Iranian Journal of Forest and Poplar Research
Year:2011 | Volume:19 | Issue:2 (44)|Papers Count:19

At the time being, in the Caspian forests two functions of wood production and forest conservation are of the great significance, but in course of time passage, it is needed to express processes concepts of planning, implementation and control of forest management plan in a innovative expression. This study tries to make an object-oriented planning and logical framework approach as performance tool on forest management plans (case study: Kheyrud) from stand point of wood production and forest conservation, design target system in a log frame and control of forest activities step by step. The results of the study express two aspects of control concept to achieve objectives (control of success) and activities (control of activities). This expression means a new concept of control in the Caspian forest management plans.

Study of sexual regeneration of oak species in Zagros forests is very important considering to sever degradation of these forests and decreasing of seed origin oaks. Acorn production is the first step in the sexual regeneration cycle which has an important impact on forest sustainability. Regarding to difficult process of acorn counting, there is unfortunately, no adequate information about acorn production of Zagros native oaks. Therefore, this research was conducted using Koenig visual method for the first time in the western oak forests of Iran. The study was carried out in a section of northern Zagros forests near to Halou village located in 40 km west of Baneh, Kurdistan province. At first, 90 gall oaks (Quercus infectoriaOlivier) were selected using stratified random sampling method. For each tree, all of acorns were counted with two methods: 1) crown counting and 2) Koenig visual estimation. Result showed that the mean, minimum and maximum of acorns number/m2 crown area were 10.3, 0.1 and 278.9, respectively. These values were 158.8, 3 and 2917 for the acorns number per tree, which indicates that total acorn production was poor in the study area. Finally, the best regression model was calculated to estimate total number of acorns using Koenig visual estimation method. Obtained model showed a high correlation which is applicable for easy estimation of acorn number of other gall oaks in the studied forest in the next years.

This research was conducted by randomized completely block design with nine spacing treatments (2×2, 2×3, 3×3, 3×4, 4×4, 4×5, 5×5, 5×6 and 6×6 m) and three replications at Chamestan research station. The research area is located in the north of Iran with mean annual precipitation of 840 mm and brown forest soil with intermediate to heavy texture. Results of ten years walnut spacing trial revealed that mean dbh, mean total height, dbh increment and total height increment of walnut in spacings of 2×2, 2×3 and 3×3 m were minimum. Trees survival was different among nine treatments. Least survival was observed in spacing of 2×2 and 2×3 m. The analysis of qualitative characteristics showed that spacings of 5×5, 5×6 and 6×6 m (with high dimensions) had the lowest quality than other spacings. With above mentioned results we are able to conclude that spacing less than 3×4 m is not suitable for wood production by ten years results.

In order to investigate the impact of drought stress, a trail was carried out in a factorial experiment in the base of randomized complete design on traits such as pigments and photosynthesis in fiveEucalyptus species (E. globulus, E. largiflorens, E. robusta, E. sideroxylon, E. tereticornis). Drought treatments contained polyethylene glycol solution with five levels (0, -1, -3, -6, -12 bar). In this investigation characteristics such as: chlorophyll and carotenoids, photosynthesis rate, leaf water potential and stomata number were studied. Most of the traits were significantly decreased under water stress condition. The highest amount of chlorophyll, carotenoids, photosynthesis and leaf water potential were related to control plants of different species. Results showed that these traits caused lower reduce under drought stress condition inE. largiflorens. Whereas these traits have positive correlation with resistance to drought, consequentlyE. largiflorens were most resistance species to drought stress. E. sideroxylon and E. tereticornis with high reduce in traits were sensitive species to drought under drought stress condition. E. globulus and E. robusta were relative high resistance species to drought stress.

Wild cherry (Prunus avium) is a native fast growing broadleaved tree in Hyrcanean forests producing valuable wood. Prunus seeds have long dormancy and there is variety of methods for breaking dormancy of its seed. This study was conducted in order to overcoming dormancy and germination ofPrunus seed. For this purpose, seeds were collected from Aliabad Katool region in forests of Golestsan province, north of Iran. The seeds with mosocarp, without mesocarp and without endocarp were subjected to warm stratification (4 weeks, 20oC) followed by cold stratification (10 weeks, 5oC). Results showed that mesocarp and endocarp had significant effects on overcoming seed dormancy and germination characteristics. Germination percent, germination speed and germination value in seeds stratified without endocarp were greater than those in seeds stratified with mesocarp and without mesocarp. The results revealed that the seeds without endocarp were the most favorable treatment to break dormancy and to improve germination characteristics inPrunus avium seeds.

