After the tests carried out in 2019, it was concluded that the three-hole method yields a resin production that does not differ significantly from that obtained with traditional methods and could therefore be an option for accurate prediction of the productive capacity.

The National Institute for Agricultural and Food Research and Technology (INIA) has finalised the drafting of this Guide which will be used to carry out an early assessment of resin production in Pinus Pinaster. This action is carried out within the Interreg Sudoe SustForest Plus project.

Given the correlation between the yields obtained with the drill treatment, it seems to be an applicable method for the early assessment of resin. From a practical point of view, it is more interesting to use radial drilling for early evaluation due to its simpler execution.

Resination by drilling

• Resination by drilling has a number of advantages over traditional methods:
• Volatile substances of industrial value do not evaporate, so the quality of the obtained wood increases, and with it, it is to be expected that its price will increase.
• The production of the tree is not influenced by the skill of the resin producer.
• The number of impurities is drastically reduced, reducing the need for filtering in the factory and making resin processing cheaper.
• The number of revisits to the tree can be reduced or limited to monitoring the resin level in the bags. This can increase the yield of the resin maker who could increase the number of trees in his stand.
• The resin obtained by radial drilling methods has proved to be the dasometric variable that best explains the variability of the resin obtained by traditional methods. Given the correlation between radial and tangential drilling production and the ease of execution of radial drilling, it is interesting to use the latter method of execution as a method of early resin selection.