Estimating rainforest biomass stocks and carbon loss from deforestation and degradation in Papua New Guinea 1972–2002: Best estimates,uncertainties and research needs

Reduction of carbon emissions from tropical deforestation and forest degradation is being considered a cost-effective way of mitigating the impacts of global warming. If such reductions are to be implemented, accurate and repeatable measurements of forest cover change and biomass will be required. In Papua New Guinea (PNG), which has one of the world's largest remaining areas of tropical forest, we used the best available data to estimate rainforest carbon stocks, and emissions from deforestation and degradation. We collated all available PNG field measurements which could be used to estimate carbon stocks in logged and unlogged forest. We extrapolated these plot-level estimates across the forested landscape using high-resolution forest mapping. We found the best estimate of forest carbon stocks contained in logged and unlogged forest in 2002 to be 4770 Mt (±13%). Our best estimate of gross forest carbon released through deforestation and degradation between 1972 and 2002 was 1178 Mt (±18%). By applying a long-term forest change model, we estimated that the carbon loss resulting from deforestation and degradation in 2001 was 53 Mt (±18%), rising from 24 Mt (±15%) in 1972. Forty-one percent of 2001 emissions resulted from logging, rising from 21% in 1972. Reducing emissions from logging is therefore a priority for PNG. The large uncertainty in our estimates of carbon stocks and fluxes is primarily due to the dearth of field measurements in both logged and unlogged forest, and the lack of PNG logging damage studies. Research priorities for PNG to increase the accuracy of forest carbon stock assessments are the collection of field measurements in unlogged forest and more spatially explicit logging damage studies.     

PARTIAL DEFORESTATION AND SHORT-TERM AUTOCHTHONOUS ENERGY INPUT TO A SMALL NEW ENGLAND STREAM1

ABSTRACT: Autochthonous energy input, in the form of periphyton production and growth, was studied before and after partial logging of the watershed surrounding School Brook, a small tributary of the Aroostook River, Maine. Due to infection by the spruce budworm (Chiristoneura fumiferana), the buffer strip on one bank of the stream was logged and only limited riparian vegetation was left. Though impacts in subsequent years are unknown, the effect of the logging on the periphyton community was insignificant during the nine months following cutting, seemingly due to several factors. Because only 5 percent of the canopy was actually removed, the intensity of available light changed little. Small springs in the area helped maintain a stable thermal regime, and only a small portion of the low gradient watershed was actually logged. Consequently, the nutrients reaching the stream did not change. The relatively low concentrations of nitrates (< 0.3 mg/l) and phosphates (< 10 μg/l), both before and in the first nine months after logging, reflect the limited autochthonous input, thereby reducing the effect of this limited cutting on the stream community.     

Forests and competing land uses in Kenya

Indigenous forests in Kenya, as in other developing countries, are under heavy pressure from competing agricultural land uses and from unsustainable cutting. The problem in Kenya is compounded by high population growth rates and an agriculturally based economy, which, even with efforts to control birth rates and industrialize, will persist into the next century. Both ecological and economic consequences of these pressures need to be considered in land-use decision making for land and forest management to be effective. This paper presents one way to combine ecological and economic considerations. The status of principal forest areas in Kenya is summarized and competing land uses compared on the basis of ecological functions and economic analysis. Replacement uses do not match the ecological functions of forest, although established stands of tree crops (forest plantations, fuel wood, tea) can have roughly comparable effects on soil and water resources. Indigenous forests have high, although difficult to estimate, economic benefits from tourism and protection of downstream agricultural productivity. Economic returns from competing land uses range widely, with tea having the highest and fuel wood plantations having returns comparable to some annual crops and dairying. Consideration of ecological and economic factors together suggests some trade-offs for improving land allocation decisions and several management opportunities for increasing benefits or reducing costs from particular land uses. The evaluation also suggests a general strategy for forest land management in Kenya.The views and interpretations expressed in this article are those of the authors and should not be attributed to the World Bank, its affiliated organizations, or any individual acting on their behalf.     

