bluuebunny/crossref_metadata_2025 huggingface dataset:
REVIEWS
Authors: Arkin. Marcus , Stoker. H. M. , Timmerman. W.A. , Laight. J. C. , Deventer. B. van , Jackson. S. P. , Kock. Gerhard de
Published: December 2007

Free Trade and Protection in the Netherlands

The Analysis of Family Budgets. By S. J. Prais and H. S. Houthakkfr.

Two Postwar Recoveries of the German Economy. By Horst Mendershausen.

The Economics of European Air Transport. By Stephen Wheatcroft.

De Ontwikkcling van de Moderne Prijsteorie. Deur J. E. Andriessen.

Oxford Regional Atlas: U.S.S.R. and Eastern Europe.

Britain and she Tide of World Affairs.
SOME CURRENT INTERNATIONAL ECONOMIC PROBLEMS
Authors: JACK D. T.
Published: December 2007

EDITORS' NOTE.—These two articles are based upon the principal public lectures given by Professor Jack at the University of the Witwatersrand in August 1956 under the auspices of the Visiting Lecturer's Trust Fund and the Johannesburg Branch of the Economic Society of South Africa.
FREE TRADE AND THE CONGO BASIN TREATIES1
Authors: MATTHEWS JACQUELINE
Published: December 2007

The Conventional Basin of the Congo is a vast area comprising several countries in Central Africa, all of which follow a commercial policy of equality of economic opportunity, commonly known as the ‘open door’ policy. A review of the Congo Basin Treaties, in which this policy was enunciated, is of particular interest at the present time when, on the one hand, the European Free Trade Area is under discussion and, on the other, several African territories appear to be on the verge of political independence and economic advancement.
THE NATIONAL INCOME AND EXPENDITURE OF SOUTH—WEST AFRICA (1920–1956)
Authors: KROGH D. C.
Published: December 2007

ThisARTICLE SETS out provisional national accounting data prepared recently for South‐West Africa and describes briefly the main sources and steps involved in deriving tlie estimates. Some attention will also be given to the question of reliability, but in viewof considcrationsof space no efTort will be made to discuss the estimating problems encountered or to examine the results obtained.
A PROBLEM OF RATING — the case of Durban
Authors: McCRYSTAL L. P.
Published: December 2007

1. There is some doubt as to whether a local authority is empowered to discriminate against “productively used” property, since to do so may be construed as a tax on things other than immovable property.

2. In the case of leasehold properties, an apportionment of the increased rate burden is likely to take place between the landlord and his tenant. To the extent that the landlord has to bear a share of the higher rate burden, there will be a decline in property values.

3. The higher rates will tend to reduce building activity and reduce the intensity of site development. The fall in building activity will have downward “multiplier” effects which would affect the level of local employment.

4. Subject to various qualifications there will be a tendency for the prices of properties with vacant possession to decline.

5. The incidence of the higher rates will fall at least partly, and in many cases entirely, on local industrial, banking and insurance firms, and also building societies. Shops and hotels may have more scope for shifting the higher rates, on the whole, but here too some businesses will have to bear a substantial part of the burden.

6. The dangers of higher rates (a) influencing industry to move out of Durban and (b) discouraging new industries from coming in, are real and should be given careful consideration by the authorities.

7. The items of expenditure which the proposed higher rates for Durban will be used to finance will largely benefit owners of dwelling houses. Since the incidence of the higher rates will fall on businesses and their customers, owners of dwelling houses will receive a concealed form of subsidy.

Some adjustment in the profitability of developing different classes of land, is also probable.

8. There is a need for a revision of the relations between the Central and Provincial Governments, and local authorities, especially as regards the amounts paid by the former in lieu of rates.

9. In view of the trend among individuals to live in one place and work in another, some grouping of local authorities into regional units might be considered.
A NOTE ON THE SUPPLY OF ECONOMISTS IN SOUTH AFRICA
Authors: TRUU M. L.
Published: December 2007

If true delight you would afford him You'd give him Adam Smith to read. A deep economist, indeed, He talked about the wealth of nations; The state relied, his friends were told, Upon its staples, not on gold—This subject filled his conversations. His father listened, frowned, and groaned, And mortgaged all the land he owned.
BOOK REVIEWS
Authors: Jensen R. C.
Published: December 2007

Book reviewed in this article:

The Northern Territory Pastoral Industry, 1863–1910, by Ross Duncan.
BOOK REVIEWS
Authors: Truu M. L.
Published: December 2007

Book reviewed in this article:

Commonwealth—State Financial Relations in Australia, by James A. Maxwell
EVOLUTION OF PUBLIC‐UTILITY INDUSTRY REGULATION: ECONOMISTS AND OTHER DETERMINANTS*
Authors: SPRENGLER JOSEPH J.
Published: December 2007

In recent history, perhaps the most notable failure to achieve general rules has been that of our regulatory agencies, particularly those charged with allocative functions… The reason for this failure lies… in the nature of the tasks assigned to these agencies; they are trying to do through adjudicative forms something that does not lend itself to accomplishment through those forms.—Lon L. Fuller.
PROFIT MAXIMISATION—CAN IT BE JUSTIFIED?
Authors: RäDEL F. E.
Published: December 2007

