Tsuga Sieboldii Research Articles

Japanese Oak Wilt Disease decreased survival probability and mean lifetime of tree populations in a secondary natural forest

ABSTRACT The purpose of this study was to assess the effects of Japanese Oak Wilt Disease on mortality in a tree population. The study site was the permanent plot of 0.26 ha established in the secondary forest dominated by Abies firma, Tsuga sieboldii and Quercus serrata at the University of Tokyo Chiba Forest in the southeastern part of the Boso peninsula, Japan. We set the two observation periods of 1999–2008 and 2009–2021, and Japanese Oak Wilt Disease invaded the study site in the middle of the second period. We collected tree age data for both alive and dead trees in the two periods based on semi-nondestructive drilling measurements for trees using a RESISTOGRAPH. Survival analyses were conducted on the second-period data, and the demographic metrics such as mortality ratios and mean lifetimes were compared between the two periods. The results showed that: the mortality ratio of the tree population at old ages, where oaks (Quercus serrata) concentrated in their age distribution, significantly increased; the effect of the oak group was significant on mortality in the tree population; the hazard for the oak group was 24 times the hazard for the other tree species group; the survival curve reflected the mass mortality in oaks at old ages, which led to the decrease of mean lifetime less than half. Consequently, it was implied that the effects of Japanese Oak Wilt Disease impacted the demographic metrics of oak trees.

Distribution of giant trees in the urban areas and western suburbs of Tokyo, Japan

ABSTRACT Giant trees reflect site environmental conditions and to elucidate the distribution pattern of the giant trees, we investigated relationships between giant tree locations and landforms. On the basis of elevation, the landforms of Tokyo were divided into four types (lowland, plateau, hill, and mountain), and tree distribution patterns were divided into five groups, including three sub-types, with occurrence patterns of representative species [I: Frequently lowlands, often plateaux and mountain type (Machilus thunbergi); II: Frequently plateaux, often lowland, hill, or mountain type (Quercus acuta, Prunus speciosa, Taxodium distichum, Liriodendron tulipifera, Cedrus deodara, Aphananthe aspera, and Prunus × yedoensis “Somei-yoshino”) with two subtypes, II-1: Typically plateaux (Cinnamomum camphora, Castanopsis sieboldii, and Ginkgo biloba) and II-2: Frequently plateaux and hills (Zelkova serrata); III: Typically plateaux and hill type (Certis sinensis var. japonica, Torreya nucifera, Carpinus tschonoskii, Quercus myrsinifolia, and Quercus serrata) with one subtype, Frequently plateaux (Prunus jamasakura); IV: Mountains often with plateaux or hill type (Acer pictum subsp. mono, Aesculus turbinate, Abies firma, Cryptomeria japonica, and Cercidiphyllum japonicum); and V: Mountain-limited type (Castanea crenata, Pterocarya rhoifolia, and Fraxinus platypoda)]. Some giant trees, including Quercus crispula, Fagus japonica, Fagus crenata, and Tsuga sieboldii, were distributed in mountainous areas but not on plateaux, hills, or in lowlands. Some unique giant trees (Aphananthe aspera, Certis sinensis var. japonica, and Carpinus tschonoskii) are self-seeding in the wild and found in plateau areas but not mountainous or hilly areas. These results suggest that the distribution of giant trees is influenced by site ecological characteristics, tree physiology, and human management and land-use.

