Assessing the Amount of Force Necessary to Pick off Cones from Siberian Larch, Scots Pine and Siberian Pine Trees

Abstract

The article presents the results of studies conducted in Eastern Siberia, dedicated to determining the amount of force required for detachment of Siberian larch, Scots pine and Siberian pine cones, which is one of the main indicators that determines the parameters of cone collecting machines and mechanisms for coniferous species. The pick-off force for the cones was measured at different collection times in the upper, middle, and lower parts of the crown and at different angles of pull-off force direction. The limits of these forces variability are: for the Scots pine – 23.5–48.1 N, for the Siberian larch – 27.5–42.2 N; for the Siberian pine – 3.9–7.8 N. The data obtained can serve as a basis for calculating the parameters of cone collecting mechanisation tools for the aforementioned species. When designing machines and mechanisms for collecting the coniferous trees’ cones, it is necessary to have initial data that determine the parameters of the working bodies. One of these parameters is the amount of effort required to separate the cones from the branches. The forces of detaching cones from trees in the European part of Russia were determined by a number of researchers. According to I.M. Zima with co-authors (1966), the force of detachment of cones in Scots pine (Pinus sylvestris L.) is 41.2 N. According to I.A. Lavrov (1970), pine cones can be torn off with a force of 21.1 N, and the cones of Siberian larch (Larix sibirica Ledeb) – with a force of 39.2 N. In Siberia, studies on the cones detachment were first carried out in 1970 by the laboratory of mechanization of the forest seeds collection and processing of the ASRIM forestry enterprise (Orlovsky et al., 2016). The detachment of Siberian larch, Scots pine and Siberian pine cones was studied in the forestry enterprises of the Krasnoyarsk and Altai regions and in the Republic of Tyva. The pull-off forces of Scots pine and Siberian larch cones were measured in the lower, middle, and upper parts of the crowns using dynamometers with a 0.1 N division value and with a maximum force recording device. The measurements were carried out along the branch, at an angle of 40°–50° and at an angle of 90° to the branch.