Current issue: 58(4)

Scopus CiteScore 2023: 3.5
Scopus ranking of open access forestry journals: 17th
PlanS compliant
Select issue
Silva Fennica 1926-1997
1990-1997
1980-1989
1970-1979
1960-1969
Acta Forestalia Fennica
1953-1968
1933-1952
1913-1932

Articles by Tapani Pohjola

Category : Article

article id 5243, category Article
Eljas Pohtila, Tapani Pohjola. (1985). Maan kunnostus männyn viljelyssä Lapissa. Silva Fennica vol. 19 no. 3 article id 5243. https://doi.org/10.14214/sf.a15422
English title: Soil preparation in reforestation of Scots pine in Lapland.
Original keywords: mänty; istutus; kulotus; maanmuokkaus; Lappi; laikutus; lautasauraus; uudistustavat; hajakylvö
English keywords: Pinus sylvestris; soil preparation; Scots pine; planting; regeneration methods; scalping; prescribed burning; disc ploughing; broadcast sowing
Abstract | View details | Full text in PDF | Author Info

The study deals with the interaction of various soil preparation and reforestation methods. The most favourable time of the year for broadcast sowing and the effect of stabilization after soil preparation on restocking were studied as special problems.

Prescribed burning, scalping and disc ploughing made a better combination with sowing than planting, and ploughing better combination with planting than sowing. The longer the period was between sowing and germination the fewer seedlings emerged. The best stocking was clearly resulted with sowing in June. Stabilization of soil after preparation had a negative effect on reforestation results.

The PDF includes a summary in English.

  • Pohtila, E-mail: ep@mm.unknown (email)
  • Pohjola, E-mail: tp@mm.unknown
article id 5235, category Article
Pekka Kilkki, Tapani Pohjola, Eljas Pohtila. (1985). Puiden ryhmittäisyyden huomioonottaminen harvennusmalleissa. Silva Fennica vol. 19 no. 2 article id 5235. https://doi.org/10.14214/sf.a15414
English title: Use of the spatial distribution of trees in thinning models.
Original keywords: harvennus; harvennusmallit; mallinnus; puiden ryhmittäisyys
English keywords: thinnings; spatial distribution; relascope plots; thinning models; basal area classes
Abstract | View details | Full text in PDF | Author Info

Thinning models are generally based on the density of the stand measured by the average basal area per hectare, for instance. These models are handicapped by the uneven structure of the stands. In uneven stands the averages are inadequate indicators for the need and amount of thinnings.

Small relascope plots were tested in the measurement of the spatial distribution of trees and in the determination of the need and amount of thinnings. The thinning quantity was determined as the difference between the actual distribution of the relascope plots into basal area classes and the ideal distribution after thinning. Sequential sampling was used in the derivation of the decision equations. A respective BASIC-program for a programmable pocket calculator is given.

The PDF includes a summary in English.

  • Kilkki, E-mail: pk@mm.unknown (email)
  • Pohjola, E-mail: tp@mm.unknown
  • Pohtila, E-mail: ep@mm.unknown
article id 5188, category Article
Eljas Pohtila, Tapani Pohjola. (1983). Vuosina 1970-1972 Lappiin perustetun aurattujen alueiden viljelykokeen tulokset. Silva Fennica vol. 17 no. 3 article id 5188. https://doi.org/10.14214/sf.a15171
English title: Results from the reforestation experiment on ploughed sites established in Finnish Lapland during 1970–1972.
Original keywords: kuusi; kylvö; mänty; istutus; maanmuokkaus; Lappi; uudistaminen; kuolleisuus; rauduskoivu; siperianlehtikuusi; auraus
English keywords: Pinus sylvestris; Norway spruce; Betula pendula; Picea abies; regeneration; soil preparation; Scots pine; silver birch; planting; ploughing; Lapland; mortality; Siberian larch; sowing; Larix sibirica
Abstract | View details | Full text in PDF | Author Info

The objective of the study was to compare different reforestation methods on ploughed areas in Finnish Lapland. Four species were compared: Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.), silver birch (Betula pendula Roth) and Siberian larch (Larix sibirica Ledeb.). The experiments were established in different parts of Lapland on different types of sites in 1970–72.

In Scots pine there was a difference of 15 percentage points in survival of seedlings between the best and worst methods of regeneration. Containerized seedlings and paper pot seedlings had the best survival rates. In Norway spruce the respective difference between sowing and planting was about 20 percentage points. In favour of planting. The survival rate can be increased by about 20 percentage points by selecting the right tree species. The average height varied from 25 cm (the sowed Norway spruce) to 179 cm (the planted silver birch) after 10 growing seasons. The birch was planted at the most fertile sites only. The longer time passed from the afforestation the clearer was the effect of the local growing conditions on the development of the seedlings. The elevation of the site was one factor seemed to influence the success of the seedlings.

The PDF includes a summary in English.

  • Pohtila, E-mail: ep@mm.unknown (email)
  • Pohjola, E-mail: tp@mm.unknown

Category : Article

article id 7628, category Article
Eljas Pohtila, Tapani Pohjola. (1983). Lehvästöruiskutuksen ajoitus kasvukauden aikana. Acta Forestalia Fennica no. 181 article id 7628. https://doi.org/10.14214/aff.7628
English title: The timing of foliage spraying during the growing season.
Original keywords: mänty; herbisidit; taimikonhoito; lehdistöruiskutus; havupuutaimikot
English keywords: Pinus sylvestris; Scots pine; herbicides; seedling stands; MCPA; spraying of foliage; clearing of seedling stands; Roundup; DM; softwood seedling stand; hardwood sprouts
Abstract | View details | Full text in PDF | Author Info

An attempt was made in the study to determine the annual periods available for foliage spraying when cleaning Scots pine (Pinus sylvestris L.) dominated seedling stands. The study was made in nine experimental fields which were established in different parts of Finland. The spraying was applied throughout the growing season by DM, MCPA and Roundup. The results were inventoried one year after the treatments.

The results showed that there were big differences both in the destruction of hardwood sprouts and in the survival of pine seedlings due to the time period of the spraying. Threshold points were observed in the range of effect of DM and MCPA. By means of these it is possible to time the spraying treatments in such a way that there remains only slight damage to pine, but hardwood sprouts are destroyed totally. The results varied with Roundup so much, among other things due to rain, that such threshold points could not be determined. This preparation both had a milder effect on the hardwood seedlings and caused slighter damage to pine than the other preparations.

In Sodankylä in Northern Finland, the pines attained a good resistance to arboricides when the efficient temperature sum of the growing season was 550, but in Punkaharju in Central Finland only when it was 850. The seed provenance of the seedlings had an effect on the resistance. The threshold temperature sums of resistance in pine were on the average 70–74% from the long-term average number of degree days at the origin of the seed. The effect on the hardwood trees grew weaker as the long-term average was filled. Resistance of pine followed with a specific lag the lignification of the shoot and the ceasing of the growth of the needles.

The PDF includes a summary in English.

  • Pohtila, E-mail: ep@mm.unknown (email)
  • Pohjola, E-mail: tp@mm.unknown

Register
Click this link to register to Silva Fennica.
Log in
If you are a registered user, log in to save your selected articles for later access.
Contents alert
Sign up to receive alerts of new content
Your selected articles