울릉도산 식물의 HepG2 세포에서 지질 축적 및 산화 스트레스 개선 효과

Oxidative stress can directly damage lipids, proteins, and DNA, which promotes the progression from steatosis to nonalcoholic fatty liver disease. This study aimed to determine the antioxidative effects of Campanula takesimana Nakai, Ilex integra THUNB., Indigofera pseudotinctoria Matsum., Rubus takesimensis Nakai, and Tsuga sieboldii from Ulleung Island and their ability to inhibit lipid accumulation in HepG2 cells. The total phenolics (TPC) and flavonoid (TFC) contents of extracts of the five plants were determined, and their antioxidative activities were analyzed using DPPH and ABTS radical scavenging ability, Fe2+ reducing capacity (FRAP), oxygen radical absorbance capacity (ORAC), and thiobarbituric acid assays. Lipid accumulation was evaluated by Oil Red O staining and intracellular triglyceride (TG) assays. Rubus takesimensis Nakai had the highest TPC among the five plants. The antioxidant activity of R. Nakai was DPPH (IC50=0.30 mg/mL), ABTS (IC50=0.33 mg/mL), FRAP (318.61 μmol FeSO4/g), and ORAC (1.74 μmol TE/g). The lipid peroxidation inhibitory effect of R. Nakai was reduced to 52.51% at 1 mg/mL. Incubating HepG2 cells with extracts of the five plants reduced lipid and TG accumulation by >50%, and inhibited lipid peroxidation by ~19%. These results provided evidence for the development of functional foods based on these five plants from Ulleung Island, due to their antioxidant activities and ability to reduce lipid accumulation.

Antibacterial Activity of Essential Oils from Pinaceae Leaves Against Fish Pathogens

Fish pathogens cause not only economic damages to fish farming but also infectious pathogens known as a zoonotic agent. Since the continued use of antibiotics to control fish pathogens entails side effects, materials of natural origin need to be developed. The purpose of this study is to discover coniferous essential oils with excellent antibacterial effects in order to develop antibiotic alternatives. We have extracted essential oils using hydro-distillation from the leaves of Abies holophylla, Pinus thunbergii, Pinus parviflora, Tsuga sieboldii, and Pinus rigitaeda, which are all Pinaceae family. And, we have evaluated antibacterial activity with the extracted essential oils against Edwardsiella tarda, Photobacterium damselae, Streptococcus parauberis, and Lactococcus garvieae, which are fish pathogens. As a result, the essential oils from A. holophylla and P. thunbergii showed the selectively strong antibacterial activity against E. tarda and P. damselae, which are gram-negative bacteria. From GC-MS analysis, it was identified that main component of A. holophylla essential oils are (-)-bornyl acetate (29.45%), D-limonene (20.47%), and camphene (11.73%), and that of P. thunbergii essential oils is α-pinene (59.81%). In addition, we found three compounds: neryl acetate, (-)-borneol, and (-)-carveol, which are oxygenated monoterpenes. These exist in a very small amount but exhibit the same efficacy as essential oil. Therefore, we expect that A. holophylla and P. thunbergii essential oils having excellent growth inhibitory effect against gram-negative fish pathogens can be used as biological products such as feed additives and fishery products.

Exploring variation in phyllosphere microbial communities across four hemlock species

AbstractThe hemlock woolly adelgid (HWA) is an insect native to Asia and likely western North America. First reported in eastern North America in 1951, it has devastated eastern hemlock (Tsuga canadensis) populations. Loss of hemlock will greatly affect the structure and function of eastern forests. Susceptibility to adelgid infestation varies within eastern hemlocks and across other hemlock species. Our study was conducted to determine whether eastern hemlocks share a similar stem (phyllosphere) microbial community with other co‐occurring hemlocks and whether community‐level shifts are associated within trees of the same species based on HWA infestation. Surprisingly, we found no difference in microbial community composition or diversity between trees of the same species based on the level of HWA infestation. However, microbial communities varied significantly across the four hemlock trees sampled, native T. canadensis and three non‐natives: Tsuga chinensis, Tsuga dumosa, and Tsuga sieboldii. Within these tree hosts, microbial communities from T. dumosa and T. chinensis clustered together, and microbial communities from T. canadensis and T. sieboldii clustered separately from all other tree species. Additionally, specific indicator taxa were identified for all the tree species sampled. These results indicate that Asian hemlocks might not fill the same niche in eastern forests as the native eastern hemlock. Further work should be conducted to determine how differences in hemlock species and associated microbial communities might scale up to alter organismal interactions involving hemlocks.

