فصلنامه جنگل و فرآورده های چوب
سال شصت و چهارم شماره 1 (بهار 1390)

Since the establishment of Hyrcanian section of National Botanical Garden in 1972, most of natural Hyrcanian trees have been transferred and planted in this section and they are 30-40 years old now. Due to lack of researches on growth procedure and adaptation of planted species in garden, the increment changes of Caucasian alder (Alnus subcordata) as an important Hyrcanian species was studied. Thirty felled trees were randomly selected and disks from their stumps were prepared. The disks were dried and prepared then annual rings widths were measured in the four geographical aspects using Vernier Caliper. The results showed that the age and diameter of sample disks were 22-30 years and 30-47 cm, respectively. Mean current annual increment was 11.9 mm. Maximum current annual increments and basal area increments were occurred in 5th and 11th years, respectively. Furthermore, drought periods had decreased diameter growth. The growth trends of these samples were matched with silvicultural growth stages.

Benefitting from emerging technologies in industry is of great importance. New developments in nanotechnology have opened new horizons in pulp processing and development of new products. Cationic Starch-Nanosilica is a new system which has found its way in virgin pulps to some extent، but no attempt has been made on its utilization in recycled pulp systems. In this study، application of Cationic Starch-Nanosilica for improving drainage and retention of Old Corrugated Container (OCC) pulp in making test-liner was investigated. Results indicated that this system increased drainage of OCC pulp. The maximum increase was observed for treatment with 1. 5% cationic starch and 0. 9% Nanosilica. In this treatment، the drainage was increased from 342 ml CSF (control pulp) to about 550 ml CSF. Fines retention was also increased using the Cationic Starch-Nanosilica system. The role of Zeta Potential as an indicator of system interactions was also monitored.

Poplar lumbers with nominal thickness of 5 cm from Taleghan region، located in west of Karaj were dried under three different schedules، including T8-F4 (recommended schedule by F. P. L for poplar)، T8-F5 and T9-F4. Dry bulb temperatures for the schedules were adjusted at 54، 54 and 60 °C، while the final temperatures were 82، 82 and 71 °C، respectively. The severity of warping، honeycombing and surface checking in kiln dried lumbers were measured and analyzed. Results showed that flat-sawn boards dried faster than quarter-sawn boards. The grain orientation had no effect on the occurrence of warp، whereas cracking largely occurred in flat-sawn lumbers.

Required data for research or decision making for lots of environmental sciences have been provided by field inventory which consume a great deal of the budget. As time and financial resources for inventory are limited، having more information about the effective factors that influences inventory is necessary. Also، new instruments in forest inventory such as GPS or laser meter needs to be studied. In this research، required time for field inventory with respect to weather and field conditions were assessed using continues correlation time study method. Required time for each part of field operation was recorded based on 150 10R plots with 300×400 sampling design. Total pure and gross time for recording plots data was 57 and 86 minutes، respectively. The results of two way ANCOVA showed a significant effect of weather and field condition on required time for measuring plots data and crossing distances between plots. Required time for measuring plot data was increased 33 and 43 percent while weather and field condition getting worse، respectively. On the other hand، undesirable weather and field condition increased time for crossing distances between plots 20% and 47% respectively. A regression model for estimating required time of inventory based on distance (d) and slope (s) between plots were developed. The results of ANCOVA also revealed that the effect of number of trees on required time for measuring data was significant but the effect of slope of plots was not significant.

The aim of this study was to utilize recycled polypropylene in wood/plastic composites production. Recycled polypropylene and two types of eucalyptus wood (wood flour & fibers) and three levels of coupling agent (MAPP) 0، 2. 5 and 5% were used in wood/plastic composites production. The mechanical and physical properties of composites were measured and analyzed. The results of this study indicated that MOR of composites produced using fibers were higher than those made from wood flour. Also، the interactive effect of particle type and coupling agent was significant on MOE and composites produced with fibers and 5% MAPP indicated the highest MOE. The results also indicated that with increasing MAPP content، tensile strength and modulus of elasticity increased. However، particle type and coupling agent had significant effects on the modulus of elasticity and the minimum value of this property was observed at 0% MAPP content while using wood flour. The results of thickness sweling and water absorbtion of composites after 2 hours immersion in boiling water showed that these properties were at their lowest levels in composites made from wood flour. Also، increasing MAPP content، decreased these properties and the minimum values were observed while applying 5% MAPP.