POTENTIAL FOR AUGMENTING WATER YIELD THROUGH FOREST PRACTICES IN WESTERN WASHINGTON AND WESTERN OREGON1

Western Washington and western Oregon comprise a water-rich region that has a very uneven annual distribution of both precipitation and streamflow. Highest demand for water coincides with lowest streamflow levels between July 1 and September 30 when less than 5 percent of annual water yield occurs. Increases in annual water yield in small, experimental watersheds in the region have ranged up to 600 mm after entire watersheds were logged and up to 300 mm in watersheds that were 25 to 30 percent logged. Most of the increase has occurred during the fall-winter rainy season, and yield increases have been largest during the wettest years. Estimated sustained increases in water yield from most large watersheds subject to sustained yield forest management are at best only 3-6 percent of unaugmented flows. Realistically, watersheds in this region will not be managed to produce more water. Water yield augmentation will continue to be only a small and variable by-product of logging. The utility of water yield augmentation is limited by its size and by its occurrence relative to the time of water demand. In some local areas, reduction of fog interception and drip or establishment of riparian phreatophytic hardwoods may reduce summer flows.     

Certified and Uncertified Logging Concessions Compared in Gabon: Changes in Stand Structure, Tree Species, and Biomass

Forest management certification is assumed to promote sustainable forest management, but there is little field-based evidence to support this claim. To help fill this gap, we compared a Forest Stewardship Council (FSC)-certified with an adjacent uncertified, conventionally logged concession (CL) in Gabon on the basis of logging damage, above-ground biomass (AGB), and tree species diversity and composition. Before logging, we marked, mapped, and measured all trees >10 cm dbh in 20 and twelve 1-ha permanent plots in the FSC and CL areas, respectively. Soil and tree damage due to felling, skidding, and road-related activities was then assessed 2–3 months after the 508 ha FSC study area and the 200 ha CL study area were selectively logged at respective intensities of 5.7 m³/ha (0.39 trees/ha) and 11.4 m³/ha (0.76 trees/ha). For each tree felled, averages of 9.1 and 20.9 other trees were damaged in the FSC and CL plots, respectively; when expressed as the impacts per timber volume extracted, the values did not differ between the two treatments. Skid trails covered 2.9 % more of the CL surface, but skid trail length per unit timber volume extracted was not greater. Logging roads were wider in the CL than FSC site and disturbed 4.7 % more of the surface. Overall, logging caused declines in AGB of 7.1 and 13.4 % at the FSC and CL sites, respectively. Changes in tree species composition were small but greater for the CL site. Based on these findings and in light of the pseudoreplicated study design with less-than perfect counterfactual, we cautiously conclude that certification yields environmental benefits even after accounting for differences in logging intensities.     

Assessing the Effects of Management Alternatives on Habitat Suitability in a Forested Landscape of Northeastern China

Forest management often has cumulative, long-lasting effects on wildlife habitat suitability and the effects may be impractical to evaluate using landscape-scale field experiments. To understand such effects, we linked a spatially explicit landscape disturbance and succession model (LANDIS) with habitat suitability index (HSI) models to assess the effects of management alternatives on habitat suitability in a forested landscape of northeastern China. LANDIS was applied to simulate future forest landscape changes under four management alternatives (no cutting, clearcutting, selective cutting I and II) over a 200-year horizon. The simulation outputs were linked with HSI models for three wildlife species, the red squirrel (Sciurus vulgaris), the red deer (Cervus elaphus) and the hazel grouse (Bonasa bonasia). These species are chosen because they represent numerous species that have distinct habitat requirements in our study area. We assessed their habitat suitability based on the mean HSI values, which is a measure of the average habitat quality. Our simulation results showed that no one management scenario was the best for all species and various forest management scenarios would lead to conflicting wildlife habitat outcomes. How to choose a scenario is dependent on the trade-off of economical, ecological and social goals. Our modeling effort could provide decision makers with relative comparisons among management scenarios from the perspective of biodiversity conservation. The general simulation results were expected based on our knowledge of forest management and habitat relationships of the species, which confirmed that the coupled modeling approach correctly simulated the assumed relationships between the wildlife, forest composition, age structure, and spatial configuration of habitat. However, several emergent results revealed the unexpected outcomes that a management scenario may lead to.     

