Sugi Trees Research Articles

Natural drying of standing Sugi trees by girdling treatment for fuel chip production

Natural drying of standing Sugi trees by girdling treatment for fuel chip production

Wood density and microfibril angle from pith to bark of a sugi cultivar (Cryptomeria japonica, Japanese cedar, Tosaaka) grown in a Nelder plot

The current stumpage price in harvesting of a 50-year-old sugi (Japanese cedar, Cryptomeria japonica) plantation is not enough to motivate forest owners to reforest. Therefore, it is vital to reduce the cost for reforestation after logging as well as for logging and wood transportation of the preceding stands. Low initial tree density has been emphasized as one of the important basic measures to reduce directly the reforestation costs. In this study, for better understanding of the mechanical properties and dimensional stability of lumbers from sugi trees grown in low initial tree density, we examined the effects of initial tree density on wood density and microfibril angle of the S2 layer in the secondary wall of tracheids in rings from pith to bark in a sugi cultivar (Tosaaka) grown in a Nelder plot (initial density zoning symbols; D (4823 trees/ha), E (3349 trees/ha), G (1615 trees/ha), H (1122 trees/ha) and J (541 trees/ha)). Ring width and latewood percentage in J tree (541 trees/ha) were significantly larger and smaller than those of other initial tree density zoning symbol trees, respectively. Average wood density and earlywood wood density in J tree (541 trees/ha) were significantly smaller than those of other initial tree density zoning symbol trees (Tukey’s honestly significant difference test (Tukey HSD), p < 0.05). However, effects of initial tree density on the microfibril angles (earlywood and latewood) in rings from pith to bark and the transition patterns of microfibril angle from earlywood to latewood in an outer ring (ring number 22) were not significant or very small. Heartwood width in H trees (1122 trees/ha) and J trees (541 trees/ha) were significantly larger than those in other initial tree density zoning symbol trees (Tukey HSD, p < 0.05). There were no significant differences of ring width, average wood density, earlywood density and microfibril angle between H trees (1122 trees/ha) and E trees (3349 trees/ha) in many rings from pith to bark (Tukey HSD, p > 0.05). Based on these results of Tosaaka, a sugi cultivar grown in a Nelder plot, it was assumed that mechanical properties and dimensional stability of lumbers from sugi trees grown in low initial tree density (1000 trees/ha) might be quite similar to those from sugi trees grown in the regular initial tree density (3000 trees/ha), although lumbers from J trees (541 trees/ha) might be different from those of sugi trees grown in the regular initial tree density (3000 trees/ha). By taking the effects of genetic factor (variation of sugi cultivars) and the interaction between genetic and environmental factor (initial tree density) into consideration, the effects of low initial tree density (1000 trees/ha) on mechanical properties and dimensional stability of lumbers from sugi plantations in Japan might be smaller than the effects recognized in Tosaaka in this study. In this study, we did not examine the effects of initial tree density on the knots and the cross grain of lumbers. Low initial tree density might increase the negative effects of knots and cross grain on mechanical properties of lumbers. However, recent wood processing technology could minimize these negative effects.

Efficient cesium encapsulation from contaminated water by cellulosic biomass based activated wood charcoal

In this study, cost-effective cellulosic biomass based activated wood charcoal was developed from Japanese Sugi tree (Cryptomeria japonica) by concentrated nitric acid modification for adsorption of Cs from contaminated water. The physicochemical properties of specimens were investigated using N2 adsorption-desorption isotherms (BET method), FESEM, FTIR, and XPS spectra analysis. The experimental results revealed that the surface area of the raw wood charcoal was significantly decreased after boiling nitric acid modification. However, several oxygen-containing acidic function groups (-COOH, –CO) were introduced on the surface. The adsorption study confirmed that the equilibrium contact time was 1 h, the optimum adsorption pH was neutral to alkaline and the suitable adsorbent dose was 1:100 (solid: liquid). The maximum Cs was removed when the concentration of Na and K were lower (5.0 mM) with Cs in solution. The Cs adsorption processes well approved by the Langmuir isotherm and pseudo-second-order kinetic models and the maximum adsorption capacity was 35.46 mgg−1. The Cs adsorption mechanism was clearly described and it was assumed that the adsorption was strongly followed by chemisorptions mechanism based on the adsorbent surface properties, kinetic model and Langmuir isotherm model. Most importantly, about 98% of volume reduction was obtained by burning (500 °C) the Cs adsorbed charcoal, which ensured safe storage and disposal of radioactive waste. Therefore, this study can offer a guideline to produce a functional adsorbent for effective Cs removal and safe radioactive waste disposal.

