Ma LüYi

Analysis of the change in the original Metasequoia glyptostroboides population and its environment in Lichuan, Hubei from 1948 to 2003

Lichuan, located at the foot of the Wuling Mountain in southwest Hubei Province of central China, is well known in the world for the discovery of the living fossil Metasequoia glyptostroboides Hu & Cheng in the 1940s. Its natural habitat has been well protected by the Chinese government. In order to provide a scientific foundation for the protection of the Metasequoia resource, it has become necessary to analyze the changes in the original, natural Metasequoia mother trees (ONMMT) and their environment from 1948 to 2003. The results and countermeasures are as follows: First, the distribution areas have little changed, involving four towns/farmland, 45 villages, 5,746 individual trees in 1983 and 5,388 trees in 2003, covering nearly 600 km2, with an average density of less than 0.1 tree/hm2. The Metasequoia distribution consists of two main types: a scattered distribution type found mainly at the foothills or near houses, roads, villages and rivers while the population distribution type is found mainly at the mountains and valleys with a minority at low elevations in the mountains and basins. The largest Metasequoia populations have 105 and 123 trees. Second, in the past, attention was only paid to the protection of individual trees while the protection of the Metasequoia population and environment was neglected. This led to a shift from the past mixed forests to pure Metasequoia forests, with a simpler structure, reduced biodiversity and conditions non-conducive for natural renewal. From 1983 to 2003, 386 original Metasequoia mother trees died. So it is vital to enhance the protection of the only original Metasequoia population in the world and its habitat. Third, modern ecological means should be taken to protect the original Metasequoia population and its habitat. Research on the restoration and rehabilitation of Metasequoia vegetation should be carried out. Restoration and rehabilitation should be put into practice in the Xiaohe Valley, where the highest concentration of Metasequoia is found. Fourth, efficient measures should be taken to stop human activities that are harmful to Metasequoia and to improve the environment of ONMMT in order to promote the protection of the ONMMT population and its ecosystem. Eco-emigration and the return of marginal agricultural land to forestry can be practiced.

Scaling-up method for stand water consumption of Quercus variabilis water conservation forest

AbstractSingle tree’s sapwood scattering style and diurnal water consumption rhythm for different diameter classes were studied in a 48-year-old Quercus variabilis stand, water protection forest in Beijing. Results showed that the tree’s sapwood area was closely related to diameter at breast height (DBH). Single tree’s daily water consumption ascended as DBH and sapwood area increased. Daily water consumption of different diameter classes in September ascended steeply in the early morning and reached the peak around 11:00, and then descended slowly to the valley at 18:00. The course of daily accumulated water consumption was in accordance with a typical Richards model (R=0.985,8). Parameters of diameter-time equation for scaling-up can be achieved by parameter-recovering method in the gradient of all diameter classes and at any time of a day, characteristic parameters of the course of daily stand water consumption were calculated from a modulated Richards equation derivative:

Analysis on the Dynamic Changes of Forest Resources and Sustainable Development in Beijing

W_{d_i t_i } = ( - 7.147 + 1.174^{d_i } )[1 - ( - 3,025.937 + d_i^{2.175} ) \cdot e^{( - 0.011t_j )} ]^{\frac{1}{{1 - d_i^{0.242} }}}

北京平原の1000000畝造林工学建設効果評価研究【JST・京大機械翻訳】

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