Shuichi Noshiro

Latitudinal trends in wood anatomy within species and genera: case study in Cornus s.l. (Cornaceae)

Latitudinal trends in wood anatomical characters in three Asiatic species of Cornus sensu lato (s.l.) were studied and compared with those for the whole genus based on an extensive sampling covering the specific distribution ranges and the generic data from a previous study. We studied 124 specimens of C. controversa growing between 31.5° and 45.3° N, 54 of C. kousa between 24.4° and 40.5° N, and 64 of C. macrophylla between 27.8° and 41.0° N. Characters studied were vessel element length, fiber length, vessel frequency, tangential vessel diameter, and vessel grouping index. At the species level no latitudinal trends were detected throughout the distribution ranges of the species. Neither tree size, altitude, nor climatic factors had a significant correlation with wood anatomical characters. In contrast, at the genus level, latitudinal trends were significant not just for the whole genus, but for both New and Old World species groups. At the genus level, latitude and three climatic factors all had a significant correlation with wood anatomical characters, but correlation coefficients with latitude were markedly high. The difference in latitudinal trends between the genus and species levels may be due to the radiation of Cornus along paleoclimatic gradients in the early Tertiary.

Lack of latitudinal trends in wood anatomy of Dodonaea viscosa (Sapindaceae), a species with a worldwide distribution

Latitudinal or altitudinal variation in several anatomical characters of wood is common for woody dicotyledonous genera with a wide distribution, but whether such variation exists at the species level is disputed. Latitudinal and altitudinal trends in wood anatomy of Dodonaea viscosa were studied, using 102 samples collected between 41.2° S and 33.3° N latitude and 7-2750 m altitude. We studied variation in four quantitative features: vessel element length, fiber length, vessel frequency, and tangential vessel diameter. Ontogenetic trends were minimal with a slight decrease or increase in the innermost stem and were negligible among the studied specimens. Throughout the distributional range of the species, no latitudinal trends were detected in either the Northern or Southern Hemispheres. Altitudinal trends were also nonexistent, except for two features in specimens from China and Japan. Absence of latitudinal or altitudinal trends in this widely distributed species suggests that in some species the species-level variation in wood anatomy is not controlled by ecological gradients.

Ecological wood anatomy of NepaleseRhododendron (Ericaceae). 1. Interspecific variation

The relationship of selected wood anatomical characters of NepaleseRhododendron with stem diameter, plant height, altitude, and plant form was investigated. We studied one to three specimens each of 26 species: five species each of trees and subtrees I, three species of subtrees II, and 13 species of shrubs. Multiple regression analysis and actual distribution of character values show that pore characters and multiseriate ray ratio have a stronger correlation with stem diameter than altitude; that pore density, vessel element length, fiber-tracheid length, and multiseriate ray density and width are equally related to altitude and stem diameter, or to altitude and plant height; and that bar number, and multiseriate ray area and height have a stronger connection with altitude. Among the characters, average pore area is most strongly correlated with stem diameter and increases exponentially as diameter increases. For wood structure of NepaleseRhododendron, 17 to 63 % of the variation is affected by non-anatomical factors. The general trends in wood structure of NepaleseRhododendron show that trees and subtrees form one continuous unit whereas shrubs form another that often has wider ranges of variation.

Ecological wood anatomy ofAlnus nepalensis (Betulaceae) in East Nepal

Wood anatomical characters ofAlnus nepalensis growing in East Nepal are evaluated against three non-anatomical factors: tree height, diameter at breast height (DBH), and altitude. Samples were taken from the outermost part of the trunk of five canopy trees at 11 localities between 790 and 2,740 m above sea level. Tree height ranged from 10 to 28 m, and DBH ranged from 15 to 80 cm. Altitude and tree height are correlated with all the vessel characters studied. Among wood anatomical characters, vessel characters measured from cross sections are strongly correlated with one another, and are also correlated with vessel element and fiber-tracheid length. Multiple regression analysis using non-anatomical factors as independent variables resulted in significant correlation at 1% level in all pore characters, vessel element length, perforation plate bar number, and fibertracheid length. Regression coefficients of significant regressions are usually largest for altitude. For wood structure ofAlnus nepalensis in East Nepal, 23 to 42% of the variation is affected by non-anatomical factors. The large contribution of altitude is considered to be an indirect measure of the effect of temperature.

