نشریه طبیعت ایران
سال چهارم شماره 3 (پیاپی 16، امرداد و شهریور 1398)

Many projects have been implemented with the aim of increasing production per unit area and selecting clones with high wood production and compatible to edaphic and climatic conditions of Markazi province. The production of common clones planted in the Markazi province is estimated to be 10-15 m3/ha/year, which is much lower than the country's average, 20-25 m3/ha/year. Poplar research has begun since 1993 by collecting and identifying native and non-native cultivars. The compatibility project was implemented with 35 clones for 10 years in 1997 and the clone P.n.56/72 with a production of 36.55 m3/ha/year was identified as the best clone. In order to study this process, the second phase of this project was carried out with the aim of investigating the effect of cutting operation on the production of different clones compared to the previous period. The results of a seven-year study showed that clone P.n.56/72 with an average production of 27.33 m3/ha/year had a significant difference with other clones, and clone P.n.betulifolia with an average production of 18.03 m3/ha/year had good condition and was introduced as a successful clone. Also, the second stage of compatibility was conducted with the aim of investigating the wood production of other clones in Arak. The results showed that clone P.n.62/154 had a significant difference with other clones with an average production of 33.21 m3/ha/year and was the most successful clone in Markazi province, which is recommended for cultivation in the prone areas of province.

Prosopis cineraria Druce, belonging to Leguminosae family, is a native plant in Bushehr province.   The seeds and pods of this plant are severely attacked by Caryedon serratus Olivier, and it is of utmost importance since the regeneration of this plant is through seeds. The integrated pest management of C. serratus, emphasizing the bioecology, natural enemies, and seed treatment with common pesticides of Confidor, Sevin and Phosphotoxin, was investigated in Bushehr province. The average length of oviposition period, larvae, and pupa was calculated to be 6.5, 24.5 and 10.5 days, respectively. The total period of life cycle from egg to adult was 42.5 days on average, and the number of pest generations was determined to be 5 to 6 generations per year. The predators like Carabidae beetles and ants feed larvae and pest eggs, respectively. The disinfection of seeds with Phosphotoxin insecticide showed the highest larval mortality rate (92.5%). For pest management, rapid collection of seeds and transfer to the storage at the time of arrival and pods fall, as well as disinfection of seeds with Phosphotoxin in storage areas is proposed.

The present situation of forage deficiency during the severe periods of drought affecting rangeland areas suggests that a rational strategy should be considered in order to provide part of livestock forage through low-common and low-water and salinity and drought- resistant forage species. In this regard, the cultivation of forage plants in saline lands using non-native Atriplex species has been considered as a beneficial forage production system for several years ago. Regarding the success of the aforementioned practices, misleading statistics have been presented and there have always been different ideas about continuing or stopping planting of Atriplex. Therefore, in the present study, different climatic and ecological aspects of planting native and non-native species of Atriplex have been studied. Referring to the positive and negative aspects of planting the non-native-Atriplex species over the past few decades, the need to pay attention to native species of Atriplex to provide forage becomes more apparent. The most important advantage of native species is its natural and easy regeneration in natural areas, which is very important for economic and ecological reasons, given the high cost of planting. In this regard, Atriplex verrucifera is a native species distributed over a wide range of saline habitats along the margin of the Urmia Lake, and forms a very suitable pasture for domestic animals and forage grazing. The amount of its production in the severe drought conditions of the past decade was estimated to be 220-250 kg dry matter per hectare, reaching by more than 500 kg of dry forage per hectare by increasing the level of water level.

Due to the wide variety of eucalyptus species and their various ecological requirements, it is necessary to select the appropriate species for afforestation and development of green spaces through compatibility testing. Accordingly, the compatibility of various species and provenances was considered. This research was carried out in the climatic conditions of Yazd and through irrigation with wastewater during 2009 to 2018. The experiment was carried out in Yazd Wastewater Treatment Plant with a randomized complete block design and four replications, with eight species and provenances, at 36 plants in each block at a distance of 3 × 3 m. Species and provenances were E. rubida, E. saligna, E. saligna20762, E. macarthurii, E. viminalis, E. sargentii, E. camaldulensis and E. microtheca. The results of the study in the first phase of the experiment showed that E. camaldulensis, E. sargentii and E. microtheca had higher and significant establishment rates (98.6, 95.1 and 42.9%). According to the results, the yield of E. camaldulensis was superior to the other two species. Our results clearly showed that in case of healthy roots, all three species showed a high potential in coppice production

Destruction of forests and natural areas causes environmental crises; thus, conservation of forests, rangelands, and genetic reserves as a national duty is important and valuable. The oak forests of Darkesh in North Khorasan province is one of the habitats that is less well-known despite its ecological and tourism potentials. This forest with an area of about 13000 ha is located a few kilometers of Golestan Forest, with a regular consistency and a combination of different types of trees, shrubs and grasses with dominant species of chestnut- leaved oak (Quercus castaneifolia C. A. Mey.). This forest is the only oak forest reserve in the eastern region of Iran. Conservation of these valuable forests, preventing a dense presence of livestock and observing appropriate season for grazing, preventing the conversion of forests into agricultural lands are the most important conservation programs for these forests, which should be considered by the authorities. Considering that this region has high tourist attractions for tourists and nature enthusiasts, attention to ecotourism reduces forest dependency of local people.

Hymenocrater yazdianus Rech. f. is a perennial plant, belonging to the Lamiaceae family. It is a local endemic species in Yazd province, center of Iran. The habitat of this species is distributed in the south and west of province in mountainous areas with a steep slope.  Based on IUCN guidelines, three criteria were used to evaluate the status of this pecies: extent of occurrence (EOO), area of occupancy (AOO) and size of populations. According to the field survey and plot sampling, H. yazdianus occupies an area of 0.001225Km2, and the extent of occurrence is 162/8 Km2. Thus, according to the results of this study, H. yazdianus is recognized as "Critically Endangered". Field observations showed that the lack of management and inappropriate exploitation such as non-observance of the grazing season and degradation of habitat were considered as the main threats to this rare species. Given the importance of conserving endemic and critically endangered species, it seems necessary to define its natural habitat areas as protected habitats as well as storing its seeds in the natural resources gene bank and doing research on the reclamation methods or planting the study species in Botanical Gardens.