Spreading device, method and powder-like mixture composition for controlling or preventing forest pathogens on tree stumps

A harvester head, comprising:

• a chain saw;
• a harvester control system configured to provide control commands to control the hydraulic circuit connected the chain saw to cut a tree forming a tree stump;
• and
• a spreading device adapted to administer onto the tree stump a composition comprising microbial propagules to control or prevent growth of a forest pathogen, the spreading device comprising:
• a spreading end connected to a tubular frame, and
• administering means for administering said composition in the form of a powder mixture, wherein said administering means comprise:
• a pressure accumulator for loading pressurized air, said pressure accumulator being connected to a first end of the tubular frame via a supply pipe;
• regulating means comprising at least one regulating valve for regulating flow of the pressurized air entering the tubular frame;
• a powder storage which contains the powder mixture comprising microbial propagule and a solid fine carrier, the powder storage comprising a flow connection of the powder mixture with the tubular frame;
• a control apparatus connected to a second end of the tubular frame for administering the powder mixture inside the tubular frame and means for blowing the powder mixture onto a tree stump via a spreading head connected to the tubular frame;
• and
• communication means comprising a transmitter and a receiver of an electromagnetic signal, the communication means configured to deliver control commands to operate the at least one regulating valve for dispensing of pressurized air and control commands to adjust a dosage of the mixture from the powder storage, the communication means operate automatically and receive data from the harvester control system, the harvester control system further configured to:
• receive a trunk diameter measurement of the tree stump;
• calculate the pressure of pressurized air and the dosage of the powder mixture based on the trunk diameter measurement of the tree stump;
• and
• provide the control apparatus with the data comprising control commands for operating the at least one regulating valve at the pressure of pressurized air calculated and the dosage of the powder mixture calculated based on the trunk diameter measurement, the control commands comprising a starting time of delivery and the pressure of pressurized air into the tubular frame, and a starting time and a duration of the dosage of the powder mixture into the tubular frame.