Silva Fennica vol. 10 no. 2 | 1976
Category : Article
In the article some aspects concerning the measurement of environmental factors are discussed. Special attention is given to the following questions: The correct way of determining the active surface in a forest ecosystem, the time factor in measurement processes, and the mutual correlative relationships between the environmental factors. Analysis of the data is also taken into consideration.
The PDF includes a summary in English.
-
Leikola,
E-mail:
ml@mm.unknown
The article is a summary of a long-term research programme which has been prepared at the Finnish Forest Research Institute. The objective of the programme was to define and subdivide the field of multiple use research to be done at the institute, and so improve both the research planning and the coordination of the work in this field between the different research departments.
The PDF includes a summary in English.
-
Jaatinen,
E-mail:
ej@mm.unknown
- Saastamoinen, E-mail: os@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 activation of CO2 exchange was monitored in two Scots pine (Pinus sylvestris L.) seedlings transferred from the field to the laboratory in December. Gas exchange was monitored by an URAS I infrared gas analyser in a so-called open IRGA-system with trap type chambers. Transpiration was also measured at the same time by weighing the potted seedlings twice a day. The measuring period lasted eleven days. During the period, the level of both transpiration and net photosynthesis increased about ten times. Furthermore, it was found that the level of photosynthesis at high temperatures was relatively lower at the beginning than at the end of the measuring period.
The PDF includes a summary in English.
-
Pelkonen,
E-mail:
pp@mm.unknown
- Smolander, E-mail: hs@mm.unknown
This paper examines the changes in forest ownership and the farm properties for sale from a business economic standpoint. The changes in forest ownership are examined on the basis of statistics and literature. The empirical data both for farms for sale and farms sold are based on the purchases made by the National Board of Forestry in 1972.
There are a number of ownership groups actively buying and selling forest land, thus giving alternatives for ownership changes. The National Board of Forestry has been active in the market since 1960. For instance, in 1972 it purchased 60% of the forest estates it was offered. Of the forest area put up for sale, 75% originated from private individuals, and 20% from inheritance sales.
The PDF includes a summary in English.
-
Hannelius,
E-mail:
sh@mm.unknown
In this study the width and height of 1,588 uniseriate and 454 fusiform rays were measured from tangential sections of four Scots pine (Pinus sylvestris L.) trunks. The samples represented various height levels and distances from the pith. The average width of the uniseriate rays was 19.7 μm and that of the fusiform rays, 51.9 μm. The average height of the uniseriate rays was 215.7 μm and that of the fusiform rays 406.2 μm. Due to this difference in height, it may be possible to develop an automatic system for distinguishing between uniseriate end fusiform rays on the basis of their height.
The PDF includes a summary in English.
-
Kärkkäinen,
E-mail:
mk@mm.unknown
Light intensity inside the canopy varies considerably both in space and time. A new apparatus was developed which is disturbed as little as possible by the above-mentioned variation. The construction is based on the linear relationships between light intensity (measured using silicon diodes) and photosynthesis. This procedure permits linear operations (summing and integration) to be carried out on the output of the diodes without any loss of accuracy. There are five diodes in each assimilation chamber. A model, in which the independent variables include ligth, measured with the present equipment, and temperature, fits the photosynthetic rates well even inside the canopy.
The PDF includes a summary in Finnish.
-
Hari,
E-mail:
ph@mm.unknown
- Huhtamaa, E-mail: mh@mm.unknown
- Pelkonen, E-mail: pp@mm.unknown
- Pohjonen, E-mail: vp@mm.unknown
- Salminen, E-mail: rs@mm.unknown
The paper deals mainly with the effects of jolting of forest tractors and processors on the health and working capacity of the driver. The literature surveyed presents especially the following points of interest: Jolting of the machine may hamper the focusing of the eyes and mastery of the controls. Long-term exposure to jolting may result in reduced sympathetic nervous activity at rest, and may impair an already existing back problem. Workers exposed to vibration, get more frequently gastric changes and changes in reproductive functions than usual. Jolting, as also the other negative physical factors of working environment, must be minimized as early as possible during the design of the machines.
The PDF includes a summary in English.
-
Wuolijoki,
E-mail:
ew@mm.unknown