Bioeconomic meta-modelling of Indonesian agroforests as carbon sinks

In many areas of developing countries, economic and institutional factors often combine to give farmers incentives to clear forests and repeatedly plant food crops without sufficiently replenishing the soils. These activities lead to large-scale land degradation and contribute to global warming through the release of greenhouse gases into the atmosphere. We investigate whether agroforestry systems might alleviate these trends when carbon-credit payments are available under the Clean Development Mechanism of the Kyoto Protocol. A meta-modelling framework is adopted, comprising an econometric-production model of a smallholding in Sumatra. The model is used within a dynamic-programming algorithm to determine optimal combinations of tree/crop area, tree-rotation length, and firewood harvest. Results show the influence of soil-carbon stocks and discount rates on optimal strategies and reveal interesting implications for joint management of agriculture and carbon.bio-economic meta-modelling, Indonesia, agroforestry, carbon credits, dynamic programming, Environmental Economics and Policy, Resource /Energy Economics and Policy,

Optimal Land-Use Decisions in the Presence of Carbon Payments and Fertilizer Subsidies: An Indonesian Case Study

The Clean Development Mechanism of the Kyoto Protocol provides the opportunity for smallholders to receive financial rewards for adopting tree-based systems that are sustainable. In this paper a meta-model is developed to simulate interactions between trees, crops and soils under a range of management regimes for a smallholding in Sumatra. The model is used within a dynamic-programming algorithm to determine optimal tree/crop areas, tree-rotation lengths, firewood-harvest and fertilizer application rates for a landholder faced with deteriorating land quality and opportunities to receive carbon credits and fertiliser subsidies. It is found th at profit maximising management strategies depend on initial soil quality. For example, incentives to participate in carbon projects only exist when the soil is degraded because the opportunity cost of the forgone crop production is low. Also, when soil-carbon stocks are low only trees should be grown and residues added to the soil to increase carbon stocks until a threshold level is reached, when it becomes optimal to switch to a steady-state system of crops with fertiliser. In this case, tree rotation lengths depend on carbon and fertiliser prices; where increases in these prices decrease the opportunity cost of growing trees and allow for longer rotations. If, however, the initial soil-carbon stock is high, the profit-maximising strategy is to grow only crops and use fertiliser, which initially depletes the soil of carbon until a steady state is reached and maintained.Land Economics/Use,

Alternative Price Expectation Formulation and Information Access

Demand and Price Analysis,

Tree-crop interactions and their environmental and economic implications in the presence of carbon-sequestration payments

Growing trees with crops has environmental and economic implications. Trees can help prevent land degradation and increase biodiversity while at the same time allow for the continued use of the land to produce agricultural crops. In fact, growing trees alongside crops is known to improve both the productivity and sustainability of the land. However, due to high labour-input requirements, high costs of establishment, and delayed revenue returns, trees are often not economically attractive to landholders. Because of the Kyoto Protocol, and the growing emphasis on market-based solutions to environmental problems, the ability of trees to sequester and store CO2 has altered the economic landscape of agroforestry systems. The economic and management implications of carbon-sequestration payments on agroforestry systems are addressed in this study using a bioeconomic modelling approach. An agroforestry system in Indonesia is simulated using a biophysical process model. A general economic analysis of this system, from the standpoint of individual landholders, is then developed and the implications for management and policy are discussed.agroforestry, bioeconomics, tree/crop interactions, carbon credits, baselines, Environmental Economics and Policy, Land Economics/Use,

ALLOCATING BIOSECURITY RESOURCES IN SPACE AND TIME

Invasive species can cause significant damage to natural environments, agricultural systems, human populations and the economy as a whole. Biological invasions are complex dynamic systems which are inherently uncertain and their control involves allocation of surveillance and treatment resources in space and time. A complicating factor is that there are at least two types of surveillance: active and passive. Active surveillance, undertaken by pest control agencies, has high sensitivity but generally low coverage because of its high cost. Passive surveillance, undertaken by the public, has low sensitivity and may have high coverage depending on human population density. Its effectiveness depends on the extent to which information campaigns succeed in engaging the public to help locate and report pests. Here we use a spatio-temporal model to study the efficient allocation of search and treatment resources in space and time. In particular we look for complementarities between passive and active surveillance. We identify strategies that increase the probability of eradication and/or decrease the cost of managing an invasion. We also explore ways in which the public can be engaged to achieve cost-effective improvements in the probability of detecting and eradicating a pest.search theory, invasive species, dispersal, passive surveillance., Environmental Economics and Policy,

Applying search theory to determine the feasibility of eradicating an invasive population in natural environments

