1

Marteloscope exercises -

comparing the «performance» of

groups with different professional

backgrounds, expertise and values

Partly based on a manuscript together with Hannes Cosyns, Bettina Joa, Ronja Mikoleit, Frank Krumm, Andreas Schuck

and Georg Winkel

Marteloscope Manager Workshop

Steigerwaldzentrum, Handthal, 25-27 April, 2018

Tobias Schulz, WSL

Observed marteloscope exercises

Site Date Participants Design

Rosskopf 04/2015 Stud., For., Train. Group comp.

Rosskopf 04/2016 Students 1

Steinkreuz 04/2016 For., others 2

Groenendaal 05/2016 Students 1

Groenendaal 05/2016 Foresters 2

Renan 06/2016 Students Group comp.

Steinkreuz 08/2016 For., others 2

Ettingen 09/2016 For., others None

Sihlwald 10/2016 Students 4

Rosskopf 04/2017 Students Group comp.

Sihlwald 10/2017 Students Group comp.

Falkenberg 10/2017 For., Nat. Con. Group comp.

Jägerhäuschen 11/2017 For., Nat. Con. Group comp.

2

Pre / post observation

Information provided betweentwo thinnngs

• Problem:

– control group?

– same forest twice?

• Solution:

– Split the plot

– Split the group

Second thinning with the tablet in hand

DESIGN 1

Pre Treat Post

Group

A

plot 1 X plot 2

Group

B

plot 2 X plot 1

Plot 1

Group A

Group B

Plot 2

DESIGN 2

Pre Treat

Group A plot 1 X plot 2

Group B plot 2 X plot 1

Learning about microhabitats

(Rosskopf, April 2016, Students)

1 2 3

Select 5

Habitat trees

Learning moment :

Microhabitats +

thinning

Select 5

Habitat trees

0.0

0.5

1.0

1.5

2.0

2.5

3.0

BEFORE AFTER

Mean

am

ou

nt

of

MH

typ

es

/ tr

ee

Microhabitat types

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

BEFORE AFTER

Me

an

am

ou

nt

of

MH

/ t

ree

Microhabitats

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

BEFORE AFTERM

ean

eco

log

ica

l va

lue

/ t

ree

Ecological value

** *

5

Jaegerhäuschen (November 2017)

6

IntroductionMscope-exercise in

teamsGroup discussion

Questionaireper team

• Trees selected• Observations:

following teams

• Expertise & preferences

• Reasoning

• Moderation• Transscripts of

Discussion

Instruction

13 Nov2017

14 Nov2017

«FORESTERS»

«NATURE CONSERVATIONISTS»

Structure of exercise, participants

• From State Nature Protection Administration• Mostly Biologists• One task can be identification of habitat trees

• From State Forestry Administration• Mostly Foresters• Marking trees is daily business

Instruction

«Removal of 50 m³ wood, selecting a minimum of trees, of which 10 % high-value wood, promotion and selection of 10 habitat trees»

Volume and value requirement plus dhbrequirement: trade-off against selection of relatively large number of habitat trees (particularly if they should have a large dhb)

7

Hypotheses for thinning

T-H2 NC FHabitat value <Number of Microhabitats <

8

T-H1 NC FEconomic value <DHB <Volume <!

Hypotheses for habitat tree selection

H-H1 NC FHabitat value >Number of Microhabitats >Tree species >?

9

H-H2 NC FEconomic value >DHB >

NC FOpportunity cost of habitat value point >

Hypothesis about «performance»

10

H-H4: Positive correlation between preference for ecological objectives / expertise in forestry/ecology and distance of solution to the “pareto-frontier”.

aggregated habitat value

Set of all possible combinations of a certain number of trees

Agg

rega

ted

eco

no

mic

val

ue

“PARETO-FRONTIER”

• Less economic expertise?• Higher preference for ecology?

• Higher economic expertise?• Less preference for ecology?

