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We explored the dynamics of dwarf bamboo populations in a beech forest 11 years before and 30 years after clear-cutting. Repeated weeding or herbicide application (sodium chlorate) was used experim...

In sparse Abies mariesii forests with an undergrowth of dense dwarf bamboo (Sasa kurilensis) in subalpine areas of snowy mountains in northern Honshu, Japan, A. mariesii saplings are more abundant ...

We investigated the factors determining the distribution and dynamics of tree species in a warm–temperate mature mixed forest of evergreen coniferous and broad-leaved tree species in a steep mountainous area for 13 years in southwest Japan, with particular focus on instability of the ground surface. Among various site conditions, landform unit was the principal factor determining the distribution of tree species, while moisture regime was the second-most important factor within the upper area. The amount of movement of sediment and litter on the ground surface in the lower area was much higher than movement within the upper area, indicating that the lower area was unstable due to mass movement caused by erosion. The effects of instability of the ground surface on mortality and recruitment varied across the dominant tree species. Symplocos prunifolia (SYMPLOCACEAE), which was distributed in the upper area, and Machilus japonica, which was distributed in the lower area, exhibited lower mortality and higher recruitment in the areas where they were mainly distributed. These results suggest that topographic niche differentiation caused habitat segregation for some species. However, for most species, such relationships were not consistently observed, and growth rates did not significantly differ between the upper and lower areas. This study, by using long-term data, demonstrates that variation in sensitivity to stability due to topography contributes to local species richness and co-existence.

Many indicators/indices provide information on whether the 2010 biodiversity target of reducing declines in biodiversity have been achieved. The strengths and limitations of the various measures used to assess the success of such measures are now being discussed. Biodiversity dynamics are often evaluated by a single biological population metric, such as the abundance of each species. Here we examined tree population dynamics of 52 families (192 species) at 11 research sites (three vegetation zones) of Japanese old-growth forests using two population metrics: number of stems and basal area. We calculated indices that track the rate of change in all species of tree by taking the geometric mean of changes in population metrics between the 1990s and the 2000s at the national level and at the levels of the vegetation zone and family. We specifically focused on whether indices based on these two metrics behaved similarly. The indices showed that (1) the number of stems declined, whereas basal area did not change at the national level and (2) the degree of change in the indices varied by vegetation zone and family. These results suggest that Japanese old-growth forests have not degraded and may even be developing in some vegetation zones, and indicate that the use of a single population metric (or indicator/index) may be insufficient to precisely understand the state of biodiversity. It is therefore important to incorporate more metrics into monitoring schemes to overcome the risk of misunderstanding or misrepresenting biodiversity dynamics.

ササ抑制処理がヒノキ天然更新施業に及ぼす効果を検証するために, 長野県三浦実験林の帯状皆伐天然更新試験地における36年間の更新木樹冠とササの被覆の変遷を空中写真を用い経時的に解析した。1969年の伐採終了後, ササ抑制処理が行われなかった対照区では, 伐採直後を除き, ササの衰退がみられなかった。除草剤散布と刈払いによるササ抑制処理を行ったササ処理区では, ササ面積比率の低下が更新初期10年間に計3回あったと推察され, ササ抑制効果の持続期間は3年間程度であったと見積られた。2005年には, 更新木樹冠の面積比率は対照区で約24%, 処理区では70%以上であり, 1979年のササ面積比率との間に負の相関がみられた。2005年における更新林分の上層木密度は, 上層平均樹高が同等の標準的な人工林に対し, 対照区で24%, 処理区で61%に相当した。以上のことから, 天然更新の成績向上に対するササ抑制処理の寄与が示唆された。

