Timberline changes in the Chornohora, the highest mountain range of the Ukrainian Carpathians, are related mainly to human activity. The most important factor influencing the timberline has been animal husbandry, with summer grazing on mountain pastures. Using historical maps and contemporary satellite data, we found that the timberline in the western Chornohora moved up by 80 m on average between 1933 and 2001, and the area of pastures (polonynas) shrank by one-third. The fastest advance of the timberline resulted from the expansion of spruce (Picea abies) and was detected far from working livestock farms. The smallest changes occurred in the case of deciduous (beech, ie Fagus silvatica, and sycamore, ie Acer pseudoplatanus) timberlines and near working farms.