The maturation of <i>Pinus sylvestris</i> seeds in relation to temperature climate in Northern Finland

Henttonen, Helena M.; Kanninen, Markku; Nygren, Markku; Ojansuu, Risto

doi:10.1080/02827588609382415

Cited by 80 publications

(63 citation statements)

References 2 publications

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“…years with abundant seed production, eventuated. The result is in agreement with Henttonen et al (1986), Sirén (1993a) and Kellomäki et al (1997) in that suitable conditions for proper seed years occur only a few times in a given century.…”

Section: Seed Production and Maturationsupporting

confidence: 82%

“…The dominant role of temperature sum for successful reproduction was clearly observed in our study (see also Henttonen et al 1986, Harju et al 1996, Kellomäki et al 1997. After the cold summers in 1998 and 1999, seed maturity and total seed crop remained very low.…”

Section: Seed Production and Maturationsupporting

confidence: 59%

“…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%

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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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Section: Seed Production and Maturationsupporting

confidence: 82%

Section: Seed Production and Maturationsupporting

confidence: 59%

Section: Introductionmentioning

confidence: 99%

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

Juntunen¹,

Neuvonen²

2006

Silva Fenn.

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“…Under such circumstances the replication curves of subfossil tree-ring chronologies are in fact expected to reflect summer temperature variability (Helama et al, 2005. Whereas the temperature control on seed maturation weakens towards the south (Henttonen et al, 1986), past temperature variations can be expected to have only minor influence on our replication records. Nonetheless, the early MCA was characterized by rising temperature levels in most of Europe (Luterbacher et al, 2016) and also in the study region .…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, the pine recruitment depends on seed crop, known to improve with increasing site fertility (Sarvas, 1962). The pine seed crop also depends on summer warmth, especially in subarctic sites (Henttonen et al, 1986). Under such circumstances the replication curves of subfossil tree-ring chronologies are in fact expected to reflect summer temperature variability (Helama et al, 2005.…”

Section: Discussionmentioning

confidence: 99%

Rereading a tree-ring database to illustrate depositional histories of subfossil trees

Helama

Luoto

Nevalainen

et al. 2017

Palaeontologia Electronica

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Extracting long‐period climate fluctuations from tree‐ring chronologies over timescales of centuries to millennia

Helama

Timonen

Lindholm

et al. 2005

Intl Journal of Climatology

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For a long time, tree-rings have been thought of as containing almost no variation at timescales of centuries and millennia, i.e. at low frequencies. Here, we show that this might be an issue of data analysis rather than an actual lack of variability. A data set of subfossil and living Scots pines from northern Fennoscandia was examined by means of their ring-width time series. The premise was that the growth trends of individual time series could be quantitatively determined and decomposed into their different elements. It was shown that not all the components of growth trends were invariant over long periods of time, and that consequently the use of a single-curve standardization (i.e. Regional Curve Standardization, RCS) may result in temporally inflated and deflated indices of ring-widths. Observed non-climatic bias in tree-ring indices was probably due to gradually changing conditions in the pine population of the forest-limit ecotone. Changes in population density seem to have hampered the previous attempts at palaeoclimate reconstruction by masking the actual low-frequency climate variability. A new approach, expected to yield unbiased tree-ring indices, was proposed. The new chronology constructed by this approach showed consistency with multi-centennial variations that are based on independent palaeoclimate evidence.

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The maturation of Pinus sylvestris seeds in relation to temperature climate in Northern Finland

Cited by 80 publications

References 2 publications

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

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

Rereading a tree-ring database to illustrate depositional histories of subfossil trees

Extracting long‐period climate fluctuations from tree‐ring chronologies over timescales of centuries to millennia

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