IN THE TRADITIONAL theory the firm's raison d'être is represented by just one single goal, viz. profit maximisation as an explanation and, in support of this, exact quantitative models by means of marginal analysis were developed indicating under which conditions profit maximisation was achieved. In fact, the models served “as a wonderful key which opens all doors to the understanding of entrepreneurial behaviour.1
THE WEALTH OF NATIONS: HOW THE NATIONAL INCOME IS PRODUCED, DIVIDED UP AND SPENT*
Authors: ROBERTSON H. M.
Published: December 2007

Economics is not a particularly happy choice as a subject for a short series of summer school lectures. It is a subject which can appear either incomprehensibly complicated and difficult, or to comprise such simple common‐sense that there is nothing to it but a series of truisms and exceedingly trite platitudes. Of course, if you choose your lecturer well (or have him chosen by the enthusiastic but incautious Robert Tobias, our Director of Extra‐Mural Studies) you may form a synthetic impression that economics manages both and consists of turning a few trite platititudes into something incomprehensible! Quite an academic achievement!
THE BUDGET AND ECONOMIC POLICY*
Authors: VAN WAASDIJK T.
Published: December 2007

The purpose of this paper is not so much to review the momentous budget introduced recently by the Minister of Finance as to use the opportunity it offers for appraising fiscal policy. A subsidiary purpose is to clear up some misunderstanding that seems to have arisen regarding the meaning of the term ‘cash budget’.
Learning Projectile Motion with the Computer Game “Scorched 3D“
Authors: Jurcevic John S.
Published: December 2007

For most of our students, video games are a normal part of their lives. We should take advantage of this medium to teach physics in a manner that is engrossing for our students. In particular, modern video games incorporate accurate physics in their game engines, and they allow us to visualize the physics through flashy and captivating graphics. I recently used the game “Scorched 3D” to help my students understand projectile motion.
Microcomputer-Based Laboratory for Archimedes' Principle and Density of Liquids
Authors: Gianino Concetto
Published: December 2007

Archimedes' principle is one of the fundamental themes of the mechanics of fluids in high school; it is described in detail in any introductory physics textbook1 and it asserts that “a body immersed, or partially immersed, in a fluid receives an upward force equal to the weight of the fluid it displaces.” In mathematical terms, Fup = ρgVx, where ρ is the fluid density, g the free-fall acceleration, and Vx the volume of the immersed portion of the body. In a partially immersed body, the fluid exerts pressure on all surfaces of the body, laterally and on the bottom [Fig. 1(a)]. Notice that the forces on the sides cancel by symmetry and the net effect of the fluid pressure is an upward buoyant force. Likewise, if the body is totally immersed [Fig. 1(b)], the fluid also exerts pressure on the top of the body, but since the pressure on the bottom will be greater than on the top (pressure increases linearly with depth in a fluid of uniform density), the result is a net upward buoyant force.
Cellular events during wound periderm formation in Dioscorea bulbifera bulbils
Authors: Knobloch Ina , Kahl Günter , Landré Pierre , Nougarède Arlette
Published: December 2007

The cytological events induced by a deep wound applied to Dioscorea bulbifera bulbils were studied using specific cytochemical methods and fluorescence and electron microscopy. Following wounding, a superficial layer with lignified (3rd h) and weakly suberized (6th h) cell walls formed in the original starchy parenchyma in contact with the wounded cells. Before the first mitoses (72nd h), an extensive dedifferentiation occurred in the underlying layers and involved reactivation of cell nuclei, nucleoli, and plastids. A concomitant aggregation of cytoplasmic ribosomes into polysomes occurred. Starch hydrolysis in the amyloplasts was evident before the first periclinal divisions. Periclinal divisions occurred in the reactivated cells from the second to the fourth layers beneath the wound. These newly meristematic cells could be divided into two to four new cells, leading to a periderm without a true phellogen. These covering layers degenerated during the period of lignification and weak suberization of cell walls. The thickness of the wound periderm depended on the age of the wounded bulbil.
Phyllotaxis: a reappraisal
Authors: Jean Roger V.
Published: December 2007

The field of research known as pyllotaxis has been the object of intense studies in the last 15 years. The present article proposes a reflection on the subject and on the objectives of this discipline and places it in a broader perspective. It stresses the necessity of a systemic and synergetic approach. The "biological problem" of phyllotaxis is redefined in the light of the fact that patterns identical to phyllotactic patterns are found in other areas of research. It is underlined that this organizational problem is fundamentally a "mathematical problem," the mathematical approach being able indeed to reach the explanatory level and the fundamental causes as well. To replace the narrow term phyllotaxis, the logo PPM, for primordial pattern morphogenesis and pyramidal pattern modelling, is proposed to underline the synergy of biological and mathematical approaches.
Nitrapyrin (2-chloro-6-(trichloromethyl)-pyridine), a nitrification inhibitor, may replace fertilizers for promoting cone bud production in southern pine seed orchards
Authors: Hare Robert C.
Published: December 2007

