In two mountain regions (Yabe and Soeda) of Fukuoka prefecture pH value, electric conductance and concentration of potassium, calcium and magnesium were measured monthly since 1985. Average pH values of precipitation were about 4.9 in both regions. It means that acid rain is falling everytime in mountain region. Average pH values of stream water in Yabe and Soeda were 6.6 and 6.8 respectively. The pH value of the stream water was near the nuetral. Decrease of the pH value of stream water in Soeda was observed since 1988 and then in 1990 these values were about 0.7 less than the values in 1985. The cause of decrease of pH value of stream water in Soeda was not detected enough. The pH value of stream water in Soeda showed varience between sampling points. At the sampling point No. 5 the lowest pH value was observed everytime and at the sampling point No. 8 the highest one was observed. Relationships between pH, electric conductance and concentration of potassium, calcium and magnesium in monthly sampled precipitation and stream water were not observed. Relationship between pH value and concentration of potassium in stream water which samplled from 45 little watersheds showed negative corelation. The pH value of stream water in multiple layered forest was higher than the one in single-layer forest.

View full abstract

The through fall and stem flow were examined for 17 years old manmade forests of Todo fir (Abies sachalinensis) and Ezo spruce (Picea jezonensis) in the suburbs of Saspporo from May, 1990 to November, 1990. The amounts of through fall, stem flow and outer rainfall were measured at every rain event, and they were analyzed for, pH, EC and base cations concentrations. Also pH and EC of the surface soils at stem base and in berween trees were measured to know the influence of the through fall and stem flow on soil. The rsults obtained are summarized as follows. 1) Proportion of the amount of stem flow to total precipitation was higher in the Todo fir forest (10%) than in the Ezo spruce forest (5%). 2) The pH value was generally the lowest for the outer rainfall, then increased in the order of Todo fir stem flow < Todo firthroughfall < Ezo spruce throughfall < Ezo spruce stem flow throughout the period. The EC was higher for the through fall and stem flow than for the outer rainfall. 3) The base cations concentrations of the throughfall and the stem flow increased in the spring and the autumn, and the increases seem to take place cooncomitantly with leaf development and defoliation, respectively. Details of the time function of each base cation level differed depending on the tree species and the kinds of rainwater. 4) The amount of H ion loadedto thesoil during the period was smaller in the Todo fir forest (15 meq/1 m^2) and Ezo spruce forest (12 meq/1 m^2) than in the outside of the forests (34 meq/1 m^2). The loaded amounts of each base cation in the forests were similar between the species, and increased by respective 2 times, 1.5-2 times and 20 times for Ca, Mg and Na, and K in comparison with the outside of the forests. 5) The pH value of the surface soil was lower at stem base than in between trees in the Todo fir forest, while the reverse was the case in the Ezo spruce forest, presumably because of the inter-species differences in rainfall distribition into throughfall and stem flow and their qualities.

View full abstract

Needles of Sugi were collected in a declined forest in Gunma prefecture and in a non-declining forest in Ibaraki predecture in October. The concentrations of nitrogen and sulfur in current and one-year-old needles of these samples were measured. Though nitrogen concentrations in one-year-old needles were lower than those in current needles in both forests, the decreasing rates of these concentrations were greater in needles of declined trees than those of in non-declined trees. Nitrogen uptake was considered to be restricted in the declined forest. The sulfur concentrations were appoximately 0.04-0.12% in all samples. The sulfur concentrations in dead needles were almost the same as those in linving needles, therefore sulfur recovery from needles at the defoliation is considered to be small.

View full abstract

Many climatic regional divisions have been produced by workers using macroscale, larger than mesoscale, analyses. In their divisions, lines showing the boundary between two nieghbouring areas were set on natural boundaries such as mountains, But from the stand point of microscale analysis, it can be said that mountains are broad land areas and have relatively great altitudinal differences. Accordingly, we can divide areas occupied by mountains into many sub-areas using micro climatic factors. In other words, boundary lines necessarily have width as a shifting belt between the two neighbouring areas. The clarify the characteristics of climate in the range of the Oku-chichibu mountains and surrounding area, regional division was carried out using the following procedure. First, the hyther graphs for about 70 observatory stations located in the range were drawn by the ordinary method. Next, the graphs were classified by differences of their pattern. The patterns were divided as follows, When the maximum monthly precipitation appeared in June this was classified as "A", in July as"B", August "C", and September "D", To these classes, some subclasses showing the variation of the number of crossing points made by two seasonal zigzag lines from winter to summer and from summer to winter on the graph were added. The regional divisions by this method, showed similar results to some of the existing divisions by other workers, and clarified some details, The characteristiecs of each dicided sub-area were analysed by the P/E index of Thornthwaite, the coefficient of humidity of Angstrom, Koppen's precipitation effectiveness, and Kira's moisture index.

View full abstract