is single tree selection suited for tasmania´s wet eucalypt forests

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Is single tree selection suited for Tasmania´s Wet Eucalypt Forests?

Lessons from the European experience

Andreas RotheUniversity of Applied Sciences Weihenstephan, Germany

Mark Neyland, John HickeyForestry Tasmania

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Overview:

• How common is single tree selection in Europe

• Experiences with single tree selection in Bavaria

• Experiences with single tree selection in Tasmania

• Conclusions

Rothe/Neyland/HickeySingle Tree Selection

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BavariaTotal area: 7.0 m haInhabitants: 12 m Forest area: 2.5 m ha State forest: 0.8 m ha total, 0.6 productiveAnnual cut: 5.0 m m3 = 8.3 m3 ha-1 y-1

(State forest)


TasmaniaTotal area: 6.8 m haInhabitants: 0.5 m Forest area: 3.3 m haState forest: 1.5 m ha, 0.7 productiveAnnual cut: 3.0 m3 = 4.3 m3 ha-1 y-1

(State forest)

ForestState Forest

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Proportion of Plenterwald (Continuous cover forests)(% of forest area)


Real Plenterwald Europe

(Schütz 2001)

Continuous cover forestry Germany

(National forest inventory 2002)

Continuous cover forestry Bavaria

(Internal inventory)

Switzerland: 8.0 % Real Plenterwald: 0.3 % Real Plenterwald: ca. 1 %

Slovenia: 4.1 % Multilayered 9%(continuous cover forests)

Continuous cover forests: 11%

Austria: < 2%

Germany: < 2%

France: 1.1 %

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Regeneration methods in Bavaria (State forests)(estimation)

Single tree selection 10 %

Group selection, shelterwood, edge cutting (<0.5 ha)

70%

Planned clear cuts < 1 %

Clear cuts after storm/insects 20 %

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Shade tolerance of European tree species

Minimum rel. light intensityfor foliage (%) (Mischerlich 1982)

1-2

1-2

3-4

5

10

20

27 (Alcorn 2002)

0 2 4 6 8

Abies alba

Fagus sylvatica

Picea abies

Quercus petraea

Pinus sylvestris

Larix decidua

Eucalyptus obliqua

Ellenberg Indicator Value Light

?

“Plenterwald species“

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Measurement of regeneration in the State Forests of Bavaria(about 150,000 inventory plots total, sampling about 15,000/year)


open regenerationregeneration without overstorey

understorey regeneration (overstorey > 30% crown cover)

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beech NW Bavaria

0

10

20

30

40

50

60

old forest understoryregeneration

young forest

prop

otio

n of

fore

st c

over

(%)

Regeneration of beech (very shade tolerant)(Lower Franconia, 100,000 ha, 30,000 inventory plots)

Nearly completely natural regeneration

Trees > 20y Understorey OpenRegeneration Regeneration

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pine E Bavaria

0

5

10

15

20

25

30

35


young forest

prop

otio

n of

fore

st c

over

(%)

Regeneration of pine (shade intolerant)(Upper Palatinate, 100,000 ha, 40,000 inventory plots)

Nearly completely natural regeneration


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0

5

10

15

20

25


young forest

prop

otio

n of

fore

st c

over

(%)

Regeneration of oak (rel. shade intolerant)(Lower Franconia, 100,000 ha, 30,000 inventory plots)

Mostly planting or sowing


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Standards method to regenerate light demanding oak

1. Planting on windthrown areas

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Standard methods to regenerate light demanding oak

2. Rapid Shelterwood System (0.5 – 4 ha)- Harvesting about 70 %

of standing volume- Sowing oak underneath

the retained trees- Harvesting the retained

trees within 5 years

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Area regenerated with oak (Spessart, Germany)

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Economic outcomeRothe/Neyland/Hickey

Single Tree Selection

Net yield of different forest management systems (Hanewinkel 1998)

Even aged Even aged Plenterwald Plenterwald with windthrow unfavourable

Bavarian State Forest Company:

Profit: 120 A$ ha-1 y-1

(2006/2007)

Profit/turnover ratio: 15 %

1. Model calculation: 2. Reality:

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Conclusions for Bavaria:1. Continuous cover methods work

well for shade tolerant species like beech, fir or spruce

2. Continuous cover forests can yield at least the same profits as even-aged forests

3. Continuous cover methods strongly disfavour light-demanding species like pine or oak

4. Regeneration of light-demanding species usually uses openings between 2-5 tree lengths in size

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And now moving to Tasmania …….

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Eucalypt regeneration at Warra at age 3(Neyland 2008)


0

2000

4000

6000

8000

SGSdispersedstripfellclearfell

Seed

lings

/ha

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0

500

1000

1500

2000

2500

3000

0 50 100 150 200 250

Distance from edge (m)

Avg.

see

dlin

gs p

er h

ecta

reCelery Top PineLeatherwoodMyrtleSassafras

Colonisation by rainforest seedlings(Tabor , et al. 2007)

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Expectation value (revenues - costs) of different regeneration techniques at Warra(Nyvold 2001)


-4000

-2000

0

2000

4000

6000

8000

10000

12000

CBS 10%Dispersed

30%Aggregated

SGS-A SGS-B

Economic outcome

$/ha

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Conclusions for Tasmania’s Wet Eucalypt Forests:

1.No examples of successful selective silviculture in Tall Wet Eucalypt forests

2.Single tree selection leads to inadequate eucalypt regeneration

3.Single tree selection is not sound from an economic point of view

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Fagussylvatica

Quercuspetrea

Eucalyptusobliqua

Naturalregeneration

Small gaps Fire, Wind ? Infrequentwildfires

shade Very tolerant Slightlytolerant

Intolerant

Tree height < 40 m < 35 m < 80 m

Understorey naked grasses Trees and shrubs

Minimumopening forregeneration

1 tree 2 tree lengths 2 tree lengths

Standardsilviculture

Shelterwood,groupselection

Rapidshelterwood

Clearfell, Burnand Sow

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How small can we go ?

Group selection with openings of about 80 m (Warra 8G)

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Overall conclusions:

1. The transfer of silvicultural experiences must be based on ecology of the site and the tree species.

2. Continuous cover methods which are hardly used for oak and pine in Europe are very unlikely to work for tall wet Eucalypt forests in Tasmania.

3. Forestry with light demanding species does not require large clearcuts but needs minmum openings of 2 - 5 tree lengths.

is single tree selection suited for tasmania´s wet eucalypt forests

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