scholarly journals Gap characteristics under oriental beech forest development stages in Kelardasht forests, northern Iran

2018 ◽  
Vol 64 (No. 2) ◽  
pp. 59-65 ◽  
Author(s):  
Parhizkar Pejman ◽  
Hassani Majid ◽  
Hallaj Mohammad Hossein Sadeghzadeh
Keyword(s):  
Beech Forest ◽  
Gap Size ◽  
Beech Forests ◽  
Northern Iran ◽  
Development Stages ◽  
Oriental Beech ◽  
Significant Difference ◽  
Gap Characteristics ◽  
Three Stages ◽  
Diameter Classes

This study was carried out to evaluate gap characteristics and gapmakers for different development stages of an oriental beech forest in northern Iran. Development stages of 1 ha square-shaped mosaic patches were identified using 100 × 100 m sampling grid and all gaps within these mosaics were recorded. Gap areas were calculated and classified into four classes and gapmakers were counted and classified into 4 decay and 4 diameter classes as well. Results showed that gaps comprised 13.7, 9.1 and 17.6% of the study area in initial, optimal and decay stages, respectively. There was a significant difference between development stages with respect to gap size and the highest amount was observed in decay stage. Medium-sized gaps were the most frequent in all three stages. Frequency distribution of gapmakers varied among development stages. Our findings revealed that 200–500 m<sup>2</sup> is the most preferable gap size for close-to-nature silvicultural approaches in Hyrcanian beech forests. To achieve this gap size 1–2 trees should be marked for harvesting operations.

scholarly journals Distribution attributes of natural canopy gaps in the Hyrcanian mixed-oriental beech forests

2021 ◽  
Vol 67 (No. 8) ◽  
pp. 367-375
Author(s):  
Asadollah Mataji ◽  
Ali Asghar Vahedi
Keyword(s):  
Forest Ecosystems ◽  
Canopy Gaps ◽  
Size Class ◽  
Stand Dynamics ◽  
Natural Disturbances ◽  
Gap Size ◽  
Beech Forests ◽  
Northern Iran ◽  
Size Classes ◽  
Oriental Beech

One of the most important issues indicating the quality and quantity of forest ecosystems is the distribution of natural disturbances resulting in canopy gaps (CGs). The present study was conducted in one of the Hyrcanian beech forests in northern Iran in summer 2018. The gap areas were classified into small (&lt; 200 m<sup>2</sup>), medium (200‒500 m<sup>2</sup>) and large gaps (500–1 000 m<sup>2</sup>) on the basis of full inventory. The univariate Ripley’s L-function was used for introducing the CG spatial pattern. Furthermore, mark correlation function (MCF) and density function (DC) in turns were used for verifying the correlation and frequency of CG size classes in each pattern. The results showed patterns of the gaps in each size class and integrated by the three size classes, they were random and cluster, respectively. Furthermore, the MCF revealed that the gap size classes were independently located in the clusters. The total frequency of the small, medium and large gaps in turns was 32, 49 and 19%, respectively. Although the density share of medium and small gaps in turns was more frequent than the large gap density in the study forest, the results of DC indicated that the frequency of each gap size class was random within each cluster, regardless of their density share. Based on the natural gap aggregations, the base circular mosaic with an area of 5 000 m<sup>2</sup> can be introduced for monitoring and specifying the forest stand dynamics.

Patchiness in old-growth oriental beech forests across development stages at multiple neighborhood scales

2019 ◽  
Vol 138 (4) ◽  
pp. 739-752 ◽  
Author(s):  
Eric K. Zenner ◽  
JeriLynn E. Peck ◽  
Khosro Sagheb-Talebi
Keyword(s):  
Beech Forests ◽  
Old Growth ◽  
Development Stages ◽  
Oriental Beech

Regeneration process in natural uneven-aged Caspian beech forests of Iran (reviewed paper)

2005 ◽  
Vol 156 (12) ◽  
pp. 477-480 ◽  
Author(s):  
Khosro Sagheb-Talebi ◽  
Bahram Delfan Abazari ◽  
Manuchehr Namiranian
Keyword(s):  
Natural Regeneration ◽  
Mixed Forest ◽  
Regeneration Process ◽  
Gap Size ◽  
Beech Forests ◽  
Oriental Beech

Regeneration process was studied within twentytwo gaps produced from natural falling of trees in a semivirgin mixed forest of oriental beech in Iran. The area of the openings varied between 163 m2 and 1683 m2, caused by falling of 1 to 6 trees. Natural regeneration depended on the gap size, and was established within the openings with different compositions.

