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Damage to Japanese cedars caused by the sugi bark borer in plots with low, medium and high planting density (1,700, 3,200, and 7,300 trees/ha, respectively) was examined in a 20-year-old sugi plantation. Radial growth and annual ring-width at breast height of three trees sampled per plot were measured by stem analysis. Stand age when each pupal chamber formed on the sample trees by the borer was also investigated by sawing the trees. There was less damage in the high density plot than in the low density plot. Radial growth at breast height increased rapidly from the 7th year after planting in all plots. The width of the annual ring reached a maximum in the 9th or 10th year, and decreased gradually thereafter. Radial growth in the low density plot was larger than that in the high density plot. Pupal chambers were first observed in the 7th year. The number of pupal chambers increased yearly, reaching a maximum in the 12th or 13th year, and decreased rapidly thereafter. These results indicate that restriction of radial growth of trees in the juvenile period by high density planting can prevent infestation of the sugi bark borer. In this study, we measured the positioning accuracy of the Global Positioning System (GPS) while walking in forested areas and analyzed the GPS data to find factors that affected the positioning accuracy. In the field tests, we repeated GPS measurements with different types of GPS receivers, types of forests and modes of GPS positioning. The GPS data were analyzed using ANOVA. As a result, the type of GPS receivers, type of forests and modes of GPS positioning were found to be a significant factor (P < 0.001) to determine positioning accuracy while any interactions between these factors were not. The result also showed that the GPS receiver with multipath rejection technology produced higher positioning accuracy than without it. Therefore, multipath errors, which are caused by the reflection of GPS signals due to nearby stems, can be a critical cause to adversely affect GPS positioning accuracy. It was also suggested that GPS positioning accuracy while walking in forested areas was affected not by basal area but by stand density. That was because temporal signal blocking occurred more often with increasing stand density while walking forested areas. As a result of multiple regression analysis, the observed Position Dilution of Precision (PDOP) was not a significant factor (P = 0.590) to determine positioning accuracy. Deciduous oak (Quercus serrata) forest is a major vegetation type of temperate broad-leaved forests in the north Kanto Region, Japan. The objective of this study is to examine the past and present human-use of the forests and to foresee the future prospects. The shiitake mushroom (Lentinus edodes) producing districts in Saitama and Tochigi were selected as the study areas. Until the 1960s more than 70% of local broad-leaved forests were used as fuelwood in the areas studied. After the revolutionary change in the forms of energy used in the 1960s, oak forests turned to being used mainly for shiitake cultivation in many rural areas. Most oak logs for shiitake have been provided within the shiitake-producing area, but in recent years the number of logs brought from other areas is increasing in fresh shiitake cultivation. Because of the rapid expansion of shiitake imports, aging of the domestic cultivators and labor shortage, domestic shiitake cultivation has declined conspicuously for the last 15 years. In addition, many forest owners and cultivators have already stopped managing the forests as they used to. As a result, if the shiitake cultivation continues to shrink, it is estimated that around 90% of the local broad-leaved forests will be abandoned by the year of 2,015 even in shiitake-producing areas. This paper describes our comparative study on forest policies in Japan, the United States, and Sweden (EU) to assess the policies of Japan for preventing global warming. The forest policies in these three countries were compared in terms of the process of policy-making, overview of policy execution, forest management, forest conservation and protection, conserved and reserve forests, urban forests, biomass utilization, forest studies and indirect slash tools, and policies for attaining the goal of the first period. The forest policies of Japan are characterized by the use of non-physical methods of CO2 absorption, such as cultivating sound forests, managing reserve forests, promoting the use of biomass, and educating people. The United States has substantial policies for physical methods for actively absorbing CO2, such as planting trees. However, the US has not been able to acquire sufficient funds for the policies, and the target absorption has not been attained. Sweden has tended to use non-physical methods and has substantial policies for promoting the certification system, assigning conservation areas, and promoting the use of biomass energy. Hydrological control of streamwater NO3- concentrations was investigated in a weathered granitic headwater forest catchment. The catchment was divided into three parts: the stream channel area, the soil sedimentation area, and the hillslope area connected to the soil sedimentation area. The discharge rate of saturated throughflow within the hillslope and catchment and the groundwater levels in the soil sedimentation area were measured in tandem with the hydrochemical observations. At the points observed, the streamwater had the lowest NO3- concentrations. The concentrations were low during baseflow conditions and increased with the discharge rate. Considering the water budget in the hillslope, about half of the total rainfall infiltrated into the bedrock. This bedrock groundwater was the dominant component of the baseflow, with low NO3- concentrations, while groundwater in the soil sediment area with relatively high concentrations flowed into the stream during rainstorms. The dynamics of the streamwater NO3- concentrations were strongly affected by the hydrological processes in the forest catchment. Especially, the baseflow NO3- concentrations were kept low by the groundwater flow passing through the bedrock. The objective of this study is establishment of vegetative propagation of Japanese black pine (Pinus thunbergii). We examined the effect of defoliation, disbudding and shape of basal cut on the rooting ability of cuttings, and we tried to find an optimal method of propagation. Cuttings were made from terminal shoots of 1-year-old seedlings. As a result, 1) When 0–46% of the needles of cuttings were removed, those rooting percentages were steady between 54 and 62%. However, when needles were removed excessively, rooting ability decreased notably. Moreover, 46% needle removal cuttings had the longest root systems. 