多雪環境下にある秋田県内の三つの小流域において, スギ人工林を対象に, スギの成林状況と広葉樹の侵入による混交林化の程度に影響を及ぼす要因を分析した。スギの密度や樹高成長は標高の増加に応じて低下し, 標高約650 m以上になると, 密度は標準値を下回るようになり, 上層木平均樹高は地位5級 (地位の最下位) の樹高曲線の値を満たさなくなった。三つの調査流域のスギ人工林内には, ミズキ, コシアブラ, リョウブ, ウワミズザクラ, ブナ, ミズナラなどの多様な広葉樹が共通して出現した。標高が増すにつれてスギ林の不成績化と広葉樹の侵入による混交林化が進む一方で, ササ類の密度も高くなり, 広葉樹の侵入・定着が阻害される場合もあった。標高870 m以上では人工林としてはもちろん混交林としても成林している状況になかった。以上の結果から, スギ人工林の経済林としての維持管理を流域スケールで効率化するためには, 標高約650 m以下, 最深積雪深およそ2.0 m以下の範囲に重点をおくことが有効である。これより高標高に存在する人工林については機能の重点を経済林から環境林へとシフトさせていく必要があると考えられる。

Naturally regenerated trees in young Cryptomeria japonica plantations were investigated in 141 quadrats of 10 × 50 m within a watershed of 1,000 ha, and factors affecting their composition and abundance were examined. The species composition of naturally regenerated trees was classified into four types. Dominant species were Swida controversa, Magnolia hypoleuca and Pterocarya rhoifolia in Type A1, Betula maximowicziana, M. hypoleuca, Quercus crispula and Castanea crenata in Type A2, Q. serrata and C. crenata in Type B1, and Pinus densiflora in Type B2. The results of path analysis showed significant influences of previous forest type and geology among the factors that correlated with the species composition of naturally regenerated trees; previous forest type in particular showed a higher absolute path coefficient value. Species composition types of naturally regenerated trees corresponded to the previous forest types: Types (A1 and A2) corresponded to the natural forests composed of Thujopsis dolabrata var. hondai, Fagus crenata, Aesculus turbinata, etc., Type B1 corresponded to the secondary Q. crispula and Q. serrata forest, and Type B2 corresponded to the secondary P. densiflora forest, respectively. The abundance of naturally regenerated trees was strongly affected by geology; i.e., plantations on soft-sedimentary dacitic tuff contained great amounts of colonizing P. densiflora trees.

In this paper we first mathematically formulate spatial genetic models that rely on dispersal kernels, using the genetic inhomogeneous Poisson process. On the basis of mapped and genotyped data pertaining to adult and juvenile trees we are able to estimate three fundamental variables of population dynamics: individual female reproductive success, seed dispersal, and pollen flow. The model was applied to a secondary Fagus crenata stand in northern Japan, regenerated after shelterwood harvesting. Highly polymorphic microsatellite data revealed that most of the juveniles around one adult tree were not that tree’s progeny and that some minor alleles were clustered there. These data suggested that another mother tree had formerly been present in the vicinity, produced offspring there and died. Inferring its genotype and location, we applied the genetic inhomogeneous Poisson process. Results confirmed that we would have wrongly assessed the regeneration if we had been unaware of the existence of the dead mother. The average distances for seed dispersal and pollen flow were 18 and 193 m, respectively. The contribution of outside mothers, simultaneously assessed using the dispersal variables in the models, ranged from 10 to 50% depending on their positions relative to preserved adults. Individual female reproductive success varied as much as fiftyfold among the eight preserved adults. Our comprehensive approach, utilizing currently available genetic information, mathematical models, and previous forestry records, helped elucidation of the past forest-regeneration processes.

