bluuebunny/crossref_metadata_2025 huggingface dataset:
Have repeated applications of nitrogen and phosphorus to a loblolly pine plantation changed stand productivity and soil nutrient supply?
Authors: (Bennett) Phelan Jennifer , Allen H. Lee
Published: April 2008

To develop a nitrogen (N) and phosphorus (P) fertilization regime that produces long-term increases in stand productivity and soil nutrient supply in loblolly pine plantations, a series of N + P fertilizer studies were established in the Southeastern United States. One of these installations was examined partway through the study to determine if changes to stand productivity and soil nutrient supply had already been achieved. Stand growth and foliar nutrient concentrations were measured for 6 years, and during the third year, a seedling bioassay was conducted with soil collected from the highest fertilization and nonfertilized treatments. Annual stand growth was increased by 14%–27% in the fertilized plots suggesting that the fertilizer regime improved stand productivity. However, results from the seedling bioassay showed that only P fertilization had caused changes in soil nutrient supply. Seedling P contents in the fertilized treatments were 3.6 times larger than those in the nonfertilized treatments. In contrast, total system N contents were equivalent in the fertilized and nonfertilized systems, and extractable nitrate (NO3–), ammonium (NH4+), and biologically active N were higher in the nonfertilized soils. Future measurements and seedlings bioassay assessments should be conducted to determine when and if long-term changes in soil quality and stand productivity are achieved.
Long-term outcome of precommercial thinning in northwestern New Brunswick: growth and yield of balsam fir and red spruce
Authors: Pitt Doug , Lanteigne Len
Published: April 2008

A study was established between 1959 and 1961 to study the long-term responses of balsam fir ( Abies balsamea (L.) Mill.) and red spruce ( Picea rubens Sarg.) to precommercial thinning. Three nominal spacings of 4 ft (1.2 m), 6 ft (1.8 m), and 8 ft (2.4 m) were compared with an unthinned control in a randomized complete block design with five replicates. At the time of thinning, natural regeneration averaged 16 years of age, 8 years after harvest. Although thinning had minimal effect on gross total volume production over a 42 to 44 year observation period, actual spacings between 2.1 and 2.5 m produced an average of 360 m3·ha–1gross merchantable volume (GMV), representing a 21% gain over unthinned stands. The same spacings produced quadratic mean diameters of 21 and 23 cm, respectively, compared with 18 cm in the unthinned stands. These size increases translated to individual stem volume gains of 33% and 62%, significantly reducing the age at which thinned stands would meet a specified minimum requirement for merchantability or habitat. The mean annual increment of GMV ranged from 6 m3·ha–1·year–1in unthinned stands, to more than 7 m3·ha·–1·year–1in the thinned stands, and had not yet culminated an average of 50 years postharvest.
Living long by staying small: stem layering as an adaptive life-history trait in shade-tolerant tree seedlings
Authors: Woods Kerry D.
Published: April 2008

Suppressed seedling banks are important in replacement dynamics in late-successional forests. However, demographic properties of seedling populations are poorly known, and there has been little attention to traits that might affect fitness in suppressed seedlings. Acer saccharum Marsh., a shade-tolerant dominant in eastern North American forests, frequently develops adventitious roots along prostrate portions of stems (“layering”). Measurements of Acer seedlings in old-growth forests in Michigan indicate that layered seedlings proportionally reduce structural allocations to older layered stem tissues, retain leaf area / height ratios of younger unlayered seedlings, and tend to survive longer. In tree seedlings, allometric consequences of normal stem growth lead to declining ratios of photosynthetic to nonphotosynthetic biomass, which potentially reduces shade tolerance and limiting age. The layering habit may defer this penalty by changing the allometry of growth. Resulting increases in life expectancy should increase chance of access to increased light and of reaching the canopy. Thus, because flowering is generally restricted to canopy trees, the tendency to layer may increase fitness. Properties of individuals in suppressed seedling banks may be selectively and ecologically important, shaping life histories and population dynamics.
How to find the rare trees in the forest — New inventory strategies for culturally modified trees in boreal Sweden
Authors: Andersson Rikard , Östlund Lars , Kempe Göran
Published: April 2008

Culturally modified trees (CMTs) in northern forests are rare traces of past human activity that provide unique information on past land use and the relationship between people and forests throughout history. There is an apparent need to provide probability sampling methods for these traces. This article describes the simulation and evaluation of circular plot sampling and strip surveying for estimating the density of culturally modified trees in 25 ha of a forest reserve in northern Sweden. CMTs were surveyed, documented, and prepared for use in simulator software and the bias, precision, and cost of different inventory strategies were calculated. For a given level of precision circular plot sampling was found to be more efficient than strip surveying for estimating the abundance frequencies of all CMTs. For smaller subpopulations of scarce CMT types, the strip-surveying method was superior. Probability sampling would be an important tool for examining larger areas and gaining more CMT information at a lower cost. The results are important for studies of cultural history in sparsely populated forested regions in northwestern North America, northern Scandinavia, and northern Russia, but there are also implications for finding other rare objects in forest ecosystems.
Modeling the decay of coarse woody debris in a subalpine Norway spruce forest of the West Carpathians, Poland
Authors: Holeksa Jan , Zielonka Tomasz , Żywiec Magdalena
Published: April 2008