Prediction of the impact of logging activities on forest cover: a case-study in the east province of Cameroon

The objective of this study was to test the value of the concept of the net commercial value of standing timber in predicting the impact of logging activities on forest-cover modifications. A study area was selected in the East province of Cameroon which contains major primary forests and which contributes strongly to national timber production. A Geographic Information System containing ecological and economic variables was used in combination with remote sensing data to define the net commercial value of standing timber in the East province. Taking account of the potential commercial value of standing timber improves our understanding of the spatial determinants of logging activities and of the resulting forest-cover modifications. The occurrence of logging-induced forest-cover modifications increases with the value of forest rent. In one of the study sites, half of the very high rent areas have already been logged. In that site, therefore, it is mostly the low rent or marginal forest areas that remain unlogged. This was not the case, however, throughout the study area as shown by the observations at another site.     

Social influences on expressed willingness to pay: results of a deliberative monetary valuation study in Colombia

Deliberative monetary valuation (DMV) methods can support environmental decision making by enabling the exchange of arguments and information to produce more democratic outcomes. The product of a valuation may be an array of expressions of willingness to pay (WTP) by individuals or a collectively agreed monetary value. Concerns have been raised, however, as to whether this product is an outcome of thoughtful and independent decision-making or influenced by social pressures to conform. Our study examines this issue and addresses concerns about the use of DMV, based on a public deliberation of forest conservation in Colombia. We analyzed the impacts of social conformity on WTP under two different decision scenarios: individual and collective. The results suggest that the impacts of social conformity are greater when a collective decision is required. These findings indicate that tensions between the differing goals of DMV could undermine its democratic promise.     

Adaptation potential of ecosystem-based management to climate change in the eastern Canadian boreal forest

Ecosystem-based management (EBM) of forests is gaining acceptance for its focus on the maintenance of the long-term integrity of ecosystem processes, but climate change challenges this view because of its impacts on these very processes. We have therefore evaluated the robustness of EBM to projected climate change, considering the role of climate on forest growth and fire regime in a boreal forest of eastern Canada. A climate sensitive growth index model was calibrated for three commercial species and used to project the evolution of merchantable volume for two climate scenarios (B1 and A2) under conventional and EBM strategies. Current burn rate and burn rates under future climate scenarios were also considered. Under the most extreme projected climate scenario, the periodic timber supply could be reduced by up to 79% through direct (growth reduction) and indirect (fire) effects. However, ecological indicators show that EBM is a more robust forest management strategy than conventional one demonstrating its adaptation potential to climate change at least in the short term.     

LONG-TERM CHANGES IN STREAMFLOW FOLLOWING LOGGING IN WESTERN OREGON AND ASSOCIATED FISHERIES IMPLICATIONS1

ABSTRACT: The long-term effect of logging on low summer streamflow was investigated with a data set of 36 years. Hydrologic records were analyzed for the period 1953 and 1988 from Watershed (WS) 1 (clear-cut logged and burned), WS 2 (unlogged control), and WS 3 (25 percent patch-cut logged and burned) in the H. J. Andrews Experimental Forest, western Cascade Range, Oregon. These records spanned 9–10 years before logging, and 21–25 years after logging and burning. Streamfiows in August were the lowest of any month, and were unaffected by occasional heavy rain that occurred at the beginning of summer. August streamfiows increased in WS 1 compared to WS 2 by 159 percent following logging in WS 1, but this increase lasted for only eight years following the start of logging in 1962. Water yield in August for 1970–1988 observed from WS 1 was 25 percent less than predicted from the control (WS 2, ANOVA, p=0.032). Water yield in August increased by 59 percent after 25 percent of the area of WS 3 was patch-cut logged and burned in 1963. In contrast to WS 1, however, water yields from WS 3 in August were consistently greater than predicted for 16 years following the start of logging, through to 1978. For the 10 years, 1979–1988, water yield observed in August from WS 3 was not different than predicted from the control (WS 2, ANOVA, p-0.175). The contrasting responses of WS 1 and 3 to logging are thought to be the result of differences in riparian vegetation caused by different geomorphic conditions. A relatively wide valley floor in WS 1 allowed the development of hardwoods in the riparian zone following logging, but the narrow valley of WS 3 and limited sediment deposits prevented establishment of riparian hardwoods. Low streamflows during summer have implications for salmonid survival. Reduced streamflow reduces the amount of rearing habitat, thus increasing competition. Combined with high water temperatures, reduced streamflow can lead directly to salmonid mortality by driving salmonids from riffles and glides, and trapping them in drying pools. Low streamflow also increases oxygen depletion caused by leaves from riparian red alders.     

