Variation in ages and growth rates of trees in Amazonian tropical forests: consequences for

carbon and forest management

Simone Vieira, Plínio Camargo, Luiz Martinelli (CENA)

Susan Trumbore (UCI), Jeff Chambers (Tulane), Niro Higuchi (INPA)

Diogo Selhorst, Foster Brown (SETEM)

Our questions – CD-08

What is the capacity for these forests to store C?Where could it be stored and for how long?

Our approach – CD-08

Look at components of C fluxes: This specific work: changes in living tree C stocks, and the environmental variables that control them.

Use radiocarbon to determine the residence time of carbon in trees and soils

ManausZF2 Reserve

Rio Branco - Catuaba Exp. Farm

SantarémTapajos National Forest

Rio Branco

Manaus

Santarém

Field sites

All terra firme forestSoils are OxisolsVariation in dry season lengthShortest in Manaus, longer in Rio Branco, Santarém

Trees

How old are tropical trees?

How fast do they grow?

How long do they store carbon?

How do characteristics vary across the Amazon basin?

Measurement of tree diameter during establishment of permanent plot

= 122.51e-0.4418x

= 470.26e-0.6893x

= 108.64e-0.454x

0.0001

0.001

0.01

0.1

1

10

100

1000

10-19,930-39,9

50-59,970-79,9

90-99,9

110-119,9

130-139,9

150-159,9

170-179,9

190-199,9

Classe de Diâmetro

ln in

diví

duos

.ha-1

Manaus

Rio Branco

Santarém

Stem frequency in DBH Class (stem ha-1)

Manaus (626), Rio Branco (467) and Santarém (460)

0

10

20

30

40

50

60

70

80

90

10-2020-30

30-4040-50

50-6060-70

70-8080-90

90-100

100-110> 110

DBH Class

Bio

mas

s (M

g.ha

-1)

Manaus

Rio Branco

Santarém

Bio

mas

s (M

g ha

-1)

Tree diameter class (cm)

Not all forests in the Amazon are equalManaus has more biomass overall, in smaller trees,than sites with a more pronounced dry season

Manaus Rio Branco Santarém 626 466 460 trees ha-1

180 95 141 Mg C ha-1

40 45 56 cm (DBH mean)

Vieira et al., 2004

Growth rates from dendrometer bands

Growth rates vary seasonally with rainfall, though not simply

Man

aus

DM

DV

(m

day

-1)

-5

0

5

10

15

0

5

10

15

20

25

30

Rainfall Diameter Variation

Rai

nfal

l (m

m d

ay-1

)

Rio

Bra

nco

DM

DV

(m

day

-1)

0

5

10

15

20

25

0

2

4

6

8

10

12

Rai

nfal

l (m

m d

ay-1

)

S

anta

rém

DM

DV

(m

day

-1)

-5

0

5

10

15

20

25

Apr-0

0

Jul-0

0

Oct-00

Jan-

01

Apr-0

1

Jul-0

1

Oct-01

Jan-

02

Apr-0

2

Jul-0

2

Oct-02

0

3

6

9

12

15

R

ainf

all (

mm

day

-1)

Mean annual growth increment –

Manaus 1.7 mm yr-1

Rio Branco 3.8 mm yr-1

Santarém 3.1 mm yr-1

Biomass increment in living trees

~ 2 Mg C ha-1 yr-1 all three sites

Radiocarbon Sample

Tree age (radiocarbon)Tree age (radiocarbon)

0

200

400

600

800

1000

1200

0 10 20 30 40 50 60 70 80 90 100110120130140

DBH (cm)

Tre

e ag

e (y

ears

)

Manaus Rio Branco Santarém

Radiocarbon and dendrometer based estimates of growth agree

mm

/yr

from

den

drom

eter

ban

ds

mm/yr from DBH and radiocarbon age

>50cm

30-50cm

10-30cmRio Branco

Manaus

SantaremSantarem

1:1

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7

Big trees grow faster than small treesm

m/y

r fr

om d

endr

omet

er b

ands

mm/yr from DBH and radiocarbon age

>50cm

30-50cm

10-30cmRio Branco

Manaus

SantaremSantarem

1:1

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7

Trees in Manaus (central Amazon) grow much slower than other areas

mm

/yr

from

den

drom

eter

ban

ds

mm/yr from DBH and radiocarbon age

>50cm

30-50cm

10-30cmRio Branco

Manaus

SantaremSantarem

1:1

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7

0

40

80

120

160

200

240

0-50 50-100 100-300 300-500 >500

Age Class (years)

ste

m h

a-1

Manaus Rio Branco Santarem

Mean age – Manaus 422 yearsRio Branco 332 years Santarém 271 years

0

20

40

60

80

100

120

140

160

180

10-30

30-50

>50

No

Indi

vidu

als/

ha

Manaus

Santarém Rio Branco

Trees can be oldExtrapolating growth rates, we estimate >20% of all trees and 15-35% of trees 10-30 cm diameter are

>300 yrs old

Age of individuals estimated from diameter/growth rate (yr)

Limited radiocarbon data available Limited radiocarbon data available agree qualitatively with age structure agree qualitatively with age structure based on Monte Carlo extrapolation of based on Monte Carlo extrapolation of

dendrometer growth ratesdendrometer growth rates

0

10

20

30

40

50

60

Manaus(n=35)

Santarem(n=22)

Rio Branco(n=27)

Model (n>3000)

Radiocarbon (n given)

% o

f in

divi

dual

s w

ith a

ge >

300

year

s

Trees Trees <10cm<10cm DBH sampled in Rio DBH sampled in Rio Branco (Catuaba Reserve) support Branco (Catuaba Reserve) support

this picture:this picture:6 of 18 (33%) had ages >45years6 of 18 (33%) had ages >45years

0

1

2

3

4

5

1 to 10 10 to 20 20 to 30 30 to 45 >45

Clearing

intact forest

Basal age (years) from radiocarbon

No

of in

divi

dual

s

Manaus

Santarém Rio Branco

Individuals/ha 626 460 466Biomass C MgC/ha 180 141 95Growth MgC/ha/yr 1.6-2.1 2.2 -3.0 3.3-3.4Mean age of C (yr)* 260 220 240 MRT of C (stock/growth)** 114 74 53 * From monte carlo simulations **biomass-weighted Data from Vieira et al. 2004

C dynamics differ with forest location

Low carbon use efficiency (NPP/GPP ~ 30% Low carbon use efficiency (NPP/GPP ~ 30% at Manaus and Santarat Manaus and Santaréém sites)m sites)

~25% of NPP used for wood growth at ~25% of NPP used for wood growth at Manaus (data pending for other sites) Manaus (data pending for other sites)

Although biomass may recover quickly Although biomass may recover quickly through fast-growing pioneer species, slow through fast-growing pioneer species, slow growing species (therefore biodiversity) will growing species (therefore biodiversity) will take centuries to recover from disturbance take centuries to recover from disturbance

Implications of low growth rates: Implications of low growth rates: