جستجوی مقالات مرتبط با کلیدواژه « اکالیپتوس » در نشریات گروه « جنگلداری »

The red flour beetle (Tribolium castaneum (Herbst)) (Tenebrionidae) is one of the main pests of stored products, especially cereal crops, all over the world. In recent years, to reduce the use of chemical pesticides, plant essential oils have gained attention. But despite their good potential, essential oils are unstable, and their toxicity decreases in a short time after use. Nanocapsule formulations can improve the efficiency of plant essential oils on stored product pests by increasing their toxicity and durability. This study was carried out with the aim of preparing nanocapsule formulations of essential oils of Eucalyptus camaldulensis Dehnh. and Eucalyptus globulus Labill. and comparing their fumigant toxicity effects and non-formulated essential oils on T. castaneum adults.

 Eucalyptus leaves were collected from the Zaghmarz Eucalyptus research station in the south of Behshahr city, Mazandran Province, in July 2018. The collected dried leaves of Eucalyptus were hydrodistilled using a Clevenger-type apparatus. Identification of the constituents of essential oils was performed using GC-MS. Sodium alginate nanocapsules were prepared using basic hydrophilic surfactants. The survey of the surface and wall morphology of nanocapsules was conducted using a transmission electron microscope. The particle size distribution of nanocapsules was also determined. Fumigant toxicity testing was performed separately for each essential oil and nano-capsulated essential oil in four concentrations and at 24, 48, and 72 hours after applying the treatments, along with the control at 25°C and a relative humidity of 65% in darkness. PoloPlus software was used to estimate the LC10, LC25, LC50, and LC95.

 According to the results, the number of compounds in the essential oils of E. globulus was higher. The most important compounds of the essential oils of the two Eucalyptus species were terpenes, and 1,8-cineole, limonene, and pinene-α were the most important terpenes in the essential oils of E. globulus and E. camaldulensis, respectively. The results obtained from the transmission electron microscope images showed that nanocapsules containing Eucalyptus essential oil have nanoscale dimensions. The average particle size distribution for E. globulus and E. camaldulensis essential oil nanocapsules was determined to be about 150 and 100 nm, respectively. The essential oil of E. globulus was more toxic than the essential oil of E. camaldulensis. The values of LC50 at 24, 48, and 72 hours after treatment for essential oil nanocapsules of E. globulus and E. camaldulensis were 5.9, 4.63, 3.8, and 9.5, 8.67, 6.7, respectively, and LC50 for raw essential oils of E. globulus and E. camaldulensis were 10.93, 9.63, 5.7, and 15.09, 12.86, 8.2 ml per liter of air, respectively. Based on the results, the nanocapsule formulation of the essential oils of both species, compared to the raw essential oil, showed a decrease in LC50, and the durability of the encapsulated essential oil also increased.

 Based on our results, nanoencapsulation of Eucalyptus essential oil increased the fumigant toxicity of the essential oils by enhancing toxicity and the controlled release of effective compounds in controlling this pest. Therefore, this nanocapsule formulation is recommended for further toxicity tests and eventually its use in storage.

Eucalyptus species are one of the most suitable tree species in terms of wood production for pulp and paper industry and leaves for pharmaceutical industry. This study aims to determine the wood and foliage production in coppiced Eucalyptus species. This study carried out on four Eucalypts species including Eucalyptus camaldulensis 9616, E. melliodora, E. stricklandii and E. Salubris with 4 treatments (1, 2, 3 shoots per stumps and control) and were planted at 1.5×  2 m spacing as statistical split plot design with 3 replications at Shooshtar Research Station, Khuzistan province.  At the end of first year, seedlings were cut 10 cm above the ground and coppice shoots treatment was applied. Survival percentages, diameter at breasts height (dbh), and height were measured yearly during dormancy on all trees. After four years of growth, all shoots were cut and stems and branches were weighed separately, and finally the biomass was recorded. The growth results of four years after the shoot treatment showed that the highest average wood yield was in the E. camaldulensis species and in the control and 3-shoot treatments with 45.4 and 38.9 tons per hectare per year, respectively. The average foliage biomass under different shoot treatments showed that in the 3-shoot treatment of  E. camaldulensis species with 10.3 ton/ha/yr. had the highest value  and was placed in the first group. Also, total of wood and foliage yield of E. camaldulensis in control and 3-shoot treatments with 50.8 and 49.9 tons per hectare per year respectively, were placed in the first group.