A Water Yield‐Oriented Practical Approach for Multifunctional Forest Management and its Application in Dryland Regions of China

Mountainous forest areas are vitally important for water supply in dryland regions which suffer from high erosion risk and severe water shortage. Massive afforestation, mainly for erosion control, may reduce the water yield and threaten local water supply security. Moreover, many over‐dense forests due to a strict logging ban policy have produced remarkably negative impacts for both forests (e.g., low timber quality, restricted natural regeneration, and high stand instability) and water yield. To satisfy the rapidly increasing demands on water supply and other services, a practical approach for managing forest stands in a multifunctional way, which particularly addresses water yielding, is urgently required. For this purpose, we integrated the existing knowledge and experience, designed an “ideal” stand structure to represent multifunctional forest (MFF) and determined its key parameters (a ground coverage of >0.7, a canopy density around 0.7, and an H/DBH ratio (tree height [m] to the diameter at breast height [cm]) of <0.7). Moreover, a decision process for MFF stand management was recommended as: (1) investigating the site quality; (2) identifying the site‐specific main forest functions; (3) quantifying the stand structure; (4) diagnosing the stand structure by comparing with the “ideal” one; and (5) arranging the functions/structure‐oriented management measures. In this way, the water‐yielding function can be improved and meanwhile other forest functions can be promoted.     

A Framework to Predict the Impacts of Shale Gas Infrastructures on the Forest Fragmentation of an Agroforest Region

We propose a framework to facilitate the evaluation of the impacts of shale gas infrastructures (well pads, roads, and pipelines) on land cover features, especially with regards to forest fragmentation. We used a geographic information system and realistic development scenarios largely inspired by the PA (United States) experience, but adapted to a region of QC (Canada) with an already fragmented forest cover and a high gas potential. The scenario with the greatest impact results from development limited by regulatory constraints only, with no access to private roads for connecting well pads to the public road network. The scenario with the lowest impact additionally integrates ecological constraints (deer yards, maple woodlots, and wetlands). Overall the differences between these two scenarios are relatively minor, with <1 % of the forest cover lost in each case. However, large areas of core forests would be lost in both scenarios and the number of forest patches would increase by 13–21 % due to fragmentation. The pipeline network would have a much greater footprint on the land cover than access roads. Using data acquired since the beginning of the shale gas industry, we show that it is possible, within a reasonable time frame, to produce a robust assessment of the impacts of shale gas extraction. The framework we propose could easily be applied to other contexts or jurisdictions.     

Brazil’s Samuel Dam: Lessons for Hydroelectric Development Policy and the Environment in Amazonia

Brazil’s Samuel Dam, which formed a 540-km² reservoir in the state of Rondônia in 1988, provides lessons for development decisions throughout Amazonia and in other tropical areas. The decision to build the dam was heavily influenced by its role in the political strategies of key decision makers. Samuel illustrates both impacts and benefits of electricity supply and the dilemmas facing decision makers regarding the various options for planned electricity generation. Environmental costs included flooding forest and stimulating illegal logging activity throughout western Amazonia because of an exception opened for Samuel in Brazil’s prohibition of export of raw logs. Samuel emitted substantially more greenhouse gases than would have been emitted by generating the same amount of electricity from oil. Contamination of fish in the reservoir resulted from methylation of mercury present in the soil. Social costs of the dam included resettlement of 238 families of farmers; impacts on indigenous people were indirect. Mitigating measures included faunal rescue and creation of a forest reserve. The lessons of Samuel include the need to consider a full range of alternatives prior to making decisions in practice and the importance of adhering to the logical sequence of decision making, where information is gathered and compared prior to the decision. It also shows the need to maintain flexibility when the costs and benefits of different alternatives change significantly over the course of the project’s planning and execution, as occurred at Samuel.     

