On volume recovery index and implications for sustainable logging in Congo Basin

Mayaka, Theodore B.; Ebaa-Atyi, R.; Nkie, Martin-Cyrille

doi:10.1016/j.foreco.2013.11.013

Cited by 4 publications

(6 citation statements)

References 31 publications

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“…This scenario would suggest that some silvicultural practices need correction. For example, for timber yield it should: (i) be established a minimum diameter of logging so that the impact on the stand structure is minimal, (ii) harvest timber species in proportion to their relative abundance to protect long-term composition, and (iii) ensure regeneration, through natural processes or silvicultural techniques (Mayaka et al, 2014). In general, monitoring of timber yield sustainability helps to maintain or extent forest resources, could prevent the loss of biological diversity, enforces forest health and vitality, and enables forests to function as protective, productive, and socio-economic actors (Jalilova et al, 2012;Larrubia et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

Procedimiento basado en análisis troncales para estimar a posteriori si el rendimiento maderable de un bosque ha sido sostenido a largo plazo

Zamudio-Sánchez,

Alvarado-Segura,

De la Cruz-De la Cruz

et al. 2023

Rev Cha Se Cie For y del Amb

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Introducción: El rendimiento maderable sostenido es la capacidad del bosque para mantener su producción a un nivel similar a través del tiempo.Objetivo: Proponer un procedimiento para estimar, a posteriori, si el rendimiento maderable de un bosque ha sido sostenido a largo plazo, mediante la evaluación de las alturas y diámetros alcanzados por árboles de la misma edad, pero establecidos en años diferentes.Materiales y métodos: Los diámetros se obtuvieron de análisis troncales y las alturas se estimaron por interpolación lineal. Los árboles se agruparon por tamaño y se realizaron regresiones de las alturas y los diámetros de árboles de la misma edad establecidos en años diferentes contra el año en que alcanzaron esa edad (YTRA, por sus siglas en inglés). Todos los árboles se analizaron mediante regresión múltiple sin considerar los grupos de tamaño; el modelo incluyó el recíproco de la edad del árbol y el YTRA como variables explicativas de la altura y el diámetro.Resultados: La regresión de alturas y diámetros contra YTRA a edades diferentes (10, 20,…, 70) mostró pendientes positivas, lo que indica que los árboles establecidos recientemente tuvieron mejor crecimiento y que el rendimiento maderable ha sido sostenido a lo largo del tiempo. Los resultados con respecto a todos los árboles en su conjunto coincidieron con los de los árboles por grupos de tamaño y concuerdan con lo que los administradores forestales observaron in situ.Conclusión: El procedimiento proporciona herramientas de uso fácil para la detección de cualquier cambio negativo que pueda poner en peligro la sostenibilidad del rendimiento maderable y para identificar posibles causas e implementar prácticas de manejo correctivas.

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Section: Discussionmentioning

confidence: 99%

Procedimiento basado en análisis troncales para estimar a posteriori si el rendimiento maderable de un bosque ha sido sostenido a largo plazo

Zamudio-Sánchez,

Alvarado-Segura,

De la Cruz-De la Cruz

et al. 2023

Rev Cha Se Cie For y del Amb

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“…The volume of the stump was estimated by applying the general volume calculation formula Vs = πd 2 h 4 (where, Vs = Stump volume in m 3 , d = mid height diameter of the stump in cm and h = stump height in cm). The recovered volume was analysed using the volume recovery index (VRI)-the ratio of harvested/extracted volume to actual volume [39,40] and presented in quantity and percentage.…”

Section: Calculation Of Wood Product Volume Recoverymentioning

confidence: 99%

Implications of Selective Harvesting of Natural Forests for Forest Product Recovery and Forest Carbon Emissions: Cases from Tarai Nepal and Queensland Australia

