Articles containing the keyword 'throughfall'

The study is part of a project designed to elucidate the nutrient budget of a Scots pine (Pinus sylvestris L.) stand. Results of variation in the nutrient contents were compared with those obtained for the previous growing season.

The potassium and calcium contents varied the greatest in the humus layer. However, in the bottom and field layer vegetation and needles the variation in the nitrogen content was the greatest. The nutrient contents of the needles were affected by the physiological stage of development, needle age and the position in the crown of the tree. The nutrient content of the rainfall increased in the order: free rainfall, throughfall, and stem flow.

The PDF includes a summary in Finnish.

• Lehtonen, E-mail: il@mm.unknown

This study forms part of a project designed to elucidate the total nutrient budget of a Scots pine (Pinus sylvestris L.) stand in Central Finland during the 1974 growing period. Precipitation has been divided up into precipitation, throughfall and stemflow.

The acidity of the rainwater was found to increase in the order – Precipitation, throughfall and stemflow. The electrolyte content of the rain water from throughfall and stemflow was higher than that of precipitation. The nutrient contents of precipitation were rather low. Throughfall and stemflow were found to leach some nutrient from the trees. This was most clear in the case of potassium. The total amounts of nutrients reaching the ground in throughfall were found to be smaller than those in precipitation. On the other hand, the amounts of potassium, calcium and magnesium in stemflow were clearly greater than those in precipitation.

The PDF includes a summary in English.

• Lehtonen, E-mail: il@mm.unknown
• Kellomäki, E-mail: sk@mm.unknown
• Westman, E-mail: cw@mm.unknown

The aim of the paper was to study the amount and distribution of rainfall in a virgin Norway spruce (Picea abies (L.) H. Karst.) stand. Special attention has been paid to the dependence of throughfall on the characteristics of the precipitation falling on an open area and the stand.

The throughfall was 62% of the precipitation in the open. The best independent variable as regards the throughfall was the amount of precipitation falling in the open. The heaviness of precipitation in the open gave no meaningful correlation. Horizontal layout of the stand was found to have some effect on the throughfall. The throughfall was also influenced by the tree species composition of the stand. Only 52% of the total variance of the amount of water caught by the rain gauges could be predicted with the characteristics of the precipitation in the open and the stand.

The PDF includes a summary in English.

• Kellomäki, E-mail: sk@mm.unknown
• Pohjapelto, E-mail: pp@mm.unknown

The purpose of the study was to measure the throughfall in a managed Scots pine (Pinus sylvestris L.) stand in Southern Finland (61°47’, 24°18’). Totally 20 summer rain gauges (collecting area 100 cm²) were placed randomly in form of a lattice of 100 squares, each 2x2 m. Six rain throughs, 15 cm x 150 cm, were placed in the experimental stand. Auxiliary precipitation measurement was done in an opening, by using four summer rain gauges, two rain throughs and one recording rain gauge. The throughfall was followed in May–September 1967.

In comparison with summer rain gauges, the rain throughs gave too low values when the precipitation was below 3 mm/rain shower. Accordingly, only the results of rain gauges were used. The rate of throughfall was determined by the amount of precipitation and the rate of heaviness of the rain shower. When trying to describe the relative amount of throughfall by using various characteristics of the stand, the equitation proposed by Seppänen (1964) proved the best. When the rate of throughfall was depicted with the distance between the summer gauge and the nearest tree, there was negative correlation between these. The correlation was negative under heavy rains, but positive in small rains.

Various factors of uncertainty are discussed. During long periods the areas under Scots pine canopies reach more rain water than those between the canopies, which may be important when analysing the spatial distribution of ground vegetation.

The PDF includes a summary in English.

• Leikola, E-mail: ml@mm.unknown

Stand precipitation and stemflow studies became necessary in connection with hydrologic studies, for instance, to explain the deviations resulting from rains in the ratios between the water content of peat and the groundwater level, throughfall during rains of variable heaviness, and effect of stand treatment on soil moisture level. In this project the distribution of rainfall in stands differing in species composition and density was studied in Central Finland in 1963–1965 in fifteen stand precipitation sample plots. In addition, rain gauges were situated under individual Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.) and birch (Betula sp.) trees.