Effect of weeding frequency, slope aspect and initial tree density on the mortality and accidental cutting of planted Sugi (&lt;i&gt;Cryptomeria Japonica&lt;/i&gt;) trees.

Effect of weeding frequency, slope aspect and initial tree density on the mortality and accidental cutting of planted Sugi (&lt;i&gt;Cryptomeria Japonica&lt;/i&gt;) trees.

Bark-feeding damage of sugi and hinoki cypress caused by sika deer, Cervus nippon: Does the sika deer prefer bark of hinoki cypress to sugi?

Abstract. Occurrence of bark-feeding damage by sika deer (Cervus nippon) was examined at 26 mixed plantations comprised of both sugi (Cryptomeria japonica) and hinoki cypress (Chamaecyparis obtusa) in Mie Prefecture, central Japan. There was no significant difference in damage ratios with the tree species in plantations with only slight damage. In plantations with a damage ratio over 5% in either tree species, hinoki cypress was debarked at a higher ratio than sugi. Hinoki cypress was damaged over a longer period than sugi. More effective countermeasures against debarking might be required for a longer period for hinoki cypress than for sugi trees.

Seasonal variations of tracheid formation and amount of auxin (IAA) and gibberellin A4 (GA4) in cambial-region tissues of mature sugi (Cryptomeria japonica) cultivar grown in a Nelder plot with different tree densities

The role of phytohormones in tracheid formation remains unclear in conifers. In this study, to obtain information on the role of auxin (IAA) and gibberellin A4 (GA4), we examined seasonal variation in the amount of phytohormones in cambial-region tissues and tracheid formation of sugi cultivar planted in a Nelder plot with different tree densities. We demonstrated that the amount of IAA was positively correlated with the number of tracheids formed in early and mid-season, but not in late season, and had no relation to tracheid differentiation. Crown length and height at the crown base had a positive and negative effect, respectively, on IAA amounts in early and mid-season, but not in late season. Height-to-diameter ratio was negatively correlated with IAA amounts in early and mid-season, but not in late season. Sugi trees with wider spacing continued tracheid formation in late season with smaller amounts of IAA, although the trees with narrower spacing ceased tracheid formation with larger amounts of IAA. Cambial growth cessation in late season might be controlled not by IAA amount, but by short-day-induced insensitivity to IAA. GA4 had no relation with the indexes of growth traits or tracheid formation.

スギ根元曲がり木における採材方法の違いがバイオマス発電向け低質材生産に及ぼす影響

スギ根元曲がり木における採材方法の違いがバイオマス発電向け低質材生産に及ぼす影響

4年生スギ人工林におけるスギの樹高と雑草木からの被圧に与える地形の影響

本研究では造林地内の空間不均質性に着目し，1）造林木の成長および造林木と雑草木との競合関係が地形により異なるか，さらに，2）場所によるランダム効果の取り扱い方の異なるモデル間で地形の効果が異なるか，を斜面長100 m傾斜角約30 度の4 年生のスギ若齢林で検討した。地形変数（尾根からの距離と傾斜角）が3，4 年生時のスギの樹高およびスギと雑草木の競合関係に与える影響を三つの統計モデル（ランダム効果を考慮しないモデル，場所のランダム効果を考慮したモデル，空間自己相関を考慮したモデル）で解析した。結果，尾根からの距離が大きいほどスギの樹高が高かった。スギの樹高が低い，または，尾根からの距離や傾斜角が大きいほど，雑草木から被圧されやすかった。他のモデルと比べ，空間自己相関を考慮したモデルでは地形変数の効果の信用区間は広がり，効果の評価が下がった。スギの成長や雑草木による被圧が斜面位置によって異なることから，斜面位置によって下刈頻度を変えることも下刈省力化の選択肢の一つとして考えられるが，一方で，要因の検出において空間情報の取り扱い方やサンプリングの方法を十分に検討する必要があると結論付けた。

Effects of application of trans-zeatin on tracheid differentiation in mature sugi (Cryptomeria japonica) trees