Whole chloroplast genome sequences of the Japanese hemlocks, Tsuga diversifolia and T. sieboldii, and development of chloroplast microsatellite markers applicable to East Asian Tsuga

ABSTRACTThe genus Tsuga is an ecologically important forest tree genus of Japan with two endemic species, the subalpine Tsuga diversifolia and the temperate Tsuga sieboldii. Despite dominating some of the most important remaining natural forests in Japan, the genetic diversity and structure of these species is unknown with genetic studies hindered by a lack of genetic resources. This study reports the complete chloroplast genome sequences of both T. diversifolia and T. sieboldii and the development of polymorphic chloroplast microsatellite markers. The chloroplast genomes of T. diversifolia and T. sieboldii are 120,802 and 120,797 bp in length, respectively and shared an identical repertoire of 35 tRNA genes, 4 rRNA genes and 72 protein-coding genes. Seven polymorphic chloroplast microsatellite loci were developed and showed an average of 2.24 alleles per locus in T. diversifolia and 3.57 in T. sieboldii. These loci were all successfully genotyped in two other East Asian species (Tsuga chinensis and Tsuga ulleungensis) with an average of 2.28 alleles per locus for both species. The high transferability of these loci, and the fact that all species contained loci with non-overlapping allele size ranges, indicates that these markers will be useful for genetic studies of all East Asian Tsuga species for investigating species boundaries, phylogeography and stand-level processes.

A Dendroecological Analysis of Forest Dynamics for Old-GrowthAbies-Tsuga-Quercuson the Boso Peninsula, Southeastern Japan

This study investigated the composition, age- and size-structure, and tree-ring relationships for an old-growth, warm-temperate, mixed-evergreen forest at the University of Tokyo Chiba Forest, Japan. A total of 32 tree species were recorded, which was dominated by Abies firma and Quercus acuta. Tsuga sieboldii dominated the recruitment after 1850, followed by Abies firma. After 1920, many individuals of Castanopsis, Cinnamomum, Cleyera and Quercus became established. The temporal pattern of conifer recruitment did not correspond to the record of strong wind events. Basal area increment in Abies firma and Castanopsis sieboldii trees increased throughout their lives, a trend not seen in the ring width index. Mean annual temperature was below the 100-year mean between 1920 and 1940 and 1960–1980, but increased rather abruptly after 1980. Mean annual precipitation decreased after 1960. Tree-ring releases are very common at the study forest, which are indicative of frequent small to moderate-sized disturbances. At least one release was recorded in every decade from 1890 to the present day, which is likely the primary causal factor promoting tree growth and recruitment. Our results suggest that early logging activities coupled with natural disturbances had a great influence on the developmental process and current structure of the study stand and that tree growth is varying in a manner consistent with forest dynamics.

ツガ天然林の更新 : IV.久保谷山周辺の温帯針葉樹林植生

ツガ天然林の更新 : IV.久保谷山周辺の温帯針葉樹林植生

Applying age-based mortality analysis to a natural forest stand in Japan

Mortality analysis of tree populations is widely applied to forest science studies. When mortality analysis is applied to forest inventories, the use of the variable of tree age is not common due to the difficulty of measuring age data censored in successive observations. The purpose of this study is to apply age-based mortality analysis, i.e., survival analysis, to the individual tree populations in a natural forest. The study site was the secondary natural stand of 0.26 ha dominated by fir (Abies firma), hemlock (Tsuga sieboldii), and oak (Quercus serrata) in the Boso peninsula, Japan. First, we measured the ages of the trees with diameter at breast height greater than or equal to 5 cm using a RESISTOGRAPH. Then, tree mortality probabilities of both non-parametric Kaplan–Meier estimates and parametric probability distributions of Gamma and Weibull were estimated by applying survival analysis techniques to the tree age data. The results implied that the survival analyses could be implemented not only by the non-parametric estimates in any cases but also by the common parametric distributions of Gamma and Weibull in cases in which the tree mortality probability distribution had a monotonously decreasing shape as observed in the immature natural stand in the study site.

