Irish forestry transplants trees at the age of 2 to 3 years onto a new site. Once the site has been prepared for the arrival of the trees, the planter will come in and place the trees on top of the mounds at a spacing of two meters. For the next couple of years one or two maintenance runs will be carried out on the fledgling Forest in order to remove or reduce competing vegetation, to fertilize when needed, or replace dead or dying trees. It is very easy to get in amongst the trees at this early stage. But, once the forest reaches their teenage years, it becomes a difficult to gain any forest access.
By the time Irish forestry reaches the age where it needs first thinning, it will be impossible for any individual to access more than a couple of meters into the forest. This is because the tree branches will have closed in to extend that they block any intrusion. This is where forestry inspection lines are needed. Around the age of 14 to 20 years, any forestry in Ireland has to be inspected to ascertain the value of thinning. The thinning process is achieved by removing about one third of the overall tree population in order to give the other two thirds a better chance of growing into decent timber.
The forestry inspection lines are created throughout the forest. They are basically a tunnel which goes from one side of the forest to the other side of the forest and are created by removing the lower branches between two sets of trees up to head height. This allows a person to walk all the way through the forest. These forest inspection lines are placed parallel to each other at about 100 m spacing. When this is carried out around the circumference of the forest, a grid system is created whereby the individual inspector can inspect any area within 100 meters of any other area.