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3 results on '"Vernimmen, Ronald R.E."'

1. Field methods for sampling tree height for tropical forest biomass estimation

Author

Sullivan, Martin J. P., Lewis, Simon L., Hubau, Wannes, Qie, Lan, Baker, Timothy R., Banin, Lindsay F., Chave, Jerome, Cuni-Sanchez, Aida, Feldpausch, Ted R., Lopez-Gonzalez, Gabriela, Arets, Eric, Ashton, Peter, Bastin, Jean-François, Berry, Nicholas J., Bogaert, Jan, Boot, Rene, Brearley, Francis Q., Brienen, Roel, Burslem, David F.R.P., de Canniere, Charles, Chudomelová, Markéta, Dančák, Martin, Ewango, Corneille, Hédl, Radim, Lloyd, Jon, Makana, Jean-Remy, Malhi, Yadvinder, Marimon, Beatriz S., Marimon Jr., Ben Hur, Metali, Faizah, Moore, Sam, Nagy, Laszlo, Pendry, Colin A., Ramírez-Angulo, Hirma, Reitsma, Jan, Rutishauser, Ervan, Abu Salim, Kamariah, Sonké, Bonaventure, Sukri, Rahayu S., Sunderland, Terry, Svátek, Martin, Umunay, Peter M., Vasquez Martinez, Rodolfo, Vernimmen, Ronald R.E., Vilanova Torre, Emilio, Vleminckx, Jason, Vos, Vincent, and Phillips, Oliver L.

Subjects
carbon stocks, above-ground biomass estimation, allometry, forest inventory, forest structure, sample size
Abstract

1. Quantifying the relationship between tree diameter and height is a key component of efforts to estimate biomass and carbon stocks in tropical forests. Although substantial site‐to‐site variation in height–diameter allometries has been documented, the time consuming nature of measuring all tree heights in an inventory plot means that most studies do not include height, or else use generic pan‐tropical or regional allometric equations to estimate height. 2. Using a pan‐tropical dataset of 73 plots where at least 150 trees had in‐field ground‐based height measurements, we examined how the number of trees sampled affects the performance of locally derived height–diameter allometries, and evaluated the performance of different methods for sampling trees for height measurement. 3. Using cross‐validation, we found that allometries constructed with just 20 locally measured values could often predict tree height with lower error than regional or climate‐based allometries (mean reduction in prediction error = 0.46 m). The predictive performance of locally derived allometries improved with sample size, but with diminishing returns in performance gains when more than 40 trees were sampled. Estimates of stand‐level biomass produced using local allometries to estimate tree height show no over‐ or under‐estimation bias when compared with biomass estimates using field measured heights. We evaluated five strategies to sample trees for height measurement, and found that sampling strategies that included measuring the heights of the ten largest diameter trees in a plot outperformed (in terms of resulting in local height–diameter models with low height prediction error) entirely random or diameter size‐class stratified approaches. 4. Our results indicate that even limited sampling of heights can be used to refine height–diameter allometries. We recommend aiming for a conservative threshold of sampling 50 trees per location for height measurement, and including the ten trees with the largest diameter in this sample., Methods in Ecology and Evolution, 9 (5), ISSN:2041-210X, ISSN:2041-2096

