Tropical forests are being cleared at a rate of 16.9 million hectares per year and timber harvesting results in over 5 million hectares becoming secondary forests annually without adequate management. This decrease and degradation affect both timber production and many environmental values. Selective and clear cutting, and burning are major causes of land degradation. An assessment is needed of harvesting impacts that influence rehabilitation methods. The harvesting impacts on ecosystems vary with time and methods of logging, timber transporting methods, logged tree species, soil characteristics, topographies, local rainfall patterns etc., and must be assessed in a range of conditions with...

Undisturbed lowland primary forest in Kutai, East Kalimantan is usually distinguished by dominance of dipterocarp species in number of individuals, in basal area and by their emergence to more than 50 m in height. Forests in most lowland concession areas have been logged selectively and suffered from surface forest fires at least twice since 1970. Canopy height and dominance levels have decreased in proportion to extent and frequency of disturbances by logging and fires but the area of pioneer species has increased proportionally with degradation. Secondary forest species or pyrophytic trees have become dominant in all forest lands. Forest degradation...

The effects of the forest fire on anatomical and ecophysiological resistance of tree species was investigated in Bukit Soeharto Education Forest, an area about 5000 ha, in East Kalimantan, Indonesia. The forest was impacted seriously by forest fire in 1998. This forest land is dominated by Dipterocarpaceae species, especially Shorea spp., with some Dryobalanops, Cotylelobium and Anisoptera species. The investigation was conducted in a single plot of burned primary forest with scattered gaps. The gaps had mixed pioneer and non-pioneer species, such as Eusideroxylon zwageri, Macaranga hypoleuca, Shorea laevis, Macaranga gigantea, Palaquium rostratum and Polyalthia sumatrana. Tree density (>10 cm...

Logging and/or forest fires cause a direct impact of reducing vegetation cover, and in many cases create a pre-condition for the increase of soil erosion rates during high rainfall. Such an increase in soil erosion rate may be higher than the normal threshold rate from a sustainable forest land productivity viewpoint. Field measurement was focused on surface runoff (overland flow) and eroded soil mass on slopes of 25-35% with light and heavy intensities of logging and control plots. Both logging intensities directly increased surface runoff and eroded soil mass, especially on timber felling, skidding trails establishment and log skidding and/or...

The research was conducted at Bukit Soeharto, East Kalimantan, Indonesia. In the natural forest there were as many sound as diseased trees. There were no clear differences in disease incidence among forests with different intensities of cutting and among different diameter classes. Observations were made on 49 trees of 15 species in sample plots. Among them only Dipterocarpus convertus, D. cornutus, Shorea leprosula, S. ovalis and S. seminis remained sound. Stem canker was judged to be the most dangerous disease. Invasion of disease in uncut forest (control) was low level compared with cutting treatments, but difference of disease invasion between...

The effects of forest fire on wood were studied on fifteen dead and living trees of various tropical species. The wood reacted in the following ways: (1) creating smaller but denser pores than normal in a concentric pattern, (2) changing dimension and numbers of axial parenchyma, (3) producing more axial intercellular canals, (4) forming decay spots in the wood, (5) creating the concentric area of fibres area or forming the vessels late, (6) creating new calluses and the bole losing its cylindrical form, (7) producing abnormal gums in the wood and (8) the bole becoming hollow. These abnormalities decrease physical...

In the Guarani preservation area 100 ha of forest land was cut to evaluate harvest impact in natural subtropical forest. Two treatments were applied: “commercial logging” in which the logging contractor works in the traditional way, and “improved harvest” in which trees are selected and the skidding trails and landings planned. Forest structure and composition, seedlings and regeneration; and soil physical parameters such as soil density, penetration resistance were measured before harvesting. The trees were cut by chainsaw and moved by a rubber tyred skidder to the landing area for loading on a truck. After harvesting, damage by cutting and...

From a study conducted in Pasoh Forest Reserve, 149 tree species in 92 genera and 38 families, all trees with a diameter breast height (dbh) of 1 cm or above were enumerated in a one hectare plot. The most abundant species was Ficus fistulosa across all dbh classes followed by Monocarpia marginalis and Dipterocarpus cornutus. The most diverse family was Euphorbiaceae with 25 species followed by Dipterocarpaceae (13 spp.) and Leguminosae (13 spp.). Stand density was 1951 stems ha-1 with Euphorbiaceae contributing about onefifth the total number of stems. High densities of pioneer species such as Macaranga spp., Vitex pinnata...

The study focused on the effect of land use activities on stream water quality in Pasoh, Negeri Sembilan, Malaysia. The stream originates in Pasoh Forest Reserve, Negeri Sembilan and then flows through four different types of land use: undisturbed forest, swamp, degraded loggedover forest and agriculture. Water quality parameters chosen for the study include pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), ammoniacal-nitrogen (NH₃-N), temperature, electrical conductivity (Ec) and turbidity. Stream flow rate was also measured. Computation of water quality status was based on Department of Environment’s (DOE)-Water Quality Index (DOE-WQI) and Harkin’s...