Male and female cone bud and cone production in loblolly (Pinustaeda L.) and slash (Pinuselliottiielliottii Engelm.) pine was significantly stimulated by June soil application of nitrapyrin (2-chloro-6-(trichloromethyl)-pyridine), a specific toxin for nitrifying and denitrifying bacteria. Nitrapyrin presumably acts by conserving ambient soil nitrogen since only 1.5–2 g promoted cone buds as effectively as 150 g of elemental nitrogen from either ammonium or nitrate sources. Nitrapyrin may serve as a less costly substitute for nitrogen fertilization in seed orchards.
Predicting leaf area and biomass of 1- to 6-year-old tanoak (Lithocarpusdensiflorus) and Pacific madrone (Arbutusmenziesii) sprout clumps in southwestern Oregon
Authors: Harrington Timothy B. , Tappeiner II John C. , Walstad John D.
Published: December 2007

To provide methods for predicting site occupancy by sprouting understory hardwoods after conifer harvest, data from 142 tanoak (Lithocarpusdensiflorus (Hook. and Arn.) Rehd.) and 165 Pacific madrone (Arbutusmenziesii Pursh) sprout clumps, 1 to 6 years old, were used to develop equations for predicting leaf area and aboveground biomass. Crown cross-section area was correlated with clump leaf area and biomass (tanoak, r2 = 0.78 and 0.77; madrone, r2 = 0.86 and 0.83), so that estimates of site occupancy may be made from ground or aerial observation. Leaf area and biomass of tanoak and madrone may also be predicted before cutting or burning from equations relating these variables to parent-tree diameter at breast height times sprout-clump age (tanoak, r2 = 0.67 and 0.67; madrone, r2 = 0.74 and 0.73). The leaf area index per sprout clump differed significantly (p ≤ 0.01) between species: tanoak, 7.03 m2 leaf area/m2 crown area; madrone, 4.13 m2 leaf area/m2 crown area. These values generally did not vary with diameter of the parent-tree stem or with clump age; thus, for each species, they represent a potential maximum leaf area index for developing sprout-clump stands up to 6 years old.
A canopy model (RM-CWU) for determining transpiration of subalpine forests. I. Model development
Authors: Kaufmann Merrill R.
Published: December 2007

A model has been developed for calculating consumptive water use of subalpine forests in the Rocky Mountains. This model, RM-CWU, is based upon the use of a submodel of stomatal behavior in which stomatal activity is predicted from photosynthetic photon flux density (PPFD) and the absolute humidity difference from leaf to air (DAH). Instantaneous transpirational flux density is calculated for layers of leaf area for each species, and transpiration is summed for the entire canopy. PPFD profiles are derived using extinction coefficients estimated for each stand, for a range of sun angles, along with estimates of PPFD above the canopy corrected for slope, aspect, obstruction of the horizon, time, and date. DAH is estimated from records collected at a centrally located weather station, using a submodel for calculating canopy temperature at higher elevations. In preliminary applications, conductances calculated with RM-CWU varied with physiographic features of the site, date and time, position in the canopy, and weather conditions, through effects on PPFD and DAH. Consumptive water use, calculated for entire stands using leaf areas predicted from basal area measurements, also varied with stand composition.
Water relations of Pinusradiata in competition with weeds
Authors: Sands Roger , Nambiar E. K. Sadanandan
Published: December 2007

Soil water profiles up to 2 m in depth and diurnal patterns of needle water potential and stomatal resistance were measured over a dry summer period in 5-, 16-, and 28-month-old radiata pine (Pinusradiata D. Don) plantations, growing with and without weed competition. Severe water stress with consequent productivity loss occurred in trees with weed competition but the severity of stress decreased progressively with increasing tree age. Transplanted seedlings in their first growing season had shallow root systems which could not efficiently exploit water at depth. By contrast, seedlings in their second and third growing seasons extracted water from at least a depth of 2 m. Trees without weed competition were not water stressed over this period even when planted at three times their normal stocking rate. Thus there is considerable capacity to increase early growth rates of radiata pine without water being the limit to growth if weeds are adequately controlled.
Invivo chlorophyll fluorescence as a possible indicator of the dormancy stage in Douglas-fir seedlings
Authors: Hawkins C. D. B. , Lister G. R.
Published: December 2007

Invivo chlorophyll fluorescence and photosynthetic pigment contents of current-year needles from five populations of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco, var. menziesii Franco and var. glauca (Beissn.) Franco) were monitored at 3- to 4-week intervals over 2 years. The results were compared with the reported stage of seedling dormancy to ascertain whether this technique would be suitable for indicating dormancy status. Minimum values of fluorescence-induction parameters, indicating winter photosynthetic inactivation, were observed during the coldest period. The lower the temperature and the greater the irradiance, the greater the apparent inactivation. An increase in chlorophyll a to chlorophyll b ratios and a decrease in total chlorophyll to carotenoid ratios, indicating a relative increase in protective carotene pigments, was associated with this period. Maximum values for the fluorescence parameters were observed during periods of maximum growth. It appears that a rapid and inexpensive means of screening for Douglas-fir's dormancy status could be developed using invivo chlorophyll fluorescence analyses.
Ectomycorrhizal formation and plantation performance of Douglas-fir nursery stock inoculated with Rhizopogon spores
Authors: Castellano Michael A. , Trappe James M.
Published: December 2007

