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Silva Fennica 1926-1997
Acta Forestalia Fennica

Articles containing the keyword 'mittausmenetelmät'

Category: Article

article id 5241, category Article
Mikko Raatikainen, Esko Rossi, Irene Vänninen. (1985). Kotipihlajan marjasadon määritysmenetelmät ja marjasato. Silva Fennica vol. 19 no. 2 article id 5241.
English title: Methods of estimation of berry yield and berry yield of rowan tree (Sorbus aucuparia).
Original keywords: mittausmenetelmät; luonnonmarjat; marjasato; pihlaja
English keywords: berry yield; measuring methods; berry crop; rowan; Sorbus aucuparia
Abstract | View details | Full text in PDF | Author Info

Berry yield of rowan tree (Sorbus aucuparia L.) was studied by picking and weighing the berries in a tree, counting the number of clusters by the eye, estimating the number of clusters by samples of 0.5 m2, and by counting the dropped berries. In the last tree methods average weight of berries in a cluster was assessed by weighing a sample of clusters. The size of the tree and the abundance of the berries influenced the choice of method. The first two methods suited for small trees, the third for a tall tree with berries in abundance, and the fourth for those cases where birds had eaten a large portion of the berries.

The berry yields of 88 rowan trees were studied in Central Finland in 1983, a year of exceptionally high berry yield. The yield of berries averaged 23 kg per tree, the number of clusters 1,249 per tree and the number of berries 42,500 per tree.

The PDF includes a summary in English.

  • Raatikainen, E-mail: mr@mm.unknown (email)
  • Rossi, E-mail: er@mm.unknown
  • Vänninen, E-mail: iv@mm.unknown
article id 5156, category Article
Martti Saarilahti. (1982). Tutkaluotaukseen perustuva metsäautotien kantavuuden arvioimismenetelmä. Silva Fennica vol. 16 no. 1 article id 5156.
English title: Predicting the bearing capacity of forest roads using a radar sounding.
Original keywords: metsätiet; mittausmenetelmät; kantavuus; tutka
English keywords: radar; bearing capacity; forest roads; measurement methods
Abstract | View details | Full text in PDF | Author Info

Good correlation between radar reflection depth when using a FM-CW radar during winter and bearing capacity measurements during spring breakup was found. Therefore, it might be possible to evaluate the bearing capacity of forest roads using the radar sounding technique.

The PDF includes a summary in Finnish.

  • Saarilahti, E-mail: ms@mm.unknown (email)
article id 5109, category Article
Esteri Ohenoja, Liisa Pohjola. (1981). Metsämaan lämpöolojen mittaaminen ruokosokerin inversioon perustuvalla menetelmällä. Silva Fennica vol. 15 no. 2 article id 5109.
English title: Sucrose inversion method for measuring the temperature conditions in forest soil.
Original keywords: metsämaa; maaperä; lämpötila; mittausmenetelmät; sakkaroosi-inversiomenetelmä
English keywords: forest soil; soil temperature; measurement methods; Sucrose inversion method
Abstract | View details | Full text in PDF | Author Info

The use and problems of the sucrose inversion method for the study of forest humus and soil are discussed. The method is based on the temperature dependence of sucrose inversion, changes in rotation angle being determined with a circle polarimeter. Average temperatures and thermal sums for forest humus in different forests in Finland were measured, using this method, for a period of ca. 100 days. The results are not considered definitive but are regarded rather as examples. Average temperatures were somewhat higher in the humus of dry and poor heath forests than in that of moist and herb-rich forests, with exceptions that could be explicable by topographic position.

The PDF includes a summary in English.

  • Ohenoja, E-mail: eo@mm.unknown (email)
  • Pohjola, E-mail: lp@mm.unknown
article id 5000, category Article
Hannu Mannerkoski. (1978). Säteilymittarin m/Frankfurt soveltuvuus energiatasemittauksiin. Silva Fennica vol. 12 no. 3 article id 5000.
English title: Use of chemical totalizer of radiation in energy balance measurements.
Original keywords: mittausmenetelmät; haihdunta; energiatase; mittauslaitteet; säteilymittari
English keywords: evaporation; measuring methods; energy balance; measuring instrument; net radiation
Abstract | View details | Full text in PDF | Author Info

The investigation is concerned with testing chemical totalizer of radiation (Frankfurt radiometer) for use in measuring the components of a simple energy balance (latent heat = net radiation – sensible heat) so as to gain an estimate for evaporation. The meter is based on the temperature dependence of the inversion rate of sugar solution. The relationship is exponential. It was found that radiation sums for 2–6-day periods can be reliably determined with this meter when global radiation is below 20 MJ·m-2d-1. Determining sensible heat is noticeably inaccurate, and hence the calculation of evaporation values, too. In comparing evaporation from different types of ground and plant cover one thus has to be content with drawing conclusions on the basis of net radiation values. The totalizer is therefore only suited to describing radiation conditions.

