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Volume 46 (2004)
- Issue 2 Pages 59-
- Issue 1 Pages 1-
Volume 46, Issue 2
Displaying 1-6 of 6 articles from this issue
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Takaki Toyoda, Nobumitsu Miyazaki, Kazuhisa Kato, Hiroki TomiyaArticle type: Article
2004 Volume 46 Issue 2 Pages 59-67
Published: December 25, 2004
Released on J-STAGE: April 03, 2017
JOURNAL FREE ACCESSSubmergence time of sea or brackish water is one of important factor for forming a distribution pattern of mangrove species. A test for clarifying the relationship between submergence time and distribution pattern of mangrove species was carried out in the Ulugan Bay, Palawan Island, the Republic of Philippine. There are remaining well mangrove forest stands, which are less impacted by human activities. Three belt transect surveys for distribution pattern of mangrove species and ground level surveys were conducted. Distribution of mangrove species from coastal side to inland side is Rhizophora mucronata (Rm)<Bruguiera gymnorrhiza (Bg)=Rhizophora apicurata (Ra)=Xylocarpus granatum (Xg)<Aegiceras floridum (Af)=Bruguiera sexangula (Bs)=Heritiera Littoralis (Hl), which was determined by distribution range of each mangrove species based on relationship between horizontal distance and ground heights. To estimate the submergence time on each tree alog the transect lines (UL3), the highest water level from ground height was measured. Then, the submergence time of appeared mangrove species was calculated from the highest water level and daily tidal change. As a result, all mangroves, except for the Rm that distributed at the most coastal side and submerged throughout the day when neap tide, are situated on the places where the ground surfaces exposed above the water level even for a short time. Besides, some stands of Bs and Hl, which distributed at the most inland side are not submerged even in spring tide in June ; thus, the study revealed the range and the marginal time of submergence in each mangrove species.View full abstractDownload PDF (1044K) -
Keizo HiraiArticle type: Article
2004 Volume 46 Issue 2 Pages 69-75
Published: December 25, 2004
Released on J-STAGE: April 03, 2017
JOURNAL FREE ACCESSWe investigated the characteristics of nitrogen mineralization in the topsoil at different topographic positions and the effects of clear cutting in a Castanopsis cuspidate secondary forest by subjecting undisturbed soil samples to kinetic analysis using the leaching incubation method. We also estimated annual amounts of nitrogen mineralization in the soil at each site from parameters of kinetic analysis and recorded soil temperatures of these soils. We also compared leaching method using the undisturbed soil and bottle incubation method using the disturbed soil to evaluate the effect of soil disturbance on the characteristics of nitrogen mineralization. As a result, easily decomposable nitrogen (N_0) was found to be highest in the soil at the soil at the site of upper slope position, but the rate constant of mineralization (k) and apparent activation energy (Ea) were highest in the soil at the ridge site. Estimated amounts of nitrogen mineralization were ranged from 13.5 to 38.5kg ha^<-1>yr^<-1> 5cm^<-1> at the sites with the highest amounts observed at the ridge site. In the soil at the site of a clear cutting where in ridge site, as rate constant of mineralization decreased and apparent activation energy was increased compared at the ridge site in the forest where was not cut. Then, turnover rate which indicates ratio of annual mineralization amounts (N) to mineralizable pool (N_0) was lowest among sites. But nitrification was increasing at the site of a clear cutting. Values of nitrogen mineralization were three times higher with the bottle incubation method than with the leaching method. Mineralization rates of the leaching method at about 1.0-3.1%, were also 2.5-3 times higher than those of the bottle method which were about 1.0-3.1%.View full abstractDownload PDF (1136K) -
Eriko ITO, Kenji ONO, Akihiro IMAYA, Hidesato KANOMATAArticle type: Article
2004 Volume 46 Issue 2 Pages 77-84
Published: December 25, 2004
Released on J-STAGE: April 03, 2017
JOURNAL FREE ACCESSWe quantified three indices of forest soil N cycling using GIS as an attempt to evaluate potential for forest nitrogen export at the catchment scale. We studied in the forest area with a total area of 134,000ha in basin of the Yahagi River. We used government-published GIS data. We classified the target forest area into seven forest types from vegetation and soil moisture based on GIS data and field research. At typical points of each forest type, we made field researches to measure nitrogen mass in soil profile (<1m). Nitrogen mineralization and nitrification rates of surface soil (0-5cm) were also measured in a laboratory incubation experiment. We estimated soil nitrogen storage to be 1,130,000t, amounts of daily maximum mineralized nitrogen to be 400t N day^<-1> and daily maximum nitrate production to be 200t N day^<-1> in the studied forest area. We made figures showing the distribution of these indices.View full abstractDownload PDF (1570K) -
