Feldpausch, Ted R. and Lloyd, J. and Lewis, Simon L. and Brienen, R.J.W. and Gloor, M. and Monteagudo Mendoza, A. and Lopez Gonzalez, G. and Banin, L. and Abu Salim, K. and Affum-Baffoe, K. and Alexiades, M. and Almeida, S. and Amaral, Ieda and Andrade, Ana and Aragao, Luiz and Araujo Murakami, A. and Arets, E.J.M.M. and Arroyo, L. and Aymard, Gerardo and Baker, T.R. de and Banki, Olaf and Berry, N. J. and Cardozo, N. and Jerome, Chave and Comiskey, J. A. and Alvarez, E. and de Oliveira, A. and Di Fiore, A. and Djagbletey, G. and Domingues, T.F. and Erwin, T. and Fearnside, P. M. and França, M. B. and Freitas, M. A. and Higuchi, Niro and Honorio C., E. and Iida, Y. and Jimenez, E. and Kassim, A.R. and Killeen, T.J. and Laurance, W.F. and Lovett, Jon C. and Malhi, Y. and Marimon, B.S. and Marimon-Junior, B.H. and Lenza, E. and Marshall, A.R. and Mendoza, Casimiro and Metcalfe, D.J. and Mitchard, E.T.A. and Neill, D.A. and Nelson, B.W. and Nilus, R. and Nogueira, E.M. and Parada, A. and Peh, K.S.-H. and Peña Cruz, A. and Peñuela, M.C. and Pitman, N.C.A. and Prieto, A. and Quesada, C.A. and Ramírez, F. and Ramirez Angulo, H. and Reitsma, J.M. and Rudas, A. and Saiz, G. and Salomao, R. P. and Schwarz, M. and Silva, N. and Silva Espejo, J.E. and Silveira, Marcos and Sonke, Bonaventura and Stropp, Juliana and Taedoumg, H. E. and Tan, S. and Ter Steege, Hans and Terborgh, J. and Torello-Raventos, M. and Van der Heijden, Geertje and Vasquez, R. and Vilanova, Emilio and Vos, V. A. and White, L. and Willcock, S. and Woell, H. and Phillip, Oliver L.
Tree height integrated into pantropical forest biomass estimates.
Aboveground tropical tree biomass and carbon storage estimates commonly ignore tree height (H). We estimate the effect of incorporating H on tropics-wide forest biomass estimates in 327 plots across four continents using 42 656 H and diameter measurements and harvested trees from 20 sites to answer the following questions: 1. What is the best H-model form and geographic unit to include in biomass models to minimise site-level uncertainty in estimates of destructive biomass? 2. To what extent does including H estimates derived in (1) reduce uncertainty in biomass estimates across all 327 plots? 3. What effect does accounting for H have on plot- and continental-scale forest biomass estimates? The mean relative error in biomass estimates of destructively harvested trees when including H (mean 0.06), was half that when excluding H (mean 0.13). Power- andWeibull-H models provided the greatest reduction in uncertainty, with regional Weibull-H models preferred because they reduce uncertainty in smaller-diameter classes (?40 cm D) that store about one-third of biomass per hectare in most forests. Propagating the relationships from destructively harvested tree biomass to each of the 327 plots from across the tropics shows that including H reduces errors from 41.8Mgha?1 (range 6.6 to 112.4) to 8.0Mgha?1 (?2.5 to 23.0). For all plots, aboveground live biomass was ?52.2 Mgha?1 (?82.0 to ?20.3 bootstrapped 95%CI), or 13%, lower when including H estimates, with the greatest relative reductions in estimated biomass in forests of the Brazilian Shield, east Africa, and Australia, and relatively little change in the Guiana Shield, central Africa and southeast Asia. Appreciably different stand structure was observed among regions across the tropical continents, with some storing significantly more biomass in small diameter stems, which affects selection of the best height models to reduce uncertainty and biomass reductions due to H. After accounting for variation in H, total biomass per hectare is greatest in Australia, the Guiana Shield, Asia, central and east Africa, and lowest in eastcentral Amazonia, W. Africa, W. Amazonia, and the Brazilian Shield (descending order). Thus, if tropical forests span 1668 million km2 and store 285 Pg C (estimate including H), then applying our regional relationships implies that carbon storage is overestimated by 35 PgC (31?39 bootstrapped 95%CI) if H is ignored, assuming that the sampled plots are an unbiased statistical representation of all tropical forest in terms of biomass and height factors. Our results show that tree H is an important allometric factor that needs to be included in future forest biomass estimates to reduce error in estimates of tropical carbon stocks and emissions due to deforestation.