Iranian Journal of Forests and Rangelands Protection Research
Year:2018 | Volume:15 | Issue:2 (30) |Papers Count:8

Constructing forest roads network is a kind of human intervention that causes disturbances in the forest. The aim of this study was to determine the effective distance of secondary forest roads on flora, life forms and chorology of plants in Hornbeam-beech Kheyrud forest in Nowshahr. For this purpose, 36 transects with a length of 100 m (eighteen transects at each fill slope and cut slope) were selected from the road edge into forest interior. Along each transect, 8 plots of 2 × 1 m were collected by intervals of zero (road edge), 5, 10, 15, 20, 30, 45 and 100 meters. The results showed that the maximum effective distance of road on the flora was 15 meters, because in other distances, the frequency of Fagaceae and Betulaceae plants became dominant, and moreover, presence of Rosaceae, Cyperaceae and Poaceae plants decreased. Furthermore, the maximum effective distance on life form was 20 meters, as a result, after this interval percentage of geophytes and hemicryptophytes decreased, however, there was an increase in percentage of phanerophytes. Also, the forest roads effect on chorology were up to a maximum distance of 15 m. Cosmopolitan and sub-cosmopolitan chorotypes were not exist in higher distances and the presence of multiregional species was declined. Dominant form of distribution altered in the form of Europe-Siberia or Europe-Siberia and Mediterranean. Using the excavator instead of bulldozer for the road constructing that provide less environment disturbance and strict compliance with longitudinal and transverse profiles of forest roads can reduce the negative effects of roads on ecosystem.

Identifying forest areas susceptible to decline in order to take preventive measures can play a significant role in inhibiting this phenomenon. Previous studies suggest the high performance of modeling to identify such areas. Hence, we used 15 models to identify forest areas prone to decline in Lorestan province. For modeling, forest areas with over 50% tree mortality were used as dependent variable, and environmental factors including annual mean rainfall, annual mean temperature, relative humidity, aridity index, evapotranspiration, dust storm index, drought index, distance to surface waters and agricultural lands, slope, aspect and NDVI as independent variables were introduced into the models. AUC of each model was multiplied by its output and the mean of these models was considered as the combined model. The forest decline risk map resulted from the combined model indicated a decline trend from central parts of the Lorestan’ s forests to the south and south-western parts. The Random forest and Support vector machine were recognized as the best models with AUC value of 1 and the Bioclim as the weakest model with AUC of 0. 75. According to the combined model, approximately 23. 7%, 7. 5%, and 19. 5% of the studied forests had low, medium, and high risk of decline respectively. The climatic factors including aridity index, rainfall, temperature, and evapotranspiration were the most influencing environmental factors, respectively. The present research, in addition to emphasizing the modeling efficiency in identification of forest areas susceptible to decline, indicated that the combination of models yields better result rather than their separate use.

The "Karebas" area is one of the habitats of various wild almond species in Chaharmahal and Bakhtiari province. During 2012-2014, collecting and identification of pests of four wild almond species, Amygdalus arabica Oliver, Amygdalus haussknechtii (C. K. Schneider), Amygdalus elaeagnifolia Spach and Amygdalus scoparia Spach was carried out in this region. Sampling was performed by the usual methods from the beginning until the end of the growing season. In order to determine the degree of infestation of pests, ten shrubs from each species in three altitude classes (1600-1800, 1800-2000, 2000 m) in both northern and southern ranges of this area were selected and infestation level was determined for each pests. The results indicated that Capnodis tenebrionis, Osphranteria coerulescens, Scolytus amygdali, Eurytoma amygdali, Cicadatra alhageos, Chlorosalta smaragdula, Empoasca decedens, Lasiocampa nana, Hystrix indica, Loranthus grewinskii and Orobanch sp have important role in destroying wild almonds in this area. In addition, we found two species of flowering parasites Loranthus grewinskii Boiss & Buhse and Orobanch sp. having a significant activity and damage on the species. Also, the infestation level of different pests varied according to the almond and pest species. In general, average pest infestation on the all selected shrubs of the four almond species in this habitat showed that the C. tenebrionis infecting crown and root and L. nana had the highest (11. 52%) and lowest (1. 66%) infestation level, respectively.

Iran's Zagros forests have faced with the Dieback phenomenon in the recent decade. This crisis has become a major concern for stakeholders, including rural and nomadic communities. The success of dieback management involves the participation of these communities, who depends on the forests. This paper aims to investigate participation of rural communities in the decision making, developing, monitoring and evaluation of the oak forest trees dieback management projects. In this descriptive-explanatory study, the data were collected through structured interviews. A sample of 250 rural households living in the surrounding of the damaged forests in the Kohgiluyeh and Boyer-Ahmad province were randomly selected through a multi-stage sampling technique. The content validity of the questionnaire was assessed through a panel of experts and its reliability was confirmed using a pilot study and the Alpha Chronbach Test (0. 662-0. 981). A confirmatory factor analysis was utilized for analyzing construct validity. Most respondents had a poor participation in decision making, monitoring and evaluation in all the stages of dieback management activities. The participants were mostly in the position of the inactive information receivers or providers at the stage of diagnosing dieback and conserving the implemented projects. The participation was significantly and positively explained by variables such as the effect of dieback damage on rural households' livelihoods, forest area proportion infected with dieback, level of education, the financial abilities and knowledge to participate in the projects, interaction between rural households and external actors, participating in extension training courses, and financial support from external organizations to enhance participation.

