Afforestation in mountainous regions is much more laborious, difficult, and demanding than that in lowlands. A thorough knowledge of the ecology is required in order to estimate the prospects of success. The slightest irregularities in the terrain give rise to large differences in micro-site, so that favorable and unfavorable sites may lie very close together. Specific threats to particular tree species from fungi, game, insects, climatic extremes, snow movements, and competition on the individual sites must be taken into account. Given these · difficulties, it is often advisable to employ special, more laborious methods of cultivation and planting; tor instance pitting rather than angle planting, or the use of potted rather than bare-rooted plants. Cluster arrangement is recommended rather than a regular planting pattern, since it allows consideration of micro-site conditions, the establishment of a good surface structure, and the preclusion of monotone stands. T temporary mechanical installations such as stakes, ties, terraces, three-cornered supports, or snow rakes are often needed to protect the afforestation against various types of snow movement. Last but not least, the growth conditions in mountainous regions impose appropriate methods of tending tor young growth and thickets. As development proceeds only slowly, the thorough documentation of work conducted is especially important lo ensure that experiences are not lost.