Legacy of logging roads in the Congo Basin

How persistent are the scars in forest cover?

authored by

Fritz Kleinschroth, Sylvie Gourlet-Fleury, Plinio Sist, Fréderic Mortier, John R. Healey

Abstract

Logging roads in the Congo Basin are often associated with forest degradation through fragmentation and access for other land uses. However, in concessions managed for timber production, secondary roads are usually closed after exploitation and are expected to disappear subsequently. Little is known about the effectiveness of this prescription and the factors affecting vegetation recovery rate on abandoned logging roads. In a novel approach we assessed logging roads as temporary elements in the forest landscape that vary in persistence depending on environmental conditions. We analyzed road persistence during the period 1986-2013 in adjacent parts of Cameroon, Central African Republic and Republic of Congo. 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 no longer distinguishable from the surrounding forest. Field based inventories confirmed significant differences between all three categories in density and richness of woody species and cover of dominant herbs. We used dead-end road segments, built for timber exploitation, as sampling units. Only 6% of them were identified as being re-opened. Survival analyses showed median persistence of four years for open roads before changing to the revegetating state and 20 years for revegetating roads before disappearance. Persistence of revegetating roads was 25% longer on geologically poor substrates which might result from slower forest recovery in areas with lower levels of soil nutrient content. We highlight the contrast amongst forests growing on different types of substrate in their potential for ecosystem recovery over time after roads have been abandoned. Forest management plans need to take these constraints into account. Logging activities should be concentrated on the existing road network and sites of low soil resource levels should be spared from business-as-usual exploitation.

External Organisation(s)

French Agricultural Research Centre for International Development (CIRAD)
Bangor University
AgroParisTech - Université Paris-Saclay

Type

Article

Journal

ECOSPHERE

Volume

6

ISSN

2150-8925

Publication date

01.04.2015

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Ecology, Evolution, Behavior and Systematics, Ecology

Sustainable Development Goals

SDG 15 - Life on Land

Electronic version(s)

https://doi.org/10.1890/ES14-00488.1 (Access: Open)