Ontogenetic wood anatomy of tree and subtree species of Nepalese Rhododendron (Ericaceae) and characterization of shrub species

Ontogenetic trends in the wood structure of Nepalese Rhododendron were studied in 15 specimens of two tree and four subtree species. Average growth ring width was constant from pith to bark in spite of occurrences of extremely narrow, false, or discontinuous rings. Vessel density, vessel area, vessel element length, and multiseriate ray height generally had an initial increase or decrease to 1.5 cm radius and near plateau or slight decrease or increase outward. Multiseriate ray density and area percentage were variable between specimens without a clear pattern. Ontogenetic trends from pith to fully mature wood in trees plus subtrees were inferred by treating the measurements in the present study with those of mature individuals in a previous study. Comparison of trends in trees plus subtrees and those in shrubs lead to ecological or systematic groupings. Vessel features showed that alpine shrub species have distinctly small, numerous vessels composed of short vessel elements. Multiseriate ray features indicated a systematic difference between the trees plus subtrees of subgenus Hymenanthes and the shrubs of subgenus Rhododendron. Vessel features of alpine shrubs may be an adaptation against frequent freeze-thaw cycles or the result of growth stress imposed by the severe alpine environment.

Larix-Picea forests of the Last Glacial Age on the eastern slope of Towada Volcano in northern Japan

Larix is an under-represented taxon in pollen assemblages, and its contribution to past forest composition is difficult to estimate from macrofossil assemblages only. Buried forests reflect the past forest composition directly, and the dimension of the component individuals and the distribution of forest stands can also be studied. Forests buried by the Towada Hachinohe pyroclastic fall deposits (To-HP) occur extensively on the eastern slope of Towada Volcano in northern Japan. Fossil woods composing these buried forests and those from lower peat-bearing deposits, named the Upper Ofudo Formation, show the formation of Larix-Picea forests, accompanied by Abies, during the period 18,600 to 12,900 yr B.P. These forests established themselves after the destruction of Picea-Larix forests at ca. 31,800 yr B.P. by the Towada Ofudo pyroclastic fall deposits (To-BP1). Throughout the Upper Ofudo Formation, Larix and Picea are dominant, and Abies is a sporadic secondary element of these Larix-Picea forests. All the trees are less than 30 cm in diameter in the lower part of the Upper Ofudo Formation, and larger individuals, up to 70 cm in diameter, are detected in the upper part and the forests buried by the To-HP. Coexistence of Larix, Picea and Abies, and the existence of a peat layer in the probable soil surface indicate that the buried forests were very similar to present-day Larix gmelinii var. japonica forests on transitional or low moors on Sakhalin. Among the large individuals of the To-HP buried forests, the growth rate of Larix was slightly higher than that of Picea or Abies which have a similar growth rate.

Vegetation change during the early last Glacial in Haboro and Tomamae, northwestern Hokkaido, Japan

Abstract Early last Glacial sediments are exposed at several points on the cliffs of marine terraces in the Haboro and Tomamae area. The sediments can be correlated by their facies and three widespread tephra layers, Kc-Hb, Toya and Aso-4. Six stages of vegetation change can be recognized from the pollen spectra of three sites: (1) Picea forest spread around the time of the Kc-Hb ash fall; (2) Larix forest spread between the K-Hb and Toya ash falls; (3) towards the Toya fall Lysichiton and Alnus increased abruptly and after that Betula became dominant around the Toya; (4) between the Toya and Aso-4, temperate deciduous broad-leaved trees such as Quercus, Ulmus, Fraxinus grew with Picea and Betula ; (5) Larix forest spread again around the time of the Aso-4 fall; (6) finally, Betula forest spread again, accompanied by temperate deciduous broad-leaved trees such as Ulmus, Quercus, Fraxinus . The Picea -dominant stage and following Larix -rich stage might correspond to oxgen isotope substage 5d while the subsequent Larix -rich stage around Aso-4 might represent substage 5d.

