Iranian Journal of Forest and Poplar Research
Year:2011 | Volume:19 | Issue:1 (43)|Papers Count:18

In order to investigate the growth and survival of exotic tree species, four species from Pinaceae, namely, Pinus pinea, Pinus ponderosa, Picea abies and Abies alba were planted in 1984 on 1600 m2 (121 trees with spacing 4x4 m) in Chamestan plateau, Mazandaran province, north of Iran. The final measurement of tree parameters were: survival percentage, mean diameter, height, and stem quality. The measurement was carried out in 2006 and the statistical analysis of data was made using the ANOVA and Duncan tests by SPSS software. Results showed that the maximum and the minimum survival belong to Picea abies (%82) and Pinus ponderosa (%53), respectively. The highest and the lowest stem quality are attributed to Picea abies, Abies alba and Pinus pinea, respectively. The maximum mean diameter (28.2 cm) and annual diameter increment (11.7 mm/y) was calculated for Pinus pinea, whereas the minimum mean diameter (11.6 cm) and annual diameter increment (4.8 mm/y) was calculated for Pinus ponderosa. The maximum height was observed in Pinus pinea (11.61 m) and the minimum height in Pinus ponderosa (5.29 m).

The aim of this research was to review of relation between tree ring width of Quercus castaneifolia C.A. Mey trees and region climate changes in the Saravan forests of Guilan province. For this purpose, the relation between these two factors was studied using Dendroclimatological study and increment borer sampling method. Weather information was obtained from Rasht meteorological station. In this study, the effect of June, July and May-July’s precipitations on tree ring width of Quercus castaneifolia was positive while, the effect of maximum temperature of July, minimum temperature of November, mean temperature of July and mean temperature of November was negative.

This research was carried out for predicting probability of forest type's presence using topographic attributes in the Educational and Research Forest of Doctor Bahramnia, district 1, with 1714 ha area.Field sampling was performed, based on cluster random sampling and systematic random sampling and 249 plots were sampled with 0.1 hectare area (without plantation area). Diameter of trees larger than 12.5 cm, species information and geographic position were registered in each plot with GPS. Since, thick trees are dominated in the canopy cover, 10 thick trees in each plot were selected to determine the forest type. Using computing of frequency percent of species, forest type in each plot was determined and four types ofFagus-Carpinus, Quercus-Carpinus, Carpinus-Parrotia and Parrotia-Acer (mixed with Carpinus betulus) were determined in the study area. The topographic attribute maps were derived from a digital terrain model and these attributes were extracted in location of plots. Logistic regression was implemented to analysis of forest type’s correlation with attributes and to construct a predictive model.The analysis was performed using 70% of the plots and each forest type map was resulted by extrapolation of model in GIS. Validation of results was performed by 30% of the remained plots and total accuracy computed for each model. Validation result of accuracy showed that spatial prediction models of forest types forFagus-Carpinus and Quercus-Carpinus have narrow amplitude than Carpinus-Parrotiaand Parrotia-Acer (mixed with Carpinus betulus) types that spread in large extent region. This result showed that spatial predictive models of forest types, which have narrow amplitude, are more acceptable. The results also showed that consideration of altitude, solar radiation potential and aspect in the model were the main factors which are controlling forest types in the study area.

Classification of forest area for determining optimum places for constructing forest roads has a great importance in protecting and managing of forest. However, high variability in classes introduces uncertainty in classification process. Fuzzy set theory provides some solutions for such problems. The aim of this research is to classify forest area for road construction based on various layers including: slope, aspect, soil, land stability, forest type and volume in Lirehsar forest, Mazandaran Province, by means of fuzzy sets theory. First, partial membership was defined and all layers converted to fuzzy layers.Then, layers were combined by geometrical mean and minimum operators. Assessment of final map showed 68 percent entropy that means an uncertainty in decision making for classification. Therefore, to classify the areas, the fuzzy method was used, since in this method, borders are not explicitly separated and changes occur very minor. The fuzzy method has the advantage that enables forest road network designers to consider the favorable range of classes and there is no need to separate the favorable and unfavorable classes from each other with high uncertainty.