Poudyal

Maraseni

Cockfield

2019

Forests

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Selective logging is one of the main natural forest harvesting approaches worldwide and contributes nearly 15% of global timber needs. However, there are increasing concerns that ongoing selective logging practices have led to decreased forest product supply, increased forest degradation, and contributed to forest based carbon emissions. Taking cases of natural forest harvesting practices from the Tarai region of Nepal and Queensland Australia, this study assesses forest product recovery and associated carbon emissions along the timber production chain. Field measurements and product flow analysis of 127 commercially harvested trees up to the exit gate of sawmills and interaction with sawmill owners and forest managers reveal that: (1) Queensland selective logging has less volume recovery (52.8%) compared to Nepal (94.5%) leaving significant utilizable volume in the forest, (2) Stump volume represents 5.5% of total timber volume in Nepal and 3.9% in Queensland with an average stump height of 43.3 cm and 40.1 cm in Nepal and Queensland respectively, (3) Average sawn timber output from the harvested logs is 36.3% in Queensland against 61% in Nepal, (4) Nepal and Queensland leave 0.186 Mg C m−3 and 0.718 Mg C m−3 on the forest floor respectively, (5) Each harvested tree damages an average of five plant species in Nepal and four in Queensland predominantly seedlings in both sites, and (6) Overall logging related total emissions in Queensland are more than double (1.099 Mg C m−3) those in Nepal (0.488 Mg C m−3). We compared these results with past studies and speculated on possible reasons for and potential implications of these results for sustainable forest management and reducing emissions from deforestation and forest degradation.

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“…Linear relationship above provided a benchmark to assess other approaches for predicting aboveground volume. For null intercept , the prediction approach is equivalent to ratio estimation, namely = × V b (Mayaka et al 2014). This simpler more intuitive rule consists of using slope of regression through the origin for expanding bole volume into aboveground volume.…”

Section: Figurementioning

confidence: 99%

“…Ecologically, the contribution of the Congo Basin forests to the global carbon cycle is difficult to assess due to several sources of uncertainty. These include (1) high plant diversity, often exceeding 300 different species ha -1 (Lewis et al 2004), (2) high variability in forest types, wood densities, tree heights, biomass and volume (Feldpausch et al 2011, Lewis et al 2013, (3) poor knowledge of natural stand dynamics such as growth, mortality and recruitment (Picard et al 2012b, Mayaka et al 2014) and (4) human disturbances (logging and deforestation) responsible for releasing greenhouse effect gas (IPCC 2007, Marshall et al 2012.…”

Section: Introductionmentioning

confidence: 99%

“…Thirdly, only traditional dendrometric measurements (diameter and height) may be obtained from some individual trees. Fourthly, destructive sampling of (mostly small) trees may cause too much disruption in the sustainable management of forest concessions, especially under reducedimpact logging schemes (Mayaka et al 2014). Fifthly, the need may occasionally arise to estimate the volume or biomass of already logged trees for policing or seeking compensation from illegal harvesting.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Construction of Multispecies Allometric

Mayaka¹,

Atyi²,

Takoudjou³

2017

JTFS

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To avoid the problem of destructive tree sampling, we tested an indirect estimation procedure whereby aboveground tree volumes are estimated using affine-transforms of traditional bole volume equations. The study compared the predictive performance of the (1) proposed procedure, (2) allometric aboveground volume equations, and (3) simple upscaling of empirical tree bole volumes (serving as benchmark procedure). The study assessed speciesand tree-individual random deviations from mean procedure effect on prediction errors. Six volume equations were each fitted to aboveground volume (a-version) and bole volume (b-version); predictions of latter volumes were affine-transformed to estimate aboveground tree volumes. Bole height, total height and diameter at breast height (dbh) were measured for 59 trees from 10 species in eastern Cameroon. The Schumacher and Hall equation ranked first in quality-of-fit. The direct and indirect approaches applied with this volume equation predicted the aboveground tree volumes equally well across all species (groupings), with bias (± RMSE of 0.153 ± 2.512 and 0.178 ± 2.56 m 3 respectively. Finally, trees within species accounted for 49.3% of the total variability in volume prediction error vs only 3.5% for species. Recommendations have been made for improvement relatively to data requirements and model building.

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On volume recovery index and implications for sustainable logging in Congo Basin

Cited by 4 publications

References 31 publications

Procedimiento basado en análisis troncales para estimar a posteriori si el rendimiento maderable de un bosque ha sido sostenido a largo plazo

Procedimiento basado en análisis troncales para estimar a posteriori si el rendimiento maderable de un bosque ha sido sostenido a largo plazo

Implications of Selective Harvesting of Natural Forests for Forest Product Recovery and Forest Carbon Emissions: Cases from Tarai Nepal and Queensland Australia

Construction of Multispecies Allometric

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