After the storm "Vivian" in 1990, bark beetle infestations caused the dieback of adjacent Norway spruce stands, such as on the Gandberg mountain forest in the Swiss Alps. Field studies were conducted in these steep snag stands to describe the short-term succession, and a mathematical model focusing on tree regeneration was used to project the long-term development. Seventy-five percent of all snags were broken 8 years after the die-back, and the ground vegetation changed to raspberry brush or it became dominated by mosses, ferns and grasses. Assuming only a moderate browsing pressure in the model, the simulations together with the investigations on snag decay and the height of piled up logs suggest that the protective effect against avalanches and rockfall will first be maintained by the snags, stumps and logs, then by both the timber and the new Picea regeneration, and finally by the new Picea trees. Thus, leaving snag stands uncleared can result in effective protection for several decades.