In February of this year a storm hit the Aquitaine region in South-west France causing extensive damage, particularly to the forests. It is thought as much as 40 million m3 of trees were felled – equivalent to about five years of normal harvesting. Many trees broke mid-stem so this wood will have to be used for panel products, paper manufacture or energy generation. Others broke at the root base so, hopefully, can be sawn.
The huge quantity of wood on the ground relative to the capacity of saw and panel mills in the area to use it, especially with the current market situation, implies that the vast majority of the wood must be stored in some way.
Logs left unprotected will soon be attacked by bacteria, sap-stain, fungi and, later, insects. Also, logs will split as they dry due to differential shrinkage in the tangential and radial directions, reducing the potential yield and value of the wood.
Clearly, the damaged trees must be cleared from the forest to minimise the risk of disease and fire.
The most practical solution is to collect the logs together in several large storage areas and keep them wet with water sprays. Inevitably there is a cost: Land rent, spraying systems, cutting logs to length, transporting and stacking them, and water.
Previous experience has shown that an efficient water spraying system needs about 15 m3/hour for 4,000m3 of stacked logs. If it is assumed that half of the wood on the ground were to be stacked, then the water requirement would be 75,000m3/hour, or 655 million m3/year. This is equivalent to 20 lakes the size of Derwent Water (for UK residents), slightly less than the volume of Lac de Biscarosse in the Aquitaine region (for French residents) and just over half of Lake George (for US residents and I’ll stop there!); in other words, a lot of water. This could turn out to be a limiting factor.
Water pollution could also become an issue, due to the ‘run-off’ from the stacks fouling nearby waterways. There will be some loss of wood
quality too, because many bacteria, and some fungi, especially Armillaria mellea, can thrive in the water-logged conditions.
If water storage is chosen, then it needs to be done quickly if it is to be efficient. Spring is in the air and with the warmer temperatures, bacteria and fungi will colonize fallen trees quickly.
Unfortunately, this situation is not new to the Aquitaine region because a similar storm hit just under 10 years ago and so, in some ways fortunately, there are people who know how to minimise the effects of this natural disaster.
