Tropical forests are decreasing at the rate of 16.9 million hectares per year due mainly to clearing for agriculture and shifting cultivation. Timber harvesting results for more than 5 million hectares of tropical forest becoming degraded looged-over forests every year without any adequate management. The decrease and degradation of tropical forests caused by anthropological activities affect not only the sustainable production of timber but also global environments. The clarified scientific information on the rehabilitation of degraded tropical forest ecosystems enables managers to devise silvicultural systems which enhance soil properties and forest resources important to sustainable production and minimise deleterious effects associated with harvesting impacts and short rotation of plantation. Rehabilitation is aimed to improve biological diversity, increasing commercial value for timber and non-timber products, increasing forest functions, improve soil fertility. Technically developments are expected for reducing logging impacts, accelerating natural regeneration, species selection, enrichment, sustainable site management, catalytic plantation, site evaluation and classification. Socioeconomic developments are also expected for local community participation and socio-economic acceptability. Following research activities have been considered (1) evaluation of forest harvesting impacts on the forest ecosystems: (i) evaluate logging and yarding methods on disturbance of forest ecosystems, (ii) analyse the demography of regenerated tree population, (iii) model a/de-gradation processes in forest ecosystems, (2) development of methods to rehabilitate logged-over forests and degraded forest lands: (i) treatments accelerating natural regeneration, (ii) development of enrichment planting methods, (3) development of silvicultural techniques on degraded forest lands: (i) development of species-site matching methods, (ii) management options for sustained productivity, (iii) social and economic acceptability of management options. In Indonesia, CIFOR co-operates with Universitas Mulawarman, and looks at (a) evaluation of forest harvesting impacts on the forest ecosystems, and (b) evaluation of forest harvesting and fire impacts on the forest ecosystems and development of methods to rehabilitate logged-over forest and degraded lands. The site is Bukit Soeharto Education Forest, a mixed Dipterocarp forest logged by INHUTANI I in 1976. The forest has been heavily burnt in 1998 after experimental treatment. The approach to rehabilitation has been through the “taungya system” whereby farmers are allowed to grow annual crops among the newly-planted trees. With the Instituto Nacional de Investigacion Agraria (INIA), Peru, the project is trying out re-vegetation of abandoned fallow fields after agricultural use. There is specific interest to select tree species having high economic value that can adapt and grow rapidly in abandoned agricultural land and on infertile soils. Sites are all located in the Ucayali region of the Peruvian Amazon. After the first two years, results are pointing to specific promising species that can be recommended. The project involves small farmers in silvicultural activities and even species choice takes into account their preferences.
Tag: fire
Effects of forest fire on wood: a biological (anatomical study)
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 or mechanical properties depending on how serious the defect is in the wood. Wood deterioration was more strongly influenced by the conditions caused by the forest fire and subsequent attacks by fungus, bacteria and insects than by fire itself. There were various effects depending on the durability and other properties of the wood. The wood was classified into four groups: “merkubung/sengon”, “akasia/medang”, “ulin” and “leda”, according to condition in the field.
Rehabilitation of degraded tropical forest ecosystems: workshop proceedings, 2-4 November 1999, Bogor, Indonesia
This conference proceedings contains 26 papers based on the activities of partner institutions that the Center for International Forestry Research (CIFOR) has facilitated. There are 4 sections: (i) evaluation of forest harvesting and fire impacts on forest ecosystems; (ii) development of methods to rehabilitate logged-over forests and degraded forest lands; (iii) development of silvicultural techniques on degraded forest lands; and (iv) network of the rehabilitation of degraded forest ecosystems.
Land cover characterization in West Sudanian savannas using seasonal features from annual landsat time series
With the increasing temporal resolution of medium spatial resolution data, seasonal features are becoming more readily available for land cover characterization. However, in the tropical regions, images can be severely contaminated by clouds during the rainy season and fires during the dry season, with possible effects to seasonal features. In this study, we evaluated the performance of seasonal features based on an annual Landsat time series (LTS) of 35 images for land cover characterization in West Sudanian savanna woodlands. First, the burnt areas were detected and removed. Second, the reflectance seasonality was modelled using a harmonic model, and model parameters were used as inputs for land cover classification and tree crown cover prediction using the random forest algorithm. Furthermore, to study the sensitivity of the approach to the burnt areas, we repeated the analyses without the first step. Our results showed that seasonal features improved classification accuracy significantly from 68.7% and 66.1% to 76.2%, and decreased root mean square error (RMSE) of tree crown cover predictions from 11.7% and 11.4% to 10.4%, in comparison to the dry and rainy season single date images, respectively. The burnt areas biased the seasonal parameters in near-infrared and shortwave infrared bands, and decreased the accuracy of classification and tree crown cover prediction, suggesting that burnt areas should be removed before fitting the harmonic model. We conclude that seasonal features from annual LTS improved land cover characterization performance, and the harmonic model, provided a simple method for computing annual seasonal features with burnt area removal. © 2016 by the authors.
