Articles containing the keyword 'seasonal variations'

The purpose of this paper is 1) to establish the possible seasonal variation of the different phases of work in the sawmill industry in Finland, 2) to study the internal and external factors influencing the seasonal character of the sawmill industry, 3) to study ha time lags between the work phases of the sawmill industry, 4) to analyse the seasonal nature of the industry’s money transactions, and 5) to give information concerning the factors influencing employment. The investigation is based on questionnaires of a random sample of sawmills concerning the time period of 1958-1960. This paper concentrates on the methods of the study, the results are reported in a separate paper in the Acta Forestalia Fennica issue 75 vol 1.

It was concluded that if seasonal variation in the sawmill industry is to be analysed on the scale it has been in the present work, sampling is the cheapest and most practicable method of collecting the material. If seasonal fluctuation of the industry is to be calculated by size classes, the sample must be allocated into strata by measuring the heterogeneity of the classes with a parameter illustrating seasonal variation. It might be useful to apply these parameters already when the total size of the sample is determined. For the smallest sawmills, for which practically all data have to be collected from primary documents, the most practical method is perhaps to send collectors to the spots. To the larger sawmills the questionnaire can perhaps be sent by mail. A moving index should be obtained for calculation of a seasonal index, but this demands long time series. The collection of the data is described in detail.

The PDF includes a summary in English.

• Ervasti, E-mail: se@mm.unknown

The purpose of the investigation was to examine the seasonal pattern in Finnish export shipments and export sales of sawn softwood in 1927-1953. Statistics concerning shipments have been obtained from the Board of Customs, and material relating to sales has been provided by the Finnish Sawmill Owner’s Association (now Finnish Sawmills Association). On the basis of original monthly statistics, 13-month moving averages were computed. Finally, a seasonal index was calculated.

According to the results, the export shipments have a fairly apparent seasonal pattern with very low figures from January to April, a peak from June to August, and thereafter a gradual decline up to the end of the year. There are also considerable variations from year to year but in general the exports follow this rhythm. In contrast to export shipments the seasonal pattern of export sales is characterised by significant irregularity. Market developments and speculation play a far greater role than the seasonal factors. Indeed, a seasonal character in export sales can scarcely be discerned.

The Acta Forestalia Fennica issue 61 was published in honour of professor Eino Saari’s 60th birthday.

The PDF includes a summary in English.

• Holopainen, E-mail: vh@mm.unknown

The present study deals with the ground water table in the soil of drained peatlands and with the technique used for its determination. The terms depth and height of the ground water table are defined in the paper. Because of the fact that the surface of peatlands moves under the influence of a great number of different factors, the depth of the ground water table and the height of the ground water table are not parallel concepts. The present paper concentrates on the depth of the ground water table.

Observations on the depth of the ground water table in the sample plots in 1966-67 and 1968-69 show that the maximum of the late summer usually exceeds that of the early spring, and that the minimum occurring in the period of snow melting is more clearly discernible than that of the fall. Great differences occur in the depths of the ground water table in different sample plots. These differences are due to the specific properties of the peat of different peat layers, which are expressed in terms of the ground water coefficient. The duration of the depth of the ground water table proved to be a useful way to express the long-term changes.

Four kinds of short-term fluctuations in the ground water table were observed: a) the ground water table falls during the night hours, although the rate of falling is slower than in daytime, b) the ground water table rests at the same depth during the night, whereas during the day it clearly falls, c) the descent of the ground water table is similar throughout the whole 24-hour period, d) the ground water table rises during the night hours and falls in daytime. Occurrence of these types are discussed. Typical short-term fluctuation is the fall due to evaporation in the daytime.

The third part of the paper discusses the techniques used to measure the changes in ground water table.

The PDF includes a summary in English.

• Heikurainen, E-mail: lh@mm.unknown