Hybridlärkens tillväxt i Snogeholm : hur påverkas produktionen i blandbestånd jämfört med trädslagsrena bestånd?

Abstract: The hybrid larch (Larix x eurolepis Henry) is a fast growing tree species and was introduced in Sweden for about 50 years ago. The high growth and expected resistance to diseases are probably the main reasons of introducing the tree species into the Swedish forests. The purpose of this thesis was to document the production of hybrid larch planted in the Snogeholm landscape laboratory and to compare the production in the pure hybrid larch stand with the mixture together with pedunculate oak (Quercus robur). The data collection in Snogeholm since the establishment has been carried out by the Swedish University of Agricultural Science (SLU). The fieldwork for the thesis was carried out in 3 stands, containing hybrid larch, pedunculate oak and a mixture of hybrid larch and pedunculate oak, in order to be able to compare the total stand production of the areas. The results show that the total production of hybrid larch in the mixed stand only is 35 % compared with the total production of hybrid larch in the pure stand. Therefore, the hypothesis that the total production of hybrid larch is equal to the planted mixture with pedunculate oak was rejected. The other hypothesis that the total production of a 2 hectare large stand containing a mixture of hybrid larch and pedunculate oak would be greater than the total production of two pure stands of 1 hectare containing hybrid larch and oak each was also rejected. In the studied case the total production was 45 % greater if hybrid larch and pedunculate oak was planted in pure stands. The results from the case-study only indicate that the total production of hybrid larch and oak under the investigated conditions can be higher when planting the two species in pure stands compared with a mixture of the two species. Further investigations are needed before any recommendations regarding the maximization of the total production can be given to the public interests. Other important values like recreation or resilience were not considered in this study.