Basidiospores of seven species of hypogeous, ectomycorrhizal fungi were inoculated on four conifer species in a bare-root nursery. Inoculation with either Rhizopogonvinicolor Smith or Rhizopogoncolossus Smith succeeded with two provenances of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco). For R. vinicolor, the high spore-application rate produced the most mycorrhizae on the greatest number of seedlings. For R. colossus, the high spore-application rate produced the most mycorrhizae on the greatest number of seedlings of seed source 062, whereas the medium rate did better with seed source 252. Stem height and root collar diameter of seedling did not differ significantly between treatments and controls. Douglas-fir seedlings inoculated or not inoculated with spores of R. vinicolor were outplanted in southwestern Oregon. After 2 years, inoculated seedlings had significantly greater survival, stem height, root collar diameter, and biomass than noninoculated seedlings. Although new feeder roots of both noninoculated and inoculated seedlings were colonized by indigenous fungi, R. vinicolor persisted on the old root systems of inoculated seedlings and colonized new feeder roots.
Root growth and root growth capacity of white spruce (Piceaglauca (Moench) Voss) seedlings
Authors: Johnson-Flanagan Anne M. , Owens John N.
Published: December 2007

Root growth in the root systems of Styroplug-grown white spruce (Piceaglauca (Moench) Voss) seedlings increases in the spring before shoot elongation and again in the fall after bud development is complete. This is followed by root dormancy and quiescence, which are distinguished on the basis of ability to elongate under root growth capacity (RGC) conditions. The number of white long lateral roots produced during RGC tests correlated significantly with the number of white long lateral roots under lathhouse conditions. Increased mitotic activity is required for root elongation. However, mitotic frequencies could not be used to assess RGC because of the confounding effects of independent growth cycles in individual roots. Cell expansion and transformation of insoluble carbohydrates are important controls of root elongation. The relationship between root and shoot growth under RGC conditions may not support the role of shoot elongation in decreasing root elongation. Conversely, this may indicate that RGC tests alter the endogenous controls of root and shoot growth.
Comparison of Douglas-fir site index and height growth curves in the Pacific Northwest
Authors: Monserud Robert A.
Published: December 2007

Site index and height growth curves produced by the major Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) site index studies in the Pacific Northwest are graphically compared. Results indicate that differences in the height growth pattern of Douglas-fir increase with increasing distance between regions. Height growth differences were extremely small between the northern Rockies and the east side of the Cascades and were rather large between the Rockies and the west side of the Cascades. The relatively small differences between the northern Rockies and the Cascade crest fell between these two extremes. Very small differences were also found between Montana and northern Idaho. A second result of the comparisons is that the type of data and the resulting methodology used to develop the site index curve system are strongly related to the similarity of the resulting curves. Curves derived from felled-tree, stem-analysis studies were quite similar to each other, but differed substantially from curves derived by harmonized guide-curve methods. Furthermore, the guide-curve systems produced curves that were surprisingly similar to each other, even though different varieties of Douglas-fir from different regions were being compared. The magnitude of the differences that could be attributed solely to different methods of site curve construction (stem analysis vs. guide curve) was demonstrated to be quite large by applying both methods to the same data. The often untenable assumptions inherent in guide-curve systems appear to affect the shape of the curves more than real regional height growth differences.
Assessing the long-run yield of a forest stand subject to the risk of fire
Authors: Reed W. J. , Errico D.
Published: December 2007

The problem of determining the effects of forest fire on stand yields is often neglected in forest yield analyses. Using previous theoretical results, "fire-adjusted, volume–rotation curves" can be developed which provide a graphical technique for determining optimal rotation age and long-run yield when the risk of fire is present. For white spruce of the northern interior of British Columbia it is shown that even modest rates of fire can result in very large reductions in long-run yield. Similar results are established for the effects of fire on land expectation value, which is dissipated very quickly under the risk of fire.
Crown releasing of red maple poles to shorten high-quality sawlog rotations
Authors: Erdmann Gayne G. , Peterson Jr. Ralph M. , Oberg Robert R.
Published: December 2007

The effects of six crown-release treatments on growth and bole quality development of 54-year-old dominant, codominant, and intermediate red maples (Acerrubrum L.) were evaluated on a good red maple site (site index = 19.3 m at 50 years) in upper Michigan. Results showed that crown release stimulated the growth of dominants, codominants, and strong intermediates without appreciably degrading log quality. The heavier 1.5- to 4.6-m crown-release treatments resulted in 7-year average DBH growth increases over the unreleased controls of 70% for dominants, 96% for codominants, and 108% for intermediates. Crown release had no effect on 8-year height growth, 3-year epicormic branching, or bole quality. Three years after treatment, unreleased trees had almost as many epicormic branches as released trees. The number of epicormic branches on individual trees was a function of dominance, log position, or height above ground, but was not related to residual stand density. Epicormic branching was also strongly correlated with the number of pretreatment epicormic branches on boles of intermediate trees, but not on dominant or codominant trees.
The use of the fluorochrome calcofluor for monitoring the extent and penetration of pyrolysis in black spruce bark hollocelluloses
Authors: Stephenson David E. , Smith David W.
Published: December 2007