Quantifying off-site effects of land use change: filters, flows and fallacies
Many external effects of land use change are based on modifications of lateral flows of soil, water, air, fire or organisms. Lateral flows can be intercepted by filters and thus the severity and spatial range of external effects of land use change is under the influence of filter effects. Wherever lateral flows are involved, research results cannot be simply scaled on an area basis, and overall impact does not follow simple linear causal relationships. This complexity has consequences for relationships amongst the primary agents who initiate or exacerbate external effects, other stakeholders who are affected by them and policymakers who attempt to mitigate problems that reach sufficient visibility in society. In this paper we review how the relative importance of lateral flows and filter effects differs among a number of externalities, and the implications this has for research methods. If flows and filters are incompletely understood, policies may be based on fallacies. Whereas ‘fire-breaks’ act as filters in the lateral flow of the high temperature pulse of a fire, smoke from land-based fires can be intercepted only by rainfall acting as a filter and the external impact of smoke is determined by the atmospheric conditions governing lateral flow and chemical transformations along the pathway. Causal relations in smoke and haze problems are relatively simple and may form a basis for designing policy interventions to reduce downwind damage. For biodiversity issues, landscape connectivity, the absence of filters restricting dispersal and movement of organisms, is increasingly recognised as an influence on the dynamics of species richness and its scaling relations. Biodiversity research methods can extend beyond the current descriptive stage into clarifying causal relations with a lateral flow perspective. The question whether connectivity is in fact desired, however, depends on stakeholder interests and situation. Forest functions in watershed protection, presumably leading to a continuous flow of clean water in the dry season through the subsoil instead of a rapid surface transfer, have been generally attributed to the trees rather than the forest, with its rough surface structure, swamps and infiltration sites. A new synthesis of site-specific hydrological knowledge and tree water balance studies may be needed to separate myth from reality, and avoid wasting public funds on tree planting under the heading of reforestation, without restoring the hydrological regime of a real forest. Soil movement can be intercepted at a range of scales and in as far as soil transport entails movement of soil fertility, filter zones can be very productive elements of a landscape. To achieve ‘integrated natural resource management’ all external effects of land use will somehow have to be taken into account in farmer decision making about the use of natural resources on and off farm. Farmers’ ecological knowledge may include concepts of lateral flows and should be further explored as an integral part of a new landscape ecological approach.
Lessons on Community-Based Fire Prevention and Peatland Restoration
Ideas, narratives and arguments on preventing natural disasters and restoring ecosystems focus on raising awareness and fostering participation from all parties. Conventional research helps in understanding socioecological systems and their interactions, but governments, communities and donors want research that makes a difference. There is an urgent need for tangible change. Research conducted with full participation and an action-oriented approach is the solution. Participatory Action Research (PAR) is designed to bring real change on the ground. PAR is transdisciplinary in nature; it integrates approaches from various disciplines and draws on both local and global wisdom. This book aims to provide an understanding of the concepts, philosophical foundations and steps involved in implementing PAR, and is complemented by examples of fire prevention and community-based peatland restoration efforts implemented in Riau Province, Indonesia. We hope it can serve as a valuable resource for researchers, private sector operators, communities, NGOs, governments and practitioners involved in natural disaster prevention and ecosystem restoration.
