Ministerium für Umwelt und Naturschutz, Landwirtschaft und Verbraucherschutz des Landes Nordrhein-Westfalen Modelling of the carbon accumulation in beech

Ministerium fürUmwelt undNaturschutz,Landwirtschaft undVerbraucherschutzdes LandesNordrhein-Westfalen

Modelling of the carbon accumulation in beech forests based upon inventory data

and with regard to the biomass and nutrient export through an intensified harvesting

Rainer Joosten


General Situation

NRW Climate protection through forestry 1. Carbon sequestration 2. Biomass energy

Political demands: Forest protection Increase the forest cropping (EU: +160 Mio m³ = > 50%)

Issue to quantify: carbon storage maximise the biomass harvest

Nutrient export through full tree harvesting


Situation in North Rhine - Westphalia

Area: 34,000 km² 18 Mio People = 527 per km² primary energetic consumption: 4,100 PJ Green energy: <1% (45% coal) CO2-emission: 16.8 t per capita

880,000 ha forest 1.1 Mio additional energy wood resources (77% hardwood) = 0.2% of the primary energetic consumption

Cologne


Aim of the study

Beech forests are the most important hardwood forests in NRW ( Developing of reliable functions for beech stands

Biomass Carbon Main-Nutrients (Ca, Mg, K , P)

connecting these functions with the inventory data on tree level

Inventory: 1 x 1 km² Tree level variables: DBH, Height Sample plot variables: Altitude, precipitation, temperature

NRW: 20 – 800 m above sea level, 550 – 1500 mm, 5° - 10,5° C


116 Sample trees from four growing regions

80 cm

40 cm

40 m

20 m

dbh height


Predicted and observed ln-transformed functions

R² = 0.995; AIC: -86.1 R² = 0.996; AIC: -100.2


Error of carbon prediction

Relative prediction error: at tree-level:

16 % At plot level

< 10 % Whole NRW (≈ 1500 inentory plots)

< 2 % Stock changes (presupposing remeasurement)

1 %


-4

-2

0

2

4

6

8

-4 -2 0 2 4 6 8

ln C (kg) observed

lnC

(kg

)p

red

icte

d

-4

-2

0

2

4

6

8

-4 -2 0 2 4 6 8

ln C (kg) observed

lnC

(kg

)p

red

icte

d

(1 ) P e llin e n . (2 ) P re tz sc h1 :1 1 :1

Comparing with six reference studies (ln C kg)

North Germany North Germany

Pre

dic

ted

(g)

Observed (g)


Comparing with six reference studies

Austria (Vienna) South Sweden

-4

-2

0

2

4

6

8

-4 -2 0 2 4 6 8

ln C(kg) observed

lnC

(kg

)p

red

icte

d

-4

-2

0

2

4

6

8

-4 -2 0 2 4 6 8

ln C (kg) observed

lnC

(kg

)p

red

icte

d

(3 ) H o c h b ic h le r1 :1 1 :1

Pre

dic

ted

(g)

Observed (g)


Comparing with six reference studies

North Spain USA

-4

-2

0

2

4

6

8

-4 -2 0 2 4 6 8

ln C (kg) observed

lnC

(kg

)p

red

icte

d

-4

-2

0

2

4

6

8

-4 -2 0 2 4 6 8

ln C (kg) observed

lnC

(kg

)p

red

icte

d

(6 ) S c h ro e d e r e t a l .(5 ) S a n ta R e g in a e t a l .

1 :1

Pre

dic

ted

(g)

Observed (g)


Estimation of aboveground Ca and Mg

0

2500

5000

7500

10000

0 2500 5000 7500 10000

g e m e s s e n e r W e rt C a in g

bere

chne

terW

ertC

ain

g

R ²= 0 ,979

0

500

1000

1500

2000

2500

0 500 1000 1500 2000 2500

g e m e s s e n e r W e rt M g in gbe

rech

nete

rWer

tMg

ing

R ²= 0 ,985

Pre

dic

ted

(g)

Observed (g)

Ca Mg

d-h-alt-temp(y) d-h-temp(v)


0

1000

2000

3000

4000

5000

6000

0 1000 2000 3000 4000 5000 6000

g e m e s s e n e r W e rt K in g

bere

chne

terW

ertK

ing

R ²= 0 ,984

0

100

200

300

400

500

600

0 100 200 300 400 500 600g e mes s en er W ert P in g

ber

ech

net

erW

ert

Pin

g

R²= 0,981

Estimation of aboveground K and PP

red

icte

d (

g)

Observed (g)

K P

d-h-alt-temp(y) d-h-preci.


Estimation of nutrient export realising the allowable yield cut of the FI

Merchantable wood (> 7 cm) : Volume: 11,2 m³ ha

–1 a-1

Biomass 6,6 Mg ha –1 a-1

Ca: 13,75 kg ha –1 a-1

Mg 2,45 kg ha –1 a-1 K 6,24 kg ha

–1 a-1 P 0,60 kg ha

–1 a-1

Branches ≤ 7 cm Volume: 2,0 m³ ha –1 a-1

Biomass 1,18 Mg ha –1 a-1 + 18 %

Ca: 5,53 kg ha –1 a-1 + 40 % Mg 0,56 kg ha –1 a-1 + 23 % K 1,49 kg ha –1 a-1 + 24

% P 0,32 kg ha –1 a-1 + 53

%


Abb. 4:

TDAC: 2,7 – 4,15 kmolc/ha*J

Verwitterung*): 0,2 – 1 kmolc/ha*J

Rei(K+Ca+Mg): 0,37 kmolc/ha*J Dh(K+Ca+Mg): 1,05 kmolc/ha*J

TD(K+Ca+Mg): 0,34 – 0,60 kmolc/ha*J

Simplified acid-base-balance in beech forests

Total deposition (TD)acid

K+Ca+Mg

weathering

Wood ≤ 7 cm

Wood > 7 cm


Conclusions

NFI provide statistically reliable data Connecting tree-level data with biomass functions should be preferred Implementing site specific variables improve the reliability Periodical remeasurement of sample plots decrease the error The application of biomass functions of foreign regions is questionable

Depending upon site and climatic conditions

Neither renunciation on full tree harvesting nor mechanical barking will balance the nutrient budget for annual depositions

Compensation only through fertilisation On fertilised sites harvest restrictions are unnecessary

Documents

Ministerium für Umwelt und Naturschutz, Landwirtschaft und Verbraucherschutz des Landes Nordrhein-Westfalen Modelling of the carbon accumulation in beech