1

Fig. 1. Location of the study area.

Table 1. Compilation of measurements of diameter and height for each sampled tree.
Species Number of sample trees Number of diameter measurement Dbh range (cm) Stem height range (m) Total height range (m)
Lonchocarpus sericeus 23 145 3.2–38.5 2.28–20.48 2.28–24.15
Drypetes floribunda 28 162 2.4–31.5 2–9.96 2–12.09
Albizia zygia 28 168 2.5–65.5 3.03–26.73 3.03–28.08
Lecaniodiscus cupanioides 22 118 3.3–29.3 3.67–13.86 4.1–15.82
Ficus sur 27 163 4.4–67.7 3.25–21.85 3.25–26.64
Zanthoxylum zanthoxyloides 19 119 4.2–31.6 3.42–10.34 4.33–12.06
Mimusops andongensis 26 164 3.9–46.4 4–20.7 4–23
Celtis brownii 27 159 3.3–29.3 2.31–14.56 2.31–16.38
Sterculia tragacantha 31 194 2.9–34.6 2.02–16.2 2.02–18.8
Cassipourea congoensis 28 143 2.8–22.4 3.22–18.7 3.22–22.66
Khaya senegalensis 27 160 3.7–40.2 3.05–19.5 4.35–24
Holarrhena floribunda 32 187 2.9–41.3 2.1–20.25 2.1–23.25
Cynometra megalophylla 19 122 2.9–36 5.35–19.32 5.35–21.28
Malacantha alnifolia 27 169 2.9–31.9 3.6–13.72 3.6–17.92
Terminalia superba 37 240 8.2–44.4 6.32–26.04 9.44–33.93
Triplochiton scleroxylon 48 309 2.3–47.5 2.4–25.44 2.4–30.52
Diospyros abyssinica 18 109 1.8–32.7 3–19.26 3–22.14
Holoptelea grandis 34 207 3.5–32.9 4.62–22.54 5.4–25.3
Table 2. Mean wood density (g cm−3) of the selected tree species in Lama forest reserve and comparison with other published data; wood density range includes all observations without modification. Wood density is given as oven-dry mass per fresh volume.
Species This study Others studies
Number of wood sample Wood
Density
range 		Mean
(Standard
deviation) 		Coefficient
of varation (%) 		Brown
1997 		Kindt et al. 2015 IPCC
2006 		Zanne et al. 2009
C. megalophylla 34 0.81–1.3 0.98 (0.08) 7.96 - - - -
D. abyssinica 31 0.45–1.90 0.86 (0.29) 33.73 - 0.83 - -
Z. zanthoxyloides 33 0.65–1.43 0.84 (0.14) 16.62 - - - -
D. floribunda 46 0.51–1.07 0.77 (0.12) 15.67 - - - -
M. andongensis 48 0.42–0.98 0.77 (0.11) 14.51 - - - -
L. cupanioides 36 0.42–1.03 0.77 (0.14) 17.86 - - - -
C. congoensis 39 0.62–0.83 0.75 (0.05) 6.64 - - - 0.66
L. sericeus 42 0.48–0.95 0.75 (0.11) 14.15 - 0.70 - 0.75
C. brownii 42 0.52–0.98 0.73 (0.09) 13.04 - 0.72 - -
A. zygia 52 0.44–0.73 0.65 (0.08) 13.31 0.46 0.51 - 0.49
H. grandis 58 0.42–0.76 0.63 (0.09) 14.08 0.59 0.61 0.59 0.59
M. alnifolia 46 0.48–0.73 0.61 (0.06) 9.24 0.45 - 0.45 -
K. senegalensis 52 0.41–0.74 0.59 (0.07) 11.83 0.60 0.66 - 0.63
T. superba 74 0.37–0.69 0.56 (0.06) 10.74 0.45 0.46 0.40–0.66 0.46
H. floribunda 57 0.43–0.61 0.54 (0.04) 8.32 - 0.47 - 0.47
T. scleroxylon 86 0.35–0.6 0.46 (0.07) 15.11 0.32 - 0.28–0.44 0.33
F. sur 50 0.32–0.52 0.45 (0.05) 11.97 - - - -
S. tragacantha 47 0.16–0.44 0.32 (0.08) 25.80 - - - -
2

Fig. 2. Linear relationship with constant variance between ln (biomass) and ln(Dbh).