Evaluating sustainable forest management strategies with the Analytic Network Process in a Pressure-State-Response framework

Nowadays forestry faces a complex management situation; the understanding of sustainable forest management (SFM) has gone far beyond the original meaning of sustainable yield of timber. SFM strategies should fulfil ecological, economic and social functions without causing damage to other ecosystems. In this understanding, forest management actions cannot be seen as isolated or mono-causal. In this case study, indicators for SFM are arranged in a Pressure-State-Response (PSR) framework at forest management unit level. This framework links pressures on the environment caused by human activities with changes of environmental state (condition) parameters. Forest management also responds to these changes by instituting environmental and economic measures to reduce pressures and restore natural resources. The Analytic Network Process (ANP) is utilized to evaluate the performance of four management strategies with regard to the PSR framework on SFM. Priorities of indicators and alternatives are modelled with the ANP resulting from the interconnections to other indicators and their respective cumulative importance. The approach allows for more detailed information on the network of human influences and their impacts on forest ecosystems and goes beyond the limitations of flat-dimensioned indicator sets.     

Optimized forest degradation model (OFDM): an environmental decision support system for environmental impact assessment using an artificial neural network

The purpose of this article is Artificial Neural Network (ANN) modeling using ecological and associated factors with forest degradation to predict the degradation of ecosystem, thereby enabling us to assess the environmental impacts of forest projects as an Environmental Decision Support System (EDSS). Results of the Multi-Layer Feed-Forward Network (MLFN), trained for Optimized Forest Degradation Model (OFDM), indicate that the performance of OFDM is more than other degradation models. Changes in forest management activities with higher value in sensitivity analysis help forest managers to decrease OFDM entity and environment impacts. The system is an intelligent EDSS, which allows the decision-maker to model criteria in forest degradation in order to reach and employ the optimal allocation plan. Considering results, multi criteria decision analysis (MCDA) approaches based on ANN, is an encouraging and robust method for solving MCDA problems.     

Socio-economic, environmental, and governance impacts of illegal logging

This article examines the main impacts of the illegal logging activities with emphasis on the most important timber production regions. Although the discussion is focused on the environmental, socio-economic and governance impacts, it must be stressed that the term forest governance is the umbrella where the economy, the environmental values, and welfare of forest-dependent communities are sheltered. Considering the effects/impacts of the illegal logging as a whole, we can summarize the following negative key points: (1) Degradation of the most valuable forest stands threatening biodiversity, including rare and endangered species. (2) Increase in soil erosion and landslides. Increase in CO₂ release and climatic changes. (3) Human rights abuses and disrespect of the basic needs of local communities and their culture. (4) Corruption, crime, coercion, and money laundering. (5) Reduction of royalties, taxes, and other charges paid by logging companies to the producer States. (6) Depreciation of legal activities due to the unfair concurrence. Despite multiple efforts, the results in the combat of illegal logging are far from satisfactory. Increase the certification area in parallel with an accurate control, devolve the state land to the ancient local owners, increase the cooperation between civil society and forest authorities, and finally strongly improve forest governance, particularly anti-money laundering laws, are crucial aspects in the combat of illegal logging. Furthermore, governments and businesses must implement the triple bottom line concept in order to reach sustainability.     

Environmental management in resource-rich Alberta, Canada: first world jurisdiction, Third World analogue?

