Heikki Hänninen. (1986). Metsäpuiden vuosirytmitutkimuksen käsitteistä ja teorioista. Silva Fennica vol. 20 no. 1 article id 5257. https://doi.org/10.14214/sf.a15436

English title: Conceptual remarks about the study of the annual rhythm of forest trees.

Original keywords: lämpösumma; ekofysiologia; fenologia; vuosirytmi; dormanssi; aklimaatio

English keywords: acclimation; temperature sum; climatic adaptation; dormancy; phenology; photoperiod; annual cycle of development

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Different approaches to the study of the annual rhythm of forest trees are described and compared by analysing the concepts and theories presented in the literature. The seasonality varying morphological and physiological state of forest trees is referred to as the annual rhythm s. lat., from which the annual ontogenetic rhythm is separated as a distinct type. The dormancy phenomena of the trees are grouped into four categories. Theories concerning the regulation of the annual rhythm are divided into two main types, the most common examples of which are the photoperiod theory and the temperature sum theory. Recent efforts towards a synthetic theory are described.

The PDF includes a summary in English.

Hänninen, E-mail: hh@mm.unknown

Category : Article

article id 7660, category Article

Heikki Hänninen. (1990). Modelling bud dormancy release in trees from cool and temperate regions. Acta Forestalia Fennica no. 213 article id 7660. https://doi.org/10.14214/aff.7660

Keywords: Pinus sylvestris; Picea abies; climatic adaptation; annual cycle; bud dormancy; quiescence; rest; growth competence

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The premises of several models obtained from literature on bud dormancy release in trees from cool and temperate regions differs from each other with respect to responses to air temperature during the rest period of the buds. The predicted timing of bud burst in natural conditions varied among the models, as did the prediction of the models for the outcome of a chilling experiment.

Experimental results with two-year old seedlings of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) did not agree with any of the models. The experimental results also deviated from abundand earlier findings, which also disagreed with any of the models. This finding suggests that Finnish provenances of Scots pine and Norway spruce differ from more southern provenances with respect to temperature regulation of bud dormancy release.

A synthesis model for the effects of air temperature on bud dormancy release in trees was developed on the basis of the previous models and the experimental results of both the present and previous studies. The synthesis model contains part of the original models as special cases. The parameters of the synthesis model represent several aspects of the bud dormancy release of trees that should be addressed separately with each species and provenance in experimental studies. Further aspects of dormancy release were discussed, in order to facilitate further development of the models.

The PDF includes a summary in Finnish.

Hänninen, E-mail: hh@mm.unknown

Category : Research article

article id 226, category Research article

Anneli Viherä-Aarnio, Pirkko Velling. (2008). Seed transfers of silver birch (Betula pendula) from the Baltic to Finland – effect on growth and stem quality. Silva Fennica vol. 42 no. 5 article id 226. https://doi.org/10.14214/sf.226

Keywords: Betula pendula; yield; provenance; climatic adaptation; stem defect

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Silver birch (Betula pendula Roth) seed origins from the Baltic countries, Finland and Russia were compared for survival, growth and stem quality, and the effect of latitudinal seed transfer distance examined in two provenance trials. The trials were located on moist upland forest soils at Tuusula (60°21’N) in southern Finland and at Viitasaari (63°11’N) in central Finland. The material consisted of 21 stand and single tree origins ranging from latitudes 54° to 63°N. Survival, height, dbh, relative stem taper, stem volume/ha and the proportion of trees with a stem defect (vertical branch or forked stem), were assessed when the trees were 22 years old. Significant differences were detected among the origins regarding all the measured traits in both trials. Southern Finnish origins produced the highest volume per unit area in central Finland, whereas Estonian and north Latvian stand seed origins, as well as the southern Finnish plus tree origins, were the most productive ones in southern Finland. The more southern the origin, the higher was the proportion of trees with a stem defect in both trials. The latitudinal seed transfer distance had a significant but relatively small effect on survival, stem volume/ha and proportion of trees with a stem defect. The proportion of trees with a stem defect increased linearly in relation to the seed transfer distance from the south. The relationship of both survival and stem volume/ha to the seed transfer distance was curvilinear. Volume/ha was increased by transferring seed from ca. 2 degrees of latitude from the south. A longer transfer from the south, as well as transfer from the north, decreased the yield.

Viherä-Aarnio, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: anneli.vihera-aarnio@metla.fi
Velling, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: pv@nn.fi

Category : Review article

article id 313, category Review article

Heikki Hänninen, Koen Kramer. (2007). A framework for modelling the annual cycle of trees in boreal and temperate regions. Silva Fennica vol. 41 no. 1 article id 313. https://doi.org/10.14214/sf.313

Keywords: frost hardiness; climatic adaptation; bud burst; climatic change; dormancy; phenology; photosynthetic capacity

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Models of the annual development cycle of trees in boreal and temperate regions were reviewed and classified on the basis of their ecophysiological assumptions. In our classification we discern two main categories of tree development: 1) fixed sequence development, which refers to irreversible ontogenetic development leading to visible phenological events such as bud burst or flowering, and 2) fluctuating development, which refers to reversible physiological phenomena such as the dynamics of frost hardiness during winter. As many of the physiological phenomena are partially reversible, we also describe integrated models, which include aspects of both fixed-sequence and fluctuating development. In our classification we further discern simple E-models, where the environmental response stays constant, and more comprehensive ES-models, where the environmental response changes according to the state of development. On the basis of this model classification, we have developed an operational modelling framework, in which we define an explicit state variable and a corresponding rate variable for each attribute of the annual cycle considered. We introduce a unifying notation, which we also use when presenting a selection of previously published models. To illustrate the various developmental phenomena and their modelling, we have carried out model simulations. Finally, we discuss the ecophysiological interpretation of the model variables, methodological aspects of the empirical development and testing of the models, the introduction of new aspects to the modelling, other closely related models, and applications of the models.

Hänninen, Plant Ecophysiology and Climate Change Group (PECC), Department of Biological and Environmental Sciences, Box 65, FI-00014 University of Helsinki, Finland E-mail: heikki.hanninen@helsinki.fi
Kramer, Alterra, P.O. Box 47, 6700 AA Wageningen, The Netherlands E-mail: kk@nn.nl

Category : Research note

article id 609, category Research note

Aleksei Fedorkov. (2001). Climatic adaptation of seed maturity in Scots pine and Norway spruce populations. Silva Fennica vol. 35 no. 1 article id 609. https://doi.org/10.14214/sf.609

Keywords: Norway spruce; Scots pine; climatic adaptation; provenance experiment; seed maturation; X-ray method

Abstract | View details | Full text in PDF | Author Info

Seed maturation of Scots pine and Norway spruce in a provenance experiment at Kortkeros (northern Russia) was examined by the X-ray method. Logarithmic relationships were found between seed anatomy development and long-term average thermal sum. Seed development in the northern populations of Scots pine and Norway spruce was a little faster than in the southern ones.

Fedorkov, Russian Academy of Sciences, Komi Science Centre, Institute of Biology, Kommunisticheskya St., 28, 167610 Syktyvkar, Russia E-mail: fedorkov@ib.komisc.ru

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