examples of ‘primary division freshwater fishes', and of which the extant osteoglossiforms have a classical ‘Gondwana distribution’. There are 9 marine, Eocene taxa (plus an otolith from the Maastrichtian of USA) and none of the 9 appear more closely-related to any other marine form in either model: they might constitute 9 separate migrations from freshwater into the sea. The phylogenetic results strongly suggest instead, that the extant osteoglossiforms have independently entered freshwater from the sea on two, perhaps even three occasions. This may have happened as late as the Eocene, and phareodonts could be yet another independent invasion of freshwater in the Late Cretaceous. The mormyriforms most likely had an independent invasion into freshwater (in one model even with notopterids as a separate migration from the sea by Mid or Early Cretaceous). Because all the closest outgroups of the Osteoglossomorpha are marine, the group obviously originated in the sea, probably by the Late Jurassic, and it is not impossible that Hiodontiforms in NE Asia and North America underwent another independent freshwater invasion very early in the Cretaceous. What then is wanting? The expected Cretaceous, marine osteoglossomorphs are not found (but note the above otolith).
New information on the cranial anatomy of the eel genus
Echelus
Rafinesque, 1810 (Ophichthidae: Anguilliformes) from the Early Eocene
Authors: Young Sally V. T. , Williams R. J. 
Published: June 2008

Abstract

Two neurocrania of the eel genus
Echelus
Rafinesque, 1810 were collected from the London Clay Formation, Eocene, from Aveley, Essex. They are identified herein as
E. branchialis
Woodward, 1901. One specimen retains an incomplete premaxillary ethmo vomerine plate, normally lost in fossil specimens, and provides further anatomical information and taxonomic characters for this species.

The geographical range of the species is extended and localities of fossil species of
Echelus
and other fossil taxa believed by various authors to be closely-related to
Echelus
species are depicted on a map of the distribution of continental crust in the northern hemisphere during Oligocene times. The distribution of such eel taxa is consistent with the supposed extent of the Eocene sea within Europe. It would appear that modern species of
Echelus
now occupy areas that are more cosmopolitan than the fossil species. During the break-up of Pangaea and the subsequent expansion of the Atlantic and Indo-Pacific Oceans species of
Echelus
have ventured beyond their original provenance of continental sea and now occupy habitats along margins of the eastern Atlantic and of the western and eastern Indo-Pacific Oceans.
Fossil Cypriniformes from China and its adjacent areas and their palaeobiogeographical implications
Authors: Chang Mee-mann , Chen Gengjiao 
Published: June 2008

Abstract
Fossil cypriniforms are abundantly represented in China and its adjacent areas, with the described taxa approximating to a total of 80 genera and 100 species and subspecies. They are known mainly from the Eocene, Miocene and Pliocene deposits. The Oligocene and Quaternary materials are relatively rare. These fossil cypriniforms represent three of the five Recent families: the Catostomidae, Cobitidae and Cyprinidae. Comparison of the Eocene catostomids from mainland East Asia with those from western North America points to an obvious transpacific distributional pattern, whereas there is only one species in Asia and more than 70 species in North America at present. Fossil cobitids are comparatively rare. Cyprinids are the most diverse and widespread group among the three families. The Miocene and Pliocene taxa shared by east mainland Asia and the Japanese Islands indicate that the fishes from these areas must have belonged to the same ichthyofauna during the Neogene. At the same time, some of them are quite similar to those from Europe, which is indicative of a closer connection between the two areas than previously thought.
Can the comparative study of the morphology and histology of the scales of
Latimeria menadoensis
and
L. chalumnae
(Sarcopterygii: Actinistia, Coelacanthidae) bring new insight on the taxonomy and the biogeography of recent coelacanthids?
Authors: Meunier François J. , Erdmann Mark V. , Fermon Yves , Caldwell Roy L. 
Published: June 2008

Abstract

SEM (Scanning electron microscopy) and photonic microscopy (ground sections) studies confirm that the scales of the coelacanth
Latimeria menadoensis
have strong morphological and histological similarities with the scales of
L. chalumnae
. They are both elasmoid scales, the external layer of which is made of radial ridges that are overlaid, on the posterior field, by odontodes. The odontodes of
L. menadoensis
are made of the typical mineralized tissues described for teeth of the coelacanth and their width is similar to that of
L. chalumnae
odontodes. Globular corpuscles are found in the isopedine contact with the external layer. Their mineralization seems to be inotropic as in the Mandl's corpuscles of teleost elasmoid scales. Scale organisation in
L. menadoensis
does not show any characteristics that may support significantly, in the absence of additional evidence, two different species in the extant coelacanths.