The mechanism of differentiation of tracheid (earlywood or latewood) should be elucidated to improve the wood properties of sugi trees (Cryptomeria japonica). Water deficit affects tracheid differentiation in conifers. However, the signals, which transmit the information of water contents in the soil to the differentiating tracheid, remain unknown. Plant responses with deficits of macronutrients or water showed some differences but also similarities, mostly involving hormonal long-distance signaling. In Arabidopsis, trans-zeatin (tZ)-type cytokinins play a role as a root-to-shoot acropetal signal. In this study, we report the effects of applying tZ alone or in combination with other phytohormones on tracheid differentiation in mature sugi trees forming latewood. The application of tZ induced the formation of earlywood-type tracheids with significantly smaller cell wall ratios and larger microfibril angles than those of controls in July, August and September. The application of indole acetic acid (IAA) in combination with tZ inhibited the effects of applied tZ, although gibberellic acid (GA3) did not. In October and November, application of tZ could not affect the xylem formation or dormancy of cambium. We hypothesized that tZ might play a role in the differentiation of earlywood tracheid.

スギ植栽木の樹高成長に及ぼす期首サイズと周辺雑草木の影響

スギ植栽木の樹高成長に及ぼす期首サイズと周辺雑草木の影響

The moisture transfer mechanism and influencing factors in wood during radio-frequency/vacuum drying

Wood from Sugi trees (Cryptomeria japonica D. Don) was used and the driving force for moisture transfer, the contribution ratio (for evaporation from the cross section) of the drying rate along the longitudinal direction to the total drying rate, the moisture transfer rate along the longitudinal direction attributed to the driving force and the dynamic permeability during the radio-frequency/vacuum drying process were calculated. The change law for these parameters and the relationships between them were analyzed, and the moisture transfer mechanism was evaluated in detail. Results showed that for a lower ambient pressure, the contribution ratio is higher, and most of the moisture is transferred along the longitudinal direction to the surroundings in the form of vapor. With decreasing moisture content, the driving force would slightly decrease as well, successively leading to a lower drying rate. The permeability of the two types of the specimen is similar during the whole drying process. However, for a higher ambient pressure, the contribution ratio is lower, and the proportion of diffusion to the moisture transfer increases, lowering the influence of the driving force on the drying rate, and the relationship between the driving force and the drying rate becomes inexplicit. Independent of the drying conditions, the permeability decreases with decreasing moisture content.

Effects of crown length on indole acetic acid (IAA) amounts in cambial region tissues in lower and upper trunks of sugi cultivars (Cryptomeria japonica) in September

Indole acetic acid (IAA) was believed to be an important regulator in xylem formation in conifers. However, few studies have been done on the endogenous amount of IAA in cambial region tissues in sugi (Cryptomeria japonica) trees. In this study, we report the IAA amounts in the lower and upper trunk of mature sugi cultivars (Kumotoshi, Yaichi and Obiaka) in September, and the effects of growth traits on the IAA amounts. The effect of height position (lower or upper trunk) on IAA amounts was found to be larger than that of genetic variation (Kumotoshi, Yaichi or Obiaka) by two-way ANOVA. There was no significant interaction effect (genetic variation × height position). The IAA amounts of all trees varied from 3 to 42 ng/cm2 at the lower trunk and 9 to 47 ng/cm2 at the upper trunk. Crown length and distance from crown base had significant positive and negative effects on IAA amounts in the trunk of sugi cultivars, respectively. Distance from crown base had a larger effect on IAA amounts than crown length. In Yaichi, taller trees had larger IAA amounts at both the lower and upper trunk.

Variation of indole acetic acid (IAA) amounts in cambial-region tissues in 7- and 24-year-old sugi (Cryptomeria japonica) trees

Recently, breeding programs have attempted to produce high growth rates for shorter rotation cycles in plantation trees. In these trees, the ratio of juvenile wood increases; thus, the juvenile wood properties should be improved for structural use. To this end, it is important to understand the influences on juvenile wood properties precisely. In this study, we report on the indole acetic acid (IAA) amounts of juvenile sugi (Cryptomeria japonica) trees in September and compare the IAA amounts to those in mature trees. The IAA amounts at the lower trunks in juvenile trees were significantly larger than those in mature trees and the IAA amounts decreased with tree height. In each stand, except a mature tree stand, there is no significant effect of IAA amounts on latewood width and MFA. However, put together all samples, the latewood width and MFA increased with IAA amounts in samples with IAA <200 ng/cm2. The samples at lower trunk in juvenile trees had significantly larger IAA amounts, larger MFA and larger latewood width than the samples in mature trees (p < 0.01). The very large IAA amounts may have a certain relation with juvenile wood properties.