Knowing the qualitative and quantitative characteristics of plantation is principal of forest management. Laleh Natural Park in DEZFOUL, with a total area of 9.31 hectares, is located 11 km far from Dezful. The 23-year old stands in the studied park were Eucalyptus and Prosopis. In order to study the number of trees, according to the small levels of the studied stands (pure Eucalyptus 1.9 hectare and mixed with Prosopis 1.7 hectare), the full calipering inventory method was selected and the certain characteristics such as diameter at the breast height and height of all trees. According to the results, the average number of trees in the pure Eucalyptus stand is equal to 110.5 trees per hectare, the average diameter at breast height of stand is 25.22 cm and the average total height is 12.10 m. Also, the average number of species in the mixed Eucalyptus and Prosopis stand is 70.6 trees per hectare, the average diameter at breast height is 27.32 cm and the average total height is 9.57 m. In order to study the effect of Eucalyptus and Prosopis on the soil of the area, 50 soil samples were taken at 2 depth of 0-10 and 10-20 cm from pure and mixed stands and some soil characteristics including texture, moisture and acidity were studies. Soil texture of both stands in this study was loam. There was no significant difference between the two populations in terms of total relative humidity. In terms of acidity, there was a significant difference between two soil depths of 0-10 and 10-20 cm soil in the pure stand which was higher at depth of 10-20 cm.

Eucalyptus species are used for afforestation in different ecological areas due to their rapid growth and high genetic diversity. The industrial performance of some species and provenances of Eucalyptus was evaluated.

The experiment was a factorial experiment based on randomized complete block design (RCBD) with two factors: 1) genotype at 6 levels and 2) time at 3 levels in four replications. Irrigation was carried out using the treated wastewater of Qom city. Selected genotypes were including six provenances of Eucalyptus camaldulensis Dehnh., E. Microtheca Muell. and E. rubida Deane & Maiden. Growth traits including: tree height, trunk diameter, height growth, diameter growth and height to diameter ratio were measured. Because of evergreen eucalyptus trees, vegetative traits were recorded in two stages yearly, one in early autumn (after summer heat stress) and the other in spring (after winter cold stress).

Statistical analysis such as analysis of variance and comparison of mean traits between genotypes and different years showed that the effect of treatment (species and provenances), replication and year effect on tree height were significant. Mean comparisons showed that species and provenances were classified into five distinct groups and one common group; E. camaldulensis 41ch was in the highest group. Trees were grouped according to the diameter of trunk, E. camaldulensis 41ch and E. camaldulensis Qom were in the first and second groups. In addition, E. camaldulensis 41ch and E. camaldulensis Qom were in the first group and E. microtheca 62 and E. rubida 166sh respectivelygroups. The diameter trunk of E. camaldulensis Qom was in the first group and E. rubida 166sh in the last group. In terms of trunk height to diameter ratio, the species were divided into two distinct groups and three common groups, based on these results, E. camaldulensis 41zh was the first group with the highest height to diameter ratio.

In general, the results showed that E. camaldulensis had the highest ratio of survival and establishment, it had the highest growth and diameter growth and E. microtheca was in the next place. E. camaldulensis seems to have a higher performance for wood production than other species and provenances, E. camaldulensis Qom was also ranked first in terms of diameter and height growth, this due to seed origin (Qom) and adaptation to regional conditions. Overall, the results showed that E. camaldulensis had the highest rank in height and diameter growth, followed by E. microtheca.

Many species used in forestation could survive even in severe conditions, but considering the growth and economic efficiency is also important. Eucalyptus species are important sources for the production of wood, paper, fuel, and oils that are commonly used for planting the forests in the tropics. The purpose of this study was to evaluate the growth of adaptable species and cultivars, industrial and fast growing eucalyptus, for planting in inefficient lands of dry areas in Ilam province. For this purpose, the vegetative growth of eight species and varieties of eucalyptus including E. camaldulensis (from four origins), E. sargentii, E. microtheca, E. melliodora and E. saligna were investigated in a five-year period.in a randomized complete block design with three replicates in Mohsenab research station of Mehran, Ilam. The data analysis was performed using ANOVA and Duncan's multiple range tests in SAS software. The results indicated that there is a significant difference between species and cultivars in terms of indicators of height, trunk diameter, and canopy. E. camaldulensis is superior regarding to vegetative growth index in this study compared to other species. Three varieties of this species has an annual production of between two to five cubic meters per hectare, Shafarood variety has shown annual yield of more than 35 m per ha.

