Quantitative and qualitative characteristics of Persian oak along altitudinal gradation and gradient (case study: Ilam province, Iran)

Quantitative and qualitative characteristics of Persian oak (Quercus persica) were studied in relation to altitude and slope variations in Ilam province. A total area of 1,500 m2 (30 × 50 m) was covered in five altitudinal classes ranging from 800 to 1,800 m a.s.l. Samples were taken based on a systematic random sampling method with 24 sample plots at each class. In total, 120 sample plots (in five classes) were collected covering four gradient categories ranging from 60%. An analysis of variance (ANOVA) was carried out to compare differences between group means in gradient categories and Duncan’s post-hoc test was performed to reveal differences between the means of various quantitative characteristics (e.g. growing stock, basal area, diameter at breast height, tree height and regeneration) and the altitudinal classes. The Kruskal-Wallis test was used to examine the differences between the means of qualitative variables and different altitudes and slopes categories. The results indicated that variations with altitudes may have a higher impact than slopes on the quantitative characteristics of the oak stands in the region while the qualitative variables of the native species were influenced by both altitudes and slope variations

Efficiency analysis of forest management units considering economics and carbon dynamic : A data envelopment analysis (DEA) approach

The aim of this paper is to measure the relative performance of forest managementunits considering economics and carbon dynamic in Caspian forests of Iran. DataEnvelopment Analysis (DEA) as a well-known and robust technique for measuringthe relative efficiency of Decision Making Units (DMUs) was used for measuring theefficiencies of 33 forest management units or DMUs. The relative efficiency of DMUswas calculated using global technical efficiency (CCR) model using three scenarios forundesirable output, like CO2 emission due to forest management activities. The mainchallenges that are considered in the modelling of the undesirable outputs were toconsider the undesirable outputs in the modelling process along with the desirableoutputs. The three scenarios were to ignore the undesirable output (scenario 1), totreat the undesirable outputs as inputs (scenario 2) and to apply a monotone decreasing transformation to the undesirable outputs and then to use the adapted variablesas outputs (scenario 3). Results of input-oriented CCR model based on scenarios1 and 2 showed that, 10 and 13 DMUs became efficient, respectively. Results of input-oriented and output-oriented CCR models based on scenario 3 indicated that 11DMUs became efficient. By including the undesirable output in efficiency analysis offorest management units, this study shows how we can expand a new path in efficiencyanalysis of forest management units and provide important input to the forestorganizations supervising the forestry sector

Economically optimal values and decisions in Iranian forest management

Stumpage price processes are estimated via regression analysis (with alternative autoregressive models) with data from the Iranian Caspian forests. The parameter estimates indicate that the stumpage price may be regarded as a stationary stochastic process. The optimal harvest decisions were calculated via stochastic dynamic programming. The harvest decisions that maximize the expected present value of all profits over time are made adaptively, conditional on the latest available price and stock level information. The results show that it is possible to determine the optimal harvesting level for different price and stock states. We may increase the expected present value by more than 26% when we let optimal adaptive decisions replace optimal deterministic planning decisions. Dynamic game theory is applied to analyze the timber market in northern Iran as a duopsony. The Nash equilibrium and the dynamic properties of the system based on marginal adjustments are determined. When timber is sold, the different mills use mixed strategies to give sealed bids. It is found that the decision probability combination of the different mills follow a special form of attractor and that centers should be expected to appear in unconstrained games. Since the probabilities of different strategies are always found in the interval [0,1], the boundaries of the feasible set are sometimes binding constraints. Then, the attractor becomes a constrained probability orbit. In the studied game, the probability that the Nash equilibrium will be reached is almost zero. The dynamic properties of timber prices derived via the duopsony game model are found also in the real empirical price series from the north of Iran. Dynamic duopoly game theory was also used to analyze the sawnwood and pulpwood markets in northern Iran. The differential equation system governing the simultaneous optimal adjustments of the decision frequencies of the two players gives cyclical solutions

Mixed strategy game theory, application in forest industry

Two large paper mills dominate the forest industry in northern Iran. Forest companies and local farmers sell pulpwood to these mills. The real pulpwood price data was collected from two paper mills in the northern part of Iran. These mills buy most pulpwood in this area. Game theory has been used in order to investigate the market structure in this region. Game theory is the study of interacting decision makers. Game theory has been widely used in economics. Most economic behaviour can be viewed as a special case of game theory. A game model includes a set of players, a set of strategies and a set of payoffs. This study focuses on the theory of dynamic duopsony games. When pulpwood is sold, the different mills use mixed strategies to give sealed bids. In each transaction, each mill (player) has two different possible strategies (decisions): a high (H) or a low (L) prices. Which price should you set? What is the optimal price of the other player? Here the situation is a noncooperative game. Nash equilibrium and dynamic properties of the system are determined. Each mill continuously observes the frequencies of the other mills action. The expected marginal profits are calculated based on this information. In case the marginal profit of mill A is strictly positive (zero or strictly negative), mill A increases (leaves unchanged, decreases) bids. In case the marginal profit of mill B is strictly positive (zero or strictly negative), mill B increases (leaves unchanged, decreases) bids. It is found that the decision probability combination of the different mills follow a special form of attractor and that centers should be expected to appear in unconstrained games.Mixed strategy games Pulpwood market Nash equilibrium Paper mills