Gap characteristics in relation to forest structure and implications for southern beech forest dynamics

2003 ◽  
Vol 33 (10) ◽  
pp. 1915-1922 ◽  
Author(s):  
Jaime G Cuevas
Keyword(s):  
Seedling Growth ◽  
Forest Structure ◽  
Tree Height ◽  
Beech Forest ◽  
Stem Diameter ◽  
Tierra Del Fuego ◽  
Gap Size ◽  
Nothofagus Pumilio ◽  
Seedling Bank ◽  
Gap Characteristics

Gap characteristics, as well as forest structure, were investigated in Nothofagus pumilio (Poepp. et Endl.) Krasser stands on two slopes in Tierra del Fuego to test the following hypotheses: (i) there exists an altitudinal decline in tree height and stem diameter, (ii) this should result in gaps of decreasing size and abundance towards the upper forest, and (iii) this, in turn, should result in a longer suppressed growth of seedlings near the treeline (that is, an older seedling bank). Mean tree height on both slopes decreased significantly with increasing altitude from 21 to 11 m and from 13 to 8 m. Mean stem diameter declined with increasing altitude from 50 to 28 cm and from 19 to 16 cm, but this trend was only significant on one slope analyzed. Gap frequency declined with increased elevation from 33 to only 3 in 2-km transects. Mean gap size also decreased significantly with increased elevation from 91 to 11 m2. Mean seedling age varied with altitude, but the expected relationship was significant only when gap frequency was controlled. The best-fit model indicates a negative correlation between altitude and tree height and stem diameter, which are positively correlated and act indirectly on gap frequency via gap size. Although restrictions on seedling growth caused by small and infrequent gaps do not seem to be stronger at upper forest elevations, they may produce a bottleneck in the life cycle of the species in the long term. This phenomenon could be overcome either through faster seedling growth and higher survival at the treeline or through an episodic regeneration, as other research has documented previously.

Forest floor and soil properties in different development stages of Oriental beech forests

2020 ◽  
pp. 103823
Author(s):  
Yahya Kooch ◽  
Mohammad Kazem Parsapour ◽  
Markus Egli ◽  
Negar Moghimian
Keyword(s):  
Soil Properties ◽  
Forest Floor ◽  
Beech Forests ◽  
Development Stages ◽  
Oriental Beech

scholarly journals Walking Cadence during Moderate-Intensity Physical Activity in Pregnant Women

2021 ◽  
Vol 18 (12) ◽  
pp. 6593
Author(s):  
Mallory Marshall ◽  
Beth Birchfield ◽  
Rebecca Rogers ◽  
Joyeuse Senga ◽  
McKenna Persch ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Pregnant Women ◽  
Pearson Correlation ◽  
Current Data ◽  
Moderate Intensity ◽  
Metabolic Alterations ◽  
Moderate Intensity Physical Activity ◽  
Metabolic Equivalents ◽  
Significant Difference ◽  
Three Stages

Evidence has established that a cadence of 100 steps/min is indicative of the moderate intensity threshold of 3 metabolic equivalents (METs), but this has only been described in non-pregnant individuals. As metabolic alterations are well established during pregnancy, the purpose of this study was to determine if the walking cadence equivalent to 3 METs in pregnant women is similar to non-pregnant populations. Pregnant females (n = 29; age = 30.3 ± 3.2 years, gestational age = 23.9 ± 6.6 weeks) in their second or third trimester (>12 weeks gestation) completed three stages of treadmill walking for 5 min at different standardized walking speeds: 2.5, 3.0, and 3.5 miles per hour (mph). Oxygen consumption (VO2) and heart rate (HR) were measured each minute and METs were calculated for each stage. Real-time continuous monitoring of walking cadence was evaluated by an OptoGait gait analysis system. Following the three standardized speed stages, participants completed an additional stage walking at a speed that elicited 100 steps/min; VO2 and HR were also collected. A one-sample t-test was used to compare MET values at each stage to the heuristic 3 MET cutoff, and Pearson correlation coefficient was calculated to evaluate the relationship between cadence and METs. Mean cadence increased linearly across the three stages (2.5 mph = 103.7 ± 4.5, 3.0 mph = 112.5 ± 5.3, and 3.5 mph = 120.4 ± 6.2 steps/min), as did METs (2.5 mph = 2.7 ± 1.7, 3.0 mph = 3.2 ± 0.8, and 3.5 mph = 4.3 ± 1.8 METs) regardless of trimester. The average treadmill speed at which women walked at 100 steps/min was 2.4 ± 0.4 mph which elicited an oxygen consumption of 9.5 mL•kg−1•min−1, or 2.7 ± 0.7 METs. There was no significant difference between METs at 3.0 mph and the conventional 3 MET cut point for moderate-intensity PA (p < 0.05). There was a moderate and significant relationship between METs and cadence (2nd trimester: r = 0.51; 3rd trimester: r = 0.42). Current data indicate for the first time that the traditionally used 3 MET cutoff for moderate-intensity activity is appropriate for pregnant women despite metabolic alterations associated with pregnancy. This may have important implications for exercise prescription in pregnant populations.