The different species form the genus Eucalyptusspp. are amongst the most important fast growing tree types of Oceania which have been planted in Iran for more than 50 years. In particular, the Eucalyptus trees were vastly planted in the southern parts of the country, from which the old-growth trees are still found in Lorestan (e.g. Malavi region) and Fars provinces. The applications to produce wood pulp, paper and leaf oils are amongst the motivations for future industrial and medicinal uses. In this study, the adaptation and performance of different industrial Eucalyptus ecotypes in Lorestan province were tested. A range of species including E. globulus (spp. bicostata), E. globulus (spp. maidenii), E. nitens, E. viminalis (spp. cygnetensis), E. camadulensis (var. obtus)and E. suggrandis (spp. suggrandis)were planted with 3 m distance within a complete randomized block design in a 2-ha field and were monitored for a 7-year period. The comparison of means by Duncan test showed the E. camadulensis (spp. obtus) and E. globulus (spp. maidenii)to be superior regarding the majority of their investigated properties in 99% confidence level.

A large area of world soil have salinity problem. Salinity affects establishment، germination and emergence of plants. Planting salt tolerant species and cultivars is a very convenient and economical way to overcome the problems associated with soil salinity. Various species of Eucalyptus introduced as salt tolerant trees and have widely used around the world. The most important elements dissolved in saline soil that inhibit the growth and crop production are reduced sodium chloride and calcium chloride. In this study has been investigated the effect of calcium chloride as a salt stress on germination and seedling growth of three species (E. camldulensis، E. microtheca and E. saligna) in two substrates، sand and MS medium. The results showed that seed germination has continued until 250 mmol of salinity in both substrates in E. microtheca while the species E. camaldulensis and E. saligna، germinated respectively until 200 and 150 mmol. The maximum and minimum total mean germination (percent and speed germination and seed vigor) and seedling growth (root and shoot length) characteristics in both substrates belong to E. microtheca and E. saligna. Thus، according to the results of this research E. microtheca can be introduced as a more resistance species to salt stress than two other species، E. camaldulensis and E. saligna in germination and primary growth stages.

Salinity is one of the most important abiotic stresses that according to its negative effects on plant growth، reduces lands’ potential productivity. Seed germination is the first stage of plant development، in which plant encounters salinity of soil. Thus، study of plant response to salinity in this stage can have an important role in determination of plant salinity resistance. The salinity resistance of plant can be determined in short time. In this study، in order to identify salinity resistance of three Eucalyptus species (E. microtheca، E. camaldulensis، E. saligna) in germination and initial growth stages، using MS media culture in vitro condition and using completely randomized factorial experiment with3 replications their seeds were exposed to 6 salinity treatments، including 0، 50، 100، 150، 200 and 250 Mm NaCl in laboratory condition. Germination percent، germination speed، seed vigor، root and shoot length، root and shoot fresh weight، root and shoot dry mass and total biomass were measured and used as salinity tolerance index (STI). E. microtheca was more salinity tolerant than E. camaldulensis and E. saligna. In order to achieve more confident results seeds of these 3 species were planted in different salinity classes of natural soil. After comparison، it was determined that results were quite consistent.

Lead is one of the most important environmental pollutants which disturbed nutrient uptake by plant. Present study was conducted with the aim of evaluation of some biotic factors potential in lead (Pb) phytoremediation and nutrient uptake by eucalyptus in Pb-contaminated soil. Treatments include three levels of bacteria (B0, Ba105 and Ps36), two levels of mycorrhiza (M0 and M1) and three levels of Pb (0, 50 and 100 mg/kg). Bacterial isolates were pseudomonas and bacillus and fungi was Glomus moseae. Results showed that increasing in soil Pb concentration improved Pb uptake by plants. Inoculation with Ba105 caused significant increase in shoot Pb uptake and this treatment caused in 55 and 19.5% increase in Pb uptake compared to control (without inoculation) and inoculation with pseudomonas Ps36. Also, mycorrhizal inoculation resulted in 23.7 and 44% increase in shoot and root Pb uptake compared to control. The greatest phosphorous uptake occurred in 0 mg/kg Pb. As Pb concentration in soil is increased, shoot and root phosphorous uptake by eucalyptus significantly. Inoculations with Ps36 and Ba105 along with mycorrhiza caused increase in shoot and root phosphorus and potassium uptake. Association of soil beneficial microorganisms (bacteria and fungi) with fast-growing and high biomass producer tree species like eucalyptus could cause improvement in phytoremediation efficiency under heavy metal stress.