Coarse woody debris (CWD) is an important structural element in forests. Its role depends on the species, size, position, and decay rate. This paper reports an attempt to determine the total residence time of CWD across all decay classes and also within successive decay classes. We simulated the process of CWD decomposition for stem size and position (snags versus logs), using matrices of the transition of CWD between decay classes. The study was based on a sample of 2785 Norway spruce snags and logs measured twice over a 10  year period in a Carpathian subalpine forest. The revealed pattern of decomposition depended highly on CWD size. When log numbers were considered, the mean total residence time increased from 71 years for small logs (diameter < 23 cm) to 90 years for medium-sized logs (23–35 cm), and to 113 years for large logs (>35 cm). In terms of volume, the mean total residence times of logs were 47, 49, and 63 years for the three diameter categories. Still shorter were the mean total residence times for log mass: 34, 41, and 41 years for the three diameter categories. The pattern of decomposition depended highly on the CWD attributes taken into consideration. The differences in decay rate between log diameter categories are considerable when the number of logs is taken into account, but they practically vanish when log mass is considered.
Long-term spatial and structural dynamics in Acadian mixedwood stands managed under various silvicultural systems
Authors: Saunders Mike R. , Wagner Robert G.
Published: April 2008

Using inventory data from a long-term silviculture experiment in east-central Maine, spatial models were developed to analyze 28 years (1974–2002) of stand structural dynamics. Differences in spatial pattern, species mingling, height differentiation, and relative stand complexity index (rSCI) were compared among five treatments: commercial clear-cutting, fixed diameter-limit, 5 year single-tree selection, three-stage shelterwood (both with and without precommercial thinning), and unharvested natural areas. Regardless of treatment, regeneration events (whether induced by natural breakup of the overstory or by harvesting) increased aggregation in spatial pattern and reduced species mingling, more so in the commercial clearcut and fixed diameter-limit treatments where hardwood densities were highest. Regular spatial patterns were rare. Height differentiation values for individual trees and stand-level mean rSCI were generally highest in untreated natural areas and 5 year selection treatments, intermediate in commercial clearcut and fixed diameter-limit treatments, and lowest in three-stage shelterwood treatments. After a brief adjustment period, precommercial thinning in a shelterwood treated stand generally increased species mingling, height differentiation, and rSCI. Two untreated natural areas exhibited divergent pathways of structural development. Dynamics in uneven-aged selection treatments more closely resembled that of the untreated natural areas than did the shelterwood, commercial clearcut, or fixed diameter-limit treatments.
Regional variation in wood specific gravity of planted loblolly pine in the United States
Authors: Jordan Lewis , Clark Alexander , Schimleck Laurence R. , Hall Daniel B. , Daniels Richard F.
Published: April 2008

Loblolly pine ( Pinus taeda L.) is the most important plantation species in the southeastern United States and specific gravity (SG) is its most important wood quality trait. Analysis of annual ring SG of breast height (1.37 m) increment cores from 3957 trees representing 147 plantations across the species natural range showed that ring SG increases with increasing age and varies significantly among physiographic regions. The South Atlantic and Gulf regions had the highest ring SGs, while the Hilly and Piedmont regions had the lowest. Based on ring SG, the juvenile period averages 4.3 years, followed by 8.6 years of transition wood, with mature wood produced by year 13. Whole-core mean SG was significantly higher in the South Atlantic (0.486) compared with the other regions (mean = 0.455), which were not statistically different from each other. Trees from the South Atlantic have significantly higher whole-core SG because they contain significantly more latewood (40.1%) compared with trees growing in other regions (33.8%). Maps indicate that stands in the South Atlantic and Gulf regions have the highest SG at a given age. Stands growing on the northern and western fringe of the natural range of loblolly pine have the lowest whole-core SG.
Key interactions between nutrient limitation and climatic factors in temperate forests: a synthesis of the sugar maple literature
Authors: St.Clair Samuel B. , Sharpe William E. , Lynch Jonathan P.
Published: April 2008

Mineral stress (nutrient deficiency and (or) ion toxicity) is a widespread phenomenon in forests around the world. However, with the exception of N limitation, its significance is often under appreciated. On weathered, acidic soils that support many of the world’s forests, P, Ca, and Mg deficiencies and toxicities of Al and Mn are important constraints to forest productivity. Nutrient resources are a primary controller of forest function and structure and have important trophic implications, because foliar nutrient status is an important determinant of leaf palatability and consumer fitness. Nutrient acquisition and utilization in forest ecosystems is strongly influenced by environmental factors, which are changing at unprecedented rates with regional and global climate shifts. Here we examine nutrient limitations common to temperate, sugar maple ( Acer saccharum Marsh.) dominated forests as a model for understanding how climatic factors influence the acquisition and utilization of nutrient resources in forest ecosystems. In general, foliar nutrient imbalances created by soil weathering and acidification impair sugar maple physiology and correlate with health decline symptoms. Extremes in light environment, temperature, precipitation, pathogen attack, and herbivory tend to induce and (or) negatively interact with nutrient imbalances in sugar maple. A conceptual model is presented that characterizes abiotic and biotic interactions influencing sugar maple health and fitness in the context of nutrient limitation.
An optimization model for locating fuel treatments across a landscape to reduce expected fire losses
Authors: Wei Yu , Rideout Douglas , Kirsch Andy
Published: April 2008

