Plant species in Oak (Quercus brantii Lindl.) understory and their relationship with physical and chemical properties of soil in different altitude classes in the Arghvan valley protected area, Iran

The present survey was carried out in Oak (Quercus brantii Lindl.) woodlands of Arghvan valley protected area, in Ilam province, western Iran. The main aim of this study was to survey the understory vegetation of oak in different classes of altitude (1400-1600, 1600-1800 and >1800 m) in the southern aspects, and their relationship with physical and chemical properties of soil. Four transects, with an interval of 200 m were selected from the lowest to the highest points of hillside. 25 individual oak trees were selected on and out of the transects as a plot center. The plot area was obtained using Whittaker’s nested plots and species / area curve. In order to find the relationship between soil properties and vegetation, and also to determine the most effective factors on the distribution of vegetation, multivariate procedures, i.e., Principal Component Analysis (PCA) and Canonical Correspondence Analysis (CCA) were used. Based on these analyses three groups were obtained. These groups exactly coordinated with our sample plots in altitudinal classes and had different soil and vegetation characteristics. The most important factors in the lowland group were pH, SP, OC, N,P and K, and those in the highland group were altitude, BD and stone percentage. The midland group was intermediate to these two groups, although its conditions were more similar to the highland group. The results also indicated a decrease in Shannon-Weiner and Margalef’s indices from lowland toward the highland

Determination of lime tree (Tilia begonifolia Stev.) stems form based on quantitative parameters (Study area: Shafaroud forests of Guilan province, Iran)

The lime tree is one of the rare and valuable species that found in the Hyrcanian moist forests with economic as well as ecological value. Identification of the quantitative and qualitative features of this species is important. In order to investigate the stem form of this species in the Shafaroud forests of Guilan Province, 141 lime trees in 39 plots were analyzed during the four stages of small pole, pole, saw-timber, and maturity. In each plot, stem-diameter at different heights was measured by using the Spiegel Relaskop. Measurements and analyses included diameter at breast height(d.b.h.) and total height. Same parameters was calculated: stem form factor based on diameter, stem form factor based on volume, form quotient, slenderness factor, ratio of stem height to total height, ratio of stem volume to total volume, correlation, and coefficient of determination to describe stem form factor. The results showed that the average stem form factor based on diameter was 0.554. The average stem form factor based on volume was 0.576, average form quotient was 2.32 and slenderness factor was 35.04%. The average ratio of stem height to total height was 82.45. In addition the results indicated a strong relationship between diameter at breast height and trunk coefficient. The ratio of stem volume to total volume revealed that 64.44 of lime volume is located in the bottom half of the trunk. The value of the parameters described here is towards a better description of stand characteristics. Obtained results indicating stability for natural lime tree in Iran

Floristic study of Dalab woodlands, north-east of Ilam province, west Iran

Abstract The present survey deals with the floristic study of Dalab Woodlands, located in Manesht and Ghelarang protected area, western Iran. It covers an area of 4335 ha. In total, 224 vascular plant species belonging to 46 families and 156 genera were identified. The largest families are Asteraceae (29 species), Fabaceae (23 species), Poaceae (22 species), and Apiaceae (18 species). Astragalus (13 species), Centaurea (9 species), Onosma (6 species), Bromus (5 species) and Amygdalus (3 species) are the most diverse genera of the region. The life form spectrum includes: hemichryptophytes (36.6 %), therophytes (33 %), cryptophytes (13.8 %), chamaephytes (8.9 %) and phanerophytes (7.6 %). From the chorological point of view, the largest proportion of the flora belongs to the Irano-Turanian (68.7 %) elements. About 22.32 % of the Dalab Woodlands species are endemic to Iran and six rare species including Alrawia bellii, Arum giganteum, Cousinia cylindracea, Echinops kotschyi, Thymbra spicata and Zeugandra iranica are also identified in this region