The extent of pyrolysis in partially burnt spruce bark was monitored using a hollocellulose-specific fluorochrome. Fluorescence and hollocellulose content decreased as exposure temperature increased. No fluorescence was observed in material exposed to temperatures above 400 °C. The depth of the pyrolysis front into the bark layer of trees burnt in wildfires helps to determine the fire severity.
Individual tree biomass estimation equations for plantation-grown white spruce in northern Minnesota
Authors: Harding R. B. , Grigal D. F.
Published: December 2007

Prediction equations for biomass of white spruce (Piceaglauca (Moench) Voss) were developed for 115 sample trees using the allometric models Y = ADB and Y = ADBHC, where Y is mass, D is diameter at breast height, and H is total height. The addition of height to the model reduced the Sy•x for all estimates except that for biomass of branches and needles. Comparison of results to other estimation equations developed in eastern Canada showed that biomass estimates were variable. Variations in stand structure and age between natural and plantation-grown trees are possible reasons for these differences.
Decomposition of coarse woody debris in an old-growth Indiana forest
Authors: MacMillan Paul C.
Published: December 2007

Decay rates of Quercus sp., Carya sp., Fagusgrandifolia, and Acer sp. coarse woody debris in an old-growth southern Indiana forest were 0.018, 0.035, 0.019, and 0.045 per year, respectively, based on changes in density over a span of 25+ years. Their respective biomass values were 15, 2.3, 0.2, and 0.4 t•ha−1. The greatest differences in decay rates of cellulose were between maple (high) and oak (low), and of lignin were between beech (high) and oak (low). Carbon to nitrogen ratios approached 100 and nitrogen to phosphorus ratios approached 20 in the older age-classes. On average, oak, hickory, beech, and maple logs contained 1.66, 1.10, 0.14, and 0.19 kg nitrogen and 0.056, 0.070, 0.005, and 0.016 kg phosphorus, respectively. Meentemeyer's model based on actual evapotranspiration predicted a decay rate of 0.80 per year, which is 27 times larger than the decay rates calculated on changes in density. Fragmentation loss rates for these four genera were estimated to be 0.288, 0.802, 1.171, and 0.338 per year, respectively. Decay rates based on diameter of coarse woody debris ranged from 0.0027 to 0.0337 per year. All these factors are important in understanding the process of decay of coarse woody debris in this forest. The roles of fragmentation in the decay of coarse woody debris and of fungitoxic extractives need more study.
A variable-exponent taper equation
Authors: Kozak A.
Published: December 2007

A different approach to fitting taper equations has been developed, which eliminates the necessity of using several functions to predict diameter inside bark at different parts of the stem. The variable form taper function is easy to develop and saves computing time. For the data used in this study, it predicted tree profile as a function of height, diameter at breast height, and height from the ground with less bias than many of the taper-estimating systems found in the literature.
Sulfur, carbon, and nitrogen relationships in forest soils across the northern Great Lakes States as affected by atmospheric deposition and vegetation
Authors: David Mark B. , Grigal David F. , Ohmann Lewis F. , Gertner George Z.
Published: December 2007

Relationships among forest soil carbon, nitrogen, and sulfur, vegetation type, and atmospheric deposition of wet sulfate were tested using 169 forested plots across Minnesota, Wisconsin, and Michigan. Plots were geographically stratified into five zones, with wet sulfate deposition increasing from 156 (zone 1) to 380 (zone 5) equiv.•ha−1 • year−1. Total S concentrations, adjusted for N levels, indicated higher concentrations in eastern than in western zones in both the upper mineral soil (ca. 0.0152 and 0.0133% S, respectively) and forest floor (ca. 0.124 and 0.113% S, respectively). This illustrates that forest soil S levels reflect geographic gradients in atmospheric sulfate deposition. Total C and N concentrations and C:N and C:S ratios were affected by vegetation type. Jack pine and red pine mineral soil had lower concentrations of C and N compared with balsam fir, maple, and aspen. Forest floor C and N showed no clear pattern.
Growth resumption and performance of nonchilled Abies seedlings after their first winter
Authors: Tung Chao-Hsiung , DeYoe David R.
Published: December 2007

Survival, phenology, and growth of containerized noble fir (Abiesprocera Rehd.) and Shasta red fir (Abiesmagnifica A. Murr. var. shastensis Lemm.) seedlings were measured in response to dormancy induction chilling, and postplanting irrigation treatments. Temperature, photoperiod, and moisture were varied to induce dormancy. Seedlings were not chilled during the first winter, but received natural chilling during the second winter. In the first growing season (no winter chilling), terminal buds did not flush, but remained alive and inactive. Buds on lateral branches flushed and extended normally. In the second season (natural winter chilling), all terminal buds and lateral buds flushed. Dormancy induction treatment did not significantly affect budbreak, survival, or growth. However, postplanting drought simulation significantly reduced height, diameter, and aboveground biomass. The results demonstrate that the terminal buds of planted, nonchilled seedlings of these true fir species can remain inactive through an entire season and then resume growth once their chilling requirements are fulfilled.
Relationship between first-season free growth components and later field height growth in maritime pine (Pinuspinaster)
Authors: Kremer Antoine , Xu Li-An
Published: December 2007

