Managing the forest that builds itself

OVER 70 people journeyed to Keshcarrigan for the first of Prosilva Ireland’s 2012 Open Forest Days on April 28 last. Guest speakers Marc Etienne from France and Thomas Vrska from the Czech Republic shed light on principles of continuous cover/close-to-nature forestry in Mary and David Legge’s forestry plantations. The Legge family have a range of forestry plantations all of which are being transformed to continuous cover forestry.

OVER 70 people journeyed to Keshcarrigan for the first of Prosilva Ireland’s 2012 Open Forest Days on April 28 last. Guest speakers Marc Etienne from France and Thomas Vrska from the Czech Republic shed light on principles of continuous cover/close-to-nature forestry in Mary and David Legge’s forestry plantations. The Legge family have a range of forestry plantations all of which are being transformed to continuous cover forestry.

Mr Etienne described how the forest builds itself and said continuous cover/close-to-nature was about using that trait to produce quality stems whilst at the same time preserving the non-economic assets of the forest.

Mr Vrska showed a sample of soil from the forest and demonstrated the positive influence of the broadleaves on its structure and quality. An inch of new hummus could be seen at the top of the sample, which had been formed through the presence of the young broadleaved forest.

He said the soil had good structure and oxygenation which was in contrast to the Legge’s sitka spruce stand where harvesters had caused compaction and the needle fall had prevented hummus building up. “The advantage of the broad leaves are in their ability to improve the soil”, he said.

Adding, this was as a result of soil analysis that in his country native beech and other broadleaves are always grown with conifer species.

Mr Vrska then directed the group to a windblown spruce tree at the edge of one of the harvester’s thinning racks. He showed us how one side of the tree’s exposed root system had been healthy when it had fallen but the other side, which had suffered from soil compaction when the harvester had passed over it, was dead. This had resulted in the de-stabilisation of the root plate and the tree had blow over. Mr Vrska explained that cable harvesting systems were used in the Czech Republic to avoid such damage.

Mr Etienne said a conifer stand has to be managed differently to a broadleaf stand.

The goal of thinning in a conifer plantation being converted to continuous cover forestry was to prolong the life of the stand overall to give it time to regenerate whilst maximising the volume of timber to sell. “So you choose the biggest and baddest trees to take. Don’t take a tree to help another, take the big ones with the bad shape.” he said.

Paddy Purser from Pro Silva Ireland said this strategy fitted nicely with the current market demands in Ireland. There would be less cost involved in marking and harvesting the selected thinnings because less trees of a bigger size were targeted. The current demand for saw logs logs meant it was also of more value to the owners to take the big trees rather than the small.

Questions were raised about the small amount of wind thrown areas in the plantation and Mr Purser said the wind was finding the weak spots in the stand and picking them out.

The resulting clear spaces would be used to advance regeneration with broadleaf species that would improve the soil fertility.

At the conclusion of the day PSI Chairman Padraig O’Tuama thanked our special guests, Marc Etienne and Tomas Vrska for so generously sharing their knowledge. He also thanked Mary and David Legge for hosting what had been a most informative and enjoyable day.