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Commercial forests require early cleaning to ensure the unhindered and uniform growth of crop trees. In order to be cost effective, non-crop vegetation should be uprooted to prevent their recovery. Performing this work manually is a labour-intensive task but it can be done mechanically. We evaluated the efficiency of two uprooting devices in direct seeded Scots pine (L.) stands ca. 1 m tall. Productivity and quality of the uprooting work was investigated across eight stands and ca. 160 sample plots in northern Karelia, eastern Finland. Time consumption of the uprooters was analyzed through a linear regression model and the work quality through a multilevel multivariate model in terms of the number of individual Scots pine seedlings, processing units (i.e., a bunch of seedlings to be harvested in the future) and broadleaves. The productivity of the narrower modified device was significantly better in terms of time consumption than the wider original device. Work quality did not differ significantly between devices when stand characteristics, regeneration success and pre-existing damage were taken into account. Results indicate that mechanical uprooting devices may be further developed to a cost-effective alternative to motor-manual techniques for the early cleaning of direct seeded commercial Scots pine stands.Pinus sylvestris

Continuous cover forestry (CCF) is gaining popularity as an alternative to rotation forest management (RFM), especially in forests with multiple uses. The success of CCF depends on the amount and quality of remaining seedlings, but the effect of harvesting on their status is not well known. In the present study, the proportion and number of undamaged seedlings after harvesting (and soil scarification) in Scots-pine-dominated stands in Northern Finland were modelled by applying logistic binomial mixed-effects and negative binomial count data models. The treatments included both CCF (gap cutting and selection cutting) and RFM (clearcutting and seed tree cutting) harvesting methods. The clearcut areas and most seed tree areas were treated with disc trenching. In the clearcutting and seed tree cutting areas, 25–34% of the inventoried seedlings were damaged. In the gap cutting and selection cuttings, c. 7% and 12% of the seedlings were damaged respectively. Harvesting machinery traffic and soil scarification were the most important causal agents of seedling damage. An increase in slash coverage also significantly increased seedling damage. The average number of undamaged seedlings in the selection cutting areas was ca. 1500 pcs ha−1, indicating at least satisfactory regeneration potential in the experimental stands. [ABSTRACT FROM AUTHOR]