Soil samples from permanent sample plots of natural mixed deciduous, logged-over mixed deciduous and the secondary stands in the tropical seasonal forest were analysed for physical and chemical properties. Bulk density and soil hardness of A-horizon in the natural stand were slightly higher than in logged-over and the secondary stands with average bulk densities 1.2, 1.1 and 1.0 g cm-³ and soil hardness 17, 16 and 15 respectively. Secondary stands had slightly higher B-horizon hardness than the natural and the logged-over stands. Total pore value (volumetric %) of the secondary stand was higher than the logged-over and the natural stands...

In East Kalimantan, drought is frequently followed by fire. The eastern part of Kutai Regency is susceptible to large-scale wildfires during severe droughts related to strong El Niño Southern Oscillation (ENSO) events as shown by the 1982-83 and 1997-98 fires. Since the 1982-83 forest fire, many trials have been conducted to rehabilitate the burned forests. However, the 1998 fires burned both natural and rehabilitated forests in East Kalimantan. It is to be expected that severe droughts related to strong ENSO events and subsequent wildfires will occur again in the near future. At the time of the next severe ENSO event,...

The objective of the forest rehabilitation study with taungya system was to find out optimum method, cash crop species, constraints, and how much this system benefits forest rehabilitation. It was carried out using red meranti (Shorea smithiana) and rubber (Hevea brasiliensis) as plantation trees, and rice (Oryza sativa), maize (Zea mays), soya bean (Glycine max) and cassava (Manihot esculenta) for intercropping. The research has shown that there are a number of constraints to the use of taungya in East Kalimantan for the rehabilitation of burnt, loggedover forest. The problems are a mix of technical, economic and social. It was found...

Preliminary results of a field study to determine the establishment of six native forest tree species of economic value on degraded areas abandoned after intensive past agricultural use are reported. Study sites were on slash-and-burn farms partially covered with abandoned agricultural areas on Ultisols dominated by invading vegetation mainly composed of Imperata brasiliensis, Rottboellia cochinchinensis and Baccharis floribunda. Tree species used in the trials were: Schizolobium amazonicum, Tabebuia serratifolia, Calycophyllum spruceanum, Terminalia oblonga, Amburana cearensis and Cedrelinga catenaeformis. These six species were planted in three degraded habitats characterised by the presence of one of the above weed species. After 13...

Effects of soil properties on growth of young tree seedlings of Hopea odorata and Azadirachta excelsa in line and gap enrichment planting in logged-over tropical lowland forest were evaluated. At 13 months, the trees were grouped into “good” and “poor” growth based on their height increment in the previous 6 months. Organic matter content, penetration resistance, soil texture, thickness of A-horizon, Ca and Mg contents differed significantly between soils with “good” and “poor” growth. Organic matter, thickness of A-horizon, Ca and Mg contents were found to be significantly higher in “good” growth soils than “poor” ones, but penetration resistance was...

Four rehabilitation methods were tested in logged-over lowland tropical forest in Pasoh Forest Reserve, Negeri Sembilan, Peninsular Malaysia. The treatments were: line planting (T1), gap planting 10m x 10m x 5 ha-¹ (T2), gap planting 20 m x 20 m x 5 ha-¹ (T3) and gap planting 10 m x 10 m x 9 ha-¹ (T4). Hopea odorata, Azadirachta excelsa and Vitex pubescens were planted in the lines and gaps. One year after planting, percentage survival of seedlings were: 97%, 96%, 93% and 93% respectively for T1, T4, T2 and T3 for Hopea odorata; 96%, 90%, 88% and 85% respectively...

A study was conducted on forest rehabilitation based on indigenous species at the Universiti Putra Malaysia, Bintulu, Sarawak. Areas of open abandoned shifting cultivation, manmade mounds, Macaranga secondary forest and shrubby undergrowth were used for trial planting with different types of planting techniques. The research showed that selected species from the natural vegetation community easily adapt to the site conditions similar to their native habitat. The planted seedlings were classified as light demanding, shade tolerant and late growth species on the basis of their height growth performance in the trials. The indigenous tree species recommended for checkerboard plantations are: Shorea...

Forest degradation due to logging is becoming an acute problem in Papua New Guinea. Research started at two sites in 1998-1999 to develop the most effective methods to rehabilitate logged-over forest sites by applying different treatments, observing changes in the forest ecosystem and determining whether these methods are more effective than allowing natural regeneration to rehabilitate the forest. It aimed to test different size gaps (10 m x 10 m x 9, 10 m x 10 m x 5, 20 m x 20 m x 5) for planting in logged-over forest and to measure the growth and survival of three...