The detectability of invasive organisms influences the feasibility of eradicating an infestation. Search theory offers a framework for defining and measuring detectability, taking account of searcher ability, biological factors and the search environment. In this paper, search theory concepts are incorporated into a population model, and the costs of search and control are calculated as functions of the amount of search effort (the decision variable). Simulations are performed on a set of weed scenarios in a natural environment, involving different combinations of plant longevity, seed longevity and plant fecundity. Results provide preliminary estimates of the cost and duration of eradication programs to assist in prioritising weeds for control. The analysis shows that the success of an eradication program depends critically on the detectability of the target plant, the effectiveness of the control method, the labour requirements for search and control, and the germination rate of the plant.bioeconomics, invasive species, operations research, population dynamics, weed control, Resource /Energy Economics and Policy,

Temporary carbon storage and discount rates

Several approaches have been proposed for accounting for temporary carbon sequestration in land-use change and forestry projects that are implemented to offset permanent emissions of carbon dioxide from the energy sector. In a previous paper, we evaluated the incentives provided by some of these approaches. In this paper, we investigate further what we call the “ideal” accounting system, where the forest owner would be paid for carbon sequestration as the service is provided and redeem payments when the forest is harvested and carbon is released back into the atmosphere. We demonstrate how discounting affects the net present value of the forest when carbon sequestration is taken into account under this ideal system. Not all carbon is released back into the atmosphere at harvest, however, since a large proportion may remain fixed in forest products for many years. Here, we compare the profitability of the forest under full redemption of credits at harvest, with partial redemption of credits at harvest followed by annual redemption post-harvest as the carbon decays in a durable forest product. The analysis is based on simulation of farm-forestry systems in south-eastern Australia.carbon accounting, reforestation, discounting, bioeconomics, Environmental Economics and Policy, Land Economics/Use,

Carbon-accounting methods and reforestation incentives

The emission of greenhouse gases, particularly carbon dioxide, and the consequent potential for climate change are the focus of increasing international concern. Temporary land-use change and forestry projects (LUCF) can be implemented to offset permanent emissions of carbon dioxide from the energy sector. Several approaches to accounting for carbon sequestration in LUCF projects have been proposed. In the present paper, the economic implications of adopting four of these approaches are evaluated in a normative context. The analysis is based on simulation of Australian farm–forestry systems. Results are interpreted from the standpoint of both investors and landholders. The role of baselines and transaction costs are discussed.Resource /Energy Economics and Policy,

Weed Search and Control: Theory and Application

The detectability of invasive organisms influences the costs and benefits of alternative control strategies, and the feasibility of eradicating an infestation. Search theory offers a mathematically rigorous framework for defining and measuring detectability, taking account of searcher ability, biological factors and the search environment. To demonstrate the application of search theory to invasive species control, invasive species detectability is incorporated into a population simulation model. The model is applied to a base set of parameter values that represent reasonable values for a hypothetical weed. The analysis shows the effects of detectability and search time on the duration of an eradication program. Furthermore, for a given level of detectability and search time, the analysis shows that the variables with the greatest influence on the duration of the eradication effort are search speed, kill efficiency and seed longevity. A series of Monte Carlo simulations are performed on a set of five scenarios, involving different combinations of plant longevity, seed longevity and plant fecundity. Results of these simulations are presented as probability distributions and allow us to calculate how the probability of eradication will be affected by search strategy.search and control, search theory, weed control, stage matrix, impedance factors, population dynamics, stochastic model, Farm Management,

Valuing the biodiversity gains from protecting native plant communities from bitou bush (Chrysanthemoides monilifera subsp rotundata (DC.) T.Norl.) in New South Wales: application of the defensive expenditure method

Valuation of the gains from protection of biodiversity is difficult because the services that provide the benefits do not normally pass through markets where prices can form. But the services sometimes pass through markets where consumers or producers behave in a market-oriented manner, and so the values implicit in this behaviour can be identified and derived. Estimates of the benefits of biodiversity protection are derived from the costs of protecting native plant communities from a major weed in Australia, by following this approach. In 1999, invasion of coastal areas of New South Wales by bitou bush (Chrysanthemoides monilifera subsp. rotundata (DC.) T. Norl.) was listed as a key process threatening native plants under the NSW Threatened Species Conservation Act 1995. In accordance with the Act, the Department of Environment and Climate Change prepared a Threat Abatement Plan (TAP) to reduce the impacts of bitou bush on biodiversity at each threatened site. The costs of protecting sites vary closely with the number of priority native species and communities at each site. Following standard economic assumptions about market transactions, these costs are interpreted to provide values the benefits of protecting extra species, communities, and sites. Key words: Bitou bush, Chrysanthemoides monilifera, threat abatement plan, valuation of biodiversity, benefit-cost analysis, weed control, defensive-expenditure method.Bitou bush, Chrysanthemoides monilifera, threat abatement plan, valuation of biodiversity, benefit-cost analysis, weed control, defensive-expenditure method, Demand and Price Analysis, Environmental Economics and Policy,