Metla Project 3144

Forest vitality

[  Suomeksi  |  Objectives  |  Results  |  Project leader  |  Researchers  |  Publications  |  More about the project  |  Metla Research  ]

Duration: 1995-2004   Keywords: crown condition, defoliation, forest condition, forest damage, Gremmeniella abietina, forest vitality, monitoring, needle analysis

Objectives

The aims of the project are

*to survey the regional distribution of forest condition in Finland *to monitor year-to-year variation in forest condition *to monitor the developement of forest nutrient status using needle analysis *to describe the spatial and temporal variation in the occurrence of forest damage *to study the factors affecting the susceptibility of stands to damage (especially to Gremmeniella abietina) *to analyze the environmental factors e.g. air pollution which may explain the regional pattern and changes in forest condition.

Results

The 2001 forest condition survey was conducted on 454 sample points arranged in 24 x 32 and 16 x 16 km grids. No changes were observed in the average defoliation level of any tree species between the years 2000 and 2001. In 2001 the average defoliation was 9 % in Scots pine (Pinus sylvestris), 19 % in Norway spruce (Picea abies), and 12 % in broadleaves. Tree mortality was at the same level as in the previous years (0.2 %).

On Scots pine and broadleaves the proportion of discoloured (extent of discoloured needle/leaf mass more than 10 %) remained at the same level (under 1 %) as in 2000, and that of Norway spruce decreased from 8 % to 6 %. The most frequent discolouration symptoms were needle tip yellowing and needle yellowing. Discolouration symptoms were mainly concentrated on needles older than two years. Moreover, the proportion of slightly discoloured (extent of discoloured needle mass 1-10 %) trees was higher than that in the previous year. This was especially the case on spruce, the first year needle sets of which had become yellow as a result of fungal diseases.

The most extensive cause of forest damage in 2001 were the heavy storms in November, about 2 million m3 of trees being lost as wind throw in southern Finland. Due to the very warm and rainy autumn in 2000, fungal diseases were more common in 2001 than 2000. In some regions in southern and western Finland, the outbreak of scleroderris pine cancer (Gremmeniella abietina) on pine was the worse for more than a decade. Rust fungi, especially Chrysomyxa ledi on Norway spruce, were common throughout almost the whole country. There were no extensive insects outbreaks in 2001.

No correlation was found between the defoliation pattern of conifers or broadleaves and the modelled sulphur or nitrogen deposition (1993) at the national level in 2001.

Project leader: Lindgren, Martti
The Finnish Forest Research Institute, Vantaa Unit, PL 18, FI-01301 VANTAA, FINLAND
Phone: +358 29 532 2537
E-mail: martti.lindgren@metla.fi

Other researchers: Heinonen, Jaakko, JO (2000-01), Nevalainen, Seppo, JO (2000-04), Poikolainen, Jarmo, MU (2000-04), Pouttu, Antti, VA (2002-04), Salemaa, Maija, VA (2000-01,2004)


Top of page

Updated 12.06.2012
Comments