This study was performed in order to find the superior poplar clones with high wood production in Research Station ofPoplus and fast growing trees in Boldaji, Chaharmahal-Bakhtiari province. We first, selected 12 exotic clones fromPopulus euramericana and Populus deltoides species. Then, the clones were planted in a completed randomized blocks design with 3 blocks and 9 replicates. The experiment started at 1999. Dbh, height and crown width of trees were measured within 8 years and total volume as well as dbh, height and volume increment of all clones were calculated. Results showed that the volume increment of clonesPopulus euramericana I-154, Populus euramericana costanzo, Populus euramericanaI-214, Populus euramericana vernirubensis and Populus euramericana 262 were 13.2, 12.83, 12.54, 12.11 and 11.65 m³/h/year, respectively; which were significantly higher than other clones.As a result, these clones are introduced as the most promising clones in term of wood production. In compare to regions with longer growth seasons, the wood production by mentioned clones seems lower, however, it should be mentioned that this wood production has been achieved only within 5.5 months of growing season in Boldaji. It seems that using year scale for the age of poplar trees could be substitute by month scale.

In temperate forests, disturbances are regarded as processes of great importance to forest vegetation. For the better perception of biodiversity, different indices were used in mountain forests of Lalis located in Chalous. Line transect method used for sampling, and plant abundances were recorded, as well. Forest gaps areas were divided into four classes including smaller than 200 m2, 200 - 400 m2, 400 - 600 m2 and larger than 600 m2 areas. In order to analyze of biodiversity, Simpson, Shannon and Wiener, Margalef, Menhenick, Peet and Camargo indices were used. Using analysis of variance, statistical difference between biodiversity indices in respect to gap sizes was found. The maximum and minimum of divers species and richness species indices were related to very large and small gaps, respectively. The highest evenness indices were related to medium and large gaps, whereas the least of evenness indices were related to small and very large gaps.

In forest ecosystems, there is an important interaction between hydrological cycle and nutrient contents. Rainfalls not only have an important role for entrance of nutrient contents to forest ecosystem, but also have an important role to transfer elements from canopy to forest floor and soil. This study performed to investigate the effect of through fall and forest floor leachate on base-cations dynamics in a mixed hyrcanian beech forest in Golestan province. Through fall and forest floor leachate samples were taken through 6 months (winter and spring 2008). Amount of base-cations (Ca2+, Mg2+, Na+and K+) were compared by T-Test between rainfalls and throughfall. Results showed that the amount of Ca2+, Mg2+, Na+and K+contents in throughfall were higher than rainfall (p<0.05). Also total content of Mg2+in throughfall and forest floor leachate compared to rainfall was higher, while Ca2+and Na+were lower, significantly (p<0.05).Finally, amount of base-cations were compared by T-Test between throughfall and forest floor leachate. Results showed that the amount of Na+, Ca2+and K+contents in throughfall were higher than that of forest floor leachate (p<0.05). In total, canopy and forest floor leaching have added 5.53, 12.42, 3.01 and 1.06 (Kg ha-1 month-1) Na+, K+, Ca2+and Mg2+, respectively to the soil that were about 97, 202, 137 and 186 percent of the amount of those cations in the rainfall.Therefore, nutrient elements leaching cause soil fertility and increasing of forest products in a short time.