Table 3. Total stem volume models, parameter estimates, standard errors of parameter estimates, adjusted coefficients of determination, relative RMSEs and bias correction. V = Volume (10−3 m3); Dbh = the Dbh at 1.3 m (cm); H = tree stem height (m); x0, x1 and x2 are model parameters; RMSE = root mean square error; σ = model residual standard deviation. Stem is described as height to crown base. Figures in brackets are standard errors of the parameters.
Species Model parameters Adjusted
R2 (%) 		Relative
RMSE (%) 		σ2/2 df
x0 x1 x2
                               Model structure: ln(V) = x0 + x1ln(Dbh)
H. grandis –1.58*** (0.11) 2.36*** (0.04)   99.03 15 0.01 32
T. scleroxylon –1.96*** (0.10) 2.48*** (0.03)   99.13 17 0.02 46
C. congoensis –1.90*** (0.11) 2.53*** (0.05)   98.74 17 0.02 26
D. abyssinica –1.92*** (0.21) 2.51*** (0.08)   98.28 24 0.04 16
Z. zanthoxyloides –1.71*** (0.18) 2.37*** (0.07)   98.6 18 0.02 17
A. zygia –1.83*** (0.13) 2.49*** (0.04)   99.3 18 0.02 26
K. senegalensis –1.76*** (0.15) 2.33*** (0.05)   98.71 18 0.02 25
M. andongensis –1.71*** (0.15) 2.35*** (0.05)   98.86 18 0.02 24
C. brownii –1.80*** (0.16) 2.37*** (0.06)   98.18 23 0.02 25
S. tragacantha –1.47*** (0.18) 2.31*** (0.06)   97.66 24 0.03 29
C. megalophylla –1.52*** (0.13) 2.31*** (0.05)   99.28 14 0.01 17
L. sericeus –1.81*** (0.14) 2.42*** (0.05)   99.13 17 0.02 21
H. floribunda –1.63*** (0.09) 2.36*** (0.03)   99.39 14 0.01 30
D. floribunda –1.53*** (0.13) 2.23*** (0.05)   98.53 19 0.02 26
L. cupanioides –1.38*** (0.21) 2.24*** (0.09)   96.88 23 0.03 20
M. alnifolia –1.46*** (0.09) 2.23*** (0.04)   99.34 13 0.01 25
T. superba –1.52*** (0.12) 2.35*** (0.04)   99.06 11 0.01 35
F. sur –1.55*** (0.13) 2.30*** (0.04)   99.22 15 0.01 25
Generic –1.48*** (0.04) 2.29*** (0.01)   97.51 32 0.05 615
                               Model structure: ln(V) = x0 + x1ln(Dbh) + x2ln(H)
H. grandis –2.10*** (0.11) 1.95*** (0.07) 0.66*** (0.10) 99.56 11 0.01 31
T. scleroxylon –2.33*** (0.07) 2.04*** (0.05) 0.64*** (0.07) 99.7 10 0.01 45
C. congoensis –2.36*** (0.17) 2.15*** (0.12) 0.60** (0.18) 99.09 14 0.01 25
D. abyssinica –2.60*** (0.26) 1.96*** (0.18) 0.91** (0.27) 98.94 19 0.03 15
Z. zanthoxyloides –2.63*** (0.21) 2.30*** (0.04) 0.53*** (0.10) 99.46 11 0.01 16
A. zygia –2.10*** (0.10) 2.15*** (0.07) 0.52*** (0.09) 99.69 12 0.01 25
K. senegalensis –1.90*** (0.10) 1.89*** (0.08) 0.62*** (0.10) 99.46 11 0.01 24
M. andongensis –2.17*** (0.10) 1.99*** (0.05) 0.64*** (0.08) 99.66 10 0.01 23
C. brownii –1.95*** (0.11) 2.04*** (0.08) 0.48*** (0.09) 99.12 14 0.01 24
S. tragacantha –1.75*** (0.11) 1.84*** (0.07) 0.69*** (0.09) 99.21 14 0.01 28
C. megalophylla –1.97*** (0.27) 2.17*** (0.09) 0.35. (0.19) 99.38 12 0.01 16
L. sericeus –2.03*** (0.11) 2.07*** (0.08) 0.50*** (0.11) 99.56 12 0.01 20
H. floribunda –1.95*** (0.07) 2.11*** (0.04) 0.44*** (0.06) 99.75 9 0.00 29
D. floribunda –2.06*** (0.10) 2.03*** (0.04) 0.59*** (0.07) 99.58 10 0.01 25
L. cupanioides –2.14*** (0.18) 1.92*** (0.07) 0.72*** (0.12) 98.9 13 0.01 19
M. alnifolia –1.85*** (0.17) 2.08*** (0.07) 0.39* (0.15) 99.46 12 0.01 24
T. superba –1.93*** (0.12) 2.14*** (0.05) 0.39*** (0.08) 99.43 9 0.00 34
F. sur –1.85*** (0.13) 2.15*** (0.13) 0.32*** (0.09) 99.47 12 0.01 24
Generic –2.10*** (0.04) 2.00*** (0.02) 0.63*** (0.53) 98.71 24 0.02 614