The Anatomy of Unusual Tracheids in Tetracentron Wood

Unusual cells are reported for mature wood and branchwood of Tetracentron. They are thin-walled tracheids, rectangular in cross section, much shorter and a little wider than normal tracheids, and arranged in conspicuous radial files. They have crowded, alternate, circular to elliptical bordered pits in the tangential walls. Their radial walls are devoid of pils, except in crossfield areas and very rarely in limited areas of the walls touching normal tracheids. In contrast, normal tracheids have scalariform and circular pits confined to the radial walls. In earlier reports the unusual tracheids have been observed in twigs and roots, but in our materials they are a regular feature of mature wood samples as well. Their possible functional and phylogenetic significance is discussed.

Application of Near-Infrared Spectroscopy for Evaluation of Drying Stress on Lumber Surface: A Comparison of Artificial Neural Networks and Partial Least Squares Regression

This study aimed to examine the feasibility of evaluating the stress level at the surface of lumber during drying using near-infrared (NIR) spectroscopy combined with artificial neural networks (ANNs). Sugi (Cryptomeria japonica D. Don) lumber with an initial moisture content ranging from 41.1 to 85.8% was dried using a commercial drying schedule. An ANN model for predicting surface-released strain (SRS) was developed based on NIR spectra collected from the lumber during drying. The predictive ability of the ANN model was compared with a partial least squares (PLS) regression model. The ANN model showed good correlation between laboratory-measured SRS and predicted SRS with an R 2 of 0.79, a root mean square error of prediction (RMSEP) of 0.0009, and a ratio of performance to deviation (RPD) of 1.81. The PLS regression model gave a lower R 2 of 0.69, a higher RMSEP of 0.0010, and a lower RPD of 1.38 than the ANN model, suggesting that the predictive performance of the ANN model was superior to the PLS regression model. The SRS evolution during drying as predicted by the models showed a similar trend to the laboratory-measured one. The predicted elapsed times to reach maximum tensile SRS and stress reversal roughly coincided with the laboratory-measured times. These results suggest that NIR spectroscopy combined with multivariate analysis has the potential to predict the drying stress level on the lumber surface and the critical periods during drying, such as the points of maximum tensile stress and stress reversal.

Forest Development during 6,300-3,000 yBP (Early to Late Jomon Periods) at the Akayama Site, Central Japan

Fossil wood assemblages deposited during 6.300–3.000 yBP, are studied at the Akayama Site, central Japan. Layer III containing fossil woods was divided into three subunits according to intercalating tephras, and total 3618 fossil woods were studied. In the composition, deciduous broad-leaved trees dominated, accompanied by some evergreen conifers. In the diameter distribution, nine taxa accounted for nearly 90% of individuals exceeding 10 cm in diameter. Spatial distribution of nine major and three minor taxa and that of thick individuals clarified the following points: 1)Fraxinus established a lowland forest during 5,000–4,500 yBP, accompanied byAlnus sect.Gymnothyrsus, Acer andAesculus turbinata; 2) small trees ofAlnus sect.Gymnothyrsus extensively intermingled in the lowlandFraxinus forest during 4,500–3,000 yBP; 3)Quercus sect.Prinus and Castanea crenata constituted escarpment forests during 6,300–3,000 yBP; 4)Carpinus sect.Eucarpinus became a major component during 5,000–4,500 yBP, andOstrya japonica replacedCastanea crenata during 4,500–3,000 yBP. Comparison with the other five contemporaneous fossil wood assemblages shows prevalence ofFraxinus-dominant forests during the Late to Latest Jomon Periods in the southern part of the Kanto Plain.