Pinuspinaster Ait. seedlings from 15 families were grown under conditions designed to accelerate growth for 21 weeks in their first season. Fifteen height growth components were assessed and compared with total height, height growth pattern, and height growth components of trees of the same families grown for 6 years on a sandy moorland site. Growth-accelerating conditions induced the formation of typical adult-like apical buds. Principal components analysis on the weekly height increments during the first growing season showed that 76% of the overall between-family variation could be attributed to the first two components. Families that were extremely poly cyclic and monocyclic in the field were separated on the graph of the two principal components. Among the 15 growth components assessed during the first growing season, 3 showed a significant correlation with total height at 6 years of age: mean stem unit length, asymptotic total height value of the Richards growth function, and the first principal component, i.e., height growth rates during the early stages of development. Mean stem unit length was the component that showed the highest stability between the first and the fifth growing seasons. Between 30 and 72% of the variation of total height (38–64% of the variation of secondary shoot length) at age 6 could be predicted by multiple regression, with a combination of two or three components assessed in the first season.
Effect of scale and spatial heterogeneity on fire-interval distributions
Authors: Baker William L.
Published: December 2007

The distribution of forest-fire intervals has been characterized by fitting statistical distributions, such as that of Weibull. The parameters of fitted distributions can then be used to compare fire regimes. Fire-interval distributions for the 187-year presettlement fire history record in the Boundary Waters Canoe Area, Minnesota, were analyzed using reconstructed "fire-year" maps. Distributions were determined for sampling units at five spatial scales, from about 25 000 to 400 000 ha. Fire-interval distributions varied from positively to negatively skewed, but for most units the Weibull distribution fit significantly. The distributions varied spatially, and cluster analysis suggested that three fire regions, each containing a relatively homogeneous fire regime, could be identified. The sources of this spatial variation are unknown. There was less variation between scales within a fire region than between fire regions. This contrasts with a previous finding, using the same fire-history data, that scale substantially affects observed landscape age-class distribution. This disparity arises because landscape age-class distributions may fluctuate even if fire-interval distributions do not fluctuate. Reconstruction of fire-interval distributions requires historical data; landscape age-class distributions at an instant in time are insufficient.
Germination success of acorns (Quercus): insect predation and tannins
Authors: Weckerly Floyd W. , Sugg Derrick W. , Semlitsch Raymond D.
Published: December 2007

Predation by curculionid larvae, tannic acid content, and germination were measured in acorns from individual trees of Quercusalba and Quercusrubra from two sites at the Meeman Biological Field Station, Shelby County, Tennessee, U.S.A. A crossed and nested analysis of variance design was used, and no significant differences were found among trees or between sites in percentages of acorns that were attacked nor in tannic acid contents. Quercusrubra acorns had significantly less predation and higher amounts of tannic acid than Q. alba acorns. Acorns of both species that were not attacked had significantly higher germination success (82% for Q. alba and 98% for Q. rubra) than acorns that were attacked. There was no significant relationship between amount of predation and tannic acid content for acorns from trees of either species. Tannic acid content appears to have an impact by reducing seed predation and may interact with seed crop size to increase annual germination success of trees.
Soil nitrogen mineralization and immobilization in response to periodic prescribed fire in a loblolly pine plantation
Authors: Bell Randy L. , Binkley Dan
Published: December 2007

Additions of 15N-labelled ammonium sulfate were used to evaluate the effects of burning at 2- and 4-year intervals during a 24-year period on nitrogen mineralization and immobilization in a loblolly pine (Pinustaeda L.) stand. Net N mineralization in 10-day laboratory incubations of Oe + Oa plus 0–10 cm mineral soil was greatest in the control (210 mg N/m2), intermediate for the 2 year interval burn treatment (87 mg N/m2), and lowest for the 4 year interval burn treatment (78 mg N/m2). Forest floor and mineral soil C/N ratios were greater for the burn treatments than for the control. All samples showed >95% immobilization of added 15N ammonium sulfate, the pattern being 2-year interval >4-year interval control. Both burning regimes appeared to increase N immobilization and decrease N availability on this very N-poor site.
Spruce budworm defoliation and growth loss in young balsam fir: recovery of growth in spaced stands
Authors: Piene Harald
Published: December 2007

