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The initiation and development of flower buds in A. turbinata were investigated in the Hiruzen forest of Tottori University, in Okayama Prefecture. The growing point surrounded with hairy scales grew thickly and differentiated to a flower bud primordium. It grew rapidly and flower primordia were formed around the floral axis. The differentiation of anthers and ovaries started at the end of July and sporogenous cells and young ovules were formed from mid to late August. Pollen mother cells and egg-shaped ovules were observed in mid September. Pollen grains were formed in early May of the next year. The style and filament elongated in mid-May and hermaphrodite flowers were completed. In immature flowers whose ovules were degraded, only filaments elongated and developed to male flowers. Flower buds were distinguishable from vegetative buds by the form of winter buds in mid-September. In order to clarify the relationship between prevalence of Japanese cedar pollinosis and allergen content, we collected pollen of 420 elite trees from 25 prefectures and investigated the variation of Cry j 1 content. There was no difference in Cry j 1 content among 4 regions (1 Hokkaido · Tohoku, 2 Kanto · Tokai, 3 Hokuriku, and 4 Kansai). So, it was thought that the prevalence is largely affected by the amount of dispersion pollen. Cry j 1 content of 420 clones showed variation from 0.38 to 10.23 pg per pollen grain and 7 clones had less than one pg per pollen grain. The heritability of Cry j 1 estimated by parent-offspring regression was very high at 1.0. From these results, it was suggested that a large number of sugi (C. japonica D. Don) trees with low allergens could be created by crossing the 7 trees selected in this study. In the forests at Ohdaigahara, central Japan, the understory is dominated by dwarf bamboo (Sasa nipponica Makino et Shibata; hereafter, sasa), which has been intensely grazed as a result of a recent overpopulation of sika deer (Cervus nippon centralis Temminck). We examined the effects of sasa and deer on the movement of soil and litter on the forest floor in experimental plots with or without the exclusion of deer and/or removal of sasa in a temperate mixed forest at Ohdaigahara. Removing sasa increased the amounts of woody leaves and branches that moved. The total amount of moved soil and litter correlated negatively with the above-ground biomass of sasa. Excluding deer decreased the total amounts of moved soil and litter to the same levels as in other Japanese forests because the aboveground biomass of sasa recovered. On the other hand, the total amount of moved soil and litter in the control plot was 1.2–4.3 times higher than in the other forests. Thus, grazing by deer increased the movement of soil and litter on the forest floor. A forest planning information system needs to be improved to provide direction for the development of the future forest GIS for the local forestry management. Moreover, at the same time, the comparability for forestry management with the existing basic local information other than forest planning information must be examined. This paper focus on the cadastral information which is one kind of basic local information. The consistency of forest planning information and cadastral information was positively examined centering on two attribute data, a boundary/boundary, and an owner name/registration name. In addition, their mutual comparability was considered. Consequently, it was confirmed that adequate adjustment existed between forest planning information and cadastral information. The result of this paper has suggested that we can use cadastral information in order to raise the accuracy of forest planning information. Mt. Usu, in southern Hokkaido, Japan, erupted in March 2000, and in July 2000 a rainfall-induced mudflow occurred on the northern slope of Mt. Konpira, near to the area that was active in the recent eruption. To investigate the effect of this mudflow sediment on gas exchange by tree root systems and tree mortality rates, gas diffusion rates were measured at two study sites at the foot of this slope in July 2001. The tree species, their diameter at breast height, and sediment thickness were also scrutinized. The relative gas diffusion coefficients in soil air (D/D0) of sediment samples were analyzed in the laboratory. The mortality rate depended on the surface sedimentary structure after the recent eruption. At the first site, where the mortality rate was almost 100%, the rainfall-induced mudflow sediment was about 20 cm thick on a pyroclastic fall deposit about 10 cm thick. At the second site, where the mortality rate was 36%, the sediment layer consisted solely of a pyroclastic fall deposit about 10 cm thick. While the D/D0 values in the pyroclastic fall deposit covered with the mudflow sediment were less than 0.005 during September 2001, the values at the site not covered by the mudflow exceeded 0.02. This