Locating fuel treatments with scarce resources is an important consideration in landscape-level fuel management. This paper developed a mixed integer programming (MIP) model for allocating fuel treatments across a landscape based on spatial information for fire ignition risk, conditional probabilities of fire spread between raster cells, fire intensity levels, and values at risk. The fire ignition risk in each raster cell is defined as the probability of fire burning a cell because of the ignition within that cell. The conditional probability that fire would spread between adjacent cells A and B is defined as the probability of a fire spreading into cell B after burning in cell A. This model locates fuel treatments by using a fire risk distribution map calculated through fire simulation models. Fire risk is assumed to accumulate across a landscape following major wind directions and the MIP model locates fuel treatments to efficiently break this pattern of fire risk accumulation. Fuel treatment resources are scarce and such scarcity is introduced through a budget constraint. A test case is designed based on a portion of the landscape (15 552 ha) within the Southern Sierra fire planning unit to demonstrate the data requirements, solution process, and model results. Fuel treatment schedules, based upon single and dual wind directions, are compared.
Wood density and stocks of coarse woody debris in a northwestern Amazonian landscape
Authors: Chao Kuo-Jung , Phillips Oliver L. , Baker Timothy R.
Published: April 2008

Coarse woody debris (CWD) is a rarely studied component of the carbon cycle. We report the first measurements of both CWD wood density and necromass in humid, lowland northwestern Amazonia, using both line-intersect and plot-based methods. Average CWD densities were not significantly different between clay-rich and white sand unflooded forests, but lower in floodplain forest (p ≤ 0.001). Necromass of CWD lying on the ground was also lower in the floodplain (10.3 ± 6.1 Mg·ha–1, mean ± 1 SE) than in the clay-rich (30.9 ± 5.4) and white sand (45.8 ± 7.3) forests (p ≤ 0.001, using the line-intersect method). These patterns are likely driven by disturbance history, species composition, and decomposition rates. Plot-based data showed that standing and fallen CWD together accounted for 6.4%–15.4% of total coarse aboveground vegetative mass (trees ≥10 cm diameter). Across humid, lowland neotropical forests, we show that wood densities of intact and partially decayed CWD are significantly related with live wood density at the same site (p = 0.026 and 0.003, respectively). We show that these relationships can be applied generally to estimate CWD wood density for humid, lowland neotropical forests wherever destructive sampling is not possible.
Effects of alternative harvesting methods on boreal forest spider assemblages
Authors: Matveinen-Huju Katja , Koivula Matti
Published: April 2008

Forestry is among the most important disturbance forces in the boreal region, having caused drastic changes to the biota. Forest industries have recently introduced alternative logging techniques to better maintain forest diversity, but little is known on how these function. We studied the short-term effects of various logging methods on ground-dwelling spiders in Finland, using pitfall traps 1 year before and 2.5 years after logging. The compared logging regimes were (i) clear-cutting, (ii) retention felling, (iii) gap felling, (iv) thinning, and (v) control. We found that (1) clear-cutting and retention felling drastically changed the spider fauna. The abundance of forest species decreased with these methods, whereas most open-habitat species showed the opposite response, being caught only after logging. Moreover, multivariate analyses (nonmetric multidimensional scaling, multivariate regression trees) indicated that clear-cutting and retention felling produced similar spider faunas. (2) Increasing retention of trees caused less abrupt changes in spider fauna. Gap felling produced variable and intermediate responses, whereas thinning closely resembled control. We conclude that retention patches of a few tens of trees within clearcuts may not function as “lifeboats” for forest spiders; gap felling preserves some forest species but also supports the colonization of open-habitat species; and the studied thinning treatment well preserves the forest-floor spider assemblage.
Forest road network design using a trade-off analysis between skidding and road construction costs
Authors: Chung Woodam , Stückelberger Jürg , Aruga Kazuhiro , Cundy Terrance W.
Published: April 2008

Designing forest road networks in a large forest land is a challenging task because many feasible alternatives exist and need to be analyzed. To provide field managers with an analytical tool that can create and analyze alternative road networks, we have developed a road network optimization model. The model formulates a large network problem in which links represent two timber transportation options from evenly distributed timber locations: on-road transportation via new roads and off-road transportation using skidders. A heuristic network algorithm is employed to solve the network problem and identify cost-efficient road networks for timber harvesting under given cost parameters. To demonstrate our model, we applied it to a 4760 ha forest in the upper part of the Mica Creek watershed in Idaho owned by Potlatch Forest Holdings, Inc. The sensitivity analyses were conducted to verify the model’s performance under various cost and volume settings. The model-generated road network was compared with a road network proposed by experienced forest engineers in Potlatch. The sensitivity analyses confirm that the model appropriately responds to changes in input parameters. Comparisons between the model output and the manually designed road network indicate that the model tends to develop a tree-shape road network to evenly cover the entire management area.
Basal area growth impacts of dwarf mistletoe on western hemlock in an old-growth forest
Authors: Shaw David C. , Huso Manuela , Bruner Howard
Published: April 2008