The aim of this study was investigation of Carbon, Nitrogen and Phosphorus dynamics in Carpinus betulusL. leaf litter in organic layer of a broad-leaved mixed forest in Gorgan. Fresh litters were collected from five plots in district one, Shastkalate forest and were placed into some litterbags with 2 mm mesh. Then, they were located in the study site. Over one year (8 sampling), chemical analysis was carried out. Result showed total Nitrogen concentration in fresh litters was 1.5% and after one year increased to 1.9%. Phosphorus concentration in fresh litter was 0.134% and increased to 0.136% after one year. Carbon to Nitrogen ratio in fresh litter was 24.5, but after one year decreased to 17.4. Carbon to Phosphorus ratio in fresh litter was 282 and after one year decreased to 245. Weight of fresh litter was 14.65gr, but decreased to 8.23gr after one year. Nitrogen content, C/N and N/P ratios of Hornbeam leaf litters were correlated with secondary weight of litter. C/N and C/P ratios were appropriated for discriminating of decomposition phases. Hornbeam Leaf litters caused soil fertility and increased site indexes. It is necessary to useCarpinus in reforestation and rehabilitation of destroyed forest, considering climate, elevation and forest degradation density.

Determination of different poplar clones by leaf traits is a simple and cheap method in early growth stages. This method has systematic value and helps to recognize the growth characteristics and effectiveness of the traits by environment or genetics. Ten poplar clones belong to three species including P. nigra, P. deltoides and P. euramericana were planted in the same conditions aspect of soil and microclimate and twenty leave traits were measured in the middle of growing season, then the data were analyzed using variance analysis, Duncan comparisons, determination of traits plasticity and cluster analysis. Variance analysis of the more traits showed high significant differences among the species and some clones. Also the traits plasticity was indicated that only eight traits including petiole length, length to width ratio, shape factor, length, width, number, perimeter and chlorophyll affected more than 50% by genetics and were useful to determineP. deltoids and P. euramericana clones whereas for P. nigra clones width in 50% of leaf length and angle between middle vein and lowest vein in the leaf right hand as well.Results of this research presented that determination of poplar inter and intra specific diversity by leaf morphological traits is suitable method.

The present study was carried out to determine the effect of soil bed and seedling transfer age of Juniper (Juniperus excelsa M. Bieb.) on its growth and early establishment under rainfed conditions. For this purpose, using a Factorial examination, under Randomized Complete Block Design and 3 replications, 540 seedlings ofJ. excelsa with treatments of seedling transfer age (2 and 3 years) and soil bed (1: 3 natural soil+2: 3 cultivated soil, 2: 3 natural soil+1: 3 cultivated soil, and natural soil) were planted in southern hills of Mashhad city (eastern province of Iran). At the end of the 2nd growing season, collar diameter growth, crown growth and seedling survival were not affected by seedling transfer age, but height growth differed with seedling transfer age. Soil bed and interaction of seedling transfer age × soil bed did not influence on either of the measured characteristics. Regarding to soil amendment costs and non-significant effect of soil bed on growth and establishment ofJ. excelsa seedlings, in such areas, changing of soil bed for afforestation development of this species is not recommended. Likewise, considering to non-significant differences of growth and establishment between 2 and 3 years seedlings, due to reduce the additional costs in nursery using 2-year old seedling is more favorable than 3 year old seedling to transfer to afforestation site.

Due to benefits of Quercus brantii Lindl. and its important role in soil and water protection, this species is very important in its environment, especially the Zagros area.Because of over harvesting, the existence of this species is in danger, so its plantation must be considered and its sowing methods must be known.Therefore, this study was carried out in Rykhlan nursery in completely randomized design with unbalanced factorial experiment. Planting depth (4-5 cm and 7-8 cm) and time (December and March) was considered as two treatments with 3 replicates and 40 pots in each replication. Results showed that planting time had significant effect on survival and shoot and root dry weight ratio. Planting depth had significant effect on all factors. Therefore, planting in December with 7-8 cm depth had the best results for all studied factors.

