Investigation of spent caustic treatment processes in Bandar Abbas oil refinery
Subject Areas : natural resorces
Zeynab Pour-Gholi
1
(Ph.D. student of Forest silviculture and Ecology, University of Gorgan, Gorgan, Iran. *(Corresponding Author))
Sedigheh Gnaei
2
(Research in statute of forest and Rangeland,Agriculture Research, Eduction and Eextension Organization (AREEO),Tehran,Iran.)
Fariborz Irandoost
3
(Ph.D. student of Forest silviculture and Ecology, University of Gorgan, Gorgan, Iran.)
Kiomars Sefidi
4
(Research in statute of forest and Rangeland,Agriculture Research, Eduction and Eextension Organization (AREEO),Tehran,Iran.)
Khosro Sagheb-Talebi
5
(Associate Prof., Forest Research Division, Research Institute of Forests and Rangelands, Tehran.)
Farshad Keivan-Behjo
6
(Professor, Department of Forest Sciences and Engineering, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran.)
Keywords: Stand development, close to nature silviculture, diameter classes, Decay degree,
Abstract :
Background and Objective: Awareness of the stand conditions and the gradual replacement of tree species in developmental stages and phases provide appropriate information about silvicultural treatments, related to the close to nature silviculture. Present study due to the importance of study of dead trees in the forest, with the aim of the estimation quality and quantity of the amount of dead trees and tree mortality rate in the gap making phase was conducted in the evolution of less disturbed beech stands. Material and Methodology:To evaluate the tree mortality and quantitative and qualitative characteristics of dead trees in the gap making phase in the forests of Asalem, three sample plots of one hectare were selected and then some properties such as diameter, height of all standing and dead trees, as well as the decay stage of dead trees were recorded. After determining the type species, dead trees based on the decay degree of were classified in one of decay classes. Also dead trees were classified in four diameter classes small diameter, mid diameter, thick and very thick diameter. To investigate of mortality rate in the diameter classes was used from the proportion of dead trees to live trees in each diameter class. Findings: The results showed that the highest mortality rates in this phase are observable at diameter of 95 cm and at the diameter classes larger than 75 cm. The average number and volume of dead trees in all the three samples were 13 trees per hectare and 36.03 m3 per hectare, respectively. Also, 68 percent of dead trees were logs and 32 percent of them were snags. The average volumes of standing and fallen dead trees were 49.3 and 50.7 percent, respectively. Discussion and Conclusions: According to the presence of more than half of the dead trees was observed in the early decay degree in this development phase and tree mortality occur in this phase of large diameter class, that are caused gaps in the canopy of trees. Opening the canopy from falling dead trees is affecting factor in the establishment of seedlings and growing of forest seeds. So it is recommended results of this study to be used in select of trees in the selection method.
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