We investigated the effect of western hemlock dwarf mistletoe ( Arceuthobium tsugense (Rosend.) G.N. Jones ssp. tsugense ) on the 13 year basal area growth of large (>45.7 cm diameter at breast height) western hemlock ( Tsuga heterophylla (Raf.) Sarg.) trees in an old-growth forest in southwestern Washington state. We controlled for spatial effects on tree growth by utilizing twenty-seven 0.4 ha plots that had uninfected, lightly, moderately, and severely infected classes of trees present on each plot. Basal area growth was analyzed using analysis of covariance of a randomized block design that was a balanced design with four treatments (infection classes) and 27 replicates (blocks or 0.4 ha plots), with initial diameter as the covariate. Basal area growth was found to be significantly different among the infection classes (F[3,77] = 10.09 and p < 0.0001). Growth of the light and moderate infection classes was not detectably different from growth of uninfected trees. However, severely infected trees grew from 16% to 46% (mean = 36%) less than uninfected trees of the same initial diameter over the period of study (1991–2004). The large trees in this stand did not show growth impacts until they were severely infected.
Crown openness as influenced by tree and site characteristics for yellow birch, sugar maple, and eastern hemlock
Authors: Lefrançois Marie-Lou , Beaudet Marilou , Messier Christian
Published: April 2008

Crown openness (CO) of mature trees influences light transmission within the forest canopy. However, in modeling, this variable is often considered constant within species, and its potential regional variability is ignored. The objective of this study was to evaluate if CO values of yellow birch ( Betula alleghaniensis Britt.), sugar maple ( Acer saccharum Marsh.), and eastern hemlock ( Tsuga canadensis (L.) Carrière) vary according to the following factors: (i) species, (ii) regional actual evapotranspiration (AET), (iii) tree size (i.e., diameter at breast height, DBH), and (iv) angle of transmission from zenith. To achieve this, CO was evaluated for 136 yellow birches, 109 sugar maples, and 68 hemlocks from different regions of western Quebec, southern Ontario, and northern Michigan. Results showed that all of the studied factors affected CO. While dominant trees can intercept light laterally as well as vertically, smaller trees are more efficient at intercepting light vertically. Increasing AET is associated with more open crowns. Given its importance in light transmission in the understory, a better understanding of how CO varies between individuals, species, and regions is needed.
Landscape-level stream fragmentation caused by hanging culverts along roads in Alberta’s boreal forest
Authors: Park David , Sullivan Michael , Bayne Erin , Scrimgeour Garry
Published: April 2008

Hanging culverts (i.e., outfall elevated above the stream surface) can fragment fish communities in streams by creating upstream movement barriers. We conducted a retrospective study of culvert stream crossings along industrial roads in Alberta’s boreal forest to describe factors relating to the occurrence of hanging culverts and to quantify watershed fragmentation. One-half (50%; 187/374) of culverts surveyed in four watersheds during 2002 and 2003 were hanging. Logistic regression showed that the occurrence of a hanging culvert was positively and significantly related to culvert age and reach slope. We quantified fragmentation in the watersheds as the length-based percentage of stream reaches above hanging culverts. In three watersheds, stream fragmentation was approximately 5%, whereas one watershed showed 20% fragmentation. Extrapolating our results to Alberta’s entire boreal forest, we estimated that several thousand hanging culverts were fragmenting tens of thousands of kilometres of streams in 2003. These numbers are likely increasing as a result of continued road development and ageing culverts. We conclude that the traditional management approach of road builders and regulatory agencies has failed to prevent the development of hanging culverts and fragmentation of small boreal streams in Alberta. We provide recommendations for future study and management of this growing problem.
Growth response following green crown pruning in plantation-grown Eucalyptus pilularis and Eucalyptus cloeziana
Authors: Alcorn Philip J. , Bauhus Jürgen , Smith R. Geoff B. , Thomas Dane , James Ryde , Nicotra Adrienne
Published: April 2008

Pruning of live branches is performed to enhance wood quality in plantation trees. Stem, branch and wood properties may be altered following pruning from below, but the extent and duration of such effects are unknown for many plantation Eucalyptus species. The effect of 0%, 20%, 50%, and 70% green crown length removal on growth and wood quality was examined in 3.5-year-old plantation-grown Eucalyptus pilularis Sm. (blackbutt) and Eucalyptus cloeziana F. Muell. (Gympie messmate) trees on two subtropical sites in eastern Australia. Growth increment of the stem at breast height was not affected by 20% crown removal. However, stem increment at breast height was reduced for up to 8 months with 50% crown removal and up to 12 months with 70% crown removal. Pruning had no impact on height growth. However, the height of trees pruned to 70%, relative to the height of the surrounding unpruned trees, was temporarily reduced 12 months after pruning in both species. Stem form, stem taper, wood density, and residual branch growth above the pruned zone were unaffected by pruning. Owing to the fast vertical crown expansion, trees were able to rapidly compensate for leaf area removal without long-term reductions in stem growth. The implications for management operations utilizing pruning as a means of enhancing timber quality are discussed.
Millennial-scale changes in local vegetation and fire regimes on Mount Constitution, Orcas Island, Washington, USA, using small hollow sediments
Authors: Sugimura Wendy Y. , Sprugel Douglas G. , Brubaker Linda B. , Higuera Philip E.
Published: April 2008