This study was carried out in the reserve area of district one of Langa region in Kelardasht. Development stages including initial, optimal and decay were identified and one sample plot with one hectare area (100 mx100 m) was selected in each development stage. Quantitative characteristics of saplings with diameter at breast height less than 7.5cm were determined in the micro plots. One hemispherical photograph was taken by Fish-eye camera lens in order to study the status of light in development stages as well as the relationship between quantitative and qualitative characteristics of saplings and relative light intensity. Light intensity parameters were processed by Gap Light Analyzer (GLA) V.2 software.Results showed that mean frequency of seedlings and saplings and mean annual height growth increased by increasing of relative light intensity in the decay stage. Frequency of trees decreased from initial to optimal stage and then towards decay stages. Maximum and minimum of stocked volume was measured at initial and decay stages, respectively. Stocked volume of larger timber classes in development stages was higher than small timber classes. Considering the obtained results, we can recommend to establish the regeneration in the optimal stage by creating gap and can improve the quality of the regeneration in the initial and decay stages by silvicultural interventions.

Iron wood (Parrotia persica) is one of the endemic species in the Hyrcanian forests that grows naturally in the northern forests of Iran. This species is reproduced through asexual reproduction using coppice shoot. In order to determine the effect of altitude on asexual regeneration of Ironwood, Kheiroud experimental forest was selected. The altitude was categorized in the groups of 1) less than 400 m, 2) 400-800 m and 3) 800-1200 m.a.s.l. The coppice shoots were also divided into two groups of a) dbh<5 and b) dbh>5 cm.90 circle plots, each 1000 m2, were laid out in the study area. Analyze of variance and Duncan’s test were used to compare the number of coppice shoots among and between the groups.Results showed that the maximum total number of coppice shoots (10.3/tree) was counted in the lower altitude group (400 m.a.s.l.) while, the maximum number of coppice shoots with dbh>5 cm (3.5/tree) was counted in higher elevations (800-1200 m.a.s.l.). The differences between groups were statistically significant. In general, producing of coppice shoots shows an inverse relation with increasing of altitude.This study suggests that silvicultural interventions should be more focused in lower elevations.

Several species of oaks (Quercus spp.) grow abundantly in the Hyrcanian, Arasbaran and Zagros forests of Iran. Taxonomy of oaks is difficult because of it's immense size and wide distribution, heterophylly, hybridization and changes in morphological features. Micromorphological characteristics of foliar and pollen features provide a valuable set of analytical characters for species delimitation inQuercus, so it' s the goal of recent studies in taxonomy of genusQuercus. In this research, for the first time in Iran, some of micromorphological characteristics of foliar (type of trichomes, the number and length of trichome rays, type of epicuticular waxes, type and shape of stomata), and pollen (shape and exine ornamentations) were studied in sixQuercus species (Q. castaneifilia C.A.Mey. subsp. castaneifolia, Q. macranthera Fisch. and C.A.Mey. ex Hohen., Q. petraea L. ex Liebl. subsp. iberica (Steven) Krassiln., Q. libani Oliv., Q. infectoriaOliv. subsp. boissieri (Reut.) O.Schwarz and Q. brantii Lindl. subsp. brantii var. brantii Zohary). The mentioned species have been accepted by different botanists and foresters. The samples were prepared from individuals in nature and the herbarium specimens and photographed by SEM and LM. Overall, five types of trichomes, two types of epicuticular waxes, four shapes of pollens, four types of structural patterns of tectum surface, four types of sculptural patterns and three types of suprasculptural patterns of pollens were recognized in the studied taxa. The most important and valuable characteristics in the studied taxa were type of trichome, the number and length of trichome rays and shape of pollen in Q. macrantheraand Q. petraea subsp. iberica; shape and exine ornamentations of pollen in Q. infectoria subsp.boissieri and type of trichome, shape and exine ornamentations of pollen in Q. castaneifolia subsp.castaneifolia, Q. libani and Q. brantii subsp. brantii var. brantii. Based on our results, the studied micromorphological characteristics have high taxonomic value in the differentiation ofQuercus species, and when employed in combination with other morphological features permit correct species identification.