suggests that the mudflow sediment cover retarded gas exchange in the rhizosphere, asphyxiating root systems; consequently, the trees died after the rain-induced mudflow occurred. Causes of falling of immature fruits during development were investigated in the stands of A. turbinata in the Tottori University forest in Okayama Prefecture. About 80–90% of immature fruits fell between mid June and late July. The cessation of ovular development, the collapse of the inside tissue of seeds, the poor development of embryos and cotyledons, and insect damage were observed as the causes of fruit fall of 55, 33, 12, and 0.8% of the fruit, respectively. The insect damage occurred mainly from early to late June and from late July to mid-August. Damage in June was caused by sacrocarp-eating larvae, and damage in July and August was causal by cotyledon-eating larvae. The cessation of ovular development in fallen fruits was observed mainly in June. The collapse of seed tissue was observed in fallen fruits from early July to mid August. The poor development of embryos and cotyledons was seen in fallen fruits from late July to mid August. Seeds of Kalopanax pictus usually require two years to initiate germination. We examined the effectiveness of three stratification treatments in reducing this period by one year. The treatments were 1) constantly maintained temperature of 25°C, 2) 30°C for 12 h, followed by 20°C for 12 h, and 3) room temperature (mean overall temperature: 22.1°C, mean daily maximum temperature: 25.6°C and mean daily minimum temperature: 18.5°C). Each treatment lasted four months, after which there followed a three-month 5°C stratification treatment. The room temperature treatment produced the highest germination rate (53.3–82%), followed by the 30°C/20°C treatment (47.2–71%), with the 25°C treatment producing the lowest germination rate (2.7–13%). We conclude that the room temperature treatment provides a simple and effective method to shorten the period to initiation of germination for K. pictus. The present study deals with the effects of application of 10 different kinds of plant growth regulators (PGRs) on breaking the dormancy of buds and shoot development in 2-year-old Aesculus turbinata seedlings. The application of gibberellins (GAs) increased the elongation of apical buds. However, bud elongation was suppressed by the application of GA synthesis inhibitors including AMO-1618 (AMO) and uniconazole-P (UNP). The elongation of lateral buds was accelerated by application of GAs, Ethrel (ET), jasmonic acid (JA), AMO and UNP. The breaking of the dormancy of both apical and lateral buds was also promoted by the treatment with GAs or JA. These results suggest that GAs are essential for the elongation of buds and not only GAs but also JA may have a role in breaking the dormancy of buds in A. turbinata seedlings. This study examined the rehabilitation of native riparian forests by removing an exotic plant Robinia pseudoacacia L., which influences the biodiversity of riparian forests. In February 1997, all the R. pseudoacacia canopy trees were cut down in an upstream riparian zone along the Arakawa River, while native trees in the sub-canopy and lower layer were left. After cutting, a mean of 49.5 sprouts, including root suckers, emerged per individual on stumps and horizontal roots. Root suckers emerged from horizontal roots located up to 11 cm underground. The number of such sprouts, including root suckers, decreased yearly, and most died after five years. After cutting, the relative light intensity and mean openness increased rapidly, but returned to pre-cutting levels after five years with the growth of branches of the native riparian trees. These results suggest that it is possible to remove R. pseudoacacia trees from riparian ecosystems when they are mixed with native trees. A distinctive bleaching is often recognized on Camellia japonica leaf litter. In a stand in which nitrogen was saturated and a control stand, the chemical composition and the mycobiota of bleached portion were studied and compared with those of the non-bleached area. Lignin and polyphenol concentrations in the bleached portion were lower than in the non-bleached portion. Carbohydrate concentration was higher in the non-bleached portion than in the bleached portion, and was higher in the control stand than in the nitrogen-saturated stand. In the bleached portion, 10 species were isolated, including anamorphic Coccomyces sp. and Xylariaceous ascomycetes Xylaria sp. (anamorph) and Geniculosporium sp. In the non-bleached portion, 7 species were isolated including Geniculosporium sp., Nodulisporium sp. The mycobiota did not differ between the nitrogen-saturation site and the control site. These results suggest that the bleaching of C. japonica leaf litter was produced by the degradation of lignin and polyphenol by Xylariaceous and Rhytismaceous ascomycetes. [ABSTRACT FROM AUTHOR] |
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