Sawmills cut beams for immediate supply and surplus saw capacity goes into stock, most of this production is in standard sections and it is available for sale from day one.
At times of low demand the beam stock in sawmills will build up, at times of high demand, like we have now and for the past few years, this stock is depleted as the saw cannot cut beams as fast as the market demands.
All across Europe, sawmills have been selling their old beam stock to satisfy this increased demand. The mills that have been able to buy sufficient logs (which is another story) have been cutting as fast as possible, and some have managed to build up some stock. But this stock is all fresh sawn and will not be seasoned for at least 3 years. If demand stays as high as it is now they will all be sold before they have had 3 years.
If the current trend of supply and demand abates, it will be 3 to 5 years before seasoned beams are reliably available again. If the current market continues, we will not see a commercial stock of seasoned beams for many years.