秋田県の佐渡スギ群落保護林において，その成立過程をスギ伐根の年輪解析によって推定した。25 ha内の3カ所のスギの風倒木43本の伐根から円板を採取した。伐根径の平均は62 cm，伐採面の年輪数は平均235年であった。伐採高に達するまでの年数を推定し，それを伐採面の年輪数に加えて求めた発生時期は西暦1681∼1731年と推定された。現在，保護林内に生育しているスギ成木（dbh 30 cm未満），幼樹（dbh 5 cm未満）の直径と肥大成長の関係から生育環境（ギャップ下，林冠下）を求める判別式を作成し，それを供試木43本に当てはめて過去の生育環境を推測した。その結果，スギは発生当初は良好な環境下にあったが成長が一度低下し，西暦1790年頃にほとんどの供試木の成長が改善するパターンがみられた。平均発生年，成長改善の平均年とも円板を採取した3カ所の間では違いがみられなかった。以上の結果から，この林分では過去に2回の広域で強度な撹乱があり，最初の撹乱で現存しているスギが発生し，2回目の撹乱で成長が改善されたと推察された。近隣の履歴などから，撹乱はいずれも伐採によるものと考えられ，最初はスギが，2回目ではその後に生育した広葉樹が主に伐採されたと推察した。

The spatial distribution of genotyped adult plants and offspring can be modeled by genetic inhomogeneous Poisson processes. This paper reports the development of a previously proposed point process model to cover safe site conditions for sapling survival, unknown seed sources and wider ranges of dispersal kernels. Suppose that a species has limited seed dispersal and shade-tolerance, and that young trees are clustered around highly isolated adults. The clustering might be formed solely by dispersed seeds from adults. However, the survival of the offspring might be influenced by shading by the adults’ crowns. The new genetic processes are applicable to such cases, as demonstrated for a young population of Fagus crenata, a shade-tolerant canopy tree species, in a 55-year-old stand regenerated after shelterwood logging. Isozyme analysis revealed that the regenerating trees were genetically related to the nearest adults, but some were not their respective daughters. The maximum likelihood method has led us to the following regeneration: seeds were dispersed mostly within 20 m of their mothers; two residual adults in the plot had equal female reproductive success; about 10% of offspring even close to the adult were not their daughters; the adults’ crowns reduced the survival of offspring up to 20–25 m away. However, the degree of model fitting was unsatisfactory. Hence, our models, in principle, can quantify two roles of highly isolated adults: providing seed sources and safe sites, but the case study suggests that other, unknown factors influence F. crenata regeneration after shelterwood harvesting.

We examined microsites for the seedling establishment of Tsuga diversifolia, Abies veitchii and Abies mariesii in a subalpine coniferous forest with moss-type undergrowth dominated by Hylocomium splendens and Pleurozium schreberi on Mt. Fuji, a less-snowy mountain located on the Pacific Ocean side of the central part of Honshu Island, Japan, and compared these microsites with cases in other regions of Japan with different undergrowth vegetation (herb type, dwarf-bamboo type) under snowier conditions. L-shaped size structures with abundant seedlings and small trees were identified for all three species. Established seedlings of T. diversifolia showed remarkable preference for elevated microsites such as fallen logs and convex ground (i.e. ground raised around trunk bases), while A. veitchii and A. mariesii indicated no significant bias toward such elevated microsites in the large seedling stage. However, the relative frequency of T. diversifolia seedlings established on flat ground reached high values of 54–77%, since the relative occupation area of the flat ground was large (85–89%). Such a large share suggests that flat ground should be regarded as the most important microsite for the seedling establishment of T. diversifolia in forests with moss-type undergrowth. This preference trait for T. diversifolia observed with moss-type undergrowth has not been reported in previous studies examining forests with herb- and dwarf bamboo-type undergrowth, where T. diversifolia seedlings are scarce on the ground and restricted to elevated microsites. We conclude that the major microsite for T. diversifolia seedling establishment changes according to the undergrowth vegetation type: a large ground share for moss-type undergrowth and a small ground share for herb- and dwarf bamboo-type undergrowth.

On a gentle leeward slope in a snowy forest limit in northern Honshu Island, Japan, mechanical damage by snow settlement and creep on Abies mariesii trees buried below the snowpack was examined to detect signs of the snow-damage effect on future survival and crown development. Damage types were recorded based on direct observation of crowns in 1996, a year of high snow accumulation exceeding 4.5 m, and 1997, a year of moderate snow accumulation. Of 153 trees examined, 63% were damaged in 1996 and 15% were damaged in 1997. The most destructive damage type was breakage of stems ≥5 cm in diameter, which occurred on eight trees in 1996 and three in 1997, resulting in foliage loss and death of some trees. The prevalent damage type was branch tearing at branch-stem junctions primarily within a height range of 4–6 m, which occurred on 171 branches in 1996 and 5 in 1997. Under snowy and windy conditions, stem breakage and branch tearing, caused by forces active within restricted layers of the snowpack, m...

