Long-term variation in Scots pine seed crop size and quality in northern Finland

Hilli, Anu; Hokkanen, Tatu; Hyvönen, Juha; Sutinen, Marja‐Liisa

doi:10.1080/02827580802334217

Cited by 15 publications

(11 citation statements)

References 12 publications

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“…Some incompletely matured seed is produced every year even along the timberline, however (Heikinheimo, 1932(Heikinheimo, , 1937. The seed crops in central Lapland were not especially good during the studied regeneration period (Hilli et al, 2008). It is possible that the differences between the yearly weather conditions have affected seed crops, germination ability, and seedling establishment.…”

Section: Discussionmentioning

confidence: 98%

Factors affecting the success of autumn direct seeding of Pinus sylvestris L. in Finnish Lapland

Hyppönen¹,

Hallikainen²

2011

Scandinavian Journal of Forest Research

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Spring and early summer have been regarded as the biologically best direct seeding dates for Scots pine. The study focused on finding out if late autumn is also a reasonable period for direct seeding of pine in Finnish Lapland and what factors affect the success of seeding. In all, the inventory-based data consisted of 50 regeneration stands and 908 sample plots sown in the autumn; the data were hierarchically structured at the levels of stand and circular plot. The method used was to construct models for the seedling establishment and seedling height. Modeling was used to analyze the principal ecological factors influencing regeneration success. The density and height models were developed using the Generalized linear mixed model (GLMM). The most significant variables affecting seedling establishment were temperature sum, proportion of prepared area, thickness of humus layer, stoniness, and distance from forest edge. Contrary to the hypothesis, late autumn can be regarded as a reasonable alternative period for direct seeding, at least in northern Fennoscandia. For confirmation of the results, more experimental research is needed. One must remember that the success of regeneration results from the combination of direct seeding and natural regeneration.

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Section: Discussionmentioning

confidence: 98%

Factors affecting the success of autumn direct seeding of Pinus sylvestris L. in Finnish Lapland

Hyppönen¹,

Hallikainen²

2011

Scandinavian Journal of Forest Research

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“…(average production 36 seeds/m 2 ). A certain masting is to be found in the species, with about two good crops every seven years (Montero et al, 2008a), although null crops are absent (Hilli et al, 2008). In the aforementioned four-year study, 16-fold average differences between years were detected, mainly related with the precipitation occurring in the spring two years before cone maturation (Calama et al, 2015b).…”

Section: Flowering Fruiting and Seed Productionmentioning

confidence: 99%

Natural regeneration in Iberian pines: A review of dynamic processes and proposals for management

et al. 2017

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Aim of study: Designing adequate silvicultural systems for natural regeneration of a forest species requires sound knowledge of the underlying ecological subprocesses: flowering and fruiting, seed dispersal and predation, seed germination, seedling emergence and seedling survival. The main objective of the present work is to carry out a review on the current knowledge about the different subprocesses governing the regeneration process for the main Iberian Pinus species, in order to propose scientifically based management schedules.Area of study: The review focuses on the five main native Pinus species within their most representative areas in the Iberian Peninsula: Pinus nigra in Cuenca mountains, Pinus sylvestris in Sierra de Guadarrama, Pinus pinaster and Pinus pinea in the Northern Plateau and Pinus halepensis in Catalonia.Material and methods: Firstly, currently available information on spatiotemporal dynamics and influential factors is introduced for each subprocess and species. Secondly, current regeneration strategies are characterized and the main bottlenecks are identified. Finally, alternative silvicultural practices proposed on the light of the previous information are presented.Main results: Different climate-mediated bottlenecks have been identified to limit natural regeneration of the Iberian pine species, with seed predation and initial seedling survival among the most influential. New approaches focusing on more gradual regeneration fellings, extended rotation periods, prevent big gaps and program fellings on mast years are presented.Research highlights: Natural regeneration of the studied species exhibit an intermittent temporal pattern, which should be aggravated under drier scenarios. More flexible management schedules should fulfil these limitations.Additional keywords: seed production; seed dispersal; seed predation; germination; regeneration fellings.Correspondence should be addressed to Rafael Calama: rcalama@inia.es

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“…This allowed us to extend the continuous series to 1953 (Sarvas ; Hilli et al . ). The cones measured in Värriö and the seed crop in Rovaniemi are related ( r 2 = 0.20) and, estimated visually, peak years are consistent between sites (Fig.…”

Section: Methodsmentioning

confidence: 97%

A prominent stepwise advance of the tree line in north‐east Finland

et al. 2014

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Summary1. The elevational limit of trees (henceforth, the 'tree line') is widely considered to be a sensitive indicator of environmental change. Here, we document the 20th century tree line advance and increase in the tree population at the tree line ecotone, along a Pinus sylvestris-dominated slope in north-eastern Finland, in conditions where growth and recruitment have generally been linked to temperature variation. 2. Using tree recruitment ages (growth to 1.3 m height) along an elevational transect, we compared recruitment to variation in environmental conditions associated with tree line dynamics, seed and cone crops, and reindeer densities. We further investigated the relationships among temperature and tree-level growth variables. 3. Results show the existence of a former tree line at approximately 400 m a.s.l. and an advance of trees that began in the 1920s and reached the top of the fell (at 470 m a.s.l.) in the 1980s. During this time, the population density of P. sylvestris increased from 4 to 468 trees within the 5.6 ha study plot. Needle and shoot lengths were positively related to air temperature but recruitment was not. 4. Average rate of P. sylvestris advance over the 20th century was consistent with earlier studies, but the temporal patterns of both upslope advance and population density increase were unexpected: both were characterized by a strongly stepwise pattern, culminating in a rapid advance and density increase in the 1970-1980s, and returning to low levels in the 1990s. 5. Despite a positive relationship between growth and temperature variables at the tree level, climatic variables, or seed and cone crops were inconsistent with recruitment patterns. For most part of the 20th century, the increase corresponded to the gradual atmospheric CO 2 increase, but of the variables screened only the changes in reindeer densities coincided with the stepwise pattern. 6. Synthesis. Our results confirmed the connection between tree-level processes and temperature variability as expected from earlier studies. However, recruitment was not correlated with any of the environmental variables. Our findings point towards complex tree line dynamics, in which biotic agents may play a major role in mediating tree line response to environmental change.

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Long-term variation in Scots pine seed crop size and quality in northern Finland

Cited by 15 publications

References 12 publications

Factors affecting the success of autumn direct seeding of Pinus sylvestris L. in Finnish Lapland

Factors affecting the success of autumn direct seeding of Pinus sylvestris L. in Finnish Lapland

Natural regeneration in Iberian pines: A review of dynamic processes and proposals for management

A prominent stepwise advance of the tree line in north‐east Finland

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