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AbstractBranch growth in Larix gmeliniiwas estimated by several methods. Sample trees were felled in Laoshan (northeastern China) and Sapporo (northern Japan). Estimates of the annual woody growth of branches calculated by the growth ratio of the cross-sectional area of each branch base were found to be lower compared with those calculated by a detailed method, in which branch growth was estimated by growth-ring analysis of radial segments in different age classes. A linear relationship was observed between the annual woody growth/whole branch mass ratio and the relative depth within the crown (RDC), where the distance between the treetop and crown base was set to 1.0. The total annual woody branch growth of each tree was estimated using this relationship by multiplying the ratio by the whole branch mass at a given RDC and adding the products from the treetop to the crown base. Alternative estimates were obtained using the total branch growth, defined as the annual woody growth plus leaf mass, and the 1 − RDC relationship. Estimates obtained by these methods were similar to those obtained by detailed growth-ring analysis of branches. Estimates obtained by the growth/mass ratio for only the stem within the crown were also compared with those obtained by detailed growth-ring analysis.

Frustration introduces a nontrivial dispersion relation of spinwave even in a ferromagnetic phase in a spin system. We study the reflection and refraction process of spinwaves in the ferromagnet/frustrated ferromagnet junction system by using the Holstein--Primakoff spinwave expansion and taking the large-$S$ limit. We discuss the relation between the incident angle and the refraction angle of spinwave, namely, the Snell's law of spinwave. As concrete examples of frustrated ferromagnets, we study the fully polarized ferromagnet phases in $J_{1}$--$J_{2}$ chains and the $J_{1}$--$J_{2}$ models on the square lattice. The interesting refraction processes, such as the splitting of the incident spinwave and the negative refraction, are discussed. We also study the transmittance and reflectance in these concrete models.

AbstractWe investigated how removal of understory dwarf bamboo (Sasa kurilensisMakino et Shibata) affected growth and water use of young Betula ermaniiCham. trees in a secondary forest in northern Japan. We compared current-year shoot morphology, leaf water-relations characteristics, and whole-tree water use of B. ermaniitrees growing with dwarf bamboo in the understory (intact plot) to those of trees growing where dwarf bamboo was experimentally removed (removal plot). Current-year shoot length and internode frequency increased, while internode length and individual leaf area decreased in response to dwarf bamboo removal. Carbon isotope composition (δ13C) of leaves did not change indicating that leaf water-use efficiency was unaffected by the presence/absence of dwarf bamboo. Pressure–volume analysis indicated that leaves in the removal plot had lower water uptake ability. During mid-summer, trees in the removal plot sustained high sap flow velocity after peaking at midday, while that of trees in the intact plot declined. In addition, whole-tree sap flux and soil-to-leaf hydraulic conductance were both higher for trees in the removal plot. We inferred that the observed changes reflect hydraulic homeostasis of B. ermaniitrees to maintain constant water-use efficiency in response to belowground competition with dwarf bamboo. Removal of dwarf bamboo is, therefore, an effective silvicultural prescription to enhance growth of overstory trees by relieving belowground competition for soil water.

AbstractWe studied the effects of line thinning on stand structure, microclimate and understory species diversity of two Cryptomeria japonicaD. Don plantations in south-central Japan. In each of two study sites we compared stand structure between the thinned stand and an adjacent unthinned stand and found that line thinning increased the growth rate of residual trees such that stand basal area may recover within 10 years after thinning. In the thinned stand, more open canopy conditions resulted in higher maximum temperatures on the forest floor during the early growing season than in the unthinned stand. The thinned stand had greater understory plant species richness and biomass than the unthinned stand. This study suggested that line thinning could potentially enhance biodiversity while simultaneously increasing tree-growth rates in overstocked Cryptomeria japonicaplantations.