2) In the case of cuttings with a part or all their buds removed, the rooting percentage was greater than that of control cuttings. 3) On the examination of treatments of the cut end, rooting ability was better for diagonal shape than for horizontal shapes, but difference in the effect was insignificant. So the optimal method is to remove half of the needles or buds from cuttings and to cut end in a diagonal shape. However, as growth of cuttings from which buds had been removed was bad, a careful needs to be paid to disbudding for commercial production. Chlorophyll fluorescence methods have been used to evaluate the effects of environmental stresses on photosynthetic properties. Chlorophyll fluorescence can provide detailed information of photosystem II (PSII) photochemistry, which is vulnerable to environmental stresses such as strong light, low temperature, heat and drought. I reviewed photoinhibition of photosynthesis and discussed the mechanism to prevent photoinhibition in drought-acclimated leaves. As drought stress is often accompanied by strong light, a decline in photosynthesis caused by stomatal closure increases the risk of photoinhibition. Energy dissipation via electron flow would be an effective way to prevent photodamage as well as thermal energy dissipation in PSII antennae. When plants are illuminated by excess light, inhibition of photosynthesis occurs by harmful molecules generated by excess excitation energy. Photochemical efficiency is also decreased during the dissipation of excitation energy by protective mechanism. Inhibition of photosynthesis by low temperature results in a considerable excess of excitation energy leading to photodamage. Although evergreen woody plants are considered to be subjected to photoinhibition, they develop many photoprotective mechanisms against photoinhibition. In this review, I summarized the molecular aspects of photoinhibition and role of photoprotective mechanisms, and discus the ecophysiological meanings of photoprotections, especially xanthophyll cycle, water-water cycle, and photodynamic screen provided by the accumulation of pigments such as rhodoxanthin and anthocyanine observed in over-wintering woody plants. Acid fog is considered to have a large influence on tree physiology because it has a high concentration of air pollutants and is persistent in the atmosphere. Long-range transported pollutants contribute to acidification of fog in mountainous areas and therefore trees grown in these areas are thought to be affected by acid fog. The effects of acid fog using tree seedlings are well documented. From the results of these experimental studies, acid fog is known to induce visible injury, reduce the dry weight and photosynthesis systems, disintegrate the epicuticular wax, alter the nutrient status, and increase the sensitivity to other stresses, such as frost, wind and ozone. In addition, the extent of these effects is dependent on the pH and the components of acid fog and tree species. In this review, we summarize these reports and discuss further developments in research. Degraded lands abandoned after failures of agricultural development are widely distributed over tropical areas. – Environmental reforestation – in degraded lands is needed for the rehabilitation of regional environments. In this paper, I review properties of problem soils in tropical Asia and stress responses of tropical trees, and discuss the development of methods of environmental reforestation. Food shortage and environmental deterioration due to rapid growth of the global population are the most serious problems that face us human beings. Improvement of tolerance of plants to abiotic stresses such as drought, high salinity, low temperature, and heat is one of the promising approaches for the future of agriculture and environmental conservation. It is essential to know at first how plants respond to environmental stresses and which molecules are involved in stress tolerance. According to recent development in genomics in Arabidopsis, it has been shown that hundreds of genes are involved in stress response and/or stress tolerance. More recently, functional genomics in woody plants has been promoted mainly in the occident. A US group, in particular, is determining the nucleotide sequence of whole poplar genome, and this information will have been released by the end of the year 2003. We are convinced that the poplar will be more important as a model forest tree in the post-genome era. We here introduce the world-wide situation of genomics in the poplar and discuss a direction of study on stress physiology in woody plants. Genetic engineering has the potential to allow the selective improvement of individual traits in woody plants without the loss of any of the desired trait of the parental line. Using such techniques, we can overcome the difficulties associated with the breeding of long-lived perennials, which need to long time to produce progeny. In this paper, we introduce recent advances in the application of genetic engineering to forest trees to solve environmental problems. And, we also discuss the necessity of flowering control of transgenic woody plants. [ABSTRACT FROM AUTHOR]