Simple Relationship Analysis between L-Band Backscattering Intensity and the Stand Characteristics of Sugi (&amp;lt;i&amp;gt;Cryptomeria japonica&amp;lt;/i&amp;gt;) and Hinoki (&amp;lt;i&amp;gt;Chamaecyparis obtusa&amp;lt;/i&amp;gt;) Trees

In this study, we have performed an analysis between the L-band backscattering intensity derived from the slope corrected ALOS PALSAR remote sensing data and the in-situ stand biophysical parameter of Sugi (Cryptomeria japonica) and Hinoki (Chamaecyparis obtusa) trees at the forests of Chiba Prefecture, Japan. Diameter at breast height (DBH), tree height, and stem volume were statistically compared with the slope corrected sigma naught backscattering in an empirical approach. It was found that the relationship between the backscattering and the stand characteristics was strongly dependent on species showing different trends between the Sugi and Hinoki trees. The Hinoki trees showed an increasing backscattering with increasing parameters (higher DBH, higher Tree height and higher stem volume), as it was mentioned on various researches, while the Sugi tree showed and decreasing backscattering with increasing parameters. We have also found for the Sugi trees that the backscattering is affected strongly by the number of stems. We have assumed that this is because of the characteristics of the Sugi trees which have high moisture content in the heartwood of the stem, compared with other tree species in Japan. The results pave the way to the possibility for estimating biophysical parameters within the forests of Japan by considering such trends and at highly rugged areas by using slope corrected imagery of the SAR data.

過去26年間のスギ花粉飛散パターンのクラスター分析

Pollinosis caused by the pollen of Sugi (Cryptopmeria japonica) trees is the most significant allergic disease occurring in the spring in Japan. For pollinosis patients and medical staff, it is important to know when the pollen dispersion would reach maximum or when the pollen count would decrease as well as knowing what would the total density of pollen grains be. These sorts of information could be useful for the purpose of disease prevention and deciding on the therapeutic regimen. In this study, we presented the sugi-dispersal patterns and cited several examples of the dispersal pattern. Airborne pollen grains were collected using a Durham sampler. Total annual pollen counts/cm2 were examined. The sugi-dispersal patterns were classified into several groups by cluster analysis using variables of ten days pollen counts distribution from February to April for the past 26 years. (1987-2012). The annual pollen count revealed an alternate rhythm consisting of an "on" year (high pollen count) and an "off" year (low pollen count). The results of the cluster analysis showed eleven off-years classified as one group (group 1), and fifteen on-years classified into three groups (groups 2A, 2B, and 2C). The dispersal pattern in group 1 was almost symmetrical with the pollen count rapidly decreasing until late-March. On the other hand, the patterns in group 2 were asymmetrical. In group 2A and 2B a high rate of dispersion was indicated after maximum dispersion, whereas in group 2C the high rate of dispersion was indicated before maximum dispersion. In group 2A, a major dispersion of almost 3000 grains was noted in late-March, and immediately proceeded to the cypress (Chamaecyparis) pollen season without any decrease seen in pollen dispersion. The periods of dispersion of over 10 pollen grains/cm2 per day were 38, 47, 47 and 51 days in groups 1, 2A, 2B and 2C, respectively. That in group 2 was significantly longer than that in group 1, but there was no significant differences between groups 2A, 2B and 2C. In conclusion, in the dispersal pattern whereby a major dispersion was seen in late-March and proceeded to the cypress pollen season such as in group 2A, patients' symptoms might be prolonged or be more serious. This new concept of dispersal pattern could very well be useful for clinical management of pollinosis.