Due to Eucalyptus potential as a fast growing species, its utilization for afforestation and industrial and medical purposes is very important. E. maculata Hook. is an important species among the other eucalypts in respect to some chemical components production and medical utilization. Sexual and asexual propagation of this species is difficult, for this reason the trial was conducted to investigate its propagation by tissue culture, using micro mature stocks.The produced explants from the mature stocks, were placed on MS medium (Murashige and Skooge) treated by ½ nitrate and various growth regulators such as Kin (Kinetin), BAP (Benzylamino purine), IBA (Indole-3-acetic acid), 2ip (2-Isopentyladenine), TDZ (Tidiazorun) and NAA (Naphtalen Acetic Acid) at different levels of concentration. After two months, growth indexes, including shoot number, shoot height, root number, root length, bud number and greenness rate were measured and recorded. Results showed that the best shooting treatment was IBA (0.01 mgl-1), BAP (0.3 mgl-1) and 2ip (0.5 mgl-1), in which average shoot number, shoot height and greenness rate were 4.63, 2.73 cm and 3.75, respectively, whereas the best rooting treatment was NAA (0.5 mgl-1) plus IBA (0.5 mgl-1), in which root length was 0.2 cm. Finally, the micropropagated plantlets were transferred to greenhouse to pass their adaptation process.

World anxiousness to earth global warmness brought a special attention to soil's potential for carbon sequestration. The purpose of the trial was to investigate effects of tree plantation on carbon sequestration at arid lands. For this reason, a site at forest park of Dehloran area in Ilam province of Iran was chosen where three tree species, including Eucalyptus camaldulensis, Prosopis juliflora and Ziziphus spina-christi had been planted before. Based on random systematic statistical method, 6- 10 sampling plots of 10 x 10 m. size were allocated for each species at planted and unplanted (control) parts, separately. Soil sampling was made in center of each plot at 0-20cm depth after removing the organic layer of the soil surface to measure carbon sequestration, N, P, K, pH, moisture, bulk density, silt, sand, clay and gravel amount. Results showed that carbon sequestration rate under the trees cover was 117.7 ton per hectare which was about five times more than the control plots (24.82 T/ha). Furthermore, only average carbon sequestration rate under P. juliflora plots was significantly more than under Z. spina-christii plots (p< 0.005). In addition, only average carbon sequestration at high density plots was significantly more than at low density plots under E. camaldulensis species. There was only significant difference between plots outside and inside crown cover of Z. spina-christii in respect to carbon sequestration rate. Overall, it might be concluded that forest plantation at Dehloran area played an important role in reducing atmospheric pollution and its area should be increased at high extent.

Trees as alive components of an ecosystem are able to convert some of the environment contaminants to unharmful substances and store some of them in their tissues and reduce their density and intensity in the air and soil by breath، root absorption and photosynthesis and other biotic functions. Trees function in such condition is completely related to environmental and habitat circumstances and their physiological potential. At beginning، five research sites at Khuzestan and Bushehr provinces were selected among the contaminated area by the Gulf War. At each site، soil sampling was made from three levels of depth (0-20، 20-40 and 40-60 cm). Soil physical and chemical characteristics test was made to measure nine metal elements and 12 other soil properties. The eucalypt species consisted of: E. camaldulensis، E. camaldulensis 9616، E. microtheca and E. sargentii which were planted under the Randomized Complete Blocks statistical design with three replicates. Before sampling the trees for determining the contaminant elements. Three individual trees were selected at each plot per one replicate to make sampling for leaf (four specimens per tree at four mean geographical directions). The data were analyzed under the variance analysis and Duncan test programs، using Excel and SAS computer soft wares. Overall، amount of the contaminants in different sites and at three levels of depth was not significantly different. The best eucalypt species and the best sites for absorbing the contaminants in their leaves are respectively as follows: 1- E. camaldulensis، E. microtheca، E. sargentii and E. camaldulensis 96162- Dezful، Isvand، Shooshtar، Karkheh and Kaki. The species which made the best performance in relation to their site interaction are respectively as follows: 1- E. microtheca firstly at Karkheh and shooshtar sites and secondly at Dezful and Isvand sites. 2- E. camaldulensis 96163- E. camaldulensis and E. sargentii.

