Fertilization program adapted to the specific needs of every stand (BAG) is first applied when the young spruce forest reach the average height of 2-4 meters. Until crown closure, fertilization occur every second year, and thereafter every 7th to every 10th year. The fertilizer mix and application rate is adapted to the current nutrient needs. The expected increase in growth rate is 3.5-5.5 m³ per hectare and year.
The use of BAG affect the silvicultural decisions. Thinning operations may be excluded or a reduced number of thinnings and shortened rotation periods can be applied in the fertilized forest.
Some young spruce stands at Asa HYEF were fertilized for the first time year 2012 (totally 36 ha). Needle analysis from autumn 2013 showed that in the whole area there is a lack of nutrients, especially phosphorus. Therefore during second fertilization (2014) stands were fertilized also with phosphorus, potassium and sulfur.