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9. THE COST-EFFICIENCY OF SEEDLING PACKAGING
SPECIFICALLY DESIGNED FOR TREE PLANTING
MACHINES
Back Tomas Ersson 1 *, Urban Bergsten 2 & Ola Lindroos 1
1 Dept. of Forest Resource Management, SLU, 901 83 Umeå, Sweden
2 Dept. of Forest Ecology and Management, SLU, 901 83 Umeå, Sweden
* back.tomas.ersson@srh.slu.se
Introduction
As an alternative to manual tree planting, mechanized tree planting has been revived in southern
Sweden in the last five years. Currently, mechanized planting in southern Sweden is only
performed using the crane-mounted Bracke Planter. The Bracke Planter plants seedlings with
biologically similar (von Hofsten 1997) or better (Ersson and Petersson 2009) results compared to
operational manual planting, but at a higher cost.
One of the key reasons why crane-mounted planting machines are still not economically
competitive with manual planting in Sweden is the lack of automated seedling handling and
feeding systems. The planting heads must instead be reloaded manually, and this task occupies
from 15% (Rantala et al. 2009) to more than 30% (Halonen 2002) of the machine’s effective
working time. Moreover, as machine productivity increases, relatively more of the effective
working time is spent manually reloading seedlings. There is, therefore, a need to automate the
feeding and handling of seedlings if crane-mounted planting machines are to become cost
competitive compared to manual planting.
The efficiency of automated handling and feeding systems is dependent on how integrated they
are with the seedling transportation system. Considering that today’s containerized seedlings are
delivered to the clearcut either in cultivation trays or cardboard boxes designed for manual
planting, there may also be a need to change how seedlings are packaged if the planting
machines are to become more productive.
However, machine-specific packaging solutions warrant extra labour, packaging, and investment
costs at the nursery as well as extra investment costs for the planting machine. Furthermore,
seedling transport costs and work methods might also be affected. Thus, the anticipated gains in
planting machine productivity due to decreased planting head reloading time must be contrasted
with these extra costs.
The aims of this study were twofold: 1) to describe seedling packaging concepts specifically
designed for planting machines; and 2) to compare the total cost of these machine-specific
packaging concepts with today’s most common seedling packaging systems (i.e. Hiko cultivation
trays and cardboard boxes).
Materials and Methods
The four seedling packaging systems used in this comparative cost analysis were described as
follows:
s1) Hiko trays: cultivation trays in which seedlings are also transported to the planting
machine. From the nursery, trays are handled individually by hand and distributed to the
contractor’s depot by light courier trucks. Trays are returned to the nursery for reuse.
s2) Cardboard boxes: single-use boxes packed by a packaging line at the nursery.
Boxes are stacked onto Euro pallets and distributed to the contractor’s depot as standard
shipping units by general groupage delivery trucks. From the depot, boxes are handled
and transported individually by the contractor. Boxes are recycled after use.
s3) Band-mounted seedlings: seedlings mounted between strips of paper, rolled into a
vertically-standing coil, and then packed into cardboard boxes at the nursery. Handling,
transportation, and recycling of boxes is otherwise equal to s2.
s4) Container modules: containers the size of a Euro pallet containing 1500-2100
seedlings in linked pots. A packing line at the nursery packs both the pots and containers
which are then distributed to the contractor’s depot by general groupage delivery trucks.
From the depot, the containers are handled individually by the contractor using a small
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