We used pollen and charcoal records from small hollows plus a network of surface samples to reconstruct stand-level vegetation and fire history at three sites on the Mount Constitution plateau of Orcas Island, Washington, USA. One record (beginning ca. 7100 calibrated years BP) is from a xeric site on the northern plateau, and two (beginning 3800 and 7650 years BP, respectively) are from mesic sites on the central and south-central plateau. Before 5300 years BP, vegetation and fire regimes at both the northern and south-central sites resembled those of current Mount Constitution forests. Around 5300 years BP, Alnus increased and Pinus decreased at the mesic south-central site, suggesting a change to moister and (or) cooler conditions, but Pinus remained dominant at or near the more xeric northern site. At both sites, charcoal deposition decreased, suggesting a decrease in fire frequency and (or) severity consistent with wetter conditions. After 2000 years BP, charcoal deposition increased at all three sites, and Pinus increased in the central and south-central sites, suggesting a return to drier conditions. Thus, stands on different sites in close proximity responded individually to the same climate change, depending on local site conditions and the ecology of the dominant trees.
Effects of competitor spacing in a new class of individual-tree indices of competition: semi-distance-independent indices computed for Bitterlich versus fixed-area plots
Authors: Stage Albert R. , Ledermann Thomas
Published: April 2008

We illustrate effects of competitor spacing for a new class of individual-tree indices of competition that we call semi-distance-independent. This new class is similar to the class of distance-independent indices except that the index is computed independently at each subsampling plot surrounding a subject tree for which growth is to be modelled. We derive the effects of distance for this class as the expected value over independent samples containing a particular subject tree. In a previous paper, we illustrated distance effects implicit in eight indices of the distance-dependent class. Here, we present distance effects of four semi-distance-independent indices: density, sum of diameters, basal area, and tree-area ratio; each determined for small fixed-area plots of 0.04 ha and for Bitterlich samples of 6 m2·ha–1. We show that several members of this new class have distance effects very similar to the distance-dependent class and should, therefore, be equally effective in accounting for competitive effects in individual-tree increment models. The comparisons should inform selection of competition indices and sampling designs for growth modelling.
Physiological trade-offs associated with methyl jasmonate - induced resistance inPinus radiata
Authors: Gould Nick , Reglinski Tony , Spiers Mike , Taylor Joe T.
Published: April 2008

Methyl jasmonate (MeJA) can induce defence responses in plants to pathogen attack, but it can also have consequences for plant growth. The transient effects of exogenous MeJA treatment on the resistance of Monterey pine ( Pinus radiata D. Don) seedlings to Diplodia pinea (Desm.) Kickx. and some physiological parameters affecting the impact of treatment on seedling growth were investigated. Following foliar application of 4.5 mmol·L–1MeJA, disease resistance was greatest 1–2 weeks after treatment and declined with time thereafter. Elevated disease resistance was accompanied by a reduction in seedling growth rate the second week following MeJA treatment. Thereafter, seedling growth rate recovered and exceeded that of the control seedlings 4–5 weeks after MeJA treatment. Within hours of MeJA treatment, reductions in both the capacity of photosystem II and transpiration rate were observed, resulting in a concomitant reduction in net CO2uptake rate. The slight reduction in transpiration rate was also associated with an increase in needle water potential. Longer term measurements showed no effect of MeJA on photosynthetic rate, transpiration rate, chlorophyll content, or shoot water potential and thus could not account for the elevated growth rate observed 4–5 weeks after treatment.
Effects of harvest intensity and aspect on a boreal transition tolerant hardwood forest. I. Initial postharvest understory composition
Authors: Fleming R. L. , Baldwin K. A.
Published: April 2008

Disturbance effects on plant communities largely reflect the degree of overstory removal, soil disturbance, and attendant vegetation destruction. We examined initial harvest-related impacts of partial and complete canopy removal, with and without soil disturbance, on north- and south-facing aspects of an older, relatively undisturbed, boreal transition tolerant hardwood forest at Turkey Lakes, Ontario. We recorded vascular plant cover in 180 25 m2plots in the 3rd postharvest year and analyzed community response using unconstrained (nonmetric multidimensional scaling) and constrained (distance-based (partial) redundancy analysis) ordination, multivariate ANOVA, indicator species analysis and diversity measures. Community composition and diversity measures were related primarily to gradients in soil disturbance and, particularly for herbaceous species, aspect-related radiative exposure. Canopy opening generally played a lesser role. There were, however, notable canopy opening – soil disturbance × aspect interaction effects on both woody and herbaceous composition. In contrast with herbs, proportionately more woody species had indicator value for south- than for north-facing aspects and for disturbed than for undisturbed soils. Understory community response and diversity measures were affected more by logging-related soil disturbance than by the amount of canopy opening associated with the silvicultural system used. Aspect-related effects, however, suggest silvicultural impacts will be both site- and species (functional group) specific.
Genetic diversity of butternut (Juglans cinerea) and implications for conservation
Authors: Ross-Davis Amy , Ostry Michael , Woeste Keith E.
Published: April 2008

