Assessment of cork production in new Quercus suber

plantations under future climate

Joana A Paulo

Margarida Tomé

João HN Palma

22 May 2012 1

Introduction

• Climate is related to several variables that affect individual tree and stand cork production:

– Tree growth rates

– Tree vitality / mortality

– Cork growth rates

– Management options like:

• cork debarking rotation (period between two consecutive cork extraction operations – a minimum of 9 years according to the Portuguese law)

• Cork debarking intensities (maximum values regulated by the Portuguese law)

2

Introduction

SUBER

Tree and cork

growth

Tree dimention

Management

Cork growth

Tree mortality

Soil

Climate

Site index

Introduction

Process based models (e.g. Yield-Safe, 3PG)

Tree growth

Average tree

dimention

Climate Soil

Cork growth

Management

Tree mortality

Objectives

• Explore a methodology that allows the hybridization of the Yield-Safe ‘big leaf’ process based model and the empirical individual tree growth model for Quercus suber L.: SUBER model

• Simulate stand growth and stand cork production variations under future climate, in new plantations

5

Material and Methods

• Yield-Safe calibration for tree potential dbh, volume and biomass growth using:

– dbh (tree rings measurements on stem discs)

– Volume and biomass measures (dots)

6

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 10 20 30 40 50 60 70 80 90 100

age

tre

e v

olu

me

(m

3/t

ree

)

0

10

20

30

40

50

60

70

0 10 20 30 40 50 60 70 80 90 100

Age (years)

db

h (

cm

)

Material and Methods

• Assumptions for Yield-Safe simulations:

– The number of trees per hectare in the stand at 15 years of age, is equal to the number of trees per hectare measured in the forest inventory in 2007

– New plantations are managed for cork production:

• high number of trees per hectare

• no agro or pastoral activities

• no fertilization

• no irrigation

• periodical understory removal

7

Material and Methods

• SUBER allometric equation for tree cork production depending on: – tree size variables (dbh and

number of main branches) – management options

variables (debarking intensity)

• Estimates of cork production assume: – Debarking intensity equal

for all trees in the stand – 9 year interval between

consecutive cork extractions in the same stand

8

0

25

50

75

100

125

150

175

200

225

250

0 10 20 30 40 50 60 70 80 90 100 110

wc

m (k

g)

dbh (under cork) (cm)

Material and Methods

• Data from 2 cork oak plantations installed in 1992 and measured in 2007 (15 years old stands): – Soil information:

• Texture • Soil depth

– Number of trees per hectare at plantation

– Forest inventory data collected in 2007: • Diameter at breast height • Total heigh

– No cork inventory data (cork thickness or cork quality) – in 2007 stands had still not been debarked

9

Material and Methods

10

Coruche (Inland)

Arenosols

Medium soil texture

135 cm soil depth

Sines (Seashore)

Luvisols

Fine soil texture

150 cm soil depth

Material and Methods

• Climate daily data: – total shortwave radiation

– precipitation

– mean temperature

• Data source: – HadRM3Q0 A1B (ENSEMBLES EU project: Hadley Center

Regional Model Normal sensitivity)

– IPCC scenario A1B

– Daily data from 1951 to 2099: • 1951-2000

• 2001-2050

• 2050-2099

11

Material and Methods

12

0

5

10

15

20

25

30

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Ave

rage

te

mp

era

ture

(ºC

)

Month

Coruche (inland)

Tmean 1951-2000

Tmean 2050-2099

0

20

40

60

80

100

120

1 2 3 4 5 6 7 8 9 10 11 12

Mo

nth

ly p

reci

pit

atio

n (

mm

)

Month

Coruche (inland)

Prec 1951-2000

Prec 2050-2099

+ 3.4 ºC

-27 %

Material and Methods

13

0

5

10

15

20

25

30

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Ave

rage

te

mp

era

ture

(ºC

)

Month

Sines (seashore)

Tmean 1951-2000

Tmean 2050-2099

+ 2.9 ºC

0

20

40

60

80

100

120

140

1 2 3 4 5 6 7 8 9 10 11 12

Mo

nth

ly p

reci

pit

atio

n (

mm

)

Month

Sines (seashore)

Prec 1951-2000

Prec 2050-2099

- 20%

Hybridization scheme

Yield-Safe

Soil and climate variables

Assimilation of carbohydrates

(crop) Assimilation of carbohydrates

(tree)

Total above ground tree biomass

Stand basal area annual increment iGti+1 = Gti+1 - Gti

Tree basal area growth igti+1 = (gti / Gti) * iGti+1

SUBER

Tree cork production

Tree diameter under cork

Stand cork production

t1 – year corresponding to age 15 of the stand (age in during the forest inventory)

Stand basal area (Gt)

Results: basal area evolution

15

0

5

10

15

20

25

0 10 20 30 40 50

Basal

are

a (

m2/h

a)

Age (years)

1951-2000

2001-2050

2050-2099

Coruche

0

5

10

15

20

25

0 10 20 30 40 50

Basal

are

a (

m2/h

a)

Age (years)

1951-2000

2001-2050

2050-2099

Sines

Results: mature cork production

16

• The effect of climate scenario on cork production differs between the two sites:

Reduction of cork production in Coruche (inland)

No large variation of cork production in Sines (seashore)

0

1000

2000

3000

4000

5000

6000

7000

1st debarking 2nd debarking 3rd debarking

2210

4550

6258

2096

4274

5686

2191

4070

5310

Mat

ure

co

rk p

rod

uct

ion

(kg

/ha)

o

n e

ach

co

rk e

xtra

ctio

n

Coruche

1951-2000

2001-2050

2050-2099

0

1000

2000

3000

4000

5000

6000

1st debarking 2nd debarking 3rd debarking

2548

4366

5485

2577

4442

5476

2726

4430

5342

Mat

ure

co

rk p

rod

uct

ion

(kg

/ha)

o

n e

ach

co

rk e

xtra

ctio

n

Sines

1951-2000

2001-2050

2050-2099

Results: mature cork production

17

• Mature cork production variation along the 50 years simulation period: – Until less 11% in cork production in Coruche considering the 2050-

2099 climate data instead of the 1951-2000 data

– Close to zero cork production variation in Sines despite the climate data

10500

11000

11500

12000

12500

13000

13500

Coruche Sines

13018

12399

12056

12495

11571

12497

Mat

ure

co

rk p

rod

uct

ion

(kg

/ha)

al

on

g 5

0 y

ear

s

1951-2000

2001-2050

2050-2099

- 11%

- 7%

Results: Impacts ↔ Mitigation ↔ Adaptation

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• Impacts: – Climate will affect tree growth, and consequently, cork production, in

quantities varying between sites, namely soil characteristics ↓ – Climate will affect cork growth, and consequently cork thickness (cork

quality?) ↓ – Climate is already affecting tree mortality rates (stress, pests and

diseases) ↓

• Mitigation: – Reduction of the debarking intensities ↓ – Increase of the debarking rotation periods ↓ – New plantations in land areas traditionally used for agricultural

activities, with ‘better’ soil characteristics ↑ • Adaptation:

– Selection of new tree species and mixed stands more resistant and well adapted to climate conditions ↓

Results: Impacts ↔ Mitigation ↔ Adaptation

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Increase or maintain cork

production

Decrease cork production

Future chalenges

20

Cork oak hybrid model

Tree dimention

(YS)

Climate

Soil

(YS)

Cork growth

(Empirical?)

Tree mortality

(Empirical? Tree or stand

level?)

Hybrid model (individual tree)

Cork quality

Thank you

21