Abstract??We investigated the effects of line thinning on the abundance of Hymenoptera in two Japanese cedar plantations in northern Hyogo Prefecture, central Japan, in order to evaluate the effectiveness of this silvicultural treatment for ecosystem management. Line thinning is a silvicultural treatment practiced in Japan, where linear stand sections are cut (25%?35% of the total number of trees) retaining one to two rows of trees. We used Malaise traps to capture Hymenoptera from the line-thinned stand (treatment plot, including thinned and retained sections) and the unthinned stand (control plot). Overall, the total number of Hymenoptera was greater in the treatment plot than in the control plot. The treatment plot hosted more functional groups and families of Hymenoptera than the control plot in both plantations. In the Kuchiotani plantation (high-elevation site), the overall abundance of Hymenoptera and of many Hymenopteran functional groups were positively correlated with both species richness and biomass of understory plants. In the Sugi plantation (low-elevation site), understory vegetation was less developed and there was no correlation with abundance of Hymenoptera. Our study indicates that line thinning is an effective silvicultural treatment for future management of overstocked Japanese cedar plantations because it can fulfill biodiversity objectives, but the effectiveness may depend on silvicultural and landscape factors.

AbstractWe investigated the effects of line thinning on the abundance of Hymenoptera in two Japanese cedar plantations in northern Hyogo Prefecture, central Japan, in order to evaluate the effectiveness of this silvicultural treatment for ecosystem management. Line thinning is a silvicultural treatment practiced in Japan, where linear stand sections are cut (25%–35% of the total number of trees) retaining one to two rows of trees. We used Malaise traps to capture Hymenoptera from the line-thinned stand (treatment plot, including thinned and retained sections) and the unthinned stand (control plot). Overall, the total number of Hymenoptera was greater in the treatment plot than in the control plot. The treatment plot hosted more functional groups and families of Hymenoptera than the control plot in both plantations. In the Kuchiotani plantation (high-elevation site), the overall abundance of Hymenoptera and of many Hymenopteran functional groups were positively correlated with both species richness and biomass of understory plants. In the Sugi plantation (low-elevation site), understory vegetation was less developed and there was no correlation with abundance of Hymenoptera. Our study indicates that line thinning is an effective silvicultural treatment for future management of overstocked Japanese cedar plantations because it can fulfill biodiversity objectives, but the effectiveness may depend on silvicultural and landscape factors.

Arthropods play vital roles in various ecosystem functions and respond acutely to habitat manipulation. Diversity and community dynamics of arthropods are strongly correlated with ecosystem functioning. Arthropod community structure reflects habitat heterogeneity, as well as development and recovery of forest ecosystems after natural and anthropogenic disturbances. Arthropod community structure also reflects the degree of fragmentation and isolation of forest ecosystems on the landscape. Arthropods are good indicators of the overall biodiversity and ecosystem integrity of forests and can be used for evaluating and designing sound ecosystem management plans.

Systematic measurements of the far infrared reflection spectra of high Tc superconductors LnBa2Cu3Ox for various Ln as shown in the title were performed. Infrared reflection spectra of tetragonal LnBa2Cu3Ox exhibit Reststrahlen vibration near 640, 590, 530, 355 and 250 cm-1, common to these materials, and the spectra of the orthorhombic LnBa2Cu3Ox exhibit the characteristics of free carriers except PrBa2Cu3Ox with weak phonon structures near 617, 570, 317 and 285 cm-1. PrBa2Cu3Ox is not a superconductor, and it has no characteristic broad band due to free carriers for all x in the range of 6 to 7. Lattice dynamical calculation was performed by the use of the shell model and the calculated results express quite well the characteristic features of infrared experiments.

Cold atoms bring new opportunities to study quantum magnetism, and in particular, to simulate quantum magnets with symmetry greater than SU(2). Here we explore the topological excitations which arise in a model of cold atoms on the triangular lattice with SU(3) symmetry. Using a combination of homotopy analysis and analytic field theory we identify a family of solitonic wave functions characterized by integer charge Q=(QA,QB,QC), with QA+QB+QC=0. We use a numerical approach, based on a variational wave function, to explore the stability of these solitons on a finite lattice. We find that solitons with charge Q=(1,1,-2) spontaneously decay into a pair of solitons with elementary topological charge, and emergent interactions. This result suggests that it could be possible to realize a class of interacting soliton, with no classical analog, using cold atoms. It also suggests the possibility of a new form of quantum spin liquid, with gauge group U(1)?U(1). [ABSTRACT FROM AUTHOR]