The management of threatened and endangered species can be improved by understanding their patterns of genetic diversity and structure. This paper presents the results of the first analysis of the population genetics of butternut ( Juglans cinerea L.) using nuclear microsatellites. Butternut once was an economically and ecologically valuable hardwood, but now its numbers are rapidly decreasing throughout its native range in eastern North America. By genotyping butternut trees (n = 157) from five populations at seven highly polymorphic loci, we determined that the remaining genetic diversity for the species is considerably higher than previously estimated (mean HE= 0.75). Populations were nearly genetically homogenous (FST= 0.025), with no evidence of isolation by distance. These results indicate that butternut retains a large amount of genetic diversity, and that it is not too late to implement strategies to conserve local butternut populations.
A KINEMATIC MODEL OF THE UPPER LIMB WITH A CLAVICLE-LIKE LINK FOR HUMANOID ROBOTS
Authors: TONDU BERTRAND
Published: April 2008

Starting from a biomechanical study of the shoulder complex, the relevance of a serial nine d.o.f. kinematic model of the human arm, including a clavicle-like link, was analyzed. It is shown that this partial biomimetic joint model of the upper limb is able to mimic the ability of the natural arm to practically eliminate internal and bound singularities over a large frontal zone, so as to maintain its elbow laterally to the body. In this sense, it appears to be an advanced solution for increasing the dexterity of humanoid robot upper limbs, thus replacing classical seven d.o.f. anthropomorphic arms where a device mimicking the shoulder girdle mechanism is absent.
ON SOME ASPECTS OF HUMANOID ROBOTS GAIT SYNTHESIS AND CONTROL AT SMALL DISTURBANCES
Authors: VUKOBRATOVIĆ MIOMIR , BOROVAC BRANISLAV , RAKOVIĆ MIRKO , POTKONJAK VELJKO , MILINOVIĆ MOMČILO
Published: April 2008

This work considers some aspects of the problem of generating and preserving of two-legged gait bearing in mind the requirements for a higher degree of similarity with human gait (anthropomorphism) and robustness to the constantly present small disturbances during the walk. Reference motion was synthesized by semi-inverse method, varying the mode of ZMP traveling along a path selected in advance on the foot–ground surface. It was found that different ways of ZMP motion along the path has a decisive role in the trunk deflection in the sagittal plane. Also, the problem of classification of disturbances and their compensation during the gait is discussed in detail. The significance of the multi-link trunk in the gait synthesis and its role in the compensation of disturbances is also considered.
FINDING TEMPORAL STRUCTURE IN TEXT: MACHINE LEARNING OF SYNTACTIC TEMPORAL RELATIONS
Authors: BETHARD STEVEN , MARTIN JAMES H. , KLINGENSTEIN SARA
Published: April 2008

This research proposes and evaluates a linguistically motivated approach to extracting temporal structure from text. Pairs of events in a verb-clause construction were considered, where the first event is a verb and the second event is the head of a clausal argument to that verb. All pairs of events in the TimeBank that participated in verb-clause constructions were selected and annotated with the labels BEFORE, OVERLAP and AFTER. The resulting corpus of 895 event-event temporal relations was then used to train a machine learning model. Using a combination of event-level features like tense and aspect with syntax-level features like the paths through the syntactic tree, support vector machine (SVM) models were trained which could identify new temporal relations with 89.2% accuracy. High accuracy models like these are a first step towards automatic extraction of temporal structure from text.
INTERACTIVE VIDEO ANNOTATION BY MULTI-CONCEPT MULTI-MODALITY ACTIVE LEARNING
Authors: WANG MENG , HUA XIAN-SHENG , MEI TAO , TANG JINHUI , QI GUO-JUN , SONG YAN , DAI LI-RONG
Published: April 2008

Active learning has been demonstrated to be an effective approach to reducing human labeling effort in multimedia annotation tasks. However, most of the existing active learning methods for video annotation are studied in a relatively simple context where concepts are sequentially annotated with fixed effort and only a single modality is applied. However, we usually have to deal with multiple modalities, and sequentially annotating concepts without preference cannot suitably assign annotation effort. To address these two issues, in this paper we propose a multi-concept multi-modality active learning method for video annotation in which multiple concepts and multiple modalities can be simultaneously taken into consideration. In each round of active learning, this method selects the concept that is expected to get the highest performance gain and a batch of suitable samples to be annotated for this concept. Then, a graph-based semi-supervised learning is conducted on each modality for the selected concept. The proposed method is able to sufficiently explore the human effort by considering both the learnabilities of different concepts and the potentials of different modalities. Experimental results on TRECVID 2005 benchmark have demonstrated its effectiveness and efficiency.
ONTONOTES: A UNIFIED RELATIONAL SEMANTIC REPRESENTATION
Authors: PRADHAN SAMEER S. , HOVY EDUARD , MARCUS MITCH , PALMER MARTHA , RAMSHAW LANCE , WEISCHEDEL RALPH
Published: April 2008