Table 4. Total stem biomass models, parameter estimates, standard errors of parameter estimates, adjusted coefficients of determination, relative RMSEs and bias correction. X = Biomass (kg); Dbh = the Dbh at 1.3 m (cm); H = tree stem height (m); x0, x1 and x2 are model parameters; RMSE = root mean square error; σ = model residual standard deviation. Stem is described as height to crown base. Figures in brackets are standard errors of the parameters.
Species Model parameters Adjusted
R2 (%) 		Relative
RMSE (%) 		σ2/2 df
x0 x1 x2
                               Model structure: ln(X) = x0 + x1ln(Dbh)
H. grandis –2.44*** (0.10) 2.51*** (0.04)   99.23 16 0.01 32
T. scleroxylon –2.64*** (0.14) 2.44*** (0.05)   98.24 24 0.03 46
C. congoensis –2.25*** (0.12) 2.56*** (0.06)   98.6 17 0.02 26
D. abyssinica –2.06*** (0.29) 2.49*** (0.11)   96.74 34 0.08 16
Z. zanthoxyloides –2.36*** (0.21) 2.55*** (0.08)   98.27 22 0.02 17
A. zygia –2.63*** (0.17) 2.60*** (0.05)   98.92 23 0.03 26
K. senegalensis –2.50*** (0.16) 2.40*** (0.06)   98.56 22 0.02 25
M. andongensis –1.98*** (0.20) 2.35*** (0.07)   97.99 24 0.03 24
C. brownii –2.30*** (0.18) 2.44*** (0.07)   97.89 23 0.03 25
S. tragacantha –2.93*** (0.22) 2.40*** (0.08)   96.48 32 0.05 29
C. megalophylla –1.68*** (0.16) 2.37*** (0.06)   98.99 17 0.02 17
L. sericeus –2.39*** (0.17) 2.53*** (0.06)   98.76 21 0.02 21
H. floribunda –2.33*** (0.11) 2.39*** (0.04)   99 18 0.02 30
D. floribunda –2.09*** (0.16) 2.35*** (0.06)   98.15 22 0.03 26
L. cupanioides –2.21*** (0.25) 2.47*** (0.10)   96.44 27 0.04 20
M. alnifolia –1.91*** (0.12) 2.21*** (0.04)   98.94 17 0.02 25
T. superba –2.38*** (0.16) 2.45*** (0.05)   98.31 16 0.01 35
F. sur –2.52*** (0.17) 2.35*** (0.05)   98.68 21 0.02 25
Generic –1.98*** (0.06) 2.30*** (0.02)   95.07 45 0.10 615
                               Model structure: ln(X) = x0 + x1ln(Dbh) + x2ln(H)
H. grandis –2.72*** (0.14) 2.28*** (0.09) 0.35516* (0.14) 99.35 14 0.01 31
T. scleroxylon –3.15*** (0.11) 1.86*** (0.08) 0.86*** (0.10) 99.28 16 0.01 45
C. congoensis –2.71*** (0.17) 2.21*** (0.13) 0.58** (0.19) 99.06 15 0.01 25
D. abyssinica –2.81*** (0.41) 1.88*** (0.28) 1.00* (0.43) 97.45 33 0.06 15
Z. zanthoxyloides –3.38*** (0.28) 2.48*** (0.59) 0.58*** (0.14) 99.14 14 0.01 16
A. zygia –2.99*** (0.12) 2.14*** (0.08) 0.70*** (0.11) 99.55 15 0.01 25
K. senegalensis –2.64*** (0.12) 1.97*** (0.10) 0.60*** (0.13) 99.2 15 0.01 24
M. andongensis –2.43*** (0.20) 2.00*** (0.11) 0.63*** (0.16) 98.72 18 0.02 23
C. brownii –2.46*** (0.13) 2.08*** (0.09) 0.52*** (0.11) 98.88 16 0.01 24
S. tragacantha –3.23*** (0.18) 1.90*** (0.12) 0.74*** (0.15) 98.03 21 0.03 28
C. megalophylla –2.50*** (0.28) 2.11*** (0.09) 0.63** (0.19) 99.36 13 0.01 16
L. sericeus –2.58*** (0.17) 2.23*** (0.13) 0.43* (0.17) 99.02 18 0.01 20
H. floribunda –2.73*** (0.10) 2.08*** (0.06) 0.55*** (0.09) 99.55 12 0.01 29
D. floribunda –2.63*** (0.15) 2.14*** (0.06) 0.60*** (0.11) 99.11 16 0.01 25
L. cupanioides –2.99*** (0.25) 2.14*** (0.10) 0.74*** (0.17) 98.16 19 0.02 19
M. alnifolia –2.35*** (0.22) 2.03*** (0.09) 0.44* (0.19) 99.09 15 0.01 24
T. superba –2.83*** (0.19) 2.21*** (0.08) 0.43** (0.13) 98.71 14 0.01 34
F. sur –2.94*** (0.17) 2.14*** (0.07) 0.45*** (0.12) 99.16 16 0.01 24
Generic –2.63*** (0.07) 1.99*** (0.03) 0.67*** (0.04) 96.35 39 0.07 614
3

Fig. 3. Generic models for stem volume and stem biomass in Lama forest reserve.

4

Fig. 4. Comparison of stem volume functions by selected tree species.

5

Fig. 5. Comparison of stem biomass functions by selected tree species.