ENGINEERING FOR RURAL DEVELOPMENT Jelgava, 22.-24.05.2019. 227 EVALUATION OF FOREST TREE PLANTING MACHINE EFFECTIVENESS Dagnija Lazdina 1 , Karlis Dumins 1, 2 , Timo Saksa 3 , Kristaps Makovskis 1 1 Latvian State Forest Research Institute “Silava”, Latvia; 2 Latvia University of Life Sciences and Technologies, Latvia; 3 Natural Resources Institute Finland (Luke), Finland dagnija.lazdina@silava.lv, karlis.dumins@silava.lv, timo.saksa@luke.fi, kristaps.makovskis@silava.lv Abstract. Soil preparation method – mounding (with varying depth of the pit and the mound height) – may be the solution for establishing new forests when the soil water regime is unfavourable, since the pit serves as a reservoir for water during rainy periods and can retain water for the dry season. Thus, seedlings planted on mounds may obtain water through the soil capillary system when needed. During the last decades extreme weather conditions have occurred more often. And as there is a labour shortage for simple forest management tasks and increased hourly labour cost mechanized planting on mounds could be a promising solution to advance tree planting practices in Latvia. The aim of this study was to compare the productivity, quality and cost of mechanized planting and manual planting in Latvian conditions, where planting density of 2-2.5 thousand seedlings per ha is used. The M-planter was selected for the mechanized establishment of forest sites on mounded soils. During field trials, when 2000 trees per ha were planted, the productivity of the M-planter was 11.2 h ha on drained peat soils, 11.6 h per ha on drained mineral soils and 14.1 h per ha on wet mineral soils. Average mechanized planting time per 1 ha was 11.9 h, while making mounds and manual planting together took 11.2 h per ha. The cost of mechanized planting experiments in Latvian conditions, depending on the number of seedlings planted and planting conditions varied between 450 and 550 EUR per ha. Tree establishment success did not differ between the sites with mechanized or manually planted seedling, but depended more on the local site conditions. Keywords: silviculture mechanization, forest regeneration, Latvia, mounding. Introduction During the last decades forest management in Latvia has been intensified [1]. There are different soil preparation methods used around the globe, but soil preparation in furrows by disc trenching is the most common technique used in boreal forests [2]. This method has one main disadvantage – it is not appropriate for wet forest sites, because the furrows flood in spring and autumn, which causes decay of planted trees. It has been proven that in those conditions the more appropriate method is soil preparation in spot mounds [3;4]. Even though spot mounding is a more expensive method than disc trenching, the results in Fenoscandinavia suggest that total costs in the whole forest regeneration cycle are lower where mounding method was used [5]. Usually soil preparation and planting are separate forest management operations, but it is possible to combine them and currently different kinds of equipment intended for providing high-quality mechanized planting are available on the market. There are two main reasons for the promotion of mechanized tree planting, of which one is economical pressure to decrease silviculture costs and labour shortage, which also increase the total costs of forest management and cause problems in accomplishing forest management tasks [6]. The main reason for mechanized planting not already being widely used is the cost in comparison to manual planting [7]. Studies in Latvia also suggest the same: mechanized planting may be too expensive as a forest management technique [8]. Previous calculations conducted in Finland suggest that mechanized planting productivity should be at least 190 seedlings planted per productive work hour to compete in cost-effectiveness with manual planting [9]. Efficiency of mechanized planting is strongly affected by the technical performance of the machine on which the planting equipment is appendant [9] as well as how efficiently forest regeneration work has been planned. Including such factors as the distance to the seedling stockpile, operator experience, how much logging residue has been left behind [6]. The quality of planting spot can be affected by different factors, such as site conditions, equipment and method used as well as experience and motivation of labour force [10]. The aim of this practical research work was to compare the productivity, quality and the cost of mechanized planting and manual planting in Latvian conditions, where planting density of 2-2.5 thousand seedlings per hectare is used. DOI: 10.22616/ERDev2019.18.N306