One of the most important principles that forest managers should consider is the kind and methods of logging and transportation of forest products. Assessment of mechanical properties of forest soils is an important criterion in selecting and using suitable machines، because the forest floor bears the pressures of machines. On the other hand proportion of machines with soil properties plays important role in sustainable yield of forests. In order to obtain these objectives، mechanical properties of forest soil such as Atterberg limits، liquidity index، plasticity index، consistency index، grain size distribution and soil classification base on Unified Soil Classification System were assessed in Kheyroud Forest. The results showed that soils are fine grained and the percentage of clay in all samples is more than 5% so the soil is sensitive to freezing. The liquidity index for most of samples is less than to 0. 5 and so wheeled skidders can be used in most of the region except samples with liquidity index more than 0. 5 which crawler skidders should be used. All samples had a liquid limit greater than 30; therefore soil is sticky and should be considered when using machines. With regard to plasticity index، the soil showed high tendency in water absorption and will be dried slowly، so the machines should be scheduled and used in dry weather. Soil can not be used for road construction without physical and mechanical improvement. The elevation range of study area is up to 900 meters above sea level so risk of freezing is rareness; therefore sensitiveness of CL and CH soils to freezing is not very important in this region.

In this research، nondestructive evaluation of finger and scarf joints manufactured with beech wood were performed using through transmission ultrasonic technique. For this purpose، sound joints were manufactured. Then ultrasonic parameters including ultrasonic wave velocity، coefficient of attenuation، maximum amplitude and root mean squares (RMS) voltage were measured in longitudinal and perpendicular direction of joints. Through- Transmission technique with transducers of 40 kHz was used for all measurements. Results showed that there was no significant different between ultrasonic parameters in perpendicular direction of the specimens with and without joints، however in longitudinal direction، the wood specimens (without joint) exhibited significantly higher ultrasonic velocity. Higher coefficient of attenuation and the lower maximum amplitude and RMS voltage were obtained in longitudinal direction of the specimens with finger joints in comparison with specimens without joint as well as with scarf joints.

Sustainability of natural resources have been one of the challenges for planners and policy makers of development، especially in less developed rural areas. Why that، in this areas the relation between exploiters and environment is more complex than developed areas. The main purpose of this study was to study the effective factors on sustainable exploitation of forest''s woods in Dejhen village in Kamyaran County. Dominant paradigm on this research was quantitative and the research method was descriptive. The statistical population consisted of 535 exploiters of village of Dejhen. A sample of 222 members was selected by randomized sampling method and based on Morgan & Krejcie sampling table. The research tool was questionnaire that its reliability was confirmed by a panel of experts and content reliability method. For determining of validity of the questionnaire the Cronbach Alpha coefficient calculated (α=0. 81). The data were processed and analyzed by SPSS software. The result showed that the most exploiters of woods were middle-age mans (57. 2%) that most individual in this group (46. 5%) have used much of forest''s woods. Result showed that in general 30. 6 % of exploiters have used much from forest''s woods. Most application of forest''s woods was in industry and handcrafts (33. 9%). Results showed that in the view of respondents، irregular cutting of trees for various expenses، grazing and cutting trees for expending tilling lands have been the most important factors of demolition of forests. Also the results showed that there was a positive and meaningful relation between the attitude to use of forest''s woods and sexuality and the number of mans with positive attitude to use of woods were more than women. Results showed that there was positive and meaningful relation between the attitude to use of forest''s woods and the age of exploiters and whatever the age have grew up the number of individual with positive attitude to exploit of forest''s woods have grew up too. For analysis of effective factors on sustainable exploitation of Forest''s woods، Factor analysis (R kind) was used. The results showed that 5 factors consist of managerial-control، economic، encouragement-motivational، educational-informational and attitude-cultural have distinguished. These 5 factors totally determined 54. 15% of total variance of the effective factors on sustainable exploit of forest''s woods.