Order of harvesting and processing storm-damaged timber – proceeding in Baden-Württemberg after "Lothar"
Before starting to harvest storm-damaged timber one should in a general
way fix in which order in with which priorities the different tree species and forest stands will be treated. Thereby
- "Absorbing capacity of the timber market"
- "Marketable assortments and timber utilization"
- "Forest protection"
to be taken into account and weighted against each other.
The speed of the harvesting and processing plays an important role.
Depending on the amount of damaged timber (volume and species) in the forest
enterprise, the situation on the timber market, the own available labour
capacity and the possibility to store timber, it is useful to stretch the
harvesting of the timber.
Hereby, the actual situation of forest protection and
its development has to be taken into account. In the following, the strategy of
harvesting and processing of storm damaged timber after the storm event "Lothar" in December 1999 of the state forest service of Baden-Württemberg will
be described as one possible approach:
The damaged hardwood has to be harvested as fast as possible conserving
the value of the timber.
Valuable timber of hardwoods is harvested before the timber of conifers.
Follow-up damages to standing forest stands by insects are minimised.
Storm broken trees are preferentially harvested. Scattered damaged trees
are processed before large storm areas. Broken trees are preferably processed. Ongoing control of live-conserved forest stands for insect attacks. The
harvesting strategy is adapted to the actual situation of forest protection.
A part of the coniferous timber from the state forest does not charge
the timber market at peak times as it is withdrawn by conservation.
A large part of the conifers from the state forest is conserved by wet
storage and only reaches the timber-market at a later point in time. Thereby
the "non-state-forest" can sell its stemwood early.
The following order has been fixed, whereas an adaptation to local
conditions was necessary:
- Clear the necessary transport- and forest roads; ensure the access to
the damaged areas and the hauling of the processed timber. It is recommended to
firstly clear the roads to the required areas (if this is in line with the
general traffic, e.g. for recreation, …) and – if possible - to process into
marketable assortments. Overhasty cutting of trees into small logs to clear
roads increases problems in marketing, storing and protecting timber against
- Start with processing beech and valuable hardwoods – minimum quality
class B and size L 3b (- mid diameter >35 cm) (3a >30cm) – at first on
large areas until 4 months after the event (in case of a winterstorm), after
that also scattered trees should be harvested until 8 months after the event.
The reason therefore is to avoid a fast devaluation of the valuable hardwood
timber. Moreover, the cost-intensive processing of small and low-valued
hardwood should be avoided for economic reasons, resp. to be restricted to
- Processing of "damage-nests", especially with broken trees of spruce and
pine (motor manual), remove stumps, process as long poles. The most important
point here is to avoid bark beetles, as broken trees will be attacked the
fastest by bark-breeding beetles (e.g. Ips typographus). Especially storm damage-nests and concentrated single
damages are starting points for bark-beetle damages. This danger has to be
minimised by completely removing the breeding-material from the beginning.
- Processing of large storm damaged areas of Norway spruce and pine with
the help of contractors until 15 months after a winterstorm. Due to the large
and nation-wide offer of harvesters and forwarders large storm-damaged areas
could be processed at the same time as "damage-nests". If there is a lack of
demand or no possibility of wet storage, processing should be postponed. Ideal
for postponing are large damaged areas with a share of broken trees of less
- Other conifers: The experiences from the storm in 1990 showed that bark
beetles at silver fir are less aggressive. There also a minor forest protection
problem with Douglas fir. Non-processed Douglas fir was estimated to be
storable in situ until 2002 (24 months after the storm event).
- Valuable logs and stemwood of oak and poplar: Oak should only be
processed on demand. Both tree species have been successfully stored unprocessed
in situ until winter 2001/2002, or even spring 2002 (12-24 months after the
- Processing of small sized conifer logs (< 20 cm dbh) and industrial hardwood
is of subordinate importance. No
treatment of logging debris in the year 2000. According to the experiences of
the year 1990 the risk of attacks by Pityogenes chalcographus can be
controlled. No danger of bark-breeding bark-beetles is issued from broadleaves.
and evaluation concerning the order of processing
Experiences have shown
that the order of processing storm damaged timber was right. The strategy "preferred and fast processing of valuable broadleaves until May 2000 (5 months
after the event)" has proven to be successful. Despite the approaching end of
the season for hardwoods and a relevant volume of oak-timber from France, an
important volume of timber could be sold to acceptable timber prices.
aspects "order of processing" and "speed of processing" have to be analysed in
a more differentiated way. Although the given targets were not fundamentally
put into question, reality increasingly deviated from the given strategies
during the summer after the storm. The strategies can therefore only partly be
looked upon successful.
- Many of large damaged areas have been processed mechanically. Due to the
higher performance of the machines these large areas were often faster
processed as the small areas , which was not according to the strategy. Some of
the contractors tried to implement themselves on the attractive large areas
instead of working on small areas using extortionary methods.
- In order to quickly fill the wet storage places, the early use of
harvesters on large areas was necessary.
- The expectations of private and community forest owners had a certain
influence on the decision not to decrease the speed of processing.
- The mental and emotional load on the collaborators lead to the desire to
clean up the damage as fast as possible.
- A lack of discipline and solidarity of some employees of the forest
service and some forest owners lead to a competition for resources and
sales-contracts. Consequently, the speed of processing increased continuously
in the first months after the storm.
Subordinate processing of small-sized conifers:
- Against previous expectations, the years after the storm have shown that
the damage caused by Pityogenes chalcographus can endanger whole forest stands.
These has to be taken into account when designing future strategies.
Results of the high speed of processing:
- In some forest districts, it was not possible to transport the logs out
of the forest due to a shortage in hauling capacity. Possibilities to store the
logs along the roads were soon exhausted. Due to the long storage times along
forest roads the situation of forest protection was deteriorated and the
quality of the logs decreased. If the situation of forest protection and labour
organisation allows for, in situ conservation (live storage) should be preferred to processing and
consecutive storage of timber along the roads.