Publications

Intentional and unintentional fire occurrences are known as main threat factors of Zagros forests which destructed wide areas of these forests in recent years. Investigating and offering management solutions in this respect can play a controller role in tackling this crisis. The aim of the study was to identify and evaluate the most important factors influencing forest firefighting techniques in Marivan forests، using SWOT technique. Due to variation of fire control management solutions، they were classified into two categories، risk and crisis management. Identification and specification of the affecting criteria on fire control was employed، using an open answer-sheet method، based on stockholder analysis. Then the obtained results of SWOT technique were quantified by AHP approach. Results showed that employment generation and income، on-time accessibility and staff efficiency (overall weight of 0.106، 0.069 and 0.068، respectively) were identified as the most important factors affecting crisis management solutions. Furthermore، prevention of fire expanse in forest، action speed and possibility of job generation (overall weight of 0.123، 0.120 and 0.118، respectively) were identified as the most important solutions for risk management. It is recommended to: 1- reconstruct and improve the local societies morale to their surrounding environment، 2- develop the villagers culture، 3- develop national decision for natural resources conservation and finally 4- avoid absolute governmental management and administration for appropriate and scientific control of forest fire.

Ground-based skidding can have detrimental effects on soil properties trough soil profile disturbance and compaction that can persist for decades. We investigated the recovery ofphysical properties of disturbed brown soils on four abandoned downhill skid trails in a deciduous mountain forest in northern Iran. The most recent skidding operations had taken place 1–5 yrs, 6–10 yrs, 11–15 yrs, and 16–20 yrs ago, providing a 20-year chronosequence with four 5-year recovery periods. For each recovery period, mean values for soil bulk density (BD), total porosity (TP), macroporosity (MP), soil moisture content (SM), and rut depth (RD)were assessed for three levels of traffic intensity (Primary (PS), Secondary (SS) and Tertiary (TS) skid trails) and two levels of slope gradients (Gentle (G) and Steep (S)) and compared to those in undisturbed (control) areas. Over the 20-year recovery period, PS trails on gentle slopes exhibited mean values that were 35–42% (BD), 3–7% (SM), and 13–19 cm (RD)greater and 18–24% (TP) and 19–28% (MP) lower compared to undisturbed areas; on steep PS trails, values were 40–46% (BD), 2–13% (SM), and 13–21 cm (RD) greater and 23–27% (TP) and 28–35% (MP) lower, respectively. While RD and SM recovered, 20 years was not long enough for the other physical soil properties, particularly on steep slopes. To minimize soil disturbance, skidding should be confined to areas with gentle slopes and alternative harvesting methods such as cable yarding should be used where slope gradients exceed 20%.

The paper investigates the effects of mule logging, including traffic volume and slope, on topsoil physical properties. A downhill mule trail is studied in the Hyrcanian forests of northern Iran. Treatment plots include combinations of primary, secondary and tertiary mule trails over gentle and steep terrain. The results showed that significant differences bulk density, total porosity, macroporosity and void ratio between the mule trail segments and the undisturbed area. Also significant differences are found between gentle and steep slopes.

Efficient allocation of resources is an essential principle in forest management. An important case in resource allocation is when the available resources are not sufficient to service all requests. One of the key elements in forest management is to minimize the total costs of the unallocated requests. With respect to high capital cost of forest operation machinery, it is necessary to reduce expenses of one cubic meter of wood extraction by appropriate Skidding Machines Allocation (SMA). Fuzzy set theory as a soft methodology and practical decision support system was used to handle uncertain variables and vague range of logs volume and physiographic conditions to develop models. The aim of this research is to present a decision support method to determine the economical activity zone of forest operation machines so that this allocation would result in the highest net profit for forest managers. To achieve this goal, all skid routes in the study area were divided into work units with 75 m width and 200 m length whereupon 379 units were formed collectively.Within each unit, the related mathematical productivity models were applied to estimate one cycle time and cost of machines. The effective factors of these models included Skidding Distance (SD), Volume of Logs per Cycle (VLC), and Number of Logs per Cycle (NLC). Three separate fuzzy inference models were developed to predict the skidding cost of each machine in the units, and then proper machines were allocated. 70% of data was used as training and the rest was feed to the models for validation and test process through the generation of fuzzy models. Membership functions and fuzzy rule bases were created with the help of scientific knowledge, experts’ viewpoints and existing machine productivity models. The results showed that the application of the presented approach helps forest managers to recognize the desirable conditions for skidding machines to reduce the total costs of skidding. In addition, SMA fuzzy rule-based models reflect how to integrate expert knowledge with engineering system design. To present an illustrative example, the models were applied to allocate three commonly used Skidders, i.e. Timberjack 450c, HSM 904, and Zetor, in a mountainous forest, whose inventory data were known and harvesting was planned for the next period. The results showed that the Zetor was the most economical option in »Very short« and »Short« (< 300 m) distances at all levels of NLC and VLC, while HSM 904 was the most cost effective machine at »Medium«, »Long« and »Very long« distances (300mto 900 m) at all levels of NLC and VLC with the exception of »Long« distance units (around 700 m), with »Low« NLC (2 pieces) and »Low« VLC (around 4 m3), as well as the units with »Very long« distance and »Low« and »Medium« volume (less than 5.5 m3), where Timberjack 450C was the most adequate machine from the economic point of view. The result of this application also showed a spatial variability in skidding costs by different machines based on skid route conditions. The implemented method can be very helpful in where and how to use skidders to gain maximum profit from forest operations.