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Silva Fennica vol. 18 no. 2 | 1984

Category : Article

article id 5213, category Article
Bo Långström. (1984). Windthrown Scots pines as brood material for Tomicus piniperda and T. minor. Silva Fennica vol. 18 no. 2 article id 5213. https://doi.org/10.14214/sf.a15392
Keywords: Pinus sylvestris; bark beetles; Scots pine; wind damages; breeding; Sweden; Tomicus piniperda; Tomicus minor; insect damage; egg galleries
Abstract | View details | Full text in PDF | Author Info

In the 1980 and 1981, windthrown and felled Scots pine (Pinus sylvestris L.) were examined at 8 localities in Sweden. The number and length of egg galleries as well as the number of exit holes of Tomicus piniperda (L.) and T. minor (Hart.) were recorded on sample sections (30 m in length) distributed at 3 m intervals on the 37 fallen pine stems, which were successfully colonized by the beetles. In addition, 78 uprooted pines were surveyed in 6 localities. Most trees were attacked by T. piniperda, but only a few by T. minor. Successful colonization often resulted in the production of several thousand beetles per tree, the maximum being approximately 1,800. The attack density of T. piniperda seldom exceeded 200 egg galleries/m3 bark area, and the brood production usually remained below 1,000 beetles/m3. Much higher figures were obtained or T. minor. In T. piniperda, the rate of reproduction (i.e. the number of exit holes /egg gallery) decreased rapidly with increasing attack density, whereas T. minor seemed to be less sensitive to intraspecific competition.

The PDF includes a summary in Finnish.

  • Långström, E-mail: bl@mm.unknown (email)
article id 5212, category Article
Heikki Kurimo. (1984). Simultaneous groundwater table fluctuation in different parts of virgin pine mires. Silva Fennica vol. 18 no. 2 article id 5212. https://doi.org/10.14214/sf.a15391
Keywords: peatlands; hydrology; groundwater table; pine bogs; groundwater table fluctuations; pine swamp
Abstract | View details | Full text in PDF | Author Info

The study discusses the amplitude of the simultaneous groundwater table fluctuations in different parts of pine mires, and factors influencing it. The assumption generally used in hydrological computations that the simultaneous vertical fluctuation in the groundwater table in different parts of mires are equal does not hold good in detail. Numerous cases were detected where the fluctuation at one place did not correspond to that at another site to a statistically significant degree. The main reason for the unequal fluctuation at the different sites seems to be the difference in the microtopography and in the hydraulic conductivity between the sites.

The PDF includes a summary in Finnish.

  • Kurimo, E-mail: hk@mm.unknown (email)
article id 5211, category Article
Risto Jalkanen, Esko Jalkanen, Jyrki Jalkanen, Marja Jalkanen. (1984). Maanpinnan rikkomisen 10-vuotisvaikutus korvasienisatoon. Silva Fennica vol. 18 no. 2 article id 5211. https://doi.org/10.14214/sf.a15390
English title: Ten-year effects of breaking the soil surface on the yield of Gyromitra esculenta.
Original keywords: korvasieni; sienisato; maankäsittely; kivennäismaa
English keywords: yield; soil preparation; mushrooms; Gyromitra esculenta; false morel; fruit bodies
Abstract | View details | Full text in PDF | Author Info

The yield of Gyromitra esculenta (Pers.) Fr. was surveyed during 1973–82 in a Norway spruce (Picea abies (L.) H. Karst.) dominated stand in Central Finland. The soil surface was treated with different light methods, mainly removing the vegetation and humus layer.

It was shown that is possible to improve the natural yield of G. esculenta by breaking the soil surface. In the 286 m2 of treated the yield could be improved over 50 fold compared to the control area. In the untreated control area, the yield per hectare was 0.98 kg/yr. In treated plots the yield was 52.4 kg/yr (in the best year 191 kg/ha/yr). Fruit bodies of G. esculenta were found in treated plots every year after the soil treatment. The yield was at its best in the two first years declining later to the level of 10–20% of the first year’s yield.

The best natural yield was reached in the last year. The previous year’s precipitation was an important factor influencing the yield of the mushroom.

The PDF includes a summary in English.