Published
2018

2. Field methods for sampling tree height for tropical forest biomass estimation

Author

Sullivan, Martin J.P., Lewis, Simon L., Hubau, Wannes, Qie, Lan, Baker, Timothy R., Banin, Lindsay F., Chave, Jerôme, Cuni Sanchez, Aida, Feldpausch, Ted R., Lopez-Gonzalez, Gabriela, Arets, Eric, Ashton, Peter, Bastin, Jean-François, Berry, Nicholas J., Bogaert, Jan, Boot, Rene, Brearley, Francis Q., Brienen, Roel, Burslem, David F.R.P., de Canniere, Charles, Chudomelová, Markéta, Dančák, Martin, Ewango, Corneille, Hédl, Radim, Lloyd, Jon, Makana, Jean-Remy, Malhi, Yadvinder, Marimon, Beatriz S., Marimon Junior, Ben Hur, Metali, Faizah, Moore, Sam, Nagy, Laszlo, Núñez Vargas, Percy, Pendry, Colin A., Ramírez-Angulo, Hirma, Reitsma, Jan, Rutishauser, Ervan, Abu Salim, Kamariah, Sonké, Bonaventure, Sukri, Rahayu S., Sunderland, Terry, Svátek, Martin, Umunay, Peter M., Vasquez Martinez, Rodolfo, Vernimmen, Ronald R.E., Vilanova Torre, Emilio, Vleminckx, Jason, Vos, Vincent, Phillips, Oliver L., Sullivan, Martin J.P., Lewis, Simon L., Hubau, Wannes, Qie, Lan, Baker, Timothy R., Banin, Lindsay F., Chave, Jerôme, Cuni Sanchez, Aida, Feldpausch, Ted R., Lopez-Gonzalez, Gabriela, Arets, Eric, Ashton, Peter, Bastin, Jean-François, Berry, Nicholas J., Bogaert, Jan, Boot, Rene, Brearley, Francis Q., Brienen, Roel, Burslem, David F.R.P., de Canniere, Charles, Chudomelová, Markéta, Dančák, Martin, Ewango, Corneille, Hédl, Radim, Lloyd, Jon, Makana, Jean-Remy, Malhi, Yadvinder, Marimon, Beatriz S., Marimon Junior, Ben Hur, Metali, Faizah, Moore, Sam, Nagy, Laszlo, Núñez Vargas, Percy, Pendry, Colin A., Ramírez-Angulo, Hirma, Reitsma, Jan, Rutishauser, Ervan, Abu Salim, Kamariah, Sonké, Bonaventure, Sukri, Rahayu S., Sunderland, Terry, Svátek, Martin, Umunay, Peter M., Vasquez Martinez, Rodolfo, Vernimmen, Ronald R.E., Vilanova Torre, Emilio, Vleminckx, Jason, Vos, Vincent, and Phillips, Oliver L.

Abstract

1. Quantifying the relationship between tree diameter and height is a key component of efforts to estimate biomass and carbon stocks in tropical forests. Although substantial site-to-site variation in height-diameter allometries has been documented, the time consuming nature of measuring all tree heights in an inventory plot means that most studies do not include height, or else use generic pan-tropical or regional allometric equations to estimate height. 2. Using a pan-tropical dataset of 73 plots where at least 150 trees had in-field ground-based height measurements, we examined how the number of trees sampled affects the performance of locally-derived height-diameter allometries, and evaluated the performance of different methods for sampling trees for height measurement. 3. Using cross-validation, we found that allometries constructed with just 20 locally measured values could often predict tree height with lower error than regional or climate-based allometries (mean reduction in prediction error = 0.46 m). The predictive performance of locally-derived allometries improved with sample size, but with diminishing returns in performance gains when more than 40 trees were sampled. Estimates of stand-level biomass produced using local allometries to estimate tree height show no over- or under-estimation bias when compared with estimates using measured heights. We evaluated five strategies to sample trees for height measurement, and found that sampling strategies that included measuring the heights of the ten largest diameter trees in a plot outperformed (in terms of resulting in local height-diameter models with low height prediction error) entirely random or diameter size-class stratified approaches. 4. Our results indicate that even remarkably limited sampling of heights can be used to refine height-diameter allometries. We recommend aiming for a conservative threshold of sampling 50 trees per location for height measurement, and including the ten trees with the la