Aphelinid and Encyrtid (Hymenoptera: Chalcidoidea) Parasitoids of Armored Scales (Hemiptera: Diaspididae) Attacking Hemlocks (Tsuga spp.) in Japan and the United States, with Description of Eight New Species

Abstract The complex of aphelinids and encyrtids (Hymenoptera: Chalcidoidea) parasitizing armored scales (Hemiptera: Diaspididae) on hemlock in Japan (Tsuga diversifolia Masters and Tsuga sieboldii Carrière) and in the eastern United States (Tsuga canadensis [L.] Carrière) was surveyed. Eight new species were discovered and are described here: Five species of Encarsia and one species each of Pteroptrix (Aphelinidae), Coccidencyrtus, and Thomsonisca (Encyrtidae). Two previously known species, Aphytis moldavicus Yasnosh and Encarsia brimblecombei Girault, are recorded for the first time from Japan. New host-parasitoid associations were found for five diaspidids: Fiorinia externa Ferris, Dynaspidiotus tsugae Marlatt, Pseudaulacaspis momi Kuwana, Lepidosaphes japonica Kuwana, and Lepidosaphes pseudotsugae Takahashi.

Diversity of proteobacterial endosymbionts in hemlock woolly adelgid (Adelges tsugae) (Hemiptera: Adelgidae) from its native and introduced range

Knowledge of intraspecific variation in symbioses may aid in understanding the ecology of widespread insects in different parts of their range. We investigated bacterial symbionts of Adelges tsugae, a pest of hemlocks in eastern North America introduced from Asia. Amplification, cloning, and sequencing of bacterial 16S rDNA, in situ hybridizations, and electron microscopy revealed that A. tsugae harbours up to five bacterial phylotypes, according to population. Three Gammaproteobacteria species are maternally transmitted. The first, designated 'Ca. Pseudomonas adelgestsugas' resides in the haemocoel, and was detected in all populations except Taiwan. The second phylotype, 'Ca. Serratia symbiotica', resides in bacteriocytes of populations on Tsuga sieboldii in Japan and in E. North America. The third phylotype, designated 'Ca. Annandia adelgestsuga', clustered within a lineage of several insect endosymbionts that included Buchnera aphidicola. It was detected in bacteriocytes in all populations, and in salivary glands of first instars. Two Betaproteobacteria phylotypes were detected in some Japanese T. sieboldii and eastern North America populations, and were observed only in salivary glands with no evidence of maternal transmission. Our results support the ideas that symbiont gain and loss has been volatile in adelgids, and that symbionts may help to trace the source of invasive species.

울릉도 너도밤나무림의 군집구조와 하층식생의 분포특성

This study was intended for Fagus engleriana stand in Is. Ulleung where the disturbance of vegetation has been caused by the exploitation and the increase of tourists. For the effective conservation and management on this issue, this study was conducted provide basic data. The sixteen study sites (<TEX>$20{\times}20m$</TEX>) were installed in the dominant Fagus engleriana stand and the base environment and vegetation were investigated. The Fagus engleriana stand was classified into two groups, The Fagus engleriana stand was classified into two groups, community A is Fagus engleriana-Sorbus amurensis and community B is Fagus engleriana-Acer pictum subsp. Mono by cluster analysis and community A were nothing signigicant by indicator species analysis. Community B were Eight species (Tsuga sieboldii, Camellia japonica, Dystaenia takesimana ect.) significant by indicator species analysis. The diameter class of 16cm to 25cm was 53.7% in population structure of Fagus engleriana, which was the highest and showed inverse J-distribution. Species diversity index (H') of investigated woody layer group ranged from 0.99 to 2.05 and that of under layer group ranged from 1.75~2.59. According to Non-metric Multidimensional Scaling (NMS) analysis, the woody layer was divided into community A developed in the region having relatively high sand content at high altitudes and community B formed at the place having relatively high clay content at low altitudes. Then this classification was significant through Multi-Response Permutation Procedures (MRPP) analysis. The distribution of understory vegetation through Detrended Correspondence Analysis (DCA) was induced by the silt content and cover degree of vegetation layer.