The Effect of Fire and Rewetting on the Groundwater Level in Tropical Peatlands
Hydrological system strongly influences the sustainability of peatlands. The drainage system in peatlands that is not designed appropriately will result in the drop of groundwater level (GWL), and thus, peat will be dried and become susceptible to fire. Efforts to restore peatlands have been carried out, one of which is peat rewetting through canal blocking. This study assessed the non-burnt and burnt peatland areas as well as an area with canal blocking to determine the effect of fire and canal blocking on the GWL for the foregoing variables. In each area, dipwells were established at a distance of 1 m (representing the canal water level), 10, 50, 100, 250, and 350 m from the canal. The study clearly showed a significant correlation between the average GWL and fire, and canal blocking as well as the distance from the canal. Fire resulted to an increase of the average GWL, from 61 cm to 50 cm below the ground. There were significant impacts on land use relevant to the average GWL. Canal blocking demonstrated its role in increasing GWL on drained peat areas by mimicking the average GWL on the reference site. This study concluded that constructing more canal blockings and planting more fire-resistant plants are critical to reduce the fire risks.
Wildfire effects on forest structure of Pinus merkusii in Sumatra, Indonesia
Pinus merkusii (Jungh. & de Vriese), the only pine species native to Indonesia, is threatened by land-use change, resource extraction, and fire. P. merkusii forests in Sumatra are subject to mixed-severity wildfires that can change forest structure over time. This project is only the second study to quantify differences between burned and unburned P. merkusii forests in Sumatra. We measured six burned-unburned paired sites for forest characteristics, regeneration, forest floor and woody debris, and effects of resin tapping. Fires killed more than 60% of P. merkusii trees and reduced tree biomass and carbon by about 40%. Fire killed trees of all sizes up to 60 cm diameter at breast height (DBH), but preferentially killed small trees with DBH less than 10 cm. Seedling regeneration of P. merkusii in the burned forest was higher on average than in the unburned forest, but the difference was not statistically significantly different and P. merkusii regeneration was low overall. Unlike continental Asian P. merkusii forests, the insular populations did not have a seedling grass stage or evidence of fire-stimulated germination. Forest floor and woody debris values were relatively low by the standards of global pine forests but comparable data do not exist for Indonesia. Recent tapping of trees for P. merkusii resin affected most trees over 20 cm DBH and was associated with high mortality in fires, suggesting that the interaction between resin tapping and fire could be lethal. Further research is needed to evaluate longer-term forest dynamics, especially for regeneration and the effects of resin tapping.
New Approach Evaluating Peatland Fires in Indonesian Factors
Until 2018, the El Niño–Southern Oscillation (ENSO) was used as an explanation for fires in Indonesia’s peatlands. However, when the 2019 fires occurred independently of El Niño, more suitable indicators and methods were required to (a) analyze, (b) evaluate and (c) forecast peatland fires. In this study, we introduced the OLR–MC index—one of the rain-related indices derived from OLR (outgoing longwave radiation) in MC (maritime continent) area in Indonesia. This index showed stronger correlation with active peatland fires than the conventional ENSO index, and is likely to be able to respond to heat and dry weather supposed to be under climate-change conditions. We then analyzed peatland fires in the top six fire years from 2002 to 2018 and showed that peatland fires occurred in three stages—surface fire, shallow peatland fire and deep peatland fire. To explain each stage, we proposed a one-dimensional groundwater level (GWL) prediction model (named as MODEL-0). MODEL-0 predicts GWL from daily rainfall. Analysis using MODEL-0 showed the GWL thresholds for the three fire stages were between -300 mm and -500 mm; peatland fire activities during the three fire stages were dependent on these GWL values. The validity of MODEL-0 was shown by comparison with the measured values of GWL in the top three fire years.
Out of fire disaster: dynamics of livelihood strategies of rural community on peatland use and management
Rural community in peatland is less concerned actor during the recurrent fire disaster. This disaster has already diminished the source of livelihoods. There is limited information about the dynamics of the livelihoods related to the use of fire in peatland. This paper examines the dynamics of rural livelihoods and the adaptation livelihoods strategies in degraded peatland. Data are collected by field survey, in-depth interview, focus group discussion in three villages at Riau Province and they are analyzed descriptively. Peatland is the only remaining important resource for the rural people after fire disaster. They will select prospective commodities based on their capabilities and access to market. Rural community are more intensive in using the resource of peatland for their livelihoods with the growing interest to several commodities. Recent community livelihoods depend on some certain commodities (palm oil, areca nut, rubber) and tend to conduct expansive and monoculture land use strategy rather than polyculture strategy. Diversification livelihood with adaptive and valuable commodities through trainings, continuous coaching and building business.