Economic growth is frequently touted as a cure for environmental ills, particularly for those in Third World countries. Here we examine that paradigm in a case study of Alberta, Canada, a wealthy, resource-rich province within a wealthy nation. Through provincial-scale datasets, we examine the increasing pressures of the forest, petroleum, and agricultural industries upon the ecosystems of Alberta within management, economic, and political contexts. We advance the thesis that economic activity leads to environmental degradation unless ecosystem-based management is integrated into economic decision making. Agricultural lands cover 31.7%, and forest management areas leased to industry cover 33.4% of Alberta; both continue to increase in extent. The rate of logging (focused on old-growth by government policy) continues a decades-long exponential rise. Current Alberta annual petroleum production is 52.5 million m3 crude oil and 117 billion m3 of gas. As of early 1999, there were approximately 199,025 oil and gas wells and a conservative total of approximately 1.5-1.8 million km of seismic lines in Alberta. Fire occurrence data indicate no downward trends in annual area burned by wildfire, which may be characterized as driven by climate and inherently variable. When logging and wildfire are combined, the annual allowable cut in Alberta is unsustainable, even when only timber supply is considered and the effects of expanding agriculture and oil and gas activities are ignored. Ecosystem degradation in Alberta is pervasive and contrasts prominently with a high standard of living. A wealth of ecological data exists that indicates current resource-based economic activities are non-sustainable and destructive of ecosystem health yet these data are not considered within the economic decision making process. Given the complex, compounded, and increasing ecosystem perturbations, a future of unpleasant ecological surprises is likely. We conclude with tentative predictions as to where current trends in Alberta may lead if decisions biased against ecosystems continue.     

Linking Multiple Accounts with GIS as Decision Support System to Resolve Forestry/Wildlife Conflicts

With shrinking forest resources and increasing demands for timber, conflicts between forestry and wildlife become more contentious and more frequent. New decision support methods are needed to address complex multiple land use conflicts. Multiple accounts methods linked with GIS and production models enable us to address trade-offs between timber and non-timber values, thus facilitating the evaluation and comparison of different management scenarios in a rapid and spatially referenced manner. The approach is documented in a case study in the trans-boundary zone between two national parks in British Columbia, where caribou/logging conflicts are widespread.     

Forests and societal values: comparing scientific and public perception of forest health

This study examines the common ground between lay people and scientists regarding forest values and definitions of forest health. With the forest at Pinery Provincial Park, Ontario, as a case study, the authors compared six ecological indicators to determine which were sensitive to the multiple impacts of visitor use, deer browsing and fire suppression. Plant cover and proportion native species were sensitive to these impacts. Sapling height was greater in low deer density areas. The authors also conducted focused discussions with local interest groups, followed by qualitative data analysis. Overall, there was good convergence between scientific and public views of forests and forest health, although this may partly be due to the groups' interest in nature and the Pinery. Subjects saw a connection between their health and the state of the global and local environment, including forests. There is a need for increased awareness in the public to the necessity of managing high deer populations in parks to protect other forest components such as biodiversity. Forest managers must consider that people greatly value forests near them for mental well being. Group responses suggested that messages explicitly linking forest benefits to human health and well being may motivate people to protect forests.     

Forest Management in Northeast China: History,Problems, and Challenges

Studies of the history and current status of forest resources in Northeast China have become important in discussions of sustainable forest management in the region. Prior to 1998, excessive logging and neglected cultivation led to a series of problems that left exploitable forest reserves in the region almost exhausted. A substantial decrease in the area of natural forests was accompanied by severe disruption of stand structure and serious degradation of overall forest quality and function. In 1998, China shifted the primary focus of forest management in the country from wood production to ecological sustainability, adopting ecological restoration and protection as key foci of management. In the process, China launched the Natural Forest Conversion Program and implemented a new system of Classification-based Forest Management. Since then, timber harvesting levels in Northeast China have decreased, and forest area and stocking levels have slowly increased. At present, the large area of low quality secondary forest lands, along with high levels of timber production, present researchers and government agencies in China with major challenges in deciding on management models and strategies that will best protect, restore and manage so large an area of secondary forest lands. This paper synthesizes information from a number of sources on forest area, stand characteristics and stocking levels, and forest policy changes in Northeastern China. Following a brief historical overview of forest harvesting and ecological research in Northeast China, the paper discusses the current state of forest resources and related problems in forest management in the region, concluding with key challenges in need of attention in order to meet the demands for multi-purpose forest sustainability and management in the future.