Trees defoliated by the spruce budworm (Choristoneurafumiferana (Clem.)) for 1 to 4 years and subsequently protected rapidly regained foliar biomass. Three plots of 25- to 30-year-old balsam fir (Abiesbalsamga (L.) Mill.) trees, on the Cape Breton Highlands of Nova Scotia, were studied. Two major factors contributed to the rapid growth recovery rates: the ability to produce epicormic shoots, combined with increased retention of older age-classes of needles, and the development of new foliage at the expense of volume growth. A complete recovery of volume increment occurred after 2 years of extreme defoliation, but not after 4 years of severe defoliation. Epicormic shoot production was only associated with shoot and bud destruction and therefore, growth recovery was slow after partial defoliation of only current foliage. In all plots studied, there was a lag of 2 to 3 years between increased foliar biomass and significant increases in volume increment.
Crown structure in western hemlock, Douglas-fir, and grand fir in western Washington: trends in branch-level mass and leaf area
Authors: Kershaw Jr. John A. , Maguire Douglas A.
Published: December 2007

Extensions of a basic allometric equation applied in predicting total foliage of individual trees were developed to estimate foliage and woody components of individual branches in western hemlock (Tsugaheterophylla (Raf.) Sarg.), Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), and grand fir (Abiesgrandis (Dougl. ex D. Don) Lindl.). Nine initial equations were fitted on both nonlinear and log-transformed scales to data collected in the western Cascade Mountains of Washington. In all cases, the logarithmic form of each equation provided the best fit to the data based on a modified likelihood criterion and residual patterns. Branch diameter was the overall best predictor of branch foliage and woody mass; however, significant (p = 0.05) improvements in fit were obtained when other structural and positional variables were included in the equations (e.g., foliated branch length and depth into crown). The effects of fertilization and site (locality) differences were explored using indicator variables for western hemlock branches. Significant site effects were observed for intercept terms for all three branch components (total foliage area, total foliage mass, and total woody mass), while fertilization effects were observed in interaction with relative height above crown base for both foliage components.
Heritability of in vitro characteristics and correlation with field performance in Pinusradiata
Authors: Bergmann Ben A. , Stomp Anne-Marie , Carson Sue D.
Published: December 2007

Twenty-nine full-sib crosses were used in an in vitro adventitious shoot production trial with Pinusradiata D. Don. Analyses with four pairs of reciprocal crosses showed that seed-size effects are significant for seed weight prior to tissue culture and embryo weight after 6 days in vitro. However, no significant influence of initial seed size was found on any other interim tissue-culture trait or on final shoot production. Narrow-sense heritabilities, calculated using nine half-sib families each comprising two full-sib crosses, were high for most tissue culture traits. For number of shoots per embryo they were 0.53 ± 0.22 based on individuals and 0.94 based on family means. Subsets of the families used in the tissue-culture study were represented in two field trials. One included parents of 11 of the control-pollinated families, and one included offspring from 13 of the control-pollinated families. Nine families were common to both field trials. Pearson correlation coefficients were determined between each of 13 in vitro traits and six field characteristics measured in one trial and seven traits in the other trial (five traits in common between the two field trials). Almost all correlations were nonsignificant. The significant correlations found were fewer than the number to be expected by chance alone when calculating such a large number of correlations. Thus, this study provides no evidence for significant associations between the in vitro traits measured, including frequency of highly proliferative embryos and shoot production per embryo, and the field characteristics assessed, including diameter, straightness, malformation, branch habit, needle retention, percent acceptable stems, Dothistroma resistance, and pilodyn rating.
Effects of competition on the foliar chemistry of young Douglas-fir in monoculture and mixed stands with young red alder
Authors: Shainsky Lauri J. , Rose Cathy L.
Published: December 2007

The effects of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) and red alder (Alnusrubra Bong.) densities on foliar chemistry of 4-year-old Douglas-fir were examined in experimentally manipulated stands. The density of each species was varied systematically in a two-way density matrix composed of five monoculture densities and 25 mixtures of all possible pairwise combinations of monoculture densities. Foliage was sampled in July of the second growing season and analysed for concentrations of nitrogen (N), phosphorus (P), starch, sugars, total nonstructural carbohydrates, and free amino acids. Response surfaces were generated, and regression analyses quantified the effects of each species' density on biochemistry. Increasing the overstory alder density resulted in increased N, free amino acid, and P concentrations in the Douglas-fir foliage, and reduced starch and total nonstructural carbohydrate concentrations. Effects of Douglas-fir density were variable and dependent on the red alder density. Trends in biochemistry correlated well with soil moisture, light, and growth rates. Conditions favoring growth were associated with reduced concentrations of N and P and elevated levels of starch and nonstructural carbohydrates. The results strongly suggest that examination of foliar chemistry should be coupled with growth, physiology, and resources if biochemical constituents are to be used for testing tree vigor.
Thirty-eight years of autogenic, woody understory dynamics in a mature, temperate pine–oak forest
Authors: Cain Michael D. , Shelton Michael G.
Published: December 2007