Published
2018

3. Long-term carbon sink in Borneo’s forests halted by drought and vulnerable to edge effects

Author

Qie, Lan, Lewis, Simon L., Sullivan, Martin J.P., Lopez-Gonzalez, Gabriela, Pickavance, Georgia C., Sunderland, Terry, Ashton, Peter, Hubau, Wannes, Abu Salim, Kamariah, Aiba, Shin-Ichiro, Banin, Lindsay F., Berry, Nicholas, Brearley, Francis Q., Burslem, David F.R.P., Dančák, Martin, Davies, Stuart J., Fredriksson, Gabriella, Hamer, Keith C., Hédl, Radim, Kho, Lip Khoon, Kitayama, Kanehiro, Krisnawati, Haruni, Lhota, Stanislav, Malhi, Yadvinder, Maycock, Colin, Metali, Faizah, Mirmanto, Edi, Nagy, Laszlo, Nilus, Reuben, Ong, Robert, Pendry, Colin A., Poulsen, Axel Dalberg, Primack, Richard B., Rutishauser, Ervan, Samsoedin, Ismayadi, Saragih, Bernaulus, Sist, Plinio, Slik, J.W. Ferry, Sukri, Rahayu Sukmaria, Svátek, Martin, Tan, Sylvester, Tjoa, Aiyen, van Nieuwstadt, Mark, Vernimmen, Ronald R.E., Yassir, Ishak, Kidd, Petra Susan, Fitriadi, Muhammad, Ideris, Nur Khalish Hafizhah, Serudin, Rafizah Mat, Abdullah Lim, Layla Syaznie, Saparudin, Muhammad Shahruney, Phillips, Oliver L., Qie, Lan, Lewis, Simon L., Sullivan, Martin J.P., Lopez-Gonzalez, Gabriela, Pickavance, Georgia C., Sunderland, Terry, Ashton, Peter, Hubau, Wannes, Abu Salim, Kamariah, Aiba, Shin-Ichiro, Banin, Lindsay F., Berry, Nicholas, Brearley, Francis Q., Burslem, David F.R.P., Dančák, Martin, Davies, Stuart J., Fredriksson, Gabriella, Hamer, Keith C., Hédl, Radim, Kho, Lip Khoon, Kitayama, Kanehiro, Krisnawati, Haruni, Lhota, Stanislav, Malhi, Yadvinder, Maycock, Colin, Metali, Faizah, Mirmanto, Edi, Nagy, Laszlo, Nilus, Reuben, Ong, Robert, Pendry, Colin A., Poulsen, Axel Dalberg, Primack, Richard B., Rutishauser, Ervan, Samsoedin, Ismayadi, Saragih, Bernaulus, Sist, Plinio, Slik, J.W. Ferry, Sukri, Rahayu Sukmaria, Svátek, Martin, Tan, Sylvester, Tjoa, Aiyen, van Nieuwstadt, Mark, Vernimmen, Ronald R.E., Yassir, Ishak, Kidd, Petra Susan, Fitriadi, Muhammad, Ideris, Nur Khalish Hafizhah, Serudin, Rafizah Mat, Abdullah Lim, Layla Syaznie, Saparudin, Muhammad Shahruney, and Phillips, Oliver L.

Abstract

Less than half of anthropogenic carbon dioxide emissions remain in the atmosphere. While carbon balance models imply large carbon uptake in tropical forests, direct on-the-ground observations are still lacking in Southeast Asia. Here, using long-term plot monitoring records of up to half a century, we find that intact forests in Borneo gained 0.43 Mg C ha−1 per year (95% CI 0.14–0.72, mean period 1988–2010) above-ground live biomass. These results closely match those from African and Amazonian plot networks, suggesting that the world’s remaining intact tropical forests are now en masse out-of-equilibrium. Although both pan-tropical and long-term, the sink in remaining intact forests appears vulnerable to climate and land use changes. Across Borneo the 1997–1998 El Niño drought temporarily halted the carbon sink by increasing tree mortality, while fragmentation persistently offset the sink and turned many edge-affected forests into a carbon source to the atmosphere.

Published
2017

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