Effects of forest floor planting and stock type on growth and root emergence of Pinus contorta seedlings in a cold northern cutblock

摘要

A two-year field trial was conducted to determine the growth response, and root emergence pattern of interior lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) seedlings in response to container type and forest floor removal. Seedlings were grown in StyroblocksTM, CopperblocksTM, or AirBlocksTM, and were planted directly into the undisturbed forest floor or into manually prepared planting spots where the forest floor had been scraped away to expose the mineral soil. Seedlings planted into scalped planting spots exhibited marginally but significantly (7%) greater above-ground growth rates (seedling stem volume); whereas seedlings planted into the forest floor produced significantly more (11%) new roots. There were no differences in above- or below-ground biomass. Seedlings grown in CopperblockTM containers produced a higher proportion of roots near the top of the plug when tested at lifting, however this pattern was not observed in the field. Given that scalping is more costly than forest floor planting, and that the increased shoot growth was relatively small, we recommend that forest floor planting be considered as an alternative to manual spot scalping for sites, such as the site tested here: those with cold, but well-drained soils and where competition from other plants is not a serious problem.