Fire in the Zagros forests disturbs some parts of these forests every year. Manna oak species (Quercus brantii) as the main species of these forests is stimulated by fire. In order to investigate post-fire resprouting of Quercus brantii, 133 sprout clumps were selected randomly in a burnt area of the Zagros forests in Kermanshah province. Some variables were recorded and classified as follows: dbh of the thickest sprouts in 4 classes, number of pre-fire sprouts in 5 classes, fire intensity in 5 classes and the number of post-fire sprouts. This study was conducted under completely randomized design with three replications for each class. Results showed that post-fire resprouting is positively related to the number of pre-fire sprouts and the fire intensity, whereas it is negatively related to the diameter of the thickest sprout. In general, the more pre-fire sprouts and more fire intensity as well as the smaller diameter size of pre-fire sprouts, would cause more post-fire sprouting in manna oak.

Determination of the sprouting potential of the Quercus brantii, the relationship between the shoots variables with the stump diameter and the number of shoots in each stool are the objectives of this study. For these purposes, a total of 93 stumps in the coppicing stands in Chaharmahal and Bakhtiari Province were selected in a growth period of personal protection. The logistic model was used to determine the potential for sprouting with age and stump diameter variables. The relationship between the shoots variables with a different model (linear and non-linear) was investigated. The results of the logistic model showed that a model including the stump diameter is the appropriate model for determining the potential of sprouting. The polynomial model in terms of model selection criteria among other models showed better results for estimating the three variable include dominant heights, mean height and number of shoots in each stool. The highest coefficient of determination (R²adj = 0.639) and the best result for the selection criteria of the model were the numbers of shoots per stool with the stump diameter. The results of ANOVA analysis showed that there were significant differences between different diameter classes. There is no significant difference between 5-25 cm and 25-55 cm diameters classes.

The aim of this study was to investigate morphological diversity and canonical correlation analysis between four environmental variables (altitude, slope, latitude, longitude) and 10 plant characteristics (collar diameter, number of sprouts, diameter at breast height, main stem height, large crown diameter, small crown diameter, leaf length, leaf width, leaflet length) in sumac (Rhus coriaria L.). Plant samples were selected from five geographical locations with unique features in two provinces of East and West Azarbaijan. According to the results of descriptive statistics, the highest coefficients of variations were observed for diameter at breast height (61%), number of sprouts (52%), collar diameter (40%) and the lowest one was observed for leaf width (21%). The highest sprout was found in the plants sampled from Nizhdarreh that can be due to its bad growth conditions. Canonical correlation analysis revealed that with increasing the amounts of latitude and reducing the amounts of slope and longitude, the length of leaves increases.

This study was carried out to understand the dynamics of Lebanon oak coppice regeneration. In this regard, the effect of thinning on both individual sprouts and stools as well as estimation of sprout biomass using allometric equation were investigated. 45 Lebanon oak trees with different sizes (i.e. DBH from 25 to 65< cm) in five sites were cut and individual stumps were fenced to monitor the sprouting behavior. In the second year after the cutting, light (six sprouts reserved in each stool) and heavy thinning (three sprouts reserved in each stool) were conducted in two third of stools equally and the rest un-thinned ones were considered as control. Data analysis, five years after thinning, showed that the most portion of individual biomass allocated to main stem (57.4%), main branches, leafs and fine branches, respectively. On average 42% of total fresh mass of sprouts were reduced due to water loss in drying process. Analysis of variance indicated that stump size has no significant effect on biomass of individual sprout either stools while it was significantly different among sites. Comparison of thinning treatments and control one showed that light thinning resulted in sprouts with the most biomass while no significant difference was observed between heavy thinning and un-thinned. Using a basic power model, allometric equation was fitted to estimate the sprout biomass. Based on regression analysis as well as derived indicators (R2, STDEV, RMSE, rRMSE and nRMSE) and models validation by leave one-out method, the collar diameter was found as the best explanatory variable in young sprouts biomass.

This study was carried out in order to compare the number of produced sprouts in Lebanon oak (Quercus libani Oliv.) tree after cutting among dbh classes in northern Zagros forests. 3 dbh classes including 25-35, 35-45 and >45 cm were compared in respect of number of produced sprouts. 5 sites in Armardeh forests were selected and results of study analyzed by random complete block design. 3 Lebanon oak trees were cut in each diameter class and in each block. The 45 cut trees were fenced in early spring 2007 individually. Data were collected two times in June and September. Results showed that 35-45 cm dbh class had the most number of sprouts (with 101 and 81 sprouts in June and September, respectively). Number of sprouts in 35-45 cm dbh class was significantly different from others in September, while no significant difference was found in number of sprouts between June and September. Mortality rate of sprout among dbh classes was not significantly different. However, linear regression trend between number of June sprout and died sprouts until September showed that mortality increased when number of June sprout increased. Since sprouting depend on positive and negative effects of stump size, balance point of these effects was introduced as optimum diameter for sprouting, which was between 35-45 cm dbh range in this study. Future investigations should be focused on finding the balance point (or range), more precisely.

In recent years dieback and decline of oak trees in Zagros forests as an important environmental issue was raised and in many areas has been destroyed trees. In this regard, in order to provide operational strategy to manage this problem and use of the resprouting ability of oak trees. Four hectares of Brant`s oak (Quercus brantii Lindl.) stands in Dasht-e Barm basin of Kazeroon, Fars province, were selected and the improvement cuttings were done. Sample trees were studied based on factorial experiment in a completely randomized design. The first treatment was stump diameter (less than 15, 15-30, and more than 30 cm) and the second treatment was dieback level of crown (full dieback and mid-dieback). Sample trees were cut during the winter of the first year of the study. Resprouting ability, height and diameter growth of sprouts and their survival were recorded every year. The results showed that 82% of the stumps produced sprout. There was no significant difference between diameter and height growth of the sprouts among diameter classes, dieback classes and their interaction classes. Based on the results, cutting of declined oaks in damaged areas (especially before crown full dieback) is one of the most important strategies for survival of oak trees.

Reforestation in arid and semi-arid region of Iran started in 1959, regarding rehabilitation of desert region. These activities developed due to success of reforestation. Parallel to the development of planted seedlings in the areas, drought in the leaves and branches was appeared. This research aimed to identify the best pruning time in order to prevent regeneration and shooting and lead to an optimal density of Haloxylon persicum in Abardezh, Varamin, Tehran province. Random systematic method was used to select seven transects of 8700 m length with 250 m distance. Total numbers of 210 trees (30 trees on each transect) were selected. A period of seven months (treatment) starting from February 2011 to August 2011 were used for pruning. The height and diameter of all samples were measured before cutting. Then they were examined again after four months and the existence of new shoots were recorded. The result of Chi- squared test showed statistically significant difference in treatments at 95% confidence interval. The Dunnett test further showed no significant difference between treatment of July and August. They were categorized in one group; the remaining treatments of February, March, April, May and June were grouped in second category. Study results imply that the best time for pruning of H. persicum in study is July and August.