Tortrix viridana L. 1758 has many parasitoids. In this investigation, we tried to identify these parasitoids and determine their effects on reducing the pest population. This project was conducted in Marivan and Bane regions during 2012 and 2013. By visiting infested forests, once a month, at least 50 eggs were collected and transported to the laboratory to emerge the possible parasitoids. Concurrent with the emergence of larvae and pupae of the pest, by weekly visits of the contaminated areas, at least 100 larvae or pupae were collected and transported to the laboratory. Parasitoids were collected by regular visits of the cages and parasitism rate, kind of parasitoid in each stage and finally the percentage of parasitism were determined. The results did not reveal any parasitoids from the eggs, however by survey of larvae and pupae as a result of this study, 10 species of parasitoid wasps belonging to six families and three species of tachinid fly emerged from the collected larvae and pupae. The results showed that larval parasitism was negligible in the early instars but it was ranged between 15 to 25% on old larval stages and pupae. Based on the results obtained over the two years, Goniozus yezo Terayama, 2006 with an average frequency of 66. 7% of the total population, had the highest frequency followed by Brachymeria minuta (Linnaeus, 1767) and Apanteles sp. with 13 and 8. 5%, respectively.

The Streblote siva (Lefebvre) (Lepidoptera: Lasiocampidae) is an invasive defoliator of Conocarpus erectus, Ziziphus spina-christi and Acacia ampliceps in southern of Iran. The relationship between fecundity and body size, egg size, Mating as well as longevity in female insects was studied under laboratory conditions. Effect of host’ s quality on growth and gain of S. siva was performed using hosts nitrogen content which was measured by the Kjeldahl technique. The strange data range of larva weight, pupae and adult female insects rose to crescendo of oviposition in order to using different nutrition on plant species. However, there were strange relationships among fecundity and pupal weight, adult weight, there was no significant difference in the egg size of the insect reared on different plants hosts (P<0. 05). The weight of 6th instar larvae was significantly correlated with female pupa and female Adult weight as well as egg number (P<0. 05). Compared with the rest of the life span of the insect, the mean of RAF50 (0. 23 ± 0. 01), indicated that the highest oviposition rate took place in the early life of it (P<0. 05). Also, the results showed that non-mating insects had a longer life span than mating insects and the sex ratio was 1: 1 (P=0. 66). The weight gain of larvae was not significantly different between two treatments, C. erectus and Z. spina-christi but, there was a significant difference compared with the third treatment, A. ampliceps. Finally, the results showed that the factors affecting larval weight gain such as different plants hosts may influence on adult size and following fecundity (P<0. 05).

The box tree moth Cydalima perspectalis (Walker, 1859) is an invasive pest causing severe damage to box trees (Buxus spp. ). It is native to Japan, Korea and China, but established populations have been recorded in a number of locations across Europe since 2007 and yet the spread of the insect is continuing. The pest was reported in northern Iran in 2016. The damage caused by the larvae of this pest, which often leads to a complete defoliation of the trees, necessitates a serious action to control it. In the present study, in the course of forest survey in the distribution areas of this pest in Guilan province, larvae that were infected with fungal mycelium were observed, which ultimately led to the isolation and identification of Beauveria bassiana (Balsamo) Vuillemin species. So far, B. bassiana has been reported as an entomopathogenic fungus, especially lepidoptera larvae in many countries, but this is the first report of the natural occurrence of this pathogenic fungus on the box tree moth. Since the biocontrol of this pest by fungal pathogens can be used as an appropriate alternative or at least a supplement to chemical pesticides, further researches on the efficacy of this entomopathogenic fungus against C. perspectalis is in progress.

The oak defoliator wasp, Periclista sp. (Hymenoptera: Tenthredinidae) is a major pest of oak tree around the world. During the last years an outbreak due to an exclusive re-emergent pest defoliator of the oak Quercus infectoria in Ghelaii rural district, Lorestan province was occurred. This pest imposing severe loss to the oak trees during April to June. After insect collection and preliminary identification of specimens, the identifying the larva was confirmed using sequencing of a COI gene fragment as a tenthredinid wasp species belonging to the genus Periclista. The oak tree Q. infectoria is the exclusive host of pest wasp species in this region. The loss caused by this pest is serious since that the larvae are highly phytophagous and can completely defoliate the oak trees. As a further study, adult stage is needed to specific identification of this wasp pest species.