Thinned trees

11

Nature Conservationists Foresters

51.160.317

157110640.632

192.9

63.163.715

164123350.438

135.9

Mean DiameterVolume

Number of MicrohabitatsHabitat value

Economic valueSG-ratio

Number of trees% high-quality wood

(cm)

(m3)

(habitat point)

(euro)

***

Significance-level

12

Habitat tree selection

Nature Conservationists Foresters

67.95526

3537385

50.53221

2602724

Mean DiameterVolume

Number of MicrohabitatsHabitat value

Economic value

(cm)

(m3)

(habitat point)

(euro)

****

******

Significance-level

13

Habitat trees:Disentangling preferences from expertise?

Nature conservationistsForesters

Habitat trees:Values, expertise and «performance»

Habitat

value

Econ.

value

Pref. Expert

Ecol.

Expert

For.

# Habitat

Trees

Op.

cost

Distance

N1 317 10829 1 4 3 10 34 225.7

N2 351.25 5148 2 5 2 8 14 92.1

N3 387.5 4325 2 5 2 12 11 117.1

N4 371 4659 2 4 2 10 12 103.7

N5 331 11594 2 2 3 10 35 226.1

F1 232 1677 4 3 5 10 7 35

F2 265 4144 3 3 5 10 15 119.6

F3 279 2366 4 4 5 10 8 50.8

F4 195 2214 4 3 4 11 11 72.4

F5 248 2429 4 3 3 11 9 42.1

F6 370 3811 4 3 4 8 10 48.2

14

15

Marteloscope «Rosskopf»(April 2015, 5 habitat trees)

16

Microhabitats (Jägerhäuschen 2017)FT: Foresters – Thinned Trees

FH: Foresters – Habitat Trees NT: Nature Conservationists – Thinned Trees

NH: Nature Conservationits – Habitat Trees

17

Qualitative analysis

• timber value

• DBH

• microhabitat structures

• „cost of habitat point“

• future microhabitat structures

• vitality and stability

risk of diminishing timber value

„eco plus tree“ / future habitat tree

longevity of habitat tree

probability for microhabitat structures

timber volume

Joa, B. & Mikoleit, R.

Citeria applied in tree selection• searching for economically valuable trees

• searching for wood defects

searching for microhabitat structures

18

Factors influencing tree selection

• preference and experience/profession

• familiarity with the stand

• visibility of microhabitat structures

• timber market

• financial compensation for conservation

• environmental laws

• work and road safety

• long-term silvicultural goals

Joa, B. & Mikoleit, R.

19

Learning during a marteloscope exercise

• Strong visualization of yours (and the others) decisions!

• Generates understanding for the others!

«before I never thought about a tree’s timber value, I onlylooked at its habitat structures… next time I have to makethe decision whether or not a tree is a valuable habitat tree, I will consider ist potential economic value, which couldmake the decision easier…»

(a nature conservationist after the exercise)

20

Conclusion habitat tree selection

• Small trees (hornbeam) vs large trees (oaks): Foresters select a lower habitat value at a lower cost

➜ «Economic consideration» or«future habitat value»? (or both?)

• Foresters are closer to the «pareto frontier», so theysolve the goal conflict «better», presumably due tohigher expertise about economic valuation

• Nature conservationists choose oak only, which probably is main reason for «lower» performance...

21

Policy implications?

• Are pecuniary incentives needed to preserve a larger number of economically interesting oak trees as habitat trees (compensation)?

• Given that they assume an important role also for the identification of habitat trees, maybe nature conservationists should gain more expertise about the economic aspect? Could help avoiding conflicts?

22

Outlook

• Future research on development on microhabitats

• Economic and ecological growth models underlyingmarteloscope inventory

• Two dimensional world too simple?

• Connection between thinning and habitat treeselection: reasons for not cutting «non-habitat-trees», competitors, spatial distribution, ...

23

Photo : Kris Vandekerkhove INBO