Ole Hofstad

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.

Optimizing management regimes for carbon storage and other benefits in uneven-aged stands dominated by Norway spruce, with a derivation of the economic supply of carbon storage

Abstract This study sought optimal sustainable management regimes of uneven-aged Norway spruce-dominated stands with multiple objectives. The criteria were financial returns, CO2 sequestration and diversity of tree size and species. At prevailing timber prices, harvest and transport costs, and interest rates, uneven-aged management for timber alone was most profitable with a 5-year cutting cycle. Lengthening the cutting cycle to 20 years decreased the net present value from timber by 10%, but raised the carbon storage by 21%, the tree species diversity by 32%, and the tree size diversity by 24%. Maximizing CO2 sequestration induced an almost pure spruce stand. A compromise policy maximized CO2 storage, while maintaining a rate of return on the capital of standing trees equal to the interest rate. A supply curve for CO2 storage was derived, showing how much forest owners would be willing to sequester as a function of the price of CO2. Maximizing the NPV from combined CO2 storage and timber production showe...Abstract The genetic variability in height growth and autumn cold hardiness were evaluated in a full-sib family of Scots pine (Pinus sylvestris (L.)) in a field trial in northern Sweden and 358 open pollinated families generated from the progeny of the full-sib cross. Height and autumn cold hardiness were assessed in the progeny of the full-sib cross at 9–19 years of age and on 3995 open pollinated progenies at three years of age. The autumn cold hardiness [critical temperature (CT)] of trees and progenies was tested by artificial freeze testing of detached needles at various temperatures. Significant genetic variation was found among progenies in both height growth and cold hardiness with a narrow sense heritability of 0.16 and 0.37, respectively. There was also a significant positive genetic correlation (r a =0.39) between height growth and CT with taller trees showing later autumn cold acclimation. It was concluded that there is significant additive genetic variance for height and CT which warrants a potential for mapping quantitative trait loci. Furthermore, the low heritability for height growth shows the importance of removing the environmental influence by using additive genetic predictions instead of phenotypic measurements thereby improving the accuracy of genetic associations.

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.

Optimal harvest and inventory of Norwegian forests

An optimal control theory model for the determination of optimal harvest and inventory is shown initially. The second part uses some aggregate data from Norwegian forestry to illustrate how the theory could be applied in the elaboration of a national forest policy. Finally the practical implications are discussed in relation to the social discount rate, industrial capacity and environmental concerns.

TENURE TRANSFORMATIONS AND SUSTAINABLE MANAGEMENT OF WOODLANDS IN UGANDA

ABSTRACT In Sub-Saharan Africa, forest degradation has been one of the major problems facing natural resource management, mainly attributed to lack of clearly defined and enforced property rights, leading to a de facto open access situation. National governments have been urged to remedy the situation through tenure changes such as privatisation and decentralization. Such restructuring and enforcement of tenure rights governing the use of forest resources have social and economic implications. This paper discusses the likely behavioural adaptations to privatization of woodland resources by various actors, and the effect of such adaptations on the rural livelihoods and the woodland resource. While private property may lead to sustainable utilization following successful exclusion of illegal exploitation and abidance to institutional specifications, this may not necessarily be the case if high exclusion costs exist. This is especially true in cases where communities have depended on these resources for their livelihoods for a long time.