Överlevnad och tillväxt för nyplantersade barrots- och täckrotsplantor : en studie av 42 bestånd i södra Sverige

Sammanfattning: The choice between bare-rooted and containerized seedlings in southern Sweden affects the investment costs as well as growth and survival. It is important to take these differences into account when choosing seedling type for reforestation. The most important differences between the two seedling-types is that bare-rooted seedlings has open root systems whereas the roots of containerized seedlings are grown in a container which may contain water and nutrients that are available for the seedling during the first period after planting. Moreover, bare-rooted seedlings are often older which results in thicker stembase and better resistance to attacks of pine-weevil (Hylobius abietis). In order to study differences in survival and growth between bare-rooted and containerized seedlings a survey study of newly planted clearcuts in south-western Sweden was made. In the study tree seedling types was included, one bare-rooted and two containerized with different ages. The population of pine weevils was probably low during the studied period which resulted in lower pine-weevil damage than normally found in this area. Because of low pine weevil damage, other damaging agents became more important. The most significant difference between the two seedling types was the amount of damage without any known damaging agent. Bare-rooted seedlings had more than four times as many damages of unknown origin as containerised. It is hypothesized that handling of the seedlings before and during planting may have been an important reason for this difference because bare-rooted seedlings are more sensitive than containerised ones. Containerised seedlings had larger height-growth and greener needles than bare-rooted seedlings after the first growing season, which indicates that containerised seedlings was able to establish faster in its new environment after planting than bare-rooted seedlings. The older containerized seedling (1.5 years) hade larger height-growth than the younger (1 years) but the difference was small. There where no measurable difference in survival between the two containerised seedling types