The Pogorevc forest preserve has been untouched and left to develop naturally on its own for over 50 years. Five individual lots that had been sampled continuously were last sampled In 1991. In 2017, measurements were once again taken on all five lots. We re-measured the diameters of the trees, assessed their condition (as either alive or dead), and determined the type of death and degree of decay in the dead specimens. The preserve provided a unique opportunity to study the demographic condition of the forest, which is slowly transitioning into the late-succession stage. We found that the tree density has decreased by more than 37%, which – aside from natural death – can be attributed to heavy windfall in 2017. The proportion of the Scots pine (Pinus sylvestris) is decreasing, and the proportion of the European spruce (Picea abies) is increasing. Tree mortality on the lots is high, and the degree of regeneration is very low, the only exception being the spruce. The annual mortality of the trees is somewhere between 0.54 % and 2.51 %. The highest annual death mortality was measured in the Scots pine (2.89 %) and the European beech (1.72 %), and the lowest in the spruce (0.92 %).