REVEGETATION OF DISTURBED AREAS ON TROPICAL FOREST: A CASE STUDY ON A GAS FIELD, SEISMIC PROGRAM ABANDONMENT AND PIPELINE RIGHT-OF-WAY (ROW) CLOSURE

摘要

This document describes the revegetation techniques and works carried out to control erosion and sediment problems along a pipeline ROW and helipads (HPs) used during a seismic prospecting and gas transport programs. HPs consist of 40×40 m cleared squares, with bare soil at the center for landing and vegetal debris piled at the perimeter. These works were part of a gas field development project in the south eastern jungle of Peru. They comprised the construction of four platforms (2 ha each), approximately 68 km of flowlines (from drilling platforms to gas plant) and a logistic base (123 ha including landing strip, gas plant and quarries). The seismic program started during the rainy season (February 2002), with a 3D block of 4150 km of seismic lines (764 km2) and 73 HPs, covering 18 ha, cleared for logistics support. The closure plan for the 73 HPs and fly camps (FCs) was prepared to include revegetation started during the dry season (August 2002). About 26500 tree seedlings were used in all, of which 23000 were natural grown seedlings gathered from surrounding forest and 3500 were produced in two small nurseries. Nurseries propagated 10 fast growing woody species. Natural grown seedlings covered 65 representative species, all familiar to local natives by their use and appearance. ROW clearing of the first 28 km of flowlines started in March 2002, after the rainy season. Stabilization began in July, mainly reconfiguring manually drainage network and slopes. Once pipelines were buried, erosion control measures (sediment traps, check dams and slope breakers) were installed. The revegetation plan included techniques, plantation layout designs and resources needed to complete the job. The work covered 28 km sections of ROW and 4 km of access roads (approximately 58 ha), combining tree planting, broadcast grass seeding and stolons transplanting, totaling 21500 tree seedlings. Over pipes, seeds and grass stolons were sown to reduce runoff quickly. On other areas, trees were planted in order to complement the stabilization of disturbed areas, to produce shadow and thus enhance the recovery of surrounding forest species.