The average precipitation in the open was 4.8 mm, the corresponding precipitation in the stand was 77% for birch, 71% for pine and 62% for spruce. Measurements of stemflow from individual sample trees showed that less than ¼ mm (about 1.5%) during a 15 mm rain in a pine stand. In the spruce stands stemflow is negligible. A part of the sample plots was in drained peatlands with a dense vegetation of small shrubs. The shrub layer retention was about 10% even during heavy rain. In a small forest clearing, the bordering effect of the forest was seen up to the distance of 5 metres from the edge of the forest. During the period of study, on an average 3% more precipitation was recorded in the clearing than in the open, the difference being probably due to the stronger wind effect in the open.

The PDF includes a summary in English.

• Päivänen, E-mail: jp@mm.unknown

Distribution of rainfall in in a Scots pine (Pinus sylvestris L.) stand and in an open place in Alajärvi in Central Finland was studies in 1959–1960. Density of the about 80 years old stand was 0.36 and the height of the trees 8–14 m. The dependence of throughfall and dependence of stemflow on 24-hour precipitation, and dependence of the distribution of 24-hour precipitation on the amount and nature of precipitation was calculated.

The precipitation of the crown of the forest depended on the rainfall. When the rainfall in the open place was over 7 mm, the rainfall within the forest was in average 89% of the rainfall in the open place, but if the rainfall in the open place was less than 1 mm, the rainfall within the forest was only 64% of that in the open place. Total stemflow in the pine stand was only 0.4%, and interception loss was 13.6%.

The PDF includes a summary in English.

• Seppänen, E-mail: ms@mm.unknown

The aim of this study was to assess the effect of cutting of different intensities on the hydrology of drained peatland. The study concerned with measuring changes in the ground water level, throughfall, and snow cover, and specially runoff. This study focused on the phenomena that occur during the growing season. Seven sample plots were measured in an area in Central Finland which had been drained about 50 years earlier and had Scots pine (Pinus sylvestris L.) stand of uniform age.

To survey the hydrological effects of cuttings, 20%, 40% and 60% of the stand volume was removed in thinnings. In addition, one sample plot was clear-cut. During the first two years after cutting the interception diminished, and throughfall increased by 7% for the 20% thinning, by 8% for the 40% thinning and by 12% for the 60% thinning. Clear cutting increased the throughfall by 29%. The thinnings increased the depth of the snow cover the more the heavier the thinning.

Even the lightest thinning raised the ground water table, but the difference between 20% and 40% thinning was not marked. Cuttings increased runoff the greater the heavier the cutting. The hydrological changes of fellings were detrimental for the site. However, there was a marked change only between the 40% and 60% thinnings. Fertilization had a favourable effect on the hydrology of the peatland by increasing the depth of ground water table, and decreasing the throughfall.

The PDF includes a summary in Finnish.

• Heikurainen, E-mail: lh@mm.unknown

• Michopoulos, Forest Research Institute of Athens, Terma Alkmanos, Athens 115 28, Greece E-mail: mipa@fria.gr
• Baloutsos, Forest Research Institute of Athens, Terma Alkmanos, Athens 115 28, Greece E-mail: gb@nn.gr
• Economou, Forest Research Institute of Athens, Terma Alkmanos, Athens 115 28, Greece E-mail: ae@nn.gr

• Zhang, College of Environmental Science and Engineering, Hunan University, Hunan Province, Changsha 410082, P.R. China; Hunan Environmental Protection Bureau, Hunan Province, Changsha, 410076, P.R. China E-mail: gz@nn.cn
• Zeng, College of Environmental Science and Engineering, Hunan University, Hunan Province, Changsha 410082, P.R. China E-mail: zgming@hnu.cn
• Jiang, College of Environmental Science and Engineering, Hunan University, Hunan Province, Changsha 410082, P.R. China; Hunan Environmental Protection Bureau, Hunan Province, Changsha, 410076, P.R. China E-mail: ymj@nn.cn
• Du, College of Environmental Science and Engineering, Hunan University, Hunan Province, Changsha 410082, P.R. China E-mail: cyd@nn.cn
• Huang, College of Environmental Science and Engineering, Hunan University, Hunan Province, Changsha 410082, P.R. China E-mail: ghh@nn.cn
• Yao, Xiangya Hospital, Central-south University, Hunan Province, Changsha 410008, P.R. China E-mail: jmy@nn.cn
• Zeng, College of Environmental Science and Engineering, Hunan University, Hunan Province, Changsha 410082, P.R. China E-mail: mz@nn.cn
• Zhang, College of Environmental Science and Engineering, Hunan University, Hunan Province, Changsha 410082, P.R. China E-mail: xlz@nn.cn
• Tan, College of Environmental Science and Engineering, Hunan University, Hunan Province, Changsha 410082, P.R. China E-mail: wt@nn.cn