Annual Report 2005 - Forest ecosystems and social significance of forests

Photo: Erkki Oksanen

Metla conducted an afforestation study on the effects of competing ground vegetation and various herbicides on growth, mortality and vole damage. The experiment was monitored during 11 years. One of the soil-active agents studied was dichlobenil and glyphosate was one of the foliar ones. A cover crop of clover (Trifolium repens L.) and fibre board mulch were used as alternative methods.

Dichlobenil turned out to be the most effective of the currently used herbicides. Test areas treated with glyphosate did not show different results from the untreated control plots, nor did the cover-crop or mulch plots.

The highest seedling mortality was on the cover-crop plots and on the plots treated with dichlobenil. Abundant ground vegetation also increased vole damage. Vole attacks were especially intensive on shorter-than-average seedlings. Effective control of ground vegetation can accelerate seedling growth and thus reduce the time over which they are vulnerable to vole damage. The tree volume on the best experiment plots, at 11 years, was almost three times as great as on control plots.

It is possible that the use of herbicides will become even more restricted than today. Thus it is essential to continue research into alternative weed control methods.

Since 1969, 240,000 ha of former agricultural fields have been afforested in Finland. Afforestation reached its peak during 1992 - 93, when more than 17,000 ha of agricultural fields were afforested. In 2004 the area of afforestation was 2640 ha.

Additional information: www.metla.fi/hanke/3277/index-en.htm and www.metla.fi/hanke/3387/index-en.htm

Back to the list of the reported finished projects in 2005

Updated:	18.09.2006 / SKon	Metla : Annual Report : Annual Report 2005

Weed control improves afforestation results of cut-away peatlands and peat fields