Climatic fluctuations and forestry in Lapland

Pohtila, Eljas

doi:10.1111/j.1600-0587.1980.tb00713.x

Cited by 20 publications

(14 citation statements)

References 17 publications

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“…Furthermore, the temperature sum during the growing season needed for 50% ripening of the seed crop must be at least 845-890 d.d. (Pohtila 1980, Henttonen et al 1986). However, some incompletely matured seed is produced every year even along the timberline (Heikinheimo 1932(Heikinheimo , 1937.…”

Section: Discussionmentioning

confidence: 99%

“…Generally, 50-150 seed trees are retained per hectare in Northern Finland, but in many cases 20-50 trees per hectare seems to be enough on dry and dryish upland forest sites (Hagner 1962, Kubin 2000. Large variation in viable seed crops between years and between stands is a characteristic of Scots pine in the north (Heikinheimo 1932, 1937, Sarvas 1937, Pohtila 1980, Henttonen et al 1986). In addition, there is a large number of ecological factors that influence the success of seedling establishment.…”

Section: Introductionmentioning

confidence: 99%

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Establishment and height development of harvested and naturally regenerated Scots pine near the timberline in North-East Finnish Lapland

Hallikainen

Hyppönen²,

Hyvönen³

et al. 2007

Silva Fenn.

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Researchers and professionals in practical forestry have faced problems concerning the regeneration success of Scots pine in natural regeneration near the timberline in North-East Lapland. The aim of the study was to analyze the seedling establishment and seedling height development of Scots pine in seed-tree stands in the area. The average number of living pine seedlings in the study stands was about 1000 ha -1 , but there was considerable variation between the stands. The seedling density was modelled using a multinomial logistic regression with a random factor. Forest site type and the time since seed-tree cutting were the most significant explanatory variables in the model. The probability of reaching the acceptable seedling density was higher on dry site types than on the more fertile ones. The probability increased with the time elapsed since the regeneration activities. Effective temperature sum and the number of intermediate pines also positively affected the probability, but the presence of residual trees negatively. On northern and eastern slopes the probability was lower than on southern and western ones. Seedling height was modelled using a linear mixed model. The age of a dominant seedling was the most positively effective explanatory variable in the height development model. Other positively affecting significant predictors were time since seed-tree cutting, number of intermediate birches, and distance between a seedling and the nearest seed tree. Degree of paludification had a negative effect. The study suggests that the regeneration of Scots pine in North-East Lapland is a relatively slow process.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Establishment and height development of harvested and naturally regenerated Scots pine near the timberline in North-East Finnish Lapland

Hallikainen

Hyppönen²,

Hyvönen³

et al. 2007

Silva Fenn.

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“…The two years 1901 and 1902 displayed exceptionallygreat contrasts concerning summer temperatures (Alexandersson, 1989) and are reported to have affected annual ring width markedly (cf. Pohtila, 1980).…”

Section: Tree Samplingmentioning

confidence: 99%

Response of old‐growth montane Picea abies (L.) Karst. forest to climatic variability in northern Sweden

1991

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SUMMARYRepeat photography and tree ring analyses were used to investigate structural change, 1938-88, of an old growth and high elevation Picea abies (L.) Karst, forest in northern Sweden. The forest, initially moribund, senescent and Top-broken, regenerated broken tops and apparently gained in vigour. Up to the 1930s this progressive change was pre-dated by an increase of annual increment growth, which subsequently declined until the 1980s, The tree-ring response concurs with the genera] course of summer temperature while canopy processes appear to lag behind. The study stresses the importance of phenotypic pJasticify for long-rerm behaviour of marginal spruce forest. It is also evident that canopy development is not a fully predictable ageing process, but to some extent dependent on climatic variability.

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“…The temperature sum required to result in 50% of anatomically mature seeds varies according to different studies within the range of 790-950 degree days (d.d. ; above the +5 °C threshold) for Scots pine (Pohtila 1980, Schildt 1985, Henttonen et al 1986, Kortesharju 1991, Harju et al 1996, Almqvist et al 1998, and about 700-800 d.d. for Norway spruce (Almqvist et al 1998).…”

Section: Introductionmentioning

confidence: 99%

Natural regeneration of Scots pine and Norway spruce close to the timberline in northern Finland

Juntunen¹,

Neuvonen²

2006

Silva Fenn.

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Two different datasets were analyzed in order to clarify the factors that affect regeneration success of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) in the climatically extreme areas in northern Finland. First, pine seed maturity and the number of cones in the trees were investigated at five pairs of study sites during the period 1997-2003. Secondly, the rate of seedling establishment and seedling survival of Scots pine and Norway spruce were monitored and compared among three different timberline zones (forest zone, timberline, tree line) in 13 localities during the period 1983-1999. The first study showed that both cone production (bud formation) and seed maturity may be limiting factors for successful reproduction in the climatically marginal habitats. Seed maturity correlated well with the temperature sum of the summer, but variation in the number of cones had a periodic component rather than strictly following the temperature sum of the summer of bud formation. Monitoring surveys since 1983 showed that pine and spruce regenerated more or less regularly in all the zones during 1983-1999. However, seedling mortality of pines was much higher compared to spruce. In general, initially small sized seedlings showed higher mortality compared with larger ones. The results suggest that besides restrictions in reproduction, stand dynamics in the timberline habitats are strongly controlled by seedling mortality due to a variety of causes.

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Climatic fluctuations and forestry in Lapland

Cited by 20 publications

References 17 publications

Establishment and height development of harvested and naturally regenerated Scots pine near the timberline in North-East Finnish Lapland

Establishment and height development of harvested and naturally regenerated Scots pine near the timberline in North-East Finnish Lapland

Response of old‐growth montane Picea abies (L.) Karst. forest to climatic variability in northern Sweden

Natural regeneration of Scots pine and Norway spruce close to the timberline in northern Finland

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