During the past few decades, Thailand has sharply lost her forest area. The forest area has been declined from 53% to 26% of the total land area in 1960-1995. The forest covers have been changed to the other types of land use, such as, farmland, urban area, orchard and etc. This study tried to show the process of deforestation in the Mae Klong Watershed Research Station (Lintin), Thongphaphum District, Kanchanburi Province, Thailand. This case study is valuable to understand drastic land use and land cover changes in rural area in Thailand. Five different time series of aerial photographs have been interpreted and land use maps have been made over the period of 1954, 1969, 1974, 1986 and 1994 to consider anthropogenic forces of land use changes in rural Thailand. From aerial interpretation, we can classify land use types into two main land use types; forest land use and farming land use. From the land use maps of 1954 and 1994, the forest covers in mountainous area have been less converted to other types of land use than those forest covers in the flat areas. But forests in mountainous area have continuously degraded over the study period. On the other hand, forest land use in the flat area have been decreased gradually from 1954 to 1974, then forest land use in the flat area have been declined rapidly during the year of 1974 and 1994 while the farming land use has been increased. From the changes of forest covers in the mountainous and flat areas, it shows that the topographic factors are related to the changes of land use and land covers in the area. In flat area, increasing of households, in the two village, is an important driving factor of converting forest area to agricultural land. Therefore anthropogenic factor directly affects land use and land cover changes in the study area.

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This study was carried out in order to determine what factors in slightly different photographs are influential when evaluating scenic coppices. For the analysis, a 450° photographs was taken with a rotatory camera. This photo was sequentially broken down into forty-seven photos of the coppice landscape. Each photo contains horizontal and gradual differences of the same location taken at the same time. Two questionnaires were then devised and distributed. The first was designed to establish categories based on compositional similarities. The second was designed to rate the photos based on the subjective comparison between each photo and its neighboring photo in the sequence. The results from the first questionnaire show that the five main factors used in determining the appropriate category for the photos are: 1) brightness, 2) main elements in the landscape other than trees, 3) conspicuous trees, 4) presence of artificial things, and 5) stand density. These factors are used in both independently and in conjunction with one another. The conclusion drawn from the second questionnaire is that the evaluation scores fluctuated according to changes in the horizontal constitution of the forest scenes. In addition, it shows that the five factors above played a key role in the evaluation process.

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A model was constructed to address the harvest scheduling problem under risk of occurrence of catastrophic events. The model was made up of an optimization and a simulation model. The optimization model provided an optimal harvest pattern under deterministic conditions. The simulation model modified the optimal harvest pattern according to a function of random risk assessing the performance of the system through net present value (NPV). The model was run a large number of times estimating mean, standard deviation and a frequency distribution for NPV. The model was run for a case study considering a forest estate of 8,412 ha located in Canterbury in New Zealand. The random component of the system was windthrow occurring at different times and with different intensities. Storms were generated randomly over a planning horizon of 50 years considering an average return period of 28 years between two successive storms. The intensity of damage was assumed to be proportional to the historical damage. As a result, NPV after taxes regarding the management of the forest estate was reduced 11 percent on average. Windthrow brought about economic losses due to reduced harvest following windthrow, reduced recovery (80%), increased total establishment costs, and the fact that trees were harvested before optimal rotation.

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As a result of increasing costs of forest management and reduced prices for timber, the area of forest land where timber plantations are managed with the expectation of profitability has declined significantly. This has made large areas of plantations 'marginal' in an economic sense. Marginal plantations can be classified into three categories ; 1) Timber plantations with no stumpage value, 2) Timber plantations with stumpage value lower than the cost of conventional high input regeneration, and 3) Timber plantations with negative expected NPVs for the next rotation. In an optimization model for even-aged forest management, forest owners should first decide the method of regeneration, assuming that the forest is clear-cut now, and then make a decision on the final cutting. Rational economic choices for management differ depending on the category of plantation. In particular, the constraints which apply to the method of regeneration have different effects in each class. For marginal plantations where stumpage value is low, the tendency for risk aversion is not significant. Given the uncertainty of timber prices in the future, it can be a rational choice for forest owners not to harvest marginal plantations immediately, but to keep the option to harvest at any time in the future. Finally, the choices for partial cutting are discussed and the question of adequate restrictions on the method of harvesting and regeneration are considered.

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In this study, we evaluate the risk of snow damage to sugi plantations in Japan. We examine the optimal rotation age (ORA) which maximizes the land expectation value (LEV), and the economic effects of snow damage. We considered two types of stem breaking damage. One is the thinning type and the other is the domino type of damage. In the case of the thinning type, if there are subsidies or higher prices, long rotations are suitable. This is because the damage ratio is lower in stands. In the case of the domino type damage, the ORA is similar to cases without damage. Snow risk has two apparently contradictory effects. One is a rotation shortening effect - harvest before the stand is damaged by snow. The other is a rotation lengthening effect, i.e. harvest later to recover, the increased management costs of snow damage. If the probability of snow damage is high for matured stands, a shorter rotation is advantageous, even in cases of thinning type damage. This is similar to the case of forest fire in preceding studies. However, if the probability of snow damage is lower for mature stands, the rotation shortening effect is often cancelled out by the rotation extending effect of increased management costs. Furthermore, if damage ratios in the stands over 30 years old are sufficiently low, even where there is domino type damage, the ORA is higher than in stands without damage under subsidy or higher price. From this, it is clear that the damage ratio at older ages is a key factor determining rotation age. The decrease in LEV following domino type damage is twice as much as that of thinning type damage. In cases, where the probability of domino type damage and damage of older stands can not be reduced to reasonable levels at a reasonable cost, natural forest management may be more appropriate than plantation management.

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An experiment implementing the control method of forest management was implemented in Hokkaido University's Nakagawa Experimental Forest in 1966, to investigate management options for natural forests in northern Hokkaido. Thirty years have passed since the experiment began. This report presents the results which have been assessed to date. The working circle area in the experimental forest covered 110.3 ha, and was a natural mixed forest with a slight majority of coniferous trees (average growing stock: 225 m³). The experimental forest was divided into 10 blocks and the management period defined as 10 years. In the first management period, many low-quality trees were found, and the growth rate in each block ranged between 2.1% and 0.8%. In the same period the total number of trees decreased from 42,438 to 40,154. The growth rate in the second management period ranged from 1.1 to 3.1%, reflecting an improvement in stand structure, but the number of trees decreased from 37,039 to 35,311. Trees planted in areas of poor natural regeneration are growing well and thus an increase in the number of trees and a further increase in growth rate are expected in the third management period.

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