At plantations of the evergreen conifer Cryptomeria japonica (ca. 20 years old) damaged by heavy snow, the growth of planted trees, composition of colonizing native hardwoods, and successional trends of tree populations were investigated. The study site of ca. 2 km ×2 km was established in 1998 within a river basin contiguous to the Shirakami Mountains which was registered as a World Natural Heritage site. This site was originally covered with old-growth forests of Fagus crenata. Twenty-one plots (each 400 m2) were established (11 in the plantations and 10 in adjacent remnant natural forests) and a census of trees was conducted in 1998 and in 2000. During this period, the mean basal area slightly decreased from 39.8 to 38.8 m2 ha−1 in the natural forests, In the plantations, the mean basal area increased from 15.3 to 20.3 m2 ha−1. Only focusing on C. japonica, the value changed from 11.4 to 14.2 m2 ha−1, which was smaller than expected in the management table for this district (14.5–22.5 m2 ha−1 on average). The smaller basal area of the plantations had resulted from a high mortality of C. japonica. That was caused by damage from heavy snow falls during winter, especially on east-facing slopes. This was considered to have resulted from spatial variation in snow depth depending on slope aspect. Native hardwoods had colonized the resulting openings in the plantations, and increased their basal area more rapidly than the planted conifers. They presently occupy 29% of the total basal area of the plantations on average. The composition of native hardwoods differed between the natural forests and the plantations; climax species occupied a significantly larger proportion of the basal area in the natural forests (e.g., F. crenata) and pioneer species had greater importance in the plantations (e.g., Pterocarya rhoifolia, Swida controversa, Phellodendron amurense). Pioneers in the plantations tended to distribute on the east-facing slopes, probably reflecting higher number of openings created there. As the result of the natural succession, tree communities in the plantations are expected to become dominated by climax species, but it will take quite a long time.

The genetic structure of Sakhalin spruce (Picea glehnii) was studied across the natural range of the species, including two small isolated populations in south Sakhalin and Hayachine, by using six microsatellite loci and maternally inherited mitochondrial gene sequences. We also analyzed P. jezoensis, a sympatric spruce in the range. Genetic diversity of P. glehnii was higher in central Hokkaido and the lowest in the Hayachine. Bayesian clustering and principal coordinate analysis by using the microsatellites indicated that the Hayachine was clearly distinct from other populations, implying that it had undergone strong genetic drift since the last glacial period. P. glehnii harbored four mitochondrial haplotypes, two of which were shared with P. jezoensis. One of the two was observed without geographical concentration, suggesting its derivation from ancestral polymorphism. Another was observed in south Sakhalin and in P. jezoensis across Sakhalin. The Bayesian clustering--by using four microsatellite loci, including P. jezoensis populations--indicated unambiguous species delimitation, but with possible admixture of P. jezoensis genes into P. glehnii in south Sakhalin, where P. glehnii is abundantly overwhelmed by P. jezoensis; this might explain the occurrence of introgression of the haplotype of P. jezoensis into P. glehnii.