In 1935, 32 ha of a pine–hardwood forest were set aside from future timber management in southern Arkansas, U.S.A. Old-growth timber had been cut to a 36-cm stump diameter before 1915. Between 1952 and 1993, four inventories were made of the overstory and midstory components (number of live trees ≥9 cm in diameter breast height (DBH) taken at 1.37 m, by 2.54-cm DBH classes). Between 1954 and 1992, four corresponding inventories were made of the woody understory vegetation (>15 cm tall but <9 cm DBH) by counting rootstocks within 52 systematically spaced 8-m2 circular quadrats. Understory species importance values (relative density + relative height + relative frequency) were used to compute diversity and similarity indices. During 38 years of assessment, no catastrophic disturbances occurred within the 32-ha forest. Although loblolly pine (Pinustaeda L.) and shortleaf pine (Pinusechinata Mill.) dominated the overstory (64% of basal area in 1954 and 63% in 1993), pines were absent from the understory in all but seedling size classes for the last 38 years. Woody understory diversity indices were essentially stable for 38 years, but the similarity of understory species tended to decline as the time between inventories increased. Relative importance values for woody understory species tended to increase for the more shade-tolerant genera and decrease for less tolerant genera. Survival and height growth of woody understory species were also found to be positively correlated with shade tolerance.
Determination of total nonstructural carbohydrates in tree species by high-performance anion-exchange chromatography with pulsed amperometric detection
Authors: Wilson Rose , Cataldo Ann , Andersen Christian P.
Published: December 2007

Tracing shifts in carbohydrate pools has become an important tool for studying the integration of plant responses to natural and anthropogenic stresses on tree species. As a result, the need for a rapid and sensitive analytical technique to measure the components in the total nonstructural carbohydrate pool in various plant tissues has increased. In this paper we report carbohydrate data for five species that were obtained using a high-performance anion-exchange chromatography method that uses an alkaline, isocratic mobile phase (160 mM NaOH) with triple-pulsed amperometric detection. This approach has been applied to the analysis of sugar alcohols, monosaccharides, disaccharides, and other oligosaccharides in ponderosa pine (Pinusponderosa Dougl. ex Laws.), black cherry (Prunusserotina Ehrh.), and other species roots, branches, stems, and needles. The results show the range of tissue concentrations found and suggest the usefulness of the anion-exchange method for the routine quantification of the total nonstructural carbohydrate pool in trees with minimal sample preparation and cleanup. Base-line resolution of the soluble carbohydrates was accomplished in less than 13 min. The chromatographic analysis of starch as glucose was complete in less than 4 min. Electrochemical detection enabled selectivity of the carbohydrates and higher sensitivity over the conventional colorimetric assays or high-performance liquid chromatography with refractive index detection. The minimum levels of quantification were 4.5 ng for myo-inositol, 4.6 ng for sorbitol, 4.5 ng for glucose and fructose, 17.1 ng for sucrose, and 29.7 ng for raffinose.
THE KINEMATICS OF PARTICLES MOVING IN RAINBOW SPACETIME
Authors: LING YI , HE SONG , ZHANG HONGBAO
Published: December 2007

The kinematics of massive particles moving in rainbow spacetime is studied. We derive the equation of geodesics when the semiclassical effect of moving particles on the background is taken into account. In particular we show that in rainbow flat spacetime the trajectory of a freely falling particle remains unchanged which is still a straight line in energy-independent coordinate system. The implication to the Unruh effect in rainbow flat spacetime is also discussed.
GENERATION OF A NONLINEAR TWO-MODE STARK SHIFT VIA NONDEGENERATE RAMAN TRANSITION
Authors: KHALIL E. M.
Published: December 2007

In this contribution, a three level atom in interaction with a two-mode quantized electromagnetic field, initially prepared in an entangled two-mode coherent state, is considered. Through the elimination of an intermediate level using the adiabatic elimination method, a nonlinear Stark shift is introduced. The exact solution of the wave function in the Schrödinger picture is obtained. Some statistical aspects through the effective two-level atom interacting with the two-mode and multiphotons processess with the nonlinear Stark shift are presented. The results are employed to perform a careful investigation of the temporal evolution of the atomic inversion, entropy squeezing and variance squeezing. It has been shown that the system is sensitive to any change in the parameter representation of the Stark shift. General conclusions reached are illustrated by numerical results.
PHASE AND LAG SYNCHRONIZATION IN COUPLED FRACTIONAL ORDER CHAOTIC OSCILLATORS
Authors: LI CHUNGUANG
Published: December 2007

Chaotic dynamics of fractional (non-integer) order systems have begun to attract much attention in recent years. In this paper, we study the phase and lag synchronization in coupled two fractional order chaotic oscillators. It is shown that with the increase of coupling strength, the system first undergoes a transition to phase synchronization, and when the coupling strength is increased further, another transition to lag synchronization occurs. It is further shown that the system with two chaotic oscillators of different orders can also exhibit phase synchronization phenomena, although the identical synchronization is impossible in this case.
AN INDEX THEOREM FOR GRAPHENE
Authors: PACHOS JIANNIS K. , STONE MICHAEL
Published: December 2007

We consider a graphene sheet folded in an arbitrary geometry, compact or with nanotube-like open boundaries. In the continuous limit, the Hamiltonian takes the form of the Dirac operator, which provides a good description of the low energy spectrum of the lattice system. We derive an index theorem that relates the zero energy modes of the graphene sheet with the topology of the lattice. The result coincides with analytical and numerical studies for the known cases of fullerene molecules and carbon nanotubes, and it extends to more complicated molecules. Potential applications to topological quantum computation are discussed.