Distribution of Vascular Plants in the Ulleung Forest Trail Area (Namyang to Taehayeong)

The result of the study on the flora of the Ulleung-do forest trail's Namyang - Taeharyeong segment showed a total of 199 taxa, including 68 families, 150 genera, 169 species, 26 varieties, 2 Formas and 2 subspecies. 1 species of Trillium tschonoskii Maxim. was observed as a Ministry of Environment-designated endangered species, and the species was observed continuously along the dense hiking trails and valley areas between Namyang and Taeharyeong. It is predicted that damage caused by collecting or stomping by individuals near the hiking region will occur. In terms of the IUCN standard, among species found in the Ulleung-do forest trail region, CR species included 1 species of Calanthe discolor for. sieboldii [Decne.] Ohwi, EN species included 5 species of Cirsium nipponicum [Maxim.] Makino, Lathracea japonica Miquel, Neocheiropteris ensata (Thunb.) Ching, Arisaema takesimense Nakai and Gymnadenia camtschatica (Cham.) Miyabe et Kudo, VU species included 7 species of Adiantum pedatum, Polypodium vulgare L., Taxus cuspidata var. latifolia Nakai, Trillium tschonoskii Maxim., Lilium hamsonii Leichtl., Hepatica maxima Nakai and Phytolacca insularis Nakai, LC species included 7 species of Asplenium scolopendrium L., Tsuga sieboldii Carriere, Maianthemum dilatatum (Wood) A. Nelson & J. F. Macbr., Fagus engleriana Seemen ex Diels, Celtis choseniana Nakai, Tiarella polyphylla D. Don and Campanula takesimana Nakai, and DD species included 2 species of Rumex longifolius DC and Lamium takesimense Nakai. The study observed a total of 20 Korean endemic species, including Athyrium acutipinulum Kodama, Arisaema takesimense Nakai, Fagus engleriana Seemen ex Diels, Silene takesimensis Uyeki et Sakata, Lamium takesimense Nakai and Veronica insularis Nakai. Fagus engleriana Seemen ex Diels especially was found distributed evenly across the study area, and Campanula takesimana Nakai, Rubus takesimensis Nakai and the Hepatica maxima Nakai were observed in small colonies, although the distribution was uneven. Ecologically significant plant species include 15 taxa of Class I, 4 taxa of Class II, 15 taxa of Class III, 27 taxa of Class IV and 2 taxa of Class V, for a total of 63 taxa. Gymnadenia camtschatica (Cham.) Miyabe et Kudo, Hepatica maxima Nakai and Silene takesimensis Uyeki et Sakata are especially exposed to becoming damaged by hikers as a result of their beautiful flowers. Naturalized plant species included the Rumex crispus L., Trifolium repens L., Oenothera biennis L., Veronica arvensis L., Erigeron annuus (L.) Pers., Ambrosia artemisifolia L. and the Sonchus oleraceus L., for a total of 4 families, 7 genera, 7 species and 7 taxa, and it has been assessed that the region included 11% of the entire naturalized plants of the Ulleung-do region. Furthermore, a method of managing and protecting Ambrosia artemisifolia L., which is a Ministry of Environment-designated invasive alien species, must be prepared.

Distribution of Vascular Plants in the Ulleung Forest Trail Area (Seokpo to Naesujeon)

The examination of the flora of the Sukpo-Naesujun section of the Ulleung forest trail revealed a total of 291 taxa, including 85 families, 211 genera, 246 species, 41 varieties, two forms, and two subspecies. In the area, the endangered plant species designated by the Ministry of Environment was Trillium tschonoskii, and rare or endangered plants designated by the Korea Forest Service were revealed to be 10 species, including Tsuga sieboldii, most of which were found around the trail. Campanula takesimana and Allium victorialis, in particular, are exposed to a threat of being collected for ornamental and eating purposes, respectively. The Korean endemic species in the area were 12 species including Fagus engleriana. In the area there were 50 floristic special plant species, the survey revealed 17 taxa of grade I, three taxa of grade II, nine taxa of grade III, 19 taxa of grade IV, and two taxa of grade V. Among them, Lilium hansonii and Trillium tschonoskii from grades IV and V are located near the trail, leading to concerns about damage by mountain climbers or residents. The naturalized plants in the area were a total of 18 taxa, including 6 families, 14 genera, 16 species, and one variety. Moreover, 25.4% of the overall naturalized plants in Ulleung-do appeared in the Ulleung forest trail.

