Silva Fennica 1926-1997 vol. 12 no. 2 | 1978
Category: Article
This paper describes the principals of the awards given by the Finnish Society of Forest Science, and lists the different acknowledgements conferred by the society.
The physical methods currently available for measuring the internal decay of living trees is examined in this study. Although this is mainly a review, it can be concluded that some measurements shed more light on the problem. Examination of ultrasonic methods reveals that the coupling of ultrasonic energy from the transducer to the tree is not efficient. Both impulse and ultrasonic testing work best with decayed and hollow trees. The electrical resistance measurements of stumps gave resistance values for sound wood 300–400 kΩ, for decayed and discoloured wood about 12 kΩ and for cambium about 12 kΩ. The neutron activation gives good results, and in particular it reveals nicely the increasing concentration of potassium in decayed wood. The internal decay of living trees was not examined.
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A study on the lingonberry (Vaccinium vitis-idaea L.) was made in 1976. The berry yield was studied by picking along 17 lines, each 1,000 m long. The picking and use of lingonberry were studied by an inquiry addressed to the families engaged in such an occupation. The marketing of the lingonberry was investigated by interviewing purchasers, and by means of reports based on purchasing certificates of the purchacers. The total yield of lingonberry in Pihtipudas was 1.2 million kg or 18 kg per hectare of productive forest. Only 7% of the total yield of the berry was picked. 47% of the lingonberries picked were used by the families themselves, 48% were sold and 5% were used for other purposes. The families who sold lingonberries earned, on an average, 350 Fmk.
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A simultaneous equation model to determine taper curve for Scots pine is presented. The diameters at relative heights are endogenous variables and height an exogenous variable. Any equations may be substituted by the measured value of diameter. Solution of the system of equations yields 11 diameters at relative heights. Intermediate values are obtained by interpolation. Interpolation allows the use of diameters measured at absolute heights, too.
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The aim of the study was to find out the technical and economical applicability of seismic survey methods of sub-surface earth investigations in forest road planning. Two seismographs, SOIL-TEST MD 1 and BISON 1570, were tested in studyin 31 cuts and 3 gravel areas. The devices proved to be usable in field conditions. Sounding one spot costs about 75 Fmk and methods’ rentability is greatly based on the ration between expected and unexpected events, which depends on the areal geology. It is profitable to purchase the device especially if digging out of unexpected bedrock causes high costs.
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The article describes the series of events and the decisions which in the years 1908–1911 resulted in transfer of the field courses in silviculture of the University of Helsinki from the old training region of the Evo Forest Institute in Central Finland, where higher education in forestry had been given since 1860. The establishment of the new training region of Siikakangas and the building of the new Forest Training Station Hyytiälä in 1911–1912 are also described, as well as the arguments behind these decisions and the motives of the forestry faculty of the University of Helsinki.
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Monoterpene hydrocarbon contents of needles in Scots pine (Pinus sylvestris L.) plants both damaged and untouched by the moose (Alces alces L.) were compared in the study. The material was collected in an 8-year-old plantation in Central Finland. Needle samples were taken from the topmost shoot whorl of the plants in the middle of April, 1976. Only minor differences were found between the plant groups. Thus, terpenes in pine presumably play no important role in the browsing preference by moose.
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A theoretical nomogram was made for estimating the costs of fully mechanized thinning and the driving speed of the machine. Based on this nomogram and the previous studies three harvesting methods were compared; systematic fully mechanized harvesting, selective fully mechanized harvesting, and manual felling combined with whole-tree chipping.
The third method was cheaper than the fully mechanized methods in a pole-stage stand. The choice of the most advantageous chipping station depended on conditions, but the smaller tree size and possibly the reduced damage on the remaining stand favour chipping on the strip road rather than chipping on the intermediate landing or at the mill.
Mechanized systematic thinning was the cheapest method for harvesting in the sapling stand. The required driving speed were so low that ergonomic factors should not hinder its use. Factors related to the future production of the stand do, however, limit its use. Mechanized selective thinning does not seem to be an economic method for harvesting in a sapling or pole-stage stand.
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The paper deals with the nutrient status of surface peat layer from virgin sedge-pine swamps and its relationship to peatland types. When the nutrients are expressed in mg/100 g peat, only easily extractable Ca and Mg correspond to the productivity status of the peatland type. N, P, and K levels in the herb rich sedge-pine swamp are generally lower than in the small sedge-pine swamps, which are the least productive ones. The differences between the site types in all the five nutrients become much clearer when the results are expressed in kg/ha. P, K, and Ca are significantly different between the site types, and correspond to the productivity of the site type. For N and Mg the same tendency can be seen. The organically bound nutrients N, and to a lesser extent, P appear to comply with the hypothesis of an increase in nutrient availability in Southern Finland.
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