  • Jalkanen, E-mail: rj@mm.unknown (email)
  • Jalkanen, E-mail: ej@mm.unknown
  • Jalkanen, E-mail: jj@mm.unknown
  • Jalkanen, E-mail: mj@mm.unknown
article id 5210, category Article
Heikki Smolander, Juha Lappi. (1984). The interactive effect of water stress and temperature on the CO2 response of photosynthesis in Salix. Silva Fennica vol. 18 no. 2 article id 5210. https://doi.org/10.14214/sf.a15389
Keywords: drought stress; willow; temperature; photosynthetic capacity; Salix sp.; Salix sp. cv. Aquatica; CO2 conductance
Abstract | View details | Full text in PDF | Author Info

The interactive effects of water stress and temperature on the CO2 response of photosynthesis was studied in Salix sp. cv. Aquatica using the closed IRGA system. A semi-empirical model was used to describe the CO2 response of photosynthesis. The interactive effect of water stress and temperature was divided into two components: the change in CO2 conductance and the change in the photosynthetic capacity. The CO2 conductance was not dependent on the temperature when the willow plant was well watered, but during water stress it decreased as the temperature increased. The photosynthetic capacity of the willow plant increased along with an increase in temperature when well-watered, but during water stress temperature had quite opposite effect.

The PDF includes a summary in Finnish.

  • Smolander, E-mail: hs@mm.unknown (email)
  • Lappi, E-mail: jl@mm.unknown
article id 5209, category Article
Jussi Kuusipalo. (1984). Diversity pattern of the forest vegetation in relation to some site characteristics. Silva Fennica vol. 18 no. 2 article id 5209. https://doi.org/10.14214/sf.a15388
Keywords: species richness; species diversity; ground vegetation; soil; fertility; site characteristics; calcium content
Abstract | View details | Full text in PDF | Author Info

A field data set representing boreal forest-floor vegetation in Southern Finland was analysed using a simultaneous equation model. Some physical and chemical characteristics of the soil and some structural characteristics of the tree stand were treated as predictors in such a way that the tree stand factor was specified to be dependent on the soil variables. Alpha diversity, measured as the total number of species per plot, was treated as a criterion variable.

The model explains 60% of variance in the alpha diversity indicating markedly strong relationships with the site characteristics. Alpha diversity appears to increase with increases in site fertility characteristics. On the other hand, measured characteristics of the tree stand indicate no significant independent effects on the alpha diversity.

The PDF includes a summary in Finnish.

  • Kuusipalo, E-mail: jk@mm.unknown (email)
article id 5208, category Article
Matti Kärkkäinen. (1984). Effect of tree social status on basic density of Norway spruce. Silva Fennica vol. 18 no. 2 article id 5208. https://doi.org/10.14214/sf.a15387
Keywords: Norway spruce; Picea abies; growth rate; canopy layer; basic density
Abstract | View details | Full text in PDF | Author Info

The effect of growth rate on wood basic density in even-age Norway spruce (Picea abies (L.) H. Karst.) plantations was studied on the basis of samples collected from 53 stands; 30 trees were sampled in each stand. The prediction of basic density with the help of growth rate and some other tree characteristics could be improved if the social status of the tree was taken into account. Within a stand, the smaller trees had a lower density, while taller trees had a higher density than they should have had on the basis of growth rate alone.

The PDF includes a summary in Finnish.

  • Kärkkäinen, E-mail: mk@mm.unknown (email)
article id 5207, category Article
Seppo Kellomäki. (1984). Havaintoja puuston kasvatustiheyden vaikutuksesta mäntyjen oksikkuuteen. Silva Fennica vol. 18 no. 2 article id 5207. https://doi.org/10.14214/sf.a15386
English title: Observations on the influence of stand density on branchiness of young Scots pines.
Original keywords: mänty; oksikkuus; oksan läpimitta; metsikön tiheys; kasvatustiheys; kuolleet oksat; elävät oksat
English keywords: Pinus sylvestris; Scots pine; stand density; branchiness; branch diameter
Abstract | View details | Full text in PDF | Author Info

The study based on young Scots pine (Pinus sylvestris L.) of varying density showed that number of living branches per whorl and total number of living branches per tree were negatively correlated with stand density. On the contrary, the number of dead branches increased with increasing stand density. The diameter of living and dead branches decreased with increasing stand density. Consequently, the branchiness, i.e. the share of the branch cross-sectional area from the surface area of the stem, decreased in dense stands compared with the thin stands. At the densest stands the branchiness, however, levelled of indicating a greater decrease of the radial growth at stems than at branches. The 2/3 power law described relatively well the relationship between stand density and mean squared branch diameter of living branches.

The PDF includes a summary in English.

  • Kellomäki, E-mail: sk@mm.unknown (email)

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