Vengasoja is a Finnish demo area with the general aim to demonstrate adaption of ditch cleaning and buffer.

Location (65.4°N:26.4°E)
Mean annual temperature 1,5°C
Growing season: 140 days
Annual precipitation 450 millimetres
Landowner: Metsähallitus

Site description

Middle boreal forest vegetation zone. Wooded riparian buffers are spared parts of Norway spruce (Picea abies) and Downy birch (Betula pubescens) dominated, lightly managed but originally natural, under-productive forest on mainly mesotrophic moraine. The demo site contains several examples of buffer zones, in accordance with Finish minimum law and different certification schemes. Each segment is 50 meters long along the stream.

Buffer zone treatment demonstrated at the Vengasoja demo area

  1. Legal minimum: All stems with commercial round wood were removed. A strip 2 meters wide along the waterline was left without cleaning and site preparation.
  2. PEFC minimum: Most commercial round wood and logging residue were removed. 5-10 meters from the waterline was left without cleaning and site preparation. The buffer has a group of retention trees.
  3. Typical Swedish and typical PEFC in Finland: About 5-7 meters wide wooded buffer. From its outer edge about 5 meters without cleaning and site preparation.
  4. Cutting with ecological aim “WAMBAF Special”: About 18 meters wide wooded buffer. Most spruce was removed, some birch also. 5 meters from the outer edge of the wooded buffer without cleaning and site preparation.
  5. Recommendation in Finland: About 10 meters wide wooded buffer, the outer edge of which (5 meter) was thinned lightly. In addition, 2-3 meters without cleaning and site preparation outside the wooded part.
  6. FSC in Finland: About 15 meters wide wooded buffer, was left intact.

Drainage site

Drain network to be cleaned consists of a pine-dominated stands in the thinning stage on mesotrophic or oligotrophic peat of medium degree of decomposition. At the time of new drainage there were natural sapling stands. The swamp was drained and fertilised in the early seventies and fertilised again in the nineties.

Conducted work and time plan for future activities

  • Delineation and marking of locations buffer strips and water protection structures in the autumn of 2016.
  • Thinning (logging) of the drained area, removal of trees from drain lines in December 2016.
  • Treatment of buffers in March 2017. Cleaning of ditches in July 2017.
  • Construction of a side road in July 2017.

Future use

Training and other demonstration purposes.

Metsähallitus is responsible for the virtual site Vengasoja.

  • Last Updated: 4/2/2024