横打撃共振法によるスギ立木の心材色の推定

横打撃共振法によるスギ立木の心材色の推定

Resistance of smoked wood to subterranean and dry-wood termite attack

Specimens from Sengon (Paraserianthes falcataria), Sugi (Cryptomeria japonica), and Pulai (Alstonia sp.) trees were exposed for 3, 8, or 15 days to the smoke generated during Mangium wood (Acacia mangium) pyrolysis, and their resistance to termite biodeterioration was compared to that of polystyrene-treated or untreated woods. All treated-wood specimens were exposed to subterranean termites (Coptotermes curvignathus Holmgren) and dry-wood termites (Cryptotermes cynocephalus Light) under laboratory conditions. The results showed that: (1) All three untreated woods were classified as class V (or very poorly resistant) to subterranean termite attack. On the other hand untreated-wood specimens of Pulai and Sugi tree were classified as class IV (or poorly resistant) and specimens of Sengon tree as class III (or moderately resistant) to dry-wood termites, based on the national Indonesian standard; (2) for all three wood species, 3-day exposure to Mangium wood smoke increased their resistance to class I (or very resistant) to subterranean termite attack; and (3) smoke treatment for 3 days for Sengon and Pulai wood specimens, and 15 days for Sugi wood specimens was required to increase their resistance to dry-wood termite attack to class I, which is the resistance level characterizing polystyrene-treated woods for all three species.

Surface Soil pH Decrease under Sugi (Cryptomeria japonica D. Don) Trees on the Lowland in the Kinki District

Surface Soil pH Decrease under Sugi (Cryptomeria japonica D. Don) Trees on the Lowland in the Kinki District

Baseline Survey and the Immediate Thinning Impact on the Stand Composition of Woody Plants and Overstory Structure of a Sugi Plantation (Cryptomeria japonica) in the Zenlen Area

The practice of forest thinning can influence the functions and structure of forest ecosystems. To investigate the effects of alternative thinning strategies on the stand structure and tree composition of a sugi (Cryptomeria japonica) plantation, this study was conducted on national forests in the Nandai Working Circle Area. In a 35-yr-old plantation, the baseline stand status was surveyed to determine the inventory of timber resources in the study area on 12 plots with a size of 1 ha each. Among them, a randomized block design was adopted for 3 treatments with 4 replications for each treatment in 1 ha. A gap thinning rule was used to remove trees with 3 levels of thinning intensity in terms of removing 0, 25, and 50% area of sugi trees in a plot. In each plot, all woody plants with a diameter at breast height (dbh) of ＞1.0 cm were tallied, tagged, identified to species, the position was recorded, and dbh was measured. Baseline survey results showed that due to variations in growth among trees in the past, inconsistencies in tree densities were evident among plots. While the basal area shared by understory woody plants was quite small in the plantation (i.e., ＜5%), the enhancement of biodiversity was obvious. In terms of Shannon diversity index, the biological diversity of all woody plants increased after thinning, but there was little change in overstory trees. Vertical evenness of the overstory tree canopy was reduced after thinning and there was a not noticeable left-truncated Weibull dbh distribution after thinning.

Monoterpene and sesquiterpene emissions from Sugi (Cryptomeria japonica) based on a branch enclosure measurements

Sugi (Cryptomeria japonica) is the dominant tree species in the forested area of Japan. The forested area is approximately 250 000 km2 and covers almost 70% of total area of Japan. However, there is little information available on biogenic volatile organic compounds (BVOCs) emissions from Sugi trees. BVOCs are known to have an important role in atmospheric chemistry due to their high reactivity and aerosol formation potential. Emissions of monoterpenes and sesquiterpenes, which are groups of BVOCs, were measured from Sugi using a bag enclosure system over four seasons at the Tanashi Experimental Station, located in a suburban area of Tokyo, Japan. Six monoterpenes accounted for the major emissions, and total monoterpene emission ranged up to 0.4 µg g–1 (dw) h–1. The emission rates of both β–farnesene; which is a sesquiterpene, and monoterpenes clearly showed temperature dependence. Only β–farnesene was detected in the sesquiterpene fraction and determined to have a larger emission rate compared to that of total monoterpenes. The coefficient β for total monoterpene and β–farnesene calculated by G93 algorithm were 0.10 and 0.22, respectively. However, β showed largely different values on August (monoterpenes) and April (β–farnesene). The emission rates of β– farnesene show almost the same values in measured individuals and ranged from the detection limit (approximately 0.1 ng g–1 (dw) h–1) to 1.5 µg g–1 (dw) h–1. The basal emission factor of monoterpenes in summer and sesquiterpenes in spring were generally lower compared to other seasons. This study indicated that Sugi trees in suburban areas emit sesquiterpene at a higher rate than total monoterpenes.