Metla Project 3232

Climatic adaptation and geographical variation of silver birch (Betula pendula Roth)

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Duration: 1998-2004   Keywords: Betula pendula, Betula pubescens, climatic adaptation, growth variation, seed transfers

Objectives

The aims of the project are
  1. to describe the variation among different geographical origins of silver birch as regards growth, stem and wood quality and adaptive traits as a function of climatic factors.
  2. to construct a model to define seed transfer rules and utilization areas of different seed origins
  3. to study the response of silver birch to climatic change on the basis of north to south seed transfers
  4. to compare silver birch and pubescent birch (B. pubescens) as regards climatic adaptation and response to seed transfers

Results

Results from field tests at early age have shown that long seed transfers from the south to the north result in high mortality and, on the surviving seedlings, recurrent leader damages, bushy like, weak growth and later, bad stem quality. On the other hand, when the northern geographical origins are transferred long distances to the south, they grow clearly slower than the local, southern origins.

In northern Finland, the local origins perform best. According to preliminary results, the safe seed transfer distance is about 0-100 d.d in south - north direction. Longer transfers always include a risk of low survival and leader damages. In southern Finland the safe transfer distance is slightly longer, about 0-150 d.d. Longer transfers than this from the north to the south result in slower growth compared to the local origins.

In a field test in southern Finland, significant differences were detected between different silver birch origins in browsing by moose. The origins imported to Finland from more southern latitudes were more frequently and more severely browsed than the native ones.

In a 22-year-old field test at Tuusula, near the south coast of Finland, origins from northern Estonia and northern Latvia as well as the native plus tree origins, produced higher volume/ha than local stand seed origins. Origins imported from the Baltic countries had, on the other hand, higher frequency stem defects, i.e. forks or vertical branches.

Project leader: Viherä-Aarnio, Anneli
The Finnish Forest Research Institute, Vantaa Unit, PL 18, FI-01301 VANTAA, FINLAND
Phone: +358 29 532 5512
E-mail: anneli.vihera-aarnio@metla.fi

Other researchers: Haapanen, Matti, VA (2002), Häkkinen, Risto, ES (2001-04), Luomajoki, Alpo, VA (2001-04), Partanen, Jouni (2002-03), Velling, Pirkko, VA (2000,2003-04)


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Updated 12.06.2012
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