Prem L. Sankhayan

A village-level economic model of land clearing, grazing, and wood harvesting for sub-Saharan Africa: with a case study in southern Senegal

Abstract A village-level dynamic, stochastic, and non-linear programming model, incorporating both economic and ecological aspects, is developed to study the complex woodland degradation processes in the sub-Saharan Africa. The emphasis is on simultaneous accounting of the effects of three major causes of woodland degradation, namely, land clearing, grazing, and extraction done for wood fuel, poles and charcoal, that has not been attempted before. The model is applied at the village level in Senegal and run for the period 1999–2020. By running different model scenarios, a number of hypotheses are tested about woodland degradation as measured through loss of vegetative biomass per unit of land. While demographic pressure was found to aggravate the woodland degradation processes, introduction of improved agricultural technology, higher cotton prices, increased rural wages, and reduced charcoal prices were found to retard the process of degradation. On the basis of the findings of this study, therefore, the role of policy makers in devising appropriate demographic and economic policies to retard the process of woodland degradation appears to be important in the sub-Saharan African nations with conditions similar to those found in Senegal.

Forest biomass density, utilization and production dynamics in a western Himalayan watershed

There is enough evidence to show that the forest biomass has decreased significantly in the Indian Himalayan state of Himachal Pradesh. The government has responded through restrictive measures to check this decline. Using tree biomass as proxy for degradation, we assessed the current state of biomass within dominant land use types and examined its implications for sustainability. The highest above-ground mean tree biomass density of 1158 t·ha−1 was recorded for the reserved forest followed by 728, 13, 11, 8, 5 and 3 t·ha−1 in the protected forest, fallow land, cultivated-unirrigated land, grassland, orchard land and cultivated-irrigated land respectively. Of the total accessible biomass, only 0.31% was extracted annually by the local people for fuel, fodder and other uses. Though, the current level of extraction may be sustainable in the short run, insufficient regeneration is observed for long term sustainability. Forest biomass production was simulated for the next 30 years with a logistic growth model and the relative significance of input variables in influencing system behaviour was analysed through sensitivity analysis. The model results highlighted the declining forest resources in the long run. Positive response through appropriate government policies can, however, change the scenario for the better.

Bio-economic modeling of land use and forest degradation at watershed level in Nepal

This paper develops a non-linear bio-economic model for analyzing the system behavior in terms of land use changes and forest degradation processes. The model is applied at a watershed level in Mardi, Nepal, to investigate the effects of alternate policy scenarios relating to the introduction of agricultural technology represented through high yielding varieties of paddy and maize; reduction in population growth rate, and increase in the prices of major agricultural crops. The model horizon extends from 2000 to 2025. The results showed that while technological improvements and increase in crop prices increase cropped area, reduced population had the opposite effect. Reduced population growth rate, and increased prices for major agricultural crops led to overall reduction in forest degradation. The study, therefore, concludes that family planning policies aimed at reduction of population growth and increase in prices of major agricultural crops can be effective policy instruments for slowing down the process of forest degradation or even in reversing it completely to regeneration.

Production and Spatial Price Differences for Charcoal in Uganda

Charcoal production activity assumes importance not only for generating large employment and income and supplying major fuel requirements in Uganda but also for triggering environmental degradation. Based on production and marketing data collected from one of the important charcoal producing districts, namely, Nakasongola, this study found that charcoal production being less capital intensive and risk free, is mainly carried out by numerous small, economically weak and unorganised individual producers. The price-distance relationship was analysed for the average prices of a bag of charcoal prevalent in each town over a stretch of 140 km between Kampala, the capital and main consuming center for charcoal in Uganda, and Kafu Bridge during the years 1995 and 1999. A movement of 1 km from Kampala resulted in a price decline of about 28 UShs in 1995 and 33 UShs in 1999 (prices held constant at 1995 level). The price-distance relationship and responsiveness of charcoal prices to distance from Kampala, as measured through distance elasticity of price, remained unchanged over the period 1995 to 1999. There is no statistical evidence to prove that the charcoal producers were better paid in 1999 than in 1995. It appears unlikely to halt the harmful environmental degradation effects of charcoal making activity without generating adequate alternate employment opportunities in rural areas and internalizing the full environmental costs of forest degradation in the consumer price of charcoal.

Land Use Changes and Forest Degradation in a Himalayan Watershed: Analysis and Policy Alternatives 1

Abstract Agriculture, horticulture, and forestry are the mainstays of the economy of the Indian state of Himachal Pradesh. The economic, technological, and institutional factors that affect land use need to be analyzed in a holistic way, especially in view of fast changing cropping patterns and declining forest density. The use of a bio-economic programming model incorporating economic and ecological factors appears to be a highly attractive tool for analysis at a micro watershed scale. The objective function of the model is to maximize the discounted gross margins from different sets of activities, namely, agricultural, livestock, and forestry over a 20 year model horizon. The model becomes non-linear by incorporating a variance and co-variance matrix of gross returns over the last five years. The model investigates the effects of alternate policy scenarios on income levels, cropping patterns, biomass use and its growth, and labour and capital requirements over next 20 years by using the General Algebraic Modelling Systems (GAMS). The biomass growth is based on a logistic growth model. Though there is a sharp increase in income by replacing traditional crops with horticultural crops, such changes are also accompanied with increased income risk. Results show a diversification strategy on the part of farmers in the study watershed rather than only maximizing profits. The biomass growth becomes sustainable if there is an increase in emigration rate, use of liquefied petroleum gas (LPG), and substitution of improved livestock. More such response through government policies can improve long term sustainability.