The level of mechanization in Croatian silviculture is considerably lower than the one reached in forest exploitation. The only exception is the nursery production whose mechanization is almost equal to the agricultural production. Special efforts are taken to replace manual work by machines when it is dealt with precious stands such as Croatian pedunculate oak forests.
In many cases the existing vegetation over large forest areas or rides of various widths should be cut up. Depending on the type, thickness, species, etc. of the vegetation, these jobs can be done with flail shredders in a short time. The appearance of the mulching machines has enabled their further use in forest soil preparation for seeding and planting of seedlings. Furthermore, mulching flail mower may be used for cutting through fire breaks; restoration of the neglected farmlands; cleaning the land from plant residues; maintenance of forest roads, etc. In the lowland forests of the pedunculate oak similar jobs must be done particularly after unsuccessful regeneration felling followed by excessive weed growth; in the case of excessive growth of unfavourable brush and tree species due to forest dieback; when efficient systems of silvicultural tracks, roads, etc. are introduced; when carrying out mechanized sowing right after soil preparation by scattering the acorn and covering it with cut plants mixed with soil, which is a future project for widening the use of the mulching flail mower.
The choice of the mulching flail mower Seppi m. Miniforst and the prime mover Steyr 8090, a tractor adapted to the work in silvicultural operations by the built-in crawling speed, double steerage (forward and backward), rpm of power take-off has resulted in an aggregate whose possibilities of use had yet to be defined.
The exploitation test was accelerated by the problems that had occurred in the transmission of the tractor, the coupling power take-off. In addition, optimal speeds, number of passes, height/depth of the machine reach had all to be standardized for the characteristic working conditions.
Key words: silvicultural pass and trail, mechanized silvicultural work, mulching flail mower, prime mover.
Correspondence: Dubravko Horvat, Faculty of Forestry, Svetosimunska 25, 41000 Zagreb, Croatia
Telefax: +385-1-218616
E-mail: dubravko.horvat@hrast.sumfak.hr