Silvicultural systems

Gary Kerr, Silviculturist, Forest Research

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What silvicultural system is this…and does it matter?

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Structure of Presentation

• Silvicultural Systems (including a show by the Llanidloes Players)

• Continuous Cover Forestry, Low Impact Silvicultural Systems and ATC

• Relevance and application• Take away messages

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What are silvicultural systems?

‘A silvicultural system may be defined as the process by which the crops constituting a forest are tended, removed and replaced by new crops, resulting in the production of woods of a distinctive form.’

(Troup, 1928)

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Four components of a silvicultural system

• Regeneration• Tending• Harvesting• [Stands of distinctive form]

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Regeneration

Tending

Harvesting

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Regenerate

Tending

HarvestingRegenerate

Tending

Harvesting

5 ha felling unit

0.1 ha felling unit

Application to a 5 ha forest stand

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Presented by the Llanidloes Players

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Silvicultural systems

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What are the main differences between a selection system and a uniform/group/irregular system?

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CCF, ATC, LISS and Silvicultural systems

• Continuous cover forestry• Alternatives to clearfelling• Low impact silvicultural systems • Close-to-nature forestry• Dauerwald• New forestry• Ecosystem management• Transformation• Uneven-aged silviculture• Irregular silviculture

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Many of these terms are used to describe approaches or processes that attempt to integrate the ever increasing range of objectives (economic, environmental, social) into forest management.

The main driver is diversity at stand and landscape scale.

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The Woodland Strategy for Wales uses the term Continuous Cover Forestry

• This is an approach to forest management and not a silvicultural system. It has 4 main guiding principles*:

• Managing the forest ecosystem• Using natural processes• Working within site limitations• Diversifying stand structure

* as described in FCIN29

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Silvicultural systems

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Low impact silvicultural systems

Small coupe felling

Coppice +/- standards

Minimum intervention

Others

CCF/ATC

Definitions

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Relevance and application

• Stands of distinctive form• When Troup and others classified different

silvicultural systems they were mainly based on examination of stands where different systems had been practised for at least 50 years

• Consideration of transformation (from even-aged to CCF) is limited…

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In the context of transformation to CCF:

• Option 1: deposit the concept of silvicultural systems in the WPB and work with the dynamics of the forest to create:

• a simple CCF structure (1 or 2 canopy layers)• a complex CCF structure (3 or more canopy layers)

• Option 2: use Silvicultural System as a ‘working hypothesis’ and not a ruling doctrine.

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Take away messages

• All silvicultural decisions must be driven by management objectives.

• Silvicultural systems are a classification of different applications of regeneration-tending-harvesting.

• Continuous Cover is an approach to forest management. There is not an exact match with different silvicultural systems.

• Silvicultural systems are best used to describe future treatment of long established woodlands.

• For transformation to continuous cover, use forest stand dynamics to develop simple or complex structures.

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..the successful application of some silvicultural systems would be impossible at present for two reasons: (i) the derelict state of many woodlands due to faulty treatment and (ii) the country is so infested with rabbits that economic forestry in any form is often difficult if not impossible.

(Troup, 1928 [paraphrased])

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Questions and feedback