To tackle the shortage of labour during the forest planting season and the rising cost of silvicultural work services, AS “Latvijas valsts meži” (LVM) has begun testing one of the world's most efficient mechanised planting machines – “PlantMax”.
Working together with experienced operators from “Plantma Forestry AB” in Sweden and researchers from the Latvian State Forest Research Institute (LVMI) “Silava”, the first tests and efficiency trials of the “PlantMax” planting machine under Latvian conditions took place in May. So far, machines of this kind are at work in Sweden, Canada, the USA, Australia and Brazil.
While studying mechanised forest planting solutions around the world, the attention of LVM's experts was drawn to the “PlantMax” planting machine developed by the Swedish company “Plantma Forestry AB”. In 2023, representatives of LVM and a delegation of Latvian private entrepreneurs travelled from Latvia to Sweden to see the forest planting machine in action. Although a prototype of the technology was created back in the 1980s, development of the “PlantMax” machine was revived and its production in Sweden began in 2018.
“The machine promises a productivity of up to 3000 seedlings per hour, which is slightly more than one hectare of regenerated area per hour. That means a forest can be planted over an area of about eight hectares in a day. By comparison, using hand tools a person plants an area of about 0.3-0.5 hectares a day in previously prepared soil. Unlike other mechanised solutions used to date, “PlantMax” stands out both for its output and for its range of application in different types of forest – this machine could be used not only on dry mineral soils but, with chains fitted, also in wetter forest types, including areas with a thicker peat layer,” explains Edmunds Linde, Silviculture Planning Manager at LVM.
During the trial, in which 30 hectares were planted with the “PlantMax” machine, researchers from LVMI "Silava" were brought in; they fitted the planting machine with video cameras in order to record the course of the work, calculate productivity and assess planting quality. The regenerated forest areas will be surveyed regularly in the coming years to evaluate how successful the regeneration has been.
Technological development and the mechanised solutions in use
The development of technology and the introduction of innovative mechanisation solutions in forest management improve the safety of those doing the work and increase efficiency, as well as helping to address the current shortage of labour in the forest sector.
LVM has been using mechanised forest planting with an excavator on mounds since 2018. Although planting takes place at the same time as soil preparation and makes it possible to work all year round, for as long as the ground is not frozen and there is no prolonged drought, planting on mounds is carried out mainly in wet areas and productivity is comparatively low – no more than one hectare a day.
In 2022, LVM introduced the practice of mechanised sowing, in which soil preparation is combined with the sowing of seed. A study of the method's efficiency concluded that output matches that of soil preparation with disc ploughs, namely from 5 to as much as 12 hectares a day. However, mechanised sowing can be carried out on dry sites that are not prone to overgrowing, where the forest is to be regenerated with pine.
The innovation of “PlantMax”
The machine is based on a mid-range forwarder from which the load bunks are removed; a soil preparation unit is installed between the front and rear tandems, the planting machine is mounted in place of the bunks, and in place of the forwarder's manipulator there is a lorry crane with a lifting capacity of 1.2 tonnes, which is the weight of a full seedling container. At the rear of the machine there are two planting “arms”, each able to carry out a planting operation once every three seconds.
Two people work on the machine: the machine operator has the main role in the team, since it is they who choose the machine's route and control the soil preparation unit. Wherever the soil preparation unit has prepared the soil, that is where the planting unit plants. The planting spot can be changed manually, or the choice can even be made to plant in unprepared soil, by the planting unit operator, who sits in a cab at the rear of the machine and loads seedlings into the planting unit from cassettes or boxes.