Afforestation with native or non-native species affects understory vegetation. These effects, besides of edaphic and climatologic factors, also depend on the species of the plants which are used. In the present study, the allelopathic effects of two species of Eucalyptus (E. camaldulensis Dehnh. and E. microtheca F.Mull.) and one species of Acacia (A. salicina Lindl) on the understory vegetation in Shiraspary region, Mamasani (Fars province) were studied. Aqueous extraction of leaves of these species was prepared in the laboratory; the effects of different densities of these extractions on the vegetative factors of Avena fatua L., Lolium perenne L., were investigated. The maximum inhibitory effect was on radical length and the minimum inhibitory effect was on seed germination. 5% density of these extractions had a stimulatory effect on the seed germination. The highest inhibitory effect on Lolium perenne was on E. camaldulensis, A. salicina, while the least inhibitory effect was on E. microtheca. The highest inhibitory effect on Avena fatua germination was on E. camaldulensis; the least inhibitory effect was after exerting A. salicina. 5% density of E. camaldulensis showed a stimulatory effect on radical growth. The 5% density of extractions increased the plumule length. The maximum inhibitory effect on the length of Lolium perenne was on A. salicina, E. camaldulensis, while the minimum inhibitory effect was on E. microtheca. The maximum inhibitory effect on length of Avena fatua was on E. camaldulensis, and the minimum inhibitory effect on radical length was on E. microtheca, A. salicina. The minimum inhibitory effect on plumule length originated from A. salicina. Compared with the control, the allelopathy effect of two Eucalyptus species was more than that of the Acacia. Both the stimulatory and inhibitory effects coincide with each other, indicating the presence of both types of allelochemicals which are capable of enhancing and suppressing at the same time. However, toxic allelochemicals are more volatile in nature than the stimulatory allelochemicals. This increased the competition ability of eucalyptuses and caused them to dominate forests and woodlands. Eucalyptus should not be cultivated in sensitive and especially arid ecosystems, so that the allelopathic effects of this species can be minimized.

In this research, the adaptation and establishment of several industrial provenances of Eucalyptus was studied during a five year period. Climatic, edaphic and floristic data were primarily collected. In this trial, 15 species and provenances of Eucalyptus were planted under Complete Randomized Blocks design with 3×3m spacing. Factors including survival, height, diameter and crown cover of the rees were assessed annually. Based on Duncan’s test, E. camaldulensis 15195, E. camaldulensis15272, E. camaldulensis 20709, E. camaldulensis 15023 and E. maidenii 300-sh ranked in the higher class in terms of survival, but they achieved the middle class with regard to height and diameter parameters. E. globulus ssp. bicostata 16731 and E. camaldulensis 41-ch were classified in the lowest class in terms of survival, despite exhibiting excellent height and diameter growth.

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 five Eucalyptus 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 in E. largiflorens. Whereas these traits have positive correlation with resistance to drought, consequently E. 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.

Studying the soil and eucalypt relationships is essential for eucalypts plantation and avoidance of their negative effects on soil productivity. For this purpose, eucalypt species trial consisting of six species (E. camaldulensis, E. macarthurii, E. maidenii, E. rubida, E. saligna, and E. viminalis) planted in 1983 was conducted. Randomized Complete Blocks with four replicates at 2 x 2 m spacing and total number of 100 seedlings at each plot was used for this research. At each plot, three trees were randomly selected and leafsampling was done for each tree at 1/3 of upper height at the end of summer. The aim of the study was to investigate the nutrients of six eucalypt species planted at Guilan province, Iran. The results showed that there was not significant difference among the replicates regarding the amount of N, P and K, but there was significant difference between the eucalypt species in respect to amount of N. There was significant correlation between K% and P% of eucalypt leaves and some soil characteristics.

Root distribution of three-year-aged Eucalypt (Eucalyptus camaldulensis Dehnh.) seedlings was determined under different soil moisture regimes in Yazd, Shahid Sadoge Desert Research Station. The seedlings were grown in lysimeters which subjected to three soil moisture regimes including; 100% (well watered), 70% (medium drought stress) and 40% (high drought stress) of field capacity (FC). Soil moisture was restored by adding the required volume of water in the basis of time domain reflectometry (TDR) reading taken from tubes installed in each lysimeters. The roots were harvested at 0-30, 30-60, 60-90 and 90-120 cm depth of the soil at the end of the experiment. Results showed that root dry weight and length decreased significantly when soil water content reduced (P <0.001). The effects of various soil moisture content treatments on root dry weight and length distribution at different depths of soil were significant (P< 0.001). Therefore, deep root development of E. camaldulensis was related to soil moisture content and intensive soil drought stress inhibited root growth in high depth of soil.

