Demography - Firestone Center for Restoration Ecology

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Structure and
Demography of
Tree Communities
in Tropical
Secondary Forest
Recovering From
Logging
Keala Cummings and
Dr. Diane Thomson
2007
Conclusions
 Forest not very developed even after 15 years
 Mature forests: up to 200-250 species/ha (Phillips, 1994)
 Small tree size
 Domination of pioneer species
 Biomass within range of literature values
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
 Literature values very variable
 Proximity to mature forest?
 Wind direction?
 Animal seed vectors?
 Rainfall?
 Other environmental factors?
Background
 60% of all tropical forests are secondary or degraded (ITTO
2002).
 As mature forest is destroyed, secondary forests become
increasingly important in maintaining biodiversity (Dunn, 2004)
and in carbon sequestration (Silver, 2000).
 Future conservation efforts may need to be primarily directed
towards secondary forests.
 Tropical secondary forest recovery is not well understood or
studied.
Background

Firestone Center for Restoration Ecology
 Located in Dominical, Costa Rica
 Donated to Pitzer College by Diane Firestone in 2005
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TIFF (Uncompressed) decompressor
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 Property previously used for cattle ranching
 Secondary forest stands 15 years old
Project goals
 Long term goals
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 To better understand:
the processes that affect/influence
recovery of secondary forest
Their value as habitat for other species
Their contribution to carbon uptake and
sequestration
Project goals
 Short term goals
 Establish long-term monitoring plots
 Characterize baseline tree community
 Species composition, abundance and distribution
 Estimate rates of
 mortality
 growth
 biomass
 biomass accumulation
 Established two new 30 x 30 m plots in secondary
forest.
Methods
 Tagged, mapped and identified all trees (n=530)
over 2.0 cm diameter at breast height (dbh).
 Measured dbh (size)
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
 Remeasured all trees tagged in third plot during
2006.
 Estimated tree biomasses and basal area using
published allometric relationships with dbh.
Results
Distribution of Tree Sizes
35
25
20
15
10
5
Tree dbh (cm)
Plot 1
90
M
or
e
80
70
60
50
40
30
20
0
10
Number trees
Number of trees
30
Results
140
120
120
100
Tree dbh (cm)
Plot 2
Tree dbh (cm)
Plot 3
• Very few mature trees, lots of saplings.
90
M
or
e
80
70
60
50
90
M
or
e
80
70
60
50
40
0
30
0
20
20
10
20
40
40
30
40
60
20
60
80
10
80
0
Number trees
100
0
Number trees
Number of trees
Distribution of Tree Sizes
Plot maps
30
30
25
25
20
20
15
15
10
10
5
5
0
0
0
5
10
15
20
(m)
Plot 2
25
30
0
5
10
15
(m)
Plot 3
20
25
30
Species diversity
Red= Psidium, Green= Piper, Blue= Other
30
30
25
25
20
20
15
15
Figure 3: Plot 2 map showing common species. Red =
Psidium, green = Piper.
10
10
5
5
0
0
0
5
10
15
(m)
Plot 2
20
25
30
0
5
10
15
20
25
(m)
Plot 3
• Total diversity= 17 spp. (most individuals from a few dominants).
30
Species diversity
30
30
25
25
20
20
15
15
10
10
5
5
0
0
0
5
10
15
(m)
Plot 2
20
25
30
0
5
10
15
20
25
30
(m)
Plot 3
• Other species- clustered due to limited dispersal?
Note: Red = Psidium, green = Piper, black = Cecropia, sea green = Miconia (#1), blue= Miconia (#2), sky blue = Miconia
(#3), lime = Miconia (#4), orange = Tuete, plum = Guanacaste, pink = tree 1, gold = tree 2, tan = tree 3, brown = tree 4,
grey = tree 5, rose = tree 6, blue grey = tree 7, white = collective unknowns.
Species Composition
80
70
Blue= Plot 1
60
Red= Plot 2
50
Yellow= Plot 3
40
30
20
10
0
n
ow
kn
Un
7
ee
Tr
6
ee
Tr
5
ee
Tr
4
ee
Tr
3
ee
Tr
2
ee
Tr
1
ee
te
Tr
as
ac
an
Gu
e
et
4)
Tu
(#
nia
3)
co
Mi
(#
nia
2)
co
Mi
(#
nia
1)
co
Mi
(#
nia
co
Mi
pia
cro
Ce
er
Pip
ium
id
Ps
• Individual plots have fairly different compositions.
Stand Characteristics
T able 1 . S tand c harac teris tic s of F ires t one plots . M eas urements are for trees •
5 c m.
____________________________________________
C harac teris tic s
P lot 1
P lot 2
P lot 3
15
11
1100
3 2 .6 2
176
162
15
16
15
14
1756
2 1 .3 4
117
-
__________________________________________________________________________________________________
S tand age at time of c ens us (yr)
S pec ies dens ity (no. s pec ies /9 02)0 m
D ens ity of trees •
5 c m dbh (no. s tems /ha)
2
B as al area (m/ha)
B iomas s 2 0 0 7 (M g/ha)
B iomas s 2 0 0 6 (M g/ha)
1733
2 4 .3 2
128
-
__________________________________________________________________________________________________
N ote: V alues of biomas s for s imilar fores ts in literature review: 1 0 - 2 4* 2 M g/ha
*Silver et al. (2000)
Future Questions:
 What limits recovery?
 Seeds?
 Site conditions?
 Species composition?
Acknowledgements
I would like to thank the Andrew W. Mellon
Foundation for their grant to the Joint Science
Department, Scripps. I would also like to thank
my advisor and project supervisor, Dr. Diane
Thomson, The Firestone Center for Restoration
Ecology, Emily Schultz, Sam Scott, Alicia Hill
and Al Binder for an amazing summer.
Literature cited

Chazdon, Robin L., Alvaro Redondo Brenes, and Braulio Vilchez Alvarado.
2005. Effects of Climate and Stand Age on Annual Tree Dynamics in Tropical
Second-Growth Rain Forests. Ecology 86(7):1808-1815.

Dunn, Robert R. 2004. Recovery of Faunal Communities During Tropical Forest
Regeneration. Conservation Biology 18 (2):302-309.

ITTO, Guidelines for the restoration management and rehabilitation of degraded
and secondary tropical forests, International Tropical Timber Organization,
Yokohama (2002).

Philips, 0. L., P. Hall, A. H. Gentry, S. A. Sawyer, and R. Vasquez. Dynamics and
species richness of tropical rain forests. Ecology 91:2805-2809.

Silver, W. L., R. Ostertag, and A.E. Lugo. The Potential for Carbon
Sequestration Through Reforestation of Abandoned Tropical Agricultural and
Pasture Lands. Restoration Ecology 8(4):394-407.
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