The research was carried out at the Forest Industry Organization’s Thongphaphum Plantation in Kanchanaburi province, Thailand. The main objective was to determine the effects of different thinning methods on coppicing ability of 17-year-old teak leading to two canopy levels. Teak stumps were planted in 1980 at a spacing of 4 x 4 m and average survival rate was 72%. In 1997 the thinning experiment was set up in a randomised block design with 3 replications and 4 treatments : low thinning, 1:1 mechanical thinning, 2:2 mechanical thinning, and clearcutting. Average stand density after thinning was 40 trees plot-¹, equivalent to...

Two commercial eucalypt sites were selected in São Paulo State, Brazil, to evaluate productivity and soil chemical and physical properties before clearcutting, and the effect of harvesting and soil tillage system on productivity of second rotation. At site 1, the Eucalyptus grandis plantation was 7 years old, on its first rotation, and reached 21 m mean height, 13.6 cm diameter breast height (dbh), an estimated commercial volume of 479 m³ ha-¹ and a mean annual increment of 68 m³ ha-¹ year-¹. At site 2, E. grandis, also on its first rotation, but 12-years-old, had 25 m mean height, dbh 16...

The accumulation and cycling of nutrients in planted forest is essential to the establishment of management practices that can lead to the sustainable production of the forest site. The uptake, accumulation and release of nutrients depend on tree age and stage of development. The knowledge of accumulation and cycling of nutrients allows the estimation of output and replacement of nutrients to the forest site. This makes it possible to correct nutritional disorders caused by the use of inadequate management techniques. The usual method of sampling biomass and nutrients is always destructive making it impossible to establish permanent plots for nutritional...

At two sites, where Eucalyptus grandis plantations were 7 and 12 years old, twelve dominant trees were cut and measured. The 12-year-old-trees were 29.4 m mean height, 19.9 cm diameter over bark and estimated volume 0.40 m³ tree-¹. The 7 year-old trees were 30.7 m mean height, 20.6 cm diameter and estimated volume 0.49 m³ tree-¹. Of total biomass, 92% was trunk (sapwood, heartwood and bark). Based on a population of 1500 trees ha-¹, there is an export of biomass of 296 t ha-¹ from 302 t ha-¹ being produced, when the entire trunk is removed. When only commercial stems...

Biological factors of fertility were assessed through the study of litter quantity and quality, soil organic matter quantity and quality, soil microfauna, soil macrofauna, organic matter dynamic, particularly decomposition and non-symbiotic nitrogen fixation in an age series of Eucalyptus PF1 and one stand of E. urograndis (E. urophylla x E. grandis). The litter system underwent drastic changes with plot age: litterfall was higher in the older plots than in the younger ones. Soluble carbon and lignin content decreased significantly with plot age and decomposition rate increased. Change in soil organic matter amount occurred in the top layer of soil only...

Komatsu Ltd. and the Forest and Nature Conservation Research and Development Center (FNCRDC) of the Ministry of Forestry, Indonesia have developed a cutting propagation technique for dipterocarp species. This technique uses a fog-cooling system to lower the temperature inside cutting boxes in a greenhouse. This method is suitable for mass production of vegetative propagules of some dipterocarps species. Rooting percentage of S. leprosula and S. selanica (meranti) cuttings was 95% and 92% respectively during the experimental stage, and 67% at mass production stage. The planting stock production of the dipterocarp cuttings in 1997 and 1998 were 42 000 and 53...

The participatory forest fire prevention programme of Forest Fire Prevention Management Project (FFPMP) aims at intensive fuel management and fire control with the integrated green belt on community land on the boundary of Berbak National Park, Jambi Province, Sumatra. It aims to motivate farmers to cultivate their land continuously, reducing fire hazards and risks through formation of fuel breaks around the forest. Participating farmers face technical limitations in seedling production, land preparation without burning, and crop planting and protection. They cannot easily perceive benefits of the green belt with line planting of the small number of trees. Land-oriented farmers experienced...

This information and dataset system aims to facilitate international exchange and synthesis of the scientific and technical information based on results of the CIFOR/Japan project on the rehabilitation of degraded tropical forest ecosystems. There are two main pathways. One path integrates general information at the study site from annual reports, site map, remote sensing data, aerial chart and vegetation map into plot data of each site. Their outputs are data on site condition, vegetation, soil, climate, etc. which are accessible to the public. Another path is to accumulate experimental raw data into “Download” the use of which is restricted and...

Tropical forests of the Asia-Pacific region are the most heavily threatened from high population density and rapid economic growth. Extensive forest areas have become degraded as a result of over-exploitation and poor management. Unless these degraded forests are rehabilitated, they will come under pressure from other land uses. Recognising this, the Forest Research Support Programme for Asia and the Pacific (FORSPSA) of FAO initiated a Rehabilitation Programme and has started to set up a series of model plots of about 100 ha in each of the ecoclimatic regions of Asia and the Pacific. Unproductive second growth forest areas will be...