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Cleaner Technology Projects in Denmark 1997
Regulering af uønsket vegetation i pyntegrøntskultur ved afgræsning med får
Miljørapport nr. 362, 1997, Miljøstyrelsen
In this project the possibility of controlling weed in Christmas-tree plantations by
sheep grazing was investigated. The investigation, among other issues, includes a study of
different sheep breed’s food preferences in Christmas-tree plantations, the
application of different grazing strategies and a calculation of costs in connection with
weed control in Christmas-tree plantations by sheep grazing.
The production of decorative greenery is a growing source of
income for the forestry. So far the production has been characterised by a huge
consumption of herbicides. In the past years a number of
restrictions on the usage of herbicides have been imposed and, at the same time, the
producers of decorative greenery have become more conscious of the environment.
The use of herbicides has decreased and many producers of decorative greenery are
becoming interested in alternative production methods with the use of fewer chemicals.
This tendency will probably spread in harmony with the consumers increasing demand for
cleaner production methods. With this in mind it was investigated whether it is possible
to introduce weed control in Christmas-tree plantations by
grazing.
The results of the investigation show that sheep grazing is not a miracle solution to
the weed problem but provided good quality of the sheep, the right breed and skilled
managers to take care of the animals, the method is a realistic alternative to traditional
methods of weed control.
Sheep grazing will, after a few years, induce a dense mat of water-consuming grass and
therefore the method should be combined with mechanical and chemical weeding at fixed
intervals i.e. 2-3 years.
During the grazing period it is necessary to inspect the plantations daily for bites
and browsing on the trees and also to make sure that the sheep are healthy and in good
condition. The management costs are therefore a critical point in the overall economy of
the method. The results from the project indicate that forest districts should operate
with a stock number of at least 100 sheep in order to keep management costs per sheep low
and make the method competitive to traditional methods of weed control.
The most suitable sheep for use in Christmas-tree plantations of Caucasian fir and
Noble fir are the improved meat breeds. Good results were achieved in the project with the
use of Shropshire, Oxforddown, Dorset, Leicester and Suffolk, whilst breeds such as Texel
and the Nordic shorttailed group i.e. Gute, Gotland, Spael, Island and Finnsheep have a
tendency to nipple the trees. Shropshire seems to be the most consistently reliable of the
breeds.
A successful use of the method depends on the quality of the animals and the
management. One of the main problems is that Christmas-tree experts are rarely also
experts in sheep-husbandry. Therefore, special courses have been started, where forestry-workers are taught fundamental sheep-management and the
specific knowledge required when combining sheep and Christmas trees.
Author/ institution
Frans Theilby, Forskningscentret for Skov & Landbrug
This report is subsidised by the National Council for Recycling and Cleaner Technology
ISSN no. 0105-3094
ISBN no. 87-7810-799-7
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