The OntoNotes project is creating a corpus of large-scale, accurate, and integrated annotation of multiple levels of the shallow semantic structure in text. Such rich, integrated annotation covering many levels will allow for richer, cross-level models enabling significantly better automatic semantic analysis. At the same time, it demands a robust, efficient, scalable mechanism for storing and accessing these complex inter-dependent annotations. We describe a relational database representation that captures both the inter- and intra-layer dependencies and provide details of an object-oriented API for efficient, multi-tiered access to this data.
WHY LAUGHING IS BETTER THAN SMILING
Authors: FERRETTI STEFANO , ROCCETTI MARCO , MIRRI SILVIA , MURATORI LUDOVICO ANTONIO , SALOMONI PAOLA
Published: April 2008

Dialectically sharing knowledge everywhere, every time and, above all, very fast — as it is nowadays possible — has revealed the existence and importance of a common, distributed intelligence growing with the contribution of many individuals (a community). The iterating refinement of any information resource by a wider and wider community of sharers leads to undoubted advantages on the final quality and effectiveness of use of this information. Following this path and focusing on the e-learning field, we present a novel system, termed LAUGH, for the cooperative creation and sharing of SMIL-based multimedia resources. Such a system allows users (typically learners and teachers) to enrich the didactical material made available to the learning community. Specifically, they can add captions/subtitles and alternative annotations to the original multimedia contents by resorting to a Wiki-type interface. This open process promotes students' participation, data decentralization, assemblage from diverse sources, sharing of knowledge as well as an improvement to the efficacy of e-learning materials. Throughout the paper, we will meticulously show that LAUGH extends and improves the functionalities provided by the SMIL standard. This motivates the title of this article.
CORPUS-BASED GESTURE ANALYSIS: AN EXTENSION OF THE FORM DATASET FOR THE AUTOMATIC DETECTION OF PHASES IN A GESTURE
Authors: MARTELL CRAIG , KROLL JOSHUA
Published: April 2008

We present the results of using an extension of the FORM gesture dataset to predict the mid-level phenomenon of phase. We compare the results of human phase prediction with automated prediction using machine-learning techniques. Specifically, we present the results of hidden Markov model experiments using an extended version of the FORM data to predict phase labels. Additionally, we compare FORM to the currently most accurate method of data gathering in this field — motion capture — by comparing the predictive accuracy of the physical gesture models produced by FORM and by motion capture for phase labeling.
Magmatism associated with Gondwanaland rifting and Neo-Tethyan oceanic basin development: evidence from the Mamonia Complex, SW Cyprus
Authors: CHAN G.H.-N. , MALPAS J. , XENOPHONTOS C. , LO C.-H.
Published: April 2008

Volcanic and intrusive rocks of the Dhiarizos Group, occurring within the Mamonia Complex of SW Cyprus, comprise mainly tholeiitic basalts, ocean island tholeiites (OIT) and other alkalic varieties, with minor alkaline lamprophyre intrusive rocks. These rocks were highly tectonized and dismembered during the collision with the Troodos oceanic lithosphere. Trace element data for the most primitive mafic igneous rock samples suggest that the tholeiitic basalts are derived from a depleted mantle source whereas the OIT and the alkalic basalts originated from variable degrees of partial melting of a spinel peridotite mantle. Alkaline lamprophyres are products of a small degree of partial melting of a deep-seated garnet lherzolite. The bulk of the tholeiites and alkalic varieties are Late Triassic in age and are interpreted as having formed during Neo-Tethyan sea-floor spreading and associated seamount volcanism. Amphibole separates from a lamprophyre intrusion have
40
Ar–
39
Ar ages of 140.7 ± 0.4 Ma. In this paper, we report for the first time an Early Cretaceous alkaline lamprophyric magmatism, which is probably associated with a renewed episode of Gondwanaland rifting. These results show that the development of the Neo-Tethyan oceanic basin in the Eastern Mediterranean was largely controlled by a two-phase rifting–drifting process.
U–Pb detrital zircon ages in synorogenic deposits of the NW Iberian Massif (Variscan belt): interplay of Devonian–Carboniferous sedimentation and thrust tectonics
Authors: MARTíNEZ CATALáN JOSé R. , FERNáNDEZ-SUáREZ JAVIER , MEIRELES CARLOS , GONZáLEZ CLAVIJO EMILIO , BELOUSOVA ELENA , SAEED AYESHA
Published: April 2008

Detrital zircons from Devonian and Carboniferous synorogenic flysch deposits occurring in an imbricate stack have been dated by laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) to: (1) obtain a maximum depositional age to constrain the maximum age limit for thrusting of exotic terranes in the NW Iberian Massif; (2) correlate the zircon age populations with published ages in nearby units to establish their possible source areas. The maximum depositional ages are Late Devonian for rocks high in the structural nappe pile (Gimonde Formation), in accordance with palynomorph dating, and around the Devonian–Carboniferous boundary for structurally lower samples (San Vitero Formation). Used in conjunction with previously published ages, the new ages are interpreted in terms of the advance of the thrust system responsible for the emplacement of exotic terranes upon the Iberian autochthon during the Variscan collision. Early Variscan zircon population ages indicate the exotic terranes as the source of synorogenic sediments, whereas their scarcity suggests derivation from the Iberian autochthon. One of the samples analysed lacks Variscan detrital zircons; this feature, together with the absence of an Early Palaeozoic zircon age population, puts into question its synorogenic character and suggests that the sample may be representative of the preorogenic parautochthon.
Structure and petrology of the Altan Uul Ophiolite: new evidence for a Late Carboniferous suture in the Gobi Altai, southern Mongolia
Authors: RIPPINGTON STEPHEN , CUNNINGHAM DICKSON , ENGLAND RICHARD
Published: April 2008