A New Species of Laricobius (Coleoptera: Derodontidae) from Japan with Phylogeny and a Key for Native and Introduced Congeners in North America

Abstract Laricobius osakensis Montgomery and Shiyake sp. nov., collected from Adelges tsugae Annand on hemlock [Tsuga sieboldii Carr. and Tsuga diversifolia (Maxim.) Mast.] in Japan, is described and illustrated. The new species was collected from several localities on Honshu, Shikokou, and Kyushu Islands. The genus has not been reported previously from Japan. Morphological features, a molecular phylogeny, and diagnostic DNA sites are provided to distinguish this new species from previously described species of the genus. Because of plans to release L. osakensis for the biological control of A. tsugae in eastern North America, a key and discussion are provided to differentiate it from the native North American species, Laricobius nigrinus Fender, Laricobius laticollis Fall, and Laricobius rubidus LeConte, and from two previously imported species—Laricobius erichsonii Rosenhauer, which is endemic in Europe, and Laricobius kangdingensis Zilahi-Balogh &amp; Jelinek, which is endemic in China.

Evaluation of Hemlock (&lt;I&gt;Tsuga&lt;/I&gt;) Species and Hybrids for Resistance to &lt;I&gt;Adelges tsugae&lt;/I&gt; (Hemiptera: Adelgidae) Using Artificial Infestation

Hemlock (Tsuga) species and hybrids were evaluated for resistance to the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae). The adelgid was accidentally introduced from Asia to the eastern United States, where it is causing widespread mortality of the native hemlocks, Tsuga canadensis (L.) Carrière and Tsuga caroliniana Engelm. These two native species plus the Asian species Tsuga chinensis (Franch.) E. Pritz and T. dumosa (D.Don) Eichler and Tsuga sieboldii Carrière, and the hybrids T. chinensis x T. caroliniana and T. chinensis x T. sieboldii, were artificially infested with the crawler stage of A. tsugae in the early spring 2006 and 2007. After 8 or 9 wk-when the spring (progrediens) generation would be mature--counts were made of the adelgid. In both years, the density of A. tsugae was highest on T. canadensis, T. caroliniana, and T. sieboldii; lowest on T. chinensis; and intermediate on the hybrids. On T. chinensis and the T. chinensis hybrids, fewer adelgids settled, fewer of the settled adelgids survived, and the surviving adelgids grew slower. Thus, the nature of the host resistance is both nonpreference (antixenosis) and adverse effects on biology (antibiosis). Tree growth (height) was associated with resistance, but no association was found between time of budbreak and resistance that was independent of the taxa. Many of the hybrids grow well, have attractive form, and are promising as resistant landscape alternatives for the native hemlocks.