Populus euphratica Oliv. forests in river floodplains of Khuzestan province are degraded heavily. Tree plantation is one of the methods for restoration of these degraded sites. The plantations of Eucalyptus camaldulensis, Acacia salicina and Dalbergia sissoo were established in randomized complete block design in 1993 with three replications along Dez river. Soil macrofauna were collected by hand sorting, using two randomly located 0.25m2 sampling frames at each plot. All macroinvertebrate organisms (macroscopic organisms) in litter and mineral soil up to 25cm, were collected. Totally, 18 samples were collected. In these treatments, earthworm constituted the largest part of soil macrofauna. Earthworm abundance and biomass were highest in Acacia plantation whereas Arthropods did not show any significant differences. Since soil macrofauna was dominated with earthworm, its variations are in line with earthworm. The abundance and biomass of earthworm and soil macrofauna were negatively correlated with the C/N ratio. Lower earthworm abundance and biomass under Eucalyptus plantation could be as a result of its leaf phenolics or soil nitrogen limitation. Totally, it could be concluded that different tree species had various effects on soil macrofauna (especially earthworm) abundance and biomass. As Acacia species increased the soil macrofauna and improved soil fertility, it could be preferred species for plantation in this area.

Tree planting with drought tolerant species, particularly Acacia and Eucalyptus species may be considered as a logical method for rehabilitation of marginal lands which can potentially meet the needs of local people in terms of wood, fuel wood, fodder, edible fruits, etc. These goals may be much better attained when the trees are planted in floodwater spreading (FWS) systems which drastically change the desert ecosystems through provision of more water and better rooting environments. In 1994, a pilot project was carried out in FWS systems in Gareh Baygan Plain in Fars Province of Iran to study the growth and performance of four Eucalyptus and four Acacia species which had previously been tested successfully in a preliminary adaptation experiment. A randomized complete block design with four replications was employed to establish the experiment. Each replication comprised of eight plots (species) and each plot contained 49 trees with 3m×3m spacing. The seedlings were irrigated only by rain and ephemeral floodwaters. In a ten year period, growth parameters including survival percentage, height and diameter at breast height were assessed or measured every year. The existence of pests or diseases and the viability of the trees were also monitored annually and the final evaluation was made at the age of ten. Survival and growth performance of the trees were quite satisfactory. Eucalyptus camaldulensis, E. oleosa, Acacia victoriae, A. salicina, and E. microtheca were all promising species, showing over eighty percent survival in the final year of experiment and were not significantly different from each other. The survival of E. fruticetorum was significantly different (p=0.0001) from those of the other species. Eucalyptus camaldulensis showed the highest growth in terms of height and diameter, while A. saligna ranked the lowest. It may be concluded that E. camaldulensis, E. oleosa, E. microtheca, E. fruticetorum, A. salicina, and A. victoriae were highly promising species and may be recommended for large-scale plantations in arid zones of southern Iran, using floodwater spreading systems. Moreover, further tests of cold resistant provenances of A. cyanophylla and A. saligna are recommended.

The aim of this study was to investigate the positive or negative effects of eucalypt plantation on different soil properties. For this reason, an eucalypt trial consisting of six species: E. camaldulensis, E. macarthurii, E. maidenii, E. rubida, E. saligna, E. viminalis which were planted in 1983 in Sheikh-Neshin state of Shafarud Company in Guilan province under experimental design of Randomized Complete Blocks with four replications at 2×2 m spacing and total number of 100 seedlings at each plot, was used for this research. Soil samples were taken from each plot, including four control ones by auger up to 60 cm. depth (totally 28 samples). Soil morphology was studied by digging three soil profiles at the eucalypt site and two adjacent parcels, including poplar plantation and the oak forest. Soil samples were taken from four soil horizons of each profile (totally 12 samples). Results showed that the species have differed significantly in respect to only few soil properties, including silt percentage, litter dry weight, bulk density, penetration resistance, pH and phosphorous amount. The soil profiles at the eucalypt site and the two adjacent sites of poplar plantation and oak forest consisted of four horizons, including A, AC, B and C. Root development at eucalypt, poplar and oak sites limited to 100, 85 and 150 cm soil depth, respectively. Overall, eucalypt plantation was able to improve soil structure and porosity, particularly at topsoil. Although there was intensive livestock traffic in the eucalypt site, but soil compaction was significantly less than the control plots and there was not significant difference between the eucalypt species in response to penetration resistance. Eucalypt plantation after 22 years reduced soil pH, but it was less than one unit.