The causes and timing of seed death in early regeneration process of Siebold's beech (Fagus crenata Blume) was studied at 15 sites along a snowfall gradient in Japan, in order to clarify why the seedling density of the species has geographic difference remarkably. Seed production did not significantly differ along the snowfall gradient. Pre-dispersal seed mortality by insect damage was higher at sites with light snowfall than at sites with heavy snowfall, but this only seemed to be a minor factor influencing the population. A large proportion of the viable nuts that fall in autumn ware killed in winter before germination. Winter mortality was much higher at sites with thin snow cover than that at sites with thick snow cover, and this factor was strongly correlated with the geographic variation of seedling regeneration probability. There was little seed mortality by winter desiccation. The main factor contributing to the geographic difference seemed to be a seed predation by rodents in winter. Deep snow cover may reduce the success of rodents finding seeds in winter. Thus the observed relationship between snowpack depth and early mortality may be due to an indirect effect through the process of seed predation.p>

In the subalpine areas of the snowy regions of Japan (the Japan Sea side), there are some mountains with no or very small stands ofAbies mariesii, although this species dominates the subalpine coniferous forests of the region. In order to discuss the cause and process of this phenomenon, present horizontal and vertical ranges, as well as physiographic conditions, of theA. mariesii forest were examined in detail on the mountains in the Tohoku District. Sites in the subalpine zone were classified into two types: ‘azonal sites’ which should be excluded from the habitat ofA. mariesii because of their edaphic or small-scale climatic properties, and ‘zonal sites’. Mountains with vast less-inclined zonal sites generally had well developed stands ofA. mariesii forest. On the mountains with only small, solitary stands ofA. mariesii, the distribution was limited to flats or slightly inclined slopes at relatively low altitudes. These less-inclined zonal sites were regarded as an important habitat for theA. mariesii forest in the Hypsithermal period and the extent of these sites controls the extent of the stands in that period and the success of the subsequent range expansion of the forest.

This data paper reports tree census data collected in a network of 34 forest sites in Japan. This is the largest forest data set freely available in Japan to date. The network is a part of the Monitoring Sites 1000 Project launched by the Ministry of the Environment, Japan. It covers subarctic to subtropical climate zones and the four major forest types in Japan. Forty-two permanent plots, usually 1 ha in size, were established in old-growth or secondary natural forests. Censuses of woody species ≥15 cm girth at breast height were conducted every year or once during 2004 to 2009. The data provide species abundance, survivorship and stem girth growth of 52,534 individuals of 334 tree and liana species. The censuses adopted common census protocol, which provide good opportunities for meta-analyses and comparative studies among forests. The data have been used for ecological studies as well as for the biodiversity reports published by the Ministry of the Environment.

Tris(ethylenediamine)- or tris(trimethylenediamine)-nickel(II) salts react with d -glucose, d -mannose, or d -fructose to give novel, octahedral, nickel(II) complexes containing glycosylamine(s) derived from the reaction of the monosaccharide with the diamine. The complexes have been characterized by elemental analysis, magnetic susceptibility, and electronic absorption, infrared, and circular dichroism spectra. The complexes from aldoses contain two sugar entities, and those from a ketose have one sugar unit. The X-ray crystal structure was determined of one of the products, in which N -(2-aminoethyl)- d -fructopyranosylamine and ethylenediamine are coordinated to a nickel ion. Crystal data for the compound: a = 12.348(5) A, b = 18.478(8) A, c = 8.464(4) A, Z = 4, space group P2 1 2 1 2 1 , 2348 unique observed reflections [Fo > 3σ(Fo)] used in the structure analysis, R = 0.068, Rw = 0.053. The sugar is coordinated to the nickel ion at three points, through the 1- and 3-hydroxyl groups and the nitrogen atom on C-2.

Die l:3-molare Umsetzung von Tris-[ethylendiamin]-Ni-dichloriddihydrat mit D-(+)-Glucose, D-(+)-Mannose und D-(-)-Fructose in Methanol (70°C) fuhrt hauptsachlich zu kristallinen blauen Komplexen, in denen durch Kondensation gebildete N-Glycoside als Liganden koordiniert sind.

Die l:3-molare Umsetzung von Tris-[ethylendiamin]-Ni-dichloriddihydrat mit D-(+)-Glucose, D-(+)-Mannose und D-(-)-Fructose in Methanol (70°C) fuhrt hauptsachlich zu kristallinen blauen Komplexen, in denen durch Kondensation gebildete N-Glycoside als Liganden koordiniert sind.