울릉도 산림식생의 공간분포 및 환경과의 상관관계 분석

본 연구는 Z-M학파의 식물사회학적 방법으로 울릉도 산림식생의 유형을 분류하고 그 공간적 분포 양상을 지도화하는데 있다. 이 지역 산림식생은 크게 우산고로쇠나무군락군의 산지 식생형과 해국군락군의 해안 저지식생형으로 양분되었으며, 군락 수준에서의 식생단위는 6개 군락, 16개 군,그리고7개 소군 등 3개 범주역에서 모두 22개 유형으로 구분되었다. 식생도 작성 면적은 5,544.9 ha이며, 이 중 너도밤나무군락이 35.2%인 1,951 ha로 가장 넓은 분포역을 나타내었으며 다음으로 송악군락 1,196 ha (21.6%), 동백나무군락 1,104 ha (19.9%), 말오줌나무군락 612.0 ha (11.0%), 해국군락 506 ha (9.1%), 솔송나무-섬 잣나무군락 174.0 ha (3.1%) 등의 순으로 나타났다. CCA 분석에 의한 식생단위와 토양인자와의 상관관계를 보면, 해안식생형에서는 <TEX>$Mg^{2+}$</TEX>, pH, <TEX>$Ca^{2+}$</TEX>등이 양의 관계, 그리고 산지식생유형에서는 전질소, 탄소, C/N율의 유기물 함량과 양이온 치환 용량 등은 높은 상관을 나타내었다. 입지환경과 종 다양성의 상관관계를 보면 해발과 사면 방향은 일정한 경향을 보이지 않지만 지형과 경사도 그리고 우점하고 있는 식생에 따라 많은 영향을 받고 있음을 알 수 있었다. This study was carried out to classify all forest vegetation types in Ulleung Island, Korea using the methodology of the Z.-M. school's phytosociology, and map out the spatial distribution patterns of those vegetation types. The forest vegetation was classified into the mountain forest type (Acer okamotoanum community group) and maritime forest type (Artemisia scoparia community group). Vegetation units at the community level were divided into three categories; six communities, sixteen groups, and seven subgroups, giving a total of 22 communities. Total area for mapping was 5,544.9 ha, of which Fagus engleriana community accounted for 1,952 ha (35.2%), Hedera rhambea community ror 1,196 ha (21.6%), Camellia japonica community for 1,104 ha (19.9%), Sambucus sieboldiana var. pendula community for 612 ha (11.0%), Aster spathulifolius community for 506 ha (9.1%), and Tsuga sieboldii - Pinus parviflora community for 174 ha (3.1%). According to canonical correspondence analysis (CCA), variables such as <TEX>$Mg^{2+}$</TEX>, pH, <TEX>$Ca^{2+}$</TEX> were positively correlated in maritime vegetation types, and variables such as total nitrogen, carbon content, C/N ratio and ration exchange capacity (CEC) were highly correlated in mountain vegetation types, respectively. The sea level and the slope direction were not showing regular trend as a factor to decide on species diversity, evenness and richness in this research area. But it seems to be affected by topography, slope degree and dominance vegetation.

Analysis of terpenoids from hemlock (Tsuga) species by solid-phase microextraction/gas chromatography/ion-trap mass spectrometry.

A sampling method for determining the volatile terpenoid composition from single needles of seven Tsuga species was developed using headspace solid-phase microextraction (SPME). A reproducible sampling method for the volatile components was generated by examination of sample storage, method of needle cutting, and headspace sampling duration. Following SPME collection of the volatile compounds from the seven Tsuga species, gas chromatography/ion-trap mass spectrometry was used to identify 51 terpenoids present in the needle headspace. A semiquantitative method was devised to express individual terpenoid amounts as a percentage of all of the identified peaks in the chromatogram. The semiquantitative results permitted facile interspecies comparison using principal component analysis. Two components were able to account for 90% of the variance and were interpreted as a "species" component and a "resistance/susceptibility" component. Three interspecies groupings were evident from the principal component analysis: (1) Tsuga canadensis and Tsuga caroliniana; (2) Tsuga chinesnsis, Tsuga diversifolia, Tsuga heterophylla, and Tsuga sieboldii; and (3) Tsuga mertensiana. The finding that T. mertensiana was grouped alone and far removed from the other species adds to the morphological evidence that this species should be segregated from other Tsuga.

Seedling success of Tsuga sieboldii along a microtopographic gradient in a mixed cool-temperate forest in Japan

Emergence and establishment of Tsuga sieboldii seedlings were monitored for six years in an old-growth mixed forest in Japan, to clarify the reason why adult T. sieboldii trees are distributed only on convex slopes. T. sieboldii seedlings germinated on exposed soils without broad-leaved litter cover on both convex and concave slopes, but they died out from concave slope during the first two years after germination. Along a gradient from convex to concave slope, litter cover became higher and surface soil erosion became severer, and T. sieboldii seedlings died at the plots with severe surface soil erosion. Other environmental variables, such as relative illuminance, vegetation cover of seedling layer and soil water potential were not significantly different between convex and concave slopes. We concluded that the restricted seedling establishment of T. sieboldii to convex slope is determined by stability of surface soils and broad-leaved litter cover.

Seed dispersal and seedling dynamics of Hinoki (Chamaecyparis obtusa), Tsuga (Tsuga sieboldii) and Morni (Abies firma

Seed dispersal and seedling dynamics of Hinoki (Chamaecyparis obtusa), Tsuga (Tsuga sieboldii) and Morni (Abies firma