The PDF includes a summary in Finnish.

  • Mannerkoski, E-mail: hm@mm.unknown (email)
article id 4997, category Article
Pasi Jartti. (1978). Tyvilahon määritysmenetelmistä. Silva Fennica vol. 12 no. 2 article id 4997.
English title: Measurement of internal decay in living trees.
Original keywords: mittausmenetelmät; laho; lahon mittaus; ultraäänimittaus; sähkönjohtokyky; inonisoiva säteily
English keywords: decay; measurement methods; ultrasonic methods; electrical resistance measurements; neutron activation
Abstract | View details | Full text in PDF | Author Info

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.

The PDF includes a summary in Finnish.

  • Jartti, E-mail: pj@mm.unknown (email)
article id 4994, category Article
Martti Saarilahti. (1978). Seismisten luotausmenetelmien soveltuvuus metsäautoteiden pohjatutkimuksiin. Silva Fennica vol. 12 no. 2 article id 4994.
English title: Seismic survey methods in forest road construction.
Original keywords: tienrakennus; metsätiet; mittausmenetelmät; seismografi; pohjatutkimus
English keywords: road construction; forest roads; seismographs; sub-surface earth investigations; measurement methods
Abstract | View details | Full text in PDF | Author Info

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.

The PDF includes a summary in English.

  • Saarilahti, E-mail: ms@mm.unknown (email)
article id 4947, category Article
Matti Kärkkäinen. (1976). Kokopuuhakkeen tiheyden mittaaminen. Silva Fennica vol. 10 no. 3 article id 4947.
English title: Measurement of basic density of total tree chips.
Original keywords: tiheys; mittausmenetelmät; hake
English keywords: basic density; wood chips; measuring methods
Abstract | View details | Full text in PDF | Author Info

The paper describes a method for the measurement of basic density of total tree chips. In the method the chips are placed in a container, which is immersed in a cylinder full of water, and the container is weighted at two levels. In the upper part of the cylinder the pressure against the air bubbles is smaller than in the lower level. In this method, the effect of air bubbles in the result can be eliminated. Besides this, due to homogenization of the material to be measured only small number of samples are needed for the estimation of the average basic density.

The PDF includes a summary in English.

  • Kärkkäinen, E-mail: mk@mm.unknown (email)
article id 4808, category Article
Erkki Lähde, Antti Oksanen. (1969). Morfologiset, gravimetriset ja fotometriset tunnukset männyn taimien juuristojen kuvaajina. Silva Fennica vol. 3 no. 4 article id 4808.
English title: Morphological, gravimetric, and photometric characteristics in describing of the root systems of pine transplants.
Original keywords: mänty; Pinus sylvestris; juuristo; taimet; mittausmenetelmät; juurten pinta-ala; morfologia
English keywords: Scots pine; seedlings; root system; surface area of the root system; morphology
Abstract | View details | Full text in PDF | Author Info

This project studied the value of various shoot and root-system characteristics as indicators of plantability of transplants. Correlation and regression analysis was used to compare these characteristics. The study material consisted of two-year Scots pine (Pinus sylvestris L.) transplants that had grown in a plastic greenhouse for the first year and then been transplanted in the open. The seedlings had been transplanted in the field without treatment or with the roots cut to a length of 8 cm. A part was transplanted without treatment into plastic pails. A gravimetric and photometric method was used to obtain a description of the surface area of the root systems.

The results show that the photometric value gives a good picture of the surface area of the root system. The greatest advantage offered by the method is the simplicity and rapidity of measurement. The gravimetric, and especially the titrimetric, measurement takes much more time per plant. Photometric measurement affects plantability little, and measured and planted transplants can be followed up in the field. In gravimetric measurements, it was found that fresh and dry weight of the plants were closely correlated.

Mycorrhizal frequency in the root systems gave a good picture of the surface area of the root system. The number of living roots-tips was also rather closely correlated with the surface area of the root system. The other morphological characteristics failed to serve as a satisfactory index for the surface area of root systems. The one closest correlated was the annual leader growth. The second best was stem diameter; the height of the plant, on the contrary, was rather poorly correlated with the other characteristics.

The PDF includes a summary in English.

  • Lähde, E-mail: el@mm.unknown (email)
  • Oksanen, E-mail: ao@mm.unknown

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