• Aucun résultat trouvé

Potentialities of using ASTER & SRTM DEM for road planning in Central African sustainable forest logging context. A case study in East Gabon

N/A
N/A
Info
Télécharger
Protected

Academic year: 2021

Partager "Potentialities of using ASTER & SRTM DEM for road planning in Central African sustainable forest logging context. A case study in East Gabon"

Copied!
1
0
0

Chargement.... (Voir le texte intégral maintenant)

Texte intégral

(1)

Objectives

Evaluate  potentialities  and  limitations  of  SRTM  and  ASTER  DEMs  for  slope  evaluation  in  sustainable forest road planning in Central Africa

Potentialities of using ASTER & SRTM DEM for road planning in a Central African 

sustainable forest logging context ‐ A case study in Gabon

University of Liege. Gembloux Agro bio-tech. Unit of Forest and Nature Management

Julien Philippart, Daphné Handerek, Philippe Lejeune, Jean-Louis Doucet

Results

Qualitative approach Quantitative approach

Contact: j.philippart@student.ulg.ac.be

Study area and logging context

 Forest concession under sustainable management in the  south‐east Gabon (0°45’00’’ S, 13°15’00’ E)  Covered by dense moist evergreen tropical forest, dominated  by Okoume (Aucoumea klaineana)  Canopy height is about 50m  Selective logging (0.5 to 2 trees / ha)  Reduced impact logging rules applied  Maximum slope limitation : ‐ 12% for primary roads ‐ 30% for secondary roads Methodology

 Five Elevation maps : 2 derived from SRTM and 3 derived from ASTER

 Two test zones : Milolé (hilly) and Okondja (flat)

 Field Data : 992 and 668 slope measures along transects in  Milolé and Okondja respectively

 Database compilation and slope comparison

Comparison of RMSE, User’s Accuracy (UA) and Global Accuracy (GA) for   maximum slope limitation of primary roads (12%) and secondary roads (30%) for the two test zones Milolé (hilly) and Okondja (flat)

Conclusions

 All DEMs show a greater GA in hilly area (Milolé) than in flat area (Okondja)   SRTM derived DEMs show a higher UA for secondary roads constraint 

 The use of corrected aster DEMs increases initial ASTER UA from 0.1 to 18.8% depending on category and slope limitation  Resampling initial SRTM 90 m DEM to SRTM 30 m does not improve slope evaluation

 Despite a relatively high RMSE for slope grade, all of the DEMs tested (under the condition of correcting artifacts) were found to be  consistent for consideration of maximum slope constraint aiming at sustainable road planning for forest logging in Central Africa

Examples of artifact and pixelisation effect for original ASTER 30m and  SRTM 90m respectively

Références

Télécharger maintenant ( PDF - 1 Page - 375.83 KB )

Documents relatifs

A probabilistic distribution approach for the classification of urban roads in complex environments

The main contribu- tion of this work is the creation of a probabilistic distribution based on Texton and Dispton maps to model weak classifiers used in a Joint Boosting

Detection of Passable Roads Using Ensemble of Global and Local Features

Finally, conventional visual descriptors and Deep Local Features were combined to create ensemble of vi- sual features and processed through SRKDA for classification, as shown in

Grouping species to model forest dynamics : a case study of a forest in the Central African Republic

The ecological groups were obtained by a cluster analysis based on species diameter growth rates, their mortality rates and recruitment rates.. A forest dynamics matrix model was

10 1.4.3 Consideration of the sustainable nature of roads

4 Contribution 2: Identification of Efficient Solutions by Using a Multi-objective Evolutionary

Impacts of logging roads on intact forest landscapes in the tropics

Intact Forest Landscapes and FSC certification in Brazilian Amazon: challenges to sustainable management. Brazilian Amazon, IFL, RIL,

Roads in the rainforests: Legacy of selective logging in Central Africa. Evaluatin the temporal and spatial dynamics of logging road networks

This contrasts with the situation in tropical forests, where road networks built for selective logging are considered a high risk for old growth forests by opening the door

Legacy of logging roads in the Congo Basin: How persistent are the scars in forest cover?

Three successive phases of road recovery were identified on LANDSAT images: open roads with bare soil, roads in the process of revegetation after abandonment and disappeared roads

Transience of logging roads in Congo basin rainforests

Logging roads are considered to be drivers of tropical forest degradation by fragment- ing the forest and opening it for human and biological invasions. However, most sec-