Predicting germination capacity of <i>Pinus sylvestris</i> and <i>Picea abies</i> seeds using temperature data from weather stations

Almqvist, Curt; Bergsten, Urban; Bondesson, Lennart; Eriksson, Urban

doi:10.1139/x98-139

Cited by 23 publications

(17 citation statements)

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“…The temperature sum required for 50% maturation of the pine seed crop varies in different studies from 800 to 890 d.d. (Henttonen et al, 1986;Harju et al, 1996;Almqvist et al, 1998), and it is about 100 d.d. lower for spruce (Almqvist et al, 1998).…”

Section: Changes In Seedling Densitymentioning

confidence: 98%

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Potential for Timberline Advance in Northern Finland, as Revealed by Monitoring during 1983-99

Juntunen¹,

Neuvonen²,

Norokorpi³

et al. 2002

ARCTIC

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ABSTRACT. Seedling density, tree density and basal area of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst) were monitored and compared in the timberline areas of northern Finland during the period 1983-99. Rows of 9-12 circular plots were established at 13 localities in four regions: pine-dominated northern and southern regions and spruce-dominated western and eastern regions. Temporal changes were monitored in three altitudinal zones: in the forest, at the coniferous timberline (where forest canopy closure ceases), and at the tree line (where coniferous trees higher than 2 m cease). Pine seedling densities decreased abruptly in the southern region, especially at the timberline, but increased slightly in the northern region. The zone · region · change interaction was significant. The change in spruce seedling densities was small in the forest and timberline zones, but the densities more than doubled at the tree line. Tree density and basal area increased in all the zones and regions. New regeneration and tree establishment during the study period indicate a potential for the tree line to advance. However, there was great heterogeneity in regeneration and seedling establishment among the localities.Key words: climate change, climatic variation, regeneration, Pinus sylvestris, Picea abies, seedling density, tree density, basal area, timberline, tree line RÉSUMÉ. La densité des semis, la densité des arbres et la surface terrière du pin sylvestre (Pinus sylvestris L.) et de l'épinette de Norvège (Picea abies [L.] Karst) ont fait l'objet d'une étude et d'une comparaison dans des zones situées à la limite de la forêt de la Finlande septentrionale durant la période allant de 1983 à 1999. Des rangées de 9 à 12 parcelles circulaires ont été créées à 13 sites répartis dans 4 zones: les régions septentrionale et méridionale où dominait le pin sylvestre, et les régions occidentale et orientale où dominait l'épinette de Norvège. On a mesuré les changements temporels dans 3 zones d'altitude différente: dans la forêt, à la limite de la forêt de conifères (là où cesse la fermeture du couvert forestier), et à la limite des arbres (là où cessent les conifères de plus de 2 m de haut). La densité de semis du pin sylvestre diminuait brusquement dans la région méridionale, en particulier à la limite de la forêt, mais elle augmentait légèrement dans la région septentrionale. L'interaction zone-région-changement était significative. Le changement dans la densité de semis de l'épinette de Norvège était faible dans la forêt ellemême et dans les zones de la limite de la forêt, mais la densité avait plus que doublé à la limite des arbres. La densité des arbres et la surface terrière augmentaient dans toutes les zones et les régions. Une nouvelle régénération et un nouvel établissement d'arbres durant la période d'étude révèlent que la limite des arbres pourrait progresser. Il y avait toutefois une grande hétérogénéité dans la régénération et dans l'établissement des semis parmi les divers sites.

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Section: Changes In Seedling Densitymentioning

confidence: 98%

“…The second inventory was made on the same plots in 1994, and the third in 1999. We mapped the distance and direction from the central point of all the trees (height ≥ 2 m) and seedlings (< 2 m) within each monitoring plot and measured the diameter of the (Henttonen et al, 1986;Harju et al, 1996;Almqvist et al, 1998).…”

Section: Sampling Design and Measurementsmentioning

confidence: 99%

Potential for Timberline Advance in Northern Finland, as Revealed by Monitoring during 1983-99

Juntunen¹,

Neuvonen²,

Norokorpi³

et al. 2002

ARCTIC

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“…Differences in linear growth rates for Scots pine compared with exponential growth rates for the initial stages of oak species [35], cause a clear initial competitive disadvantage for pine regeneration. Other factors, such as the quantity of seeds produced, depredation by herbivores, allelopathic effects among species or damage by cattle, have been suggested as explanatory variables for the same process [2,19,23]. Similarly, modifying the germination capacity of different species competing in a specific area may be one of the most significant factors affecting the competitive potential of the species involved.…”

Section: R Nuñez Et Almentioning

confidence: 99%

Predicting the probability of seed germination in Pinus sylvestris L. and four competitor shrub species after fire

2003

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-Knowledge of the regeneration of competing shrub species after wildfire in Scots pine stands is essential for the regeneration of this tree species. The germination capability of seeds is modified by the temperature reached during a fire and the length of time that seeds are subjected to high temperatures. The probability of germination was studied in the laboratory for Scots pine (Pinus sylvestris) and four shrub species characteristic of the understory in Scots pine stands in northern Spain (Cistus laurifolius, Halimium umbellatum, Halimium alyssoides and Genista florida). Germination probability was studied with a logistic model that uses duration of exposure to the fire, the temperature and the interaction of both as independent variables. Results show a higher germination rate in shrub species at high temperature than for Scots pine. Thus by limiting competition between Scots pine and understory species, using prescribed burning or mechanical site preparation, Scots pine can regenerate successfully and quickly. This model can aid management decisions in this area.germination / scots pine / shrub species / thermal shock Résumé -Prédiction des probabilités de germination après le feu de Pinus sylvestris L. et de quatre espèces de garrigue. La régénération des espèces de garrigue après le feu est un facteur déterminant pour la réinstallation de Pinus sylvestris. La température pendant l'incendie et la durée de l'exposition modifient la capacité de germination des graines. Nous avons étudié au laboratoire la germination de Pinus sylvestris et de quatre espèces de garrigue (Cistus laurifolius, Halimium umbellatum, Halimium alyssoides et Genista Florida) qui sont typiques des forêts dominées par Pinus sylvestris. Afin de définir les probabilités de germination, on a utilisé la durée de l'exposition, la température et son interaction comme variables indépendantes, dans un modèle logistique. Les résultés de la germination suggèrent que les graines des espèces de garrigue présentent une meilleure germination après exposition à des hautes températures que les graines de Pinus sylvestris. En conséquence, les feux prescrits ou les entretiens mécaniques peuvent provoquer une régénération plus rapide et plus satisfaisante de Pinus sylvestris. dynamique de germination / Pinus sylvestris / espèces du maquis / feu de forêt

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“…; 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: 96%

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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Predicting germination capacity of Pinus sylvestris and Picea abies seeds using temperature data from weather stations

Cited by 23 publications

References 1 publication

Potential for Timberline Advance in Northern Finland, as Revealed by Monitoring during 1983-99

Potential for Timberline Advance in Northern Finland, as Revealed by Monitoring during 1983-99

Predicting the probability of seed germination in Pinus sylvestris L. and four competitor shrub species after fire

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

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