Growth dynamics of Norway spruce (Picea abies [L.] KARSTEN) in natural spruce forest ecosystems of the National Park Hochharz - 1. Regeneration phaseand initial phase

Natural spruce forests in the strictly protected area of the National Park Hochharz above 920 m are structured into mosaics of formation phases connec ted in asynchronous cycles (shifting mosaic patterns) of 325 +/- 25 years. The paper describes the growth dynamics of the first two development phases after the decay of old-growth stands. The natural regeneration phase of tw o spruce ecosystems investigated is characterized by a very slow height dev elopment of spruce seedlings and saplings, small increment rates of diamete rs (CHD) and basal areas. The regeneration phase, for example, covers a per iod of 28 years. Similar conditions are found in boreal virgin spruce fores ts. Regardless of low growth rates and slight density of young crops, a pro cess of reliable, covering and stable stand regeneration is initiated. In t he following initial phase, comparable to thicket and pole stands, the abso lute and relative growth rates increase exponentially and indicate the form ing of slightly uneven-aged stand structures.