REHABILITATION OF CRITICAL LAND :

Experience from Enrichment Planting on Bushes and Imperata land

 in Sialiali, South Tapanuli North Sumatra

By :

Aswandi dan Rusli MS Harahap

Forest Research Institute of Aek Nauli in North Sumatra.

Jl. Raya Parapat Km 10,5 Sibaganding Parapat Sumatara Utara. Email : andiasw@yahoo.com

Abstract

During 2003 – 2007 period, more than 40 species were planted on different land cover in Siali-ali South Tapanuli. Endemic and exotic-past-growing species were planted on imperata grassland, under canopy of past-growing plantation and enrichment planting on bushes and young secondary forest. Height and diameter measurement indicated that land cover types were influenced the plant growth. Exotic-past-growing species i.e. Acacia crassicarpa A. Cunn. ex Benth and Eucalyptus urophylla ST. Blake were grew well on open site i.e. imperata grassland and bushes, but endemic species i.e. Shorea platyclados V.Sl, and S. ovalis Bl have good performance in diameter and height growth on more closed-vegetation area i.e. young secondary forest. Dryobalanops aromatica Gearth plantation where their seedling originaly from Natal North Sumatra on bushland showed good performance in diemeter and height growth. Average of height trees at three years old plantation were 160 centimeters. Enrichment plantation with Shorea pinanga Scheff seedlings at 10 years old Acacia crassicarpa stand were indicated good adaptability this species under fast-growing species canopy which average of height were reached 80 centimeters in two years plantation. There were significant different between growth of Anisoptera costata Roxb. dan Shorea ovata Dyer at 10 years old plantation in secondary forest and bushes. Average of diameter and heigh S. ovata that planted under young secondary forest canopy were smaller (only 0.5 centimeters and 0.5 meters) as compared to their plantation in bushes (7.4 centimeters and 13.68 meters). More significant difference were showed by A. costata plantation. Average of diameter were 12.75 centimeters in bushes but only 0.62 centimeters under young forest canopy. Average of diameter and height A. costata were attainded 12.8 centimeters and 16.50 meters which planted on bushes.

Keywords: enrichment planting, indigenous species, exotic fast-growing species, secondary forest, imperata land, bushes