Jianjun Zhang, Akira ShimizuArticle type: Article
2004 Volume 46 Issue 2 Pages 85-92
Published: December 25, 2004
Released on J-STAGE: April 03, 2017
JOURNAL FREE ACCESSSoil moisture variation in forests for soil and water conservation in the China Loess Plateau was investigated. Based on the result, annual change of soil moisture content can be divided into four periods, consuming period, increase period, decrease period, and steady period, respectively. Soil moisture contents of ruderal land and shrubbery land are 20mm more than that of arbor stand. The soil moisture content of the slope arbor stand facing to south keeps under 60% of field moisture capacity in most months yearly; while the bottom of valley keeps above 60% of field moisture capacity all year round. On average, the frequencies that the soil moisture content is under 60% of field moisture capacity were ranked as: the mixture forest stand of Robinia pseudoacacia and Pinus tabulaeformis (96%), Pinus tabulaeformis forest stand (88-94%), Robinia pseudoacacia forest stand (78-95%), shrubbery land (50-58%), and ruderal land (23-42%). Results suggest that it is better to plant trees in the bottom of valley and to plant the species with low level of water-consuming such as Ostryopsis davidiana in the China Loess Plateau area in order to form naturally regenerated forests, which not only consumes small amount of soil water but also can prevent soil erosion.View full abstractDownload PDF (1122K) -
Tetsuya Matsui, Tomoki Nakaya, Tsutomu Yagihashi, Hiroshi Taoda, Nobuy ...Article type: Article
2004 Volume 46 Issue 2 Pages 93-102
Published: December 25, 2004
Released on J-STAGE: April 03, 2017
JOURNAL FREE ACCESSWe developed three different types of predictive distribution models for the presence/absence of Fagus crenata forests with four climatic parameters, and compared their performance. Generalised Linear Models (GLMs), Generalised Additive Models (GAMs), and Tree-Based Models (TMs) were compared in this way, due to their popularity in predicting plant species distributions. Four climatic factors; the minimum temperature of the coldest month (TMC), the warmth index (WI), winter precipitation (PRW), and summer precipitation (PRS); were used as explanatory variables in the model development. For GLMs, two sets of explanatory variables were applied, one of which was based solely on the four climatic terms (GLM-Simple), while the other included two-level interaction terms and quadratic polynomial terms (GLM-Complex). The models' performance was compared with AIC (Akaike's information criterion), residual deviance, and accuracy measures, including Kohen's kappa statistic and overall prediction success, which are often used in predictive modelling studies. The resulting values all indicated that TMs performed best, followed by GAMs, GLM-Complex, and GLM-Simple. We envisaged that the superiority of the TMs may be due to their binary recursive partitioning nature, which appears to give them a high capacity to capture the non-homogeneous Japanese climatic patterns nationwide. The model can explain the relationships between F. crenata forest distribution and climate factors well, although the forests are widely distributed under non-homogeneous climatic systems in Japan. We therefore support the use of TMs in predicting the presence/absence distributions of widely distributed forest types or plant species under the Japanese climate systems.View full abstractDownload PDF (1104K) -
Masayuki Araki, Kiyokazu KawadaArticle type: Article
2004 Volume 46 Issue 2 Pages 103-109
Published: December 25, 2004
Released on J-STAGE: April 03, 2017
JOURNAL FREE ACCESSAn isopleth chart for P/PETt of the Eurasian continent was drawn to clarify general patterns and tendencies using climatic normals of monthly precipitation and temperature from 1961 to 1990. The P/PETt relates annual precipitation and annual sum of monthly potential evapotranspiration calculated by Thornthwait's formula (1948). The method may be dated but is still effective for estimating the climatic vegetation indexes, because that requires only annual precipitation and monthly air temperature. General patterns in the isoplethes of P/PETt agreed well with those in some other climatic charts, such as the rain factor by Lang (1920) and aridity index by Martonne (1926). A detailed isopleth chart of P/PETt was then redrawn for the steppe and surrounding areas of Inner Mongolia with 0.1 intervals of P/PETt, where the same data as in Fig.2 were used. Isopleth patterns in the detailed chart were similar to those in the chart drawn by Qion and Line (1965) based on Penman's formula for China. Finally, arid limits for the following vegetation zones were determined based on P/PETt by comparing the chart with the map of grass land types in Inner Mongolia (Li, 1991): forest 0.9, forest steppe 0.6, typical steppe 0.4, desert steppe 0.3, steppificated desert 0.2, and desert under 0.2. Here the three zones of P/PET<0.5 are the subdivisions of the desert.View full abstractDownload PDF (967K)
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