0637-B4
Parviz Fatehi; Manoucher Namiranian 1
Oak (Quercus castanifolia) is a light demander species that spreads over south,western and west-southern foothills whit little to medium slope. Depending on the site and climate,it can be found from plain to the elevation of 2000m. from the sea level. The soil has a heavy texture and the homus is ototroph to mesotroph. In the early ages, the growth in diamete is so little an the maximum is at the age of 70 to 45. In the first years, oak has so much height growth and its about 65 cm. It can be found single or in groups in the upper storey and hornbeam is in the lower storey. The stem qualityis studied in two sites( Noshahr and Gorgan),the result show that about 60% of stems in Noshahr and 40% in Gorgan don't have any branch in the first ten metres
Iran is a vast country that has different climatic and geographic situation and this causes the diversity of its fona and flora. So more than seven thousand different plants has been found in this region. Enough rain,proper temperature,the moisture of caspion sea and their moving toward the Alborz foothill an the long growing period (between 6 to 8 month) cause very good broad-leave deidious forest with more than 80 tree species and 50 shrub species in the north of Iran. The length of this strip is about 800 km. And the depth varies between 20 to 70 km.
One of the most valuable commercial trees in this area is oak(Quercus castanifolia)that consists 6.6 percent of the surface and 7 percent of the volme.
Oak is a light demanding tree of fagaceae family,Quercus genus, that its height is more than 40m. and its diameter reaches to 2-2.5 metres. Because of its rough skin and being tall, it is sensative to thunderstorm. Naturally it spreads were Caucasia forest and hyrcanian site.
The purpose of this research is studing about oak in different sourcse,that have been printed in Iran,specially the thises,were written in research forest of Tehran univ. As this paper is an analysis of other sources,the method is based on different books, theises and personal notes and visits of the writer, that are result of five years studing in natural resources faculty of Tehran university.
About the site, the least hright of sea level is about 300m. in Noshahr and the heighest part is about 1000m. above sea level. After 1000m. high,because of raining increase and the big rate of clouds and fog and the temperature's decrease, oak can't grow. Although this boundry is 1800m. in Gorgan. The despersion of oak in different parts fllows the ecological interests of it. It prefers the places whit more light and warmer. This stydy showed that 46.5 percent of oaks can be found in southern and west-southern foothills, 30.4 percent in western,18.8 percent in eastern and south-eastern and 4.3 percent in north and east-northen slope. (Bahri,1988). This species likes the sites with little or medium slopes. Different researches showed that 88.5 percent of them are in slopes between 0 to 25 percent. The most important sites for oak are in foothills or top of the mountains, because the best light circumstances are at the top pf mountains and the best soil can be found in foothills and places with little slope.
The favourite soil for this species is loam or sandy-loam on calsic bed rocks, the drainage is good. Accroding to the Deshuffer classifications(1984) ,the oak site's soils are mostly brown forest soil that varies from ototroph to mesotroph and this soil is rich in organic materials.
The diametre increases as the years pass and the tre becomes older. Asstudies on diameter scattering showed in Noshaht,most of the tree have small to medium diameters and along with the diametre's increasing, the number of the trees decrease. Studies showed that up to the age of the 35, the diameter growthis about 0. 54 centimetre and after that it increases and it reaches to 0.64 c. at the age of 70. Between two ages of 70 to 95 the growth has the highest rate and it's about 0.74 c. per year. Oak is one of the tallest trees in the forest and sometimes it's more than 40 metres high. The average height of oak trees in Noshahr is 27.3 and it's 20.84 metres in Gorgan. (Dargahi,1984). The rate of growing is in the highestamount in the first years and as the age of the tree increases ,the amount of height growinh decreses and it's the leastwhen it becomes old. The stand status was studied according to craft classification. In the stands that were investigated,53. 6 percent of the tree were in the highest storey, 24.6 percent were dominant and 21.8 percent of them were codminant. for studing the appearance quality of the stem, the tree divided in tree groups, 53.6 percent of the trees were good, 34.8 percent were medium and 11.6 percent has weak guality. (Bahri,1988).
Oak, the indegenious species of hyrcanian forest, consists the dominant tree of Oak-hornbeam (Qerceto-carpinetum) societies. The highest boundry of it's scattering in Noshahr is 1000 metres above sea level and 1800 m. in Gorgan. AS The height increases,the number per hrctar decreases. Oak has the most height growth and the least diametregrowthin the first ages and after getting to higher storeies in the stand and getting more light, the height growth decreases and the diametre growth increases. Because of placing the oak stand in low slopes of foothills that are suitable for livestock's grazing and harvesting without any rules in before, the natural appearance of the stands changed, the regeneration disturbed and the stands become open. Comparing two sites of Noshahr and Gorgan showed that Noshahr has a better sitoution according to its good climatic nd edaphic circumstances.
1 M. Sc. student
E-mail: [email protected]
Natural Resources Faculty of Tehran University
Po. B. :31585-4314
Fax: +982612227765