Altan Uul and Nemegt Uul are mountain ranges in southern Mongolia containing polydeformed Mid- to Late Palaeozoic sedimentary, volcanic and metamorphic rocks uplifted at a restraining bend along the Gobi–Tien Shan left-lateral strike-slip fault system. Altan and Nemegt Uul contain part of an intra-oceanic island arc that was active during the Carboniferous. Thrust-bound sequences of highly fractured pillow basalt, cumulate gabbro, peridotite, serpentinite and jasperoid occur directly north of the arc rocks in at least three discrete belts and are interpreted to be fragments of an ophiolite. Metamorphosed marine sediments that have undergone intense contractional strain lie north of, and structurally below, the ophiolitic rocks. The gabbros within the ophiolitic sequences have undergone prograde metamorphic reactions consistent with an ocean-floor environment, and trace element analyses are similar to those from cumulate gabbros of the Oman ophiolite. Combined field and petrological evidence suggests that there is an east–west-trending south-dipping Late Carboniferous suture in Altan and Nemegt Uul that may be regionally correlated in the southern Gobi Altai region. This proposed suture represents a new and important tectonic boundary between tectonostratigraphic terranes in southern Mongolia, requiring modification of existing models of Late Palaeozoic terrane accretion in the Central Asian Orogenic Belt.
Regional-scale subsurface sand remobilization: geometry and architecture
Authors: VIGORITO MARIO , HURST ANDREW , CARTWRIGHT JOE , SCOTT ANTHONY
Published: April 2008

An architectural hierarchy of clastic sills is recognized in the Panoche Giant Injection Complex in which staggered, stepped with erosive top surfaces, and multi-layered geometries occur in that stratigraphic order upward. Genetic relationships between parent depositional sand bodies, the sand injections, a zone of hydraulic fracture and a palaeo sea floor are seen at a scale previously observed only by using seismic data. Sills and randomly oriented dykes intrude into a hydraulically fractured shale unit above and below which dykes predominate. Erosive surfaces (scallops) are identified on sills that, along with smaller erosional features, record low-viscosity turbulent flow during sand injection. Sand extrusions occur where dykes reach the palaeo sea floor.
Terrestrial laser scanning in geology: data acquisition, processing and accuracy considerations
Authors: BUCKLEY SIMON J. , HOWELL J.A. , ENGE H.D. , KURZ T.H.
Published: April 2008

Terrestrial laser scanning, or lidar, is a recent innovation in spatial information data acquisition, which allows geological outcrops to be digitally captured with unprecedented resolution and accuracy. With point precisions and spacing of the order of a few centimetres, an enhanced quantitative element can now be added to geological fieldwork and analysis, opening up new lines of investigation at a variety of scales in all areas of field-based geology. Integration with metric imagery allows 3D photorealistic models to be created for interpretation, visualization and education. However, gaining meaningful results from lidar scans requires more than simply acquiring raw point data. Surveys require planning and, typically, a large amount of post-processing time. The contribution of this paper is to provide a more detailed insight into the technology, data collection and utilization techniques than is currently available. The paper focuses on the workflow for using lidar data, from the choice of field area and survey planning, to acquiring and processing data and, finally, extracting geologically useful data. Because manufacturer specifications for point precision are often optimistic when applied to real-world outcrops, the error sources associated with lidar data, and the implications of them propagating through the processing chain, are also discussed.
Provenance of Lower Cretaceous sediments in the Wandel Sea Basin, North Greenland
Authors: RØhr T.S. , Andersen T. , Dypvik H.
Published: April 2008

Detrital zircons in Lower Cretaceous sedimentary formations from the Wandel Sea Basin (Kilen, Peary Land) were dated by U–Pb and analysed for Hf isotopes by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Samples from Kilen and Peary Land display a wide range of U–Pb ages, with significant zircon populations at 1.0–1.1 and 1.8–2.0 Ga. Major hiati occur between 2.1 and 2.4 and from 0.48 to 0.91 Ga. Low initial ϵ
Hf
values indicate that recycled crust components are significant in Caledonian-aged zircons, and in Palaeoproterozoic (1.8–2.0 Ga) and Neoarchaean zircon populations. Other U–Pb age populations in the studied samples are dominated by zircons with positive ϵ
Hf
values indicating a significant contribution of mantle-derived material in these periods. A narrow range of ϵ
Hf
values is commonly seen within a given U–Pb age population, and the values seen in the samples are in general correlated with the different age populations and their frequency. One exception is the 1.8–2.0 Ga population, where variations suggest variable sources. The U–Pb and Hf data are consistent with Greenland as the sole source of zircon from the studied sandstones.