Quantitative attributes of forest stands are valuable data that are very important for the evaluation of forest resources. Regarding to unique structure of Zagros forests, we tried to predict tree density using SPOT5-HRG satellite data in this study. A systematic random grid consisting of 319 circle plots (0.1 ha) were used to collect field data. Spectral values related to field plots were extracted from original and the artificial bands composed of vegetation indices and principle component analysis. Ancillary data such as slope, aspect and elevation were also used. Multiple regression and stepwise method were used to predict tree density from 4 original spectral bands and 16 artificial bands as independent variables. Ancillary data didn' t improve the results. For considering geographic aspects effects, the study also was done for different aspects, separately. In the general model, predictive variables were PCAC2 (the 2nd component of PCA) and B2 (Red band) with the adjusted coefficient of determination of 0.26%. In the suggested models for the northern, southern, eastern and western forests, independent variables are PCAC2, Ratio, PCAC2, AVI, B1 and PVI, AVI, B3, with the adjusted coefficient of determination of 31%, 34%, 19% and 42%, respectively. The Results of model validation tests showed that all of the presented equations had a reliable validation and are useful for this area, however, for better estimation of tree density, we should find the other approaches.

As a necessary tool, statistical distributions have a wide application in forest. Actual and future condition of stands, description of stand structure and reaction of stands to silvicultural interventions are other applications of these functions in forest management. In order to study the statistical distributions, three sample plots of one hectare, were selected in three development stages of an untouched beech stand in Shafaroud forest. DBH of all trees (larger than 7.5 cm) within the sample plots were assessed. Distribution functions were fitted to the stem number distribution in diameter classes and were compared to the observed data within development stages using Kolmogrove-Smirnov, Anderson-Darling and Chi-Square tests by Easyfit software. Results showed that 1) for initial stage, three-parameter log-normal, 2) for optimal stage, beta and 3) for decay stage, Johnson’s SB have been fitted. In general, three-parameter log-normal function has been fitted well for all three stages.

Appropriate growth characteristics and resistance of poplar seedlings to pests and diseases are important criteria for selection of poplar clones in the nurseries. For this purpose, nine different exotic poplar clones (P. deltoides and P. euramericana) and one native species (P. caspica) were compared in Astaneh Ashrafieh station in Guilan province.3600 cuttings, each 20 cm long and containing 3 buds, were planted in randomized complete block design and in three replications. At the end of growing season, the seedlings survival, diameter and height growth and resistance against poplar clearwing moth were studied. Statistical analysis was performed using SPSS software. Results showed that P.d.69.55, P.d.77.51and P.e.triplo illustrated the highest diameter and highest growth, but P.d.77.51 showed more resistance against clearwing moth. P.caspica, the native poplar species, showed the lowest growth rate, but is one of the resistant species to pests and diseases and scored the second rank after P.d.73.51.

In this paper, regeneration status of forest species in relation to different ecological factors was discussed. Ecological characteristics of studied regions in 110 sample plots of circular shapes, each of 500 m2 and 535 micro-plots of 2.25 m2 were investigated. Sampling was done in 4 regions within elevation between 800-2400 m above sea level and in three parallel lines on general slopes. Vertical distance between sampling units in slope direction was 100 m and overall distances between locations were 500-1000 m. Positioning of samples units were prepared with GIS and GPS. Statistical data were analyzed using EXCEL and SPSS software. Complete soil profile in center of macroplots and top soil active horizon in center microplots were studied. Results indicated that physiographical, topographical, and edaphical variation have high effects on sexual regeneration frequency in the studied area. The mean regeneration number in elevation class of higher than 1800 m, also in slope class>60% and in northern and western directions was higher than other classes and directions. Also it was higher in Asmari formation, in rocky, coarse and sharp stones regions and in slopes. The frequency of regeneration was also higher in soil nitrogen class of 0.30-0.45 percent, in soil available phosphorus class of more than 20 mg/kg (ppm) and in soil organic matter class of 3-4.5 percent.

The effect of arbuscular mycorrhizae fungi (AMF) on morphological and physiological characteristics of Pistacia khinjukunder drought stress were studied in Ilam, Iran. First, the mycorrhizae fungi associated withPistacia khinjuk trees were isolated and identified and then their effects on morphological and physiological characteristics ofPistacia khinjuk under greenhouse condition were assayed. It was found that survival of seedling was not affected by mycorrhizae and irrigation, but other physiological and morphological characteristics were affected, separately. Therefore, mycorrhizae as well as irrigation increased root collar diameter, seedling height, terminal growth, leaf number, refresh weight of shoot and root, root volume, leaf area, photosynthesis and transpiration. In contrast to irrigation, AMF didn’t effect on root length, root dry weight, leaf surface temperature, stomatal conductance and photosynthesis. So, we can propose that in dry and sub dry region, for best success in afforestation, seedling is better to be associated with AMF.

