Volume and Aboveground Biomass Models for Dry Miombo Woodland in Tanzania

Table 3

Average error in percent of measured values as observed for previously published volume and biomass equations for miombo woodlands when applied to species-specific and mixed-species datasets prepared in this study. Models developed in this study are included for comparison. Symbols: 𝑌 is volume (m³) or biomass (kg); Dbh is diameter at breast height (cm); ht is total height (m); BA is basal area (cm²); and 𝑁 is sample size.

Model†	Source	Name of species	Average error in percent for the datasets prepared in this study
			B. spiciformis	C. molle	D. arbutifolia	Shrubs	Trees	Combined
Model (3) = total volume	This study		1.99	2.90	2.04	18.48	1.66	6.54
ln(𝑌)=𝑎+𝑏ln(Dbh)+𝑐ln(ht)
(7) log10𝑌=−3.85+2.49log10Dbh	Abbot et al. [24]	Brachystegia boehmii	−10.73	21.76	12.01	29.98	8.44	15.34
𝑁=27, Dbh: 8–40 cm
(8) log10𝑌(litres)=−1.2875+2.8436log10Dbh	Temu [22]	Brachystegia spiciformis	−6.03	17.12	0.12	2.82	10.48	7.45
𝑁=unknown, Dbh: 5–43 cm
(9) 𝑌=0.092Dbh^2.59	Malimbwi and Temu [23]	Pterocarpus angolensis	−21.16	4.45	−6.86	−1.11	−4.45	−3.64
𝑁=25, Dbh: 6–61 cm
(10) log10𝑌=−4.22+2.76log10Dbh	Abbot et al. [24]	Mixed species (17 spp.)	−15.36	8.77	−5.7	−2.66	1.06	−0.20
𝑁=51, Dbh: 5–40
(11) 𝑌=0.0001Dbh^2.032ht^0.66	Malimbwi et al. [13]	Mixed species (13 spp.)	−20.91	−1.94	−11.0	−7.45	−12.82	−11.26
𝑁=17, Dbh: 8–43 cm
Model (3) = total biomass	This study		1.60	2.88	1.22	21.90	2.47	8.96
ln(𝑌)=𝑎+𝑏ln(Dbh)+𝑐ln(ht)
(12) 𝑌=0.06Dbh^2.012ht^0.71	Malimbwi et al. [13]	Mixed species (13 spp.)	−38.56	−23.44	−30.61	−20.51	−8.07	−11.68
𝑁=17, Dbh: 8–43 cm
(13) 𝑌=0.0263Dbh^1.505ht^1.762	Chamshama et al. [14]	Mixed species (20 spp.)	−28.17	−33.17	−36.28	−41.81	−16.29	−24.46
𝑁=30, Dbh: 1.1–50 cm
(14) 𝑌=0.1027Dbh^2.4798	Mugasha et al. [15]	Mixed species (49 spp.)	−24.21	4.52	−6.81	8.85	21.19	17.39
𝑁=167, Dbh: 1.1–110 cm
(15) 𝑌=0.0763Dbh^2.2046ht^0.4918	Mugasha et al. [15]	Mixed species (49 spp.)	−20.38	−1.27	−11.09	−3.35	15.57	9.75
𝑁=167, Dbh: 1.1–110 cm
(16) log10𝑌=−0.535+log10BA	Brown [1]	Mixed species (not indicated)	−50.02	−30.29	−35.91	−19.27	−19.04	−19.26
𝑁=191, Dbh: 3–30 cm

†For each model, the range of diameters in the material forming the basis for the model is specified.