Chapters authored
Larch: A Promising Deciduous Conifer as an Eco-Environmental Resource
Larch species are widely distributed in the northern hemisphere where permafrost and seasonal frozen soil exist. This species with heterophyllous shoots has been intensively planted in northeast Asia as well as in northeast China as the principal afforestation species for restoring agricultural lands to forests from 1999. Although approximately 15 species exist in the northern hemisphere and they are easy to hybridize. Among them, Japanese larch grows the fastest and was exported to Europe as a breeding species from early 20s. Although Japanese larch is tolerant to cold, it suffered from various biological stresses. After nearly 40 years of vigorous breeding effort, hybrid larch F1 (Dahurian larch × Japanese one) was developed with simple propagation methods. With the use of free-air CO2 enriched (FACE) systems, we revealed growth responses of the F1 and its parent larches to environmental conditions. From experiments, F1 showed high responses to elevated CO2 and O3 but not so much to N loading. As future perspectives for larch plantations as an important eco-environmental resource, we expect to afforest F1 seedlings infected with ectomycorrhizae (e.g., Suillus sp.) for efficient afforestation at nutrient-poor sites and at the same time for the production of delicious mushrooms.
Part of the book: Conifers
Vigor and Health of Urban Green Resources under Elevated O3 in Far East Asia
Conservation of urban greens is an essential action for city residents, however, declining symptoms and/or traces in the annual ring of trees grown are found in parks and forest stands in a city as well as its suburb with a high level of ozone (O3). Urban greens, including roof-green, provide comfortable conditions for the people and a moderate environment in a city. They are exposed to severe environments; heat, drought, air-pollutions, etc. even with intensive management of the people. How can we proceed with the conservation and wise use of urban greens? We should know the ecophysiological responses of urban trees to such a global environment as well as a local one. Defensive capacities of urban greens should be analyzed in terms of damages caused by biotic and abiotic stresses, and it is important to understand their interactions from the viewpoint of plant-insect/disease. There is a concern that some green areas are suffering from an outbreak of insects and diseases, reducing the vigor and health of urban greens. We discuss these based on specific examples, such as man-made forests, in cities in far east Asia for considering our approach to how to keep urban green resources.
Part of the book: Vegetation Dynamics, Changing Ecosystems and Human Responsibility
Essential Role of Symbiotic Microorganisms Supporting Forests in East Asia under Changing Environment
Regeneration success of forests is strongly dependent on symbiotic microorganisms, that is, arbuscular mycorrhiza (AM) and ectomycorrhiza (ECM). In the northeastern part of Asia, larch and birch are used as timber resources, and in the south, fir, cedar, cypress, and oak are used as timber resources. Planted forests have reached the time of harvesting and/or thinning, and after the forestry practices, it is expected that they will become mixed forests equipped with resistance to weather damage; that is, drought, heat, typhoons, etc. On the other hand, the physical production environment has changed greatly, therefore, we investigated the growth of the major trees and the role of mycorrhizal fungi in the northeastern Asia. Elevated O3 decreased growth, colonization rates of ECM, and the biodiversity; however, elevated CO2 moderated or increased them in larch. Except for disease of rot and damping off, we discuss wise use of symbiotic microbe in far East Asia.
Part of the book: Symbiosis in Nature