This paper presents the results of an elimination trial of exotic needle-leaves in the form of Randomized Completely Blocks Design with three replications at three elevations of Nowshahr region: i) nine species of needle-leaves in lower altitude (450 m.a.s.l.) of Patom district, Kheiroud forest after 19 years, ii) twelve species in middle altitude (1000 m.a.s.l.) of Namkhane district, Kheiroud forest after 18 years, and iii) twelve species in higher altitude (1250 m.a.s.l.) Golband-Veysar forest after 19 years of plantation. Survival, diameter at breast height, collar diameter and total height of trees were measured every year. Final results (2008) indicated that: i)Sequoia sempervirens (origin of California- Nowshahr), Cryptomeria japonica(origin of Japan- Kelardasht) and Pinus nigra var. calabrica (origin of south France) were the promising species in the lower altitude, ii)Picea abies (origin of former Yugoslavia-Kelardasht), Abies nordmaniana (origin of Turkey) and Abies alba (origin of Bulgaria) were the promising species in the middle altitude and iii)Pseudotsuga menziensii (origin of Washington), Abies alba(origin of Bulgaria), Abies nordmaniana (origin of Turkey) and Abies bormulleriana (origin of Turkey) were the promising species in the higher elevation.

The main aim of the present research was to measure interception (I) by individual trees of Pinus eldarica and Cupressus arizonica that extensively planted in afforestation projects of the arid zone in Iran. The selected trees were located inside a forest plantation in a dry area at Semnan province, where mean annual precipitation and air temperature are 127 mm and 16oC, respectively. The gross rainfall (GR) was measured by the mean of three hand-made gauges placed in an open area neighboring to the chosen trees. Five individual trees were selected for measurements of through fall (TF). Eight TF collectors were positioned beneath the tree canopies in the four main directions to average into TF mean per species. I was calculated as the difference between GR and TF for each tree and I was finally averaged into the means of P. eldarica and C. arizonica. Measurements were made on a rainfall event basis during 2009 summer season, from March to October. The cumulative GR depth of 12 events was 37.9 mm, I (P. eldarica): 17.2 mm, and I (C. arizonica): 12.3 mm. On the event scale average ratios of I: GR were 68% (1.4 mm per event) and 55% (1 mm per event) for P. eldarica and C. arizonica, respectively. Strong positive correlations were observed between I and GR (P. eldarica, R2 =0.94, C.arizonica, R2 =0.87). Our measurements suggested that intercepted GR or I: GR ratio by the canopies, and loss through evaporation decreased, as the size of rainfall events increased. The results showed that interception is a significant component of the seasonal water balance in the afforestation of the arid zone of Iran.

For impelementing this research, 20 superior Poplar clones were selected from the experimental nurseries at Safrabasteh Research Station in Guilan province. From each clone, 75 seedlings were planted within a randomized complete block design in 3 replications in February of 1994. During the growing season, resistance of clones to pests and deiseases was studied. At the end of every growing season, diameter, and tree height were measured and the mean annual diameter and height growth as well as the current diameter, height and volume increment were calculated. Results showed that P. deltoides 63.51 and P. euramericana triplo had the maximum mean dbh with 20.9 cm and 19.8 cm, respectively. The maximum mean height was calculated for P. deltoides 63.51 and P.x.63.5 (natural hybrid) with 21.9 m and 20.1 m, respectively. The maximum mean volume increment of 21.33 m3/ha/y was computed for P. deltoides 63.51. P. euramericana I-214 showed the lowest, whereas P. caspica showed the highest resistance against pests.

Regarding to special situation of northern forests in Iran, chainsaw is a unique cutoff. Nevertheless, study to evaluat operation efficiency is imperative. Present study was carried out with the aim of time study of cutting operation, estimating the productivity and costs of chainsaw, and developing a regression model. According to the results of this study, the hourly production of cutting by chainsaw with and without delay time were 51.6 m3/h (9.6 trees/h) and 86.2 m3/h (16 trees/h), respectively. Cutting productivity was increased related to DBH as power model and on the other hand the unit cost was decreased. Total cutting cycle time with and without delay time were averaged 6.24 and 3.74 minutes, respectively.

To investigate the effect of recent oak decline, which covers a relatively vast area of Fars province, the oak forests of Dashte-Barm which were most exposed to drying was selected as the primary site to study. Firstly, base maps were provided. In initial forest surveys, the damaged as well as undisturbed sites were determined.120 trees in affected area and 30 trees in non- affected area were randomly selected. The dried trees were categorized in for groups according to the drying percent. These classes were: %25, %25-%50, %50-%75, and more than %75. All factors including human factors (branch and/or clear cutting and prunning, rain-fed farming under the trees in the forest floor, etc.), climatic factors (rainfall and temperature), disturbing factors (pests and diseases) were assessed. Furthermore, quantitive and qualitative variables of high and coppice trees were separately recorded. Results showed that 58.3% of all dried and dead trees were coppice which consisted the most dead trees. The maximum numbers of dried and dead trees were those that were in their middle age, which are classified in 15-25 cm of diameter class. In term of drying percent, the maximum numbers of dried trees were in the fourth class (%75-%100).