Productivity and economic assessment of Vaccinium arctostaphylos

Vaccinium arctostaphylos (Caucasian whortleberry) is one of the most important wild berries with remarkable properties that grows in Iran and the Caucasus region. The objective of this research is to determine the productivity and economic value of V. arctostaphylos fruits in Hyrcanian forests of Iran. We used a survey to determine the economic value and we conducted a forest inventory to estimate the fruit production. The inventory results revealed that the average number of bushes and fruit production were 3900 per ha and 137 kg per ha, respectively. The survey results showed that the total market margin of fruit production is 81.29%, which indicates that the intermediaries earn more profit than the local harvester. The profit gained from the forest due to harvesting of V. arctostaphylos fruit was 161 million IRR/ha or about 1238 USD per ha. The harvesting of this fruit has created job for 500 local people in the study area during the harvesting period. The net present value (NPV) of fruit production and timber harvesting was calculated for comparison. Results indicated that the NPV of fruit harvesting is 1.79 times higher than the NPV of timber harvesting. Regarding to the harvesting moratorium in Iranian Hyrcanian forests, an optimal and sustainable harvest of V. arctostaphylos fruit can be an important source of income for forest dwellers and local people.

Stochastic Dynamic Programming with Markov Chains for Optimal Sustainable Control of the Forest Sector with Continuous Cover Forestry

We present a stochastic dynamic programming approach with Markov chains for optimal control of the forest sector. The forest is managed via continuous cover forestry and the complete system is sustainable. Forest industry production, logistic solutions and harvest levels are optimized based on the sequentially revealed states of the markets. Adaptive full system optimization is necessary for consistent results. The stochastic dynamic programming problem of the complete forest industry sector is solved. The raw material stock levels and the product prices are state variables. In each state and at each stage, a quadratic programming profit maximization problem is solved, as a subproblem within the STDP algorithm

Economical evaluation of current forest uses (Case study: Shafaroud forests, Gilan province)

The aim of this research is to evaluate current uses of forest (animal husbandry and wood harvesting) in district no. 11 of Shafaroud forest with an area of 2200 ha in Guilan province. Factors including stumpage price, annual growth rate and rate of interest were used to determine the net present value of timber harvesting. Furthermore, price, animal husbandry costs and rate of interest were applied to determine the net present value of animal husbandry in forest. Economic analysis revealed the net present value of 30105809 IRR per hectare gained by wood harvesting and animal husbandry in forest, with 92.7% and 7.3%, proportions of forestry and animal husbandry, respectively. In other words, net present value of animal husbandry is about 12.7% lower than forestry. The results of this study showed that the present forestry practice in the study area enables the timber production management. In order to manage the forest based on sustainability and meet the forest dwellers needs, forest management is suggested to be planned toward the social forestry

A game theory approach to the Iranian forest industry raw material market

Dynamic game theory is applied to analyze the timber market in northern Iran as a duopsony. The Nash equilibrium and the dynamic properties of the system based on marginal adjustments are determined. When timber is sold, the different mills use mixed strategies to give sealed bids. It is found that the decision probability combination of the different mills follow a special form of attractor and that centers should be expected to appear in unconstrained games. Since the probabilities of different strategies are always found in the interval [0,1], the boundaries of the feasible set are sometimes binding constraints. Then, the attractor becomes a constrained probability orbit. In the studied game, the probability that the Nash equilibrium will be reached is almost zero. The dynamic properties of timber prices derived via the duopsony game model are found also in the real empirical price series from the north of Iran

Linear programming approach for optimal forest plantation

The aim of this research was to identify species suitable for plantation. We first identified species for potentially suitable for plantation based on ecological capabilities regarding soil properties. We determined the area of plantation for different species based on ecological capabilities. Then, we collected relevant data such as growth patterns of different species, labor requirements for plantation and plantation cost. A linear programming model and two integer linear programming models were used for optimization. The appropriate species based on ecological capabilities were ash, elm, maple, oak and bald cypress. A linear programming model was used based on ecological capabilities classification to determine the land area of different species for plantation. Then, two integer linear programming models were employed to select the species for plantation. We set ecological properties unequal for all of the species in the first run of the integer programming model. Two groups were classified: group one included maple and ash; group two included bald cypress, oak and elm. The second integer programming model assumed equal ecological properties for all the species. Results of linear programming showed that maple and bald cypress were appropriate for plantation at the site and their plantation areas should be 151.3 and 355.3 ha, respectively. Results of the first integer linear programming model showed that maple and bald cypress would be economically profitable for plantation. The results of the second integer linear programming model showed that only bald cypress would be appropriate for plantation

Dynamic growth models for continuous cover multi species forestry in Iranian Caspian forests

This study concerns some of the relevant topics of the Iranian Caspian forestry planning problem, in particular the first central components in this modelling process, such as forest modelling, forest statistics and growth function estimations. The required data such was collected from Iranian Caspian forests.  To do so, 201 sample plots were determined and the parameters such as number of tree, tree diameter at breast height  and trees height were measured at each sample plot. Three sample plots at different 3 elevations were chosen to measure the tree increment. Data has been used to estimate a modified logistic growth model and a model that describes the growth of basal area of individual trees as a function of basal area. General function analysis has been applied in combination with regression analysis. The results are interpreted from ecological perspectives. Furthermore, a dynamic multi species growth model theory is developed and analyzed with respect to dynamic behavior, equilibria, convergence and stability. Logistic growth models have been found useful in continuous cover forest management optimization. Optimization of management decisions in a changing and not perfectly predictable world should always be based on adaptive optimization