فصلنامه تحقیقات جنگل و صنوبر ایران
سال چهاردهم شماره 2 (پیاپی 24، تابستان 1385)

Natural gum and resins are basic materials required by different industries, including food, pharmaceutical, cosmetic, painting, etc. They are extracted from various plants such as coniferous, citrus, elm, oleaster, apricot and wild pistachio species. The main problem is that the gum should be extracted from mature and aged trees. Cutting the trees bark and some times the young wooden layer of the stem or young branches, is one of the methods of extracting gum and resin in these trees. Insects bit and bark damage by some fungi also is a way to extract gums, because the trees produce gum or resin against disease contamination. In that case, the plants are very aged and weak. Thus, gum and resin exudation, particularly when is repetitive, can lead to general plant weakness and finally to its death..It was tried to obtain extract from young seedlings of Pistacia atlantica in this research program which require a preliminary study of resin and gum ducts physical structure and their growth and development process. Resin ducts were studied in root, shoot and leaf by picking one-year organ samplings. Samples were fixed with FAA fluid and kept in fridge (4- 8 °C) for a while. Then the samples were hydrated with an alcohol series and cut using Rm-2035 microtome. five to 10 thick sections were stained with periodic acid and Schiff’s reagent (PAS) and toluidine blue O. Preparations were studied under a light microscope and photographs were taken using 100 ISO Konica Minolta color film.As a result, the number of gum duct in the bark of root, stem and leaf was discriminated in Pistacia atlantica seedlings. The results showed that it is possible to identify different genotypes of Pistacia atlantica through this differentiation. Moreover, it might be demonstrated that despite of former idea for resin production of seedlings, it is possible to have resin product at seedling stage

Poplar as fast growing tree with a great potential of coppicing at consecutive periods is the most suitable tree species to provide wood at short period. The high volume of wood at short periods (2-5years) produced under the short rotation system is used in different industries such as particle board, pulp and paper.In this study, 18 poplar clones of various groups and species were being examined in two 4 year rotation period. A randomized complete blocks design with three replications was applied. Overall, cuttings of each clone were planted in each plot including 10 cuttings on each planting row. At end of the first year, the seedlings were clear-cut to produce vigorous shoots and roots (to provide more nutrition for shoots). The annual measurements contained: survival, height, stem diameter, total number of shoots and those more than two meters height and shoots diameter at breast height. At the end of each rotation period, the measurements including: intermediate diameter, collar diameter and classification of wood products, based on different parts of crown, wet and dry weights of the wood were determined under field and laboratory conditions. The results for two consecutive harvesting showed that:-P.e. vernirubensis, P.e. 561/41, P.e. triplo and P.e. costanzo were able to produce the highest yield of 24 to 27 tone/ha/year dry matter. -In terms of survival rate, the four above mentioned clones and P.nigra clones achieved the highest and both P.deltoides and P.alba achieved the lowest percentage. -The second rotation period produced higher volume of wood (about double) compared to the first period due to the optimal establishment, vast and vigorous roots and modified growing conditions.