Morphometric, genetic diversity and phylogenetic analysis of Taenia hydatigena (Pallas, 1766) larval stage in Iranian livestock

Parasitology ◽  
2019 ◽  
Vol 147 (2) ◽  
pp. 231-239
Author(s):  
Shahabeddin Sarvi ◽  
Laya Ebrahimi Behrestaghi ◽  
Abbas Alizadeh ◽  
Seyed Abdollah Hosseini ◽  
Shaban Gohardieh ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Larval Stage ◽  
Sequence Data ◽  
Genetic Difference ◽  
12S Rrna ◽  
Northern Iran ◽  
Taenia Hydatigena ◽  
Cysticercus Tenuicollis ◽  
Significant Difference ◽  
Cox 1

AbstractCysticercus tenuicollis as metacestode of Taenia hydatigena is the most prevalent taeniid species in livestock. Eighty-eight C. tenuicollis samples were collected from sheep (n = 44) and goats (n = 44) of the northern Iran from 2015 to 2016. The isolated parasites were characterized by morphometric keys. The DNA of the larval stage was extracted, amplified and sequenced targeting mitochondrial 12S rRNA and Cox 1 markers. A significant difference in larval rostellar hook length was observed in 12S rRNA haplotypes. Analysis of molecular variance of 12S rRNA indicated a moderate genetic diversity in the C. tenuicollis isolates. The pairwise sequence distance of C. tenuicollis showed an intra-species diversity of 0.3–0.5% and identity of 99.5–100%. Using the 12S rRNA sequence data we found a moderate genetic difference (Fst; 0.05421) in C. tenucollis isolates collected from livestock of the northern and southeastern regions of Iran. We concluded that the genetic variants of C. tenuicollis are being undoubtedly distributing mostly in different parts of Iran. Further studies with a larger number of T. hydatigena isolates collected from various intermediate and definitive hosts are needed to study this evolutionary assumption and also to determine the apparent genetic differences observed in the studied regions.

The impact of forest roads on understory plant diversity in temperate hornbeam-beech forests of Northern Iran

2017 ◽  
Vol 189 (8) ◽  
Author(s):  
Azade Deljouei ◽  
Ehsan Abdi ◽  
Matteo Marcantonio ◽  
Baris Majnounian ◽  
Valerio Amici ◽  
...  
Keyword(s):  
Plant Diversity ◽  
Beech Forests ◽  
Northern Iran ◽  
Forest Roads ◽  
Understory Plant ◽  
The Impact

Effect of a single bout of exercise and chronic exercise training on insulin sensitivity in racing sled dogs

2014 ◽  
Vol 10 (3) ◽  
pp. 167-172 ◽  
Author(s):  
S.E. Pratt-Phillips ◽  
R.J. Geor ◽  
M. Buser ◽  
A. Zirkle ◽  
A. Moore ◽  
...  
Keyword(s):  
Insulin Sensitivity ◽  
Exercise Training ◽  
Exercise Bout ◽  
Post Exercise ◽  
Exercise Challenge ◽  
Sled Dogs ◽  
Significant Difference ◽  
Single Bout ◽  
Three Stages

Two experiments were designed to investigate the role of exercise on insulin sensitivity (IS) in Alaskan racing sled dogs. In both experiments, IS was quantified with an isoglycemic-hyperinsulinemic clamp (IHC), whereby IS was defined as the glucose infusion rate (GIR) divided by the mean insulin concentration during the clamp. In Experiment 1, IS was quantified in 12 racing sled dogs during three stages of exercise training: unexercised for 4 months over the summer (deconditioned), and after two and four months of exercise conditioning. At each stage IS was assessed in unexercised dogs (n=6) and 60 h following a standard exercise challenge (n=6) consisting of a 35.4 km run completed in 2.5 h. In Experiment 2, IS was assessed in deconditioned dogs (n=6) and in well-conditioned dogs that had either completed a 708 km race 5-days prior (n=3) or were unraced for the previous month (n=3). In Experiment 1, there were no significant differences (Pã0.05) in GIR or IS between the three levels of conditioning, nor were there any effects of the exercise bout 60 h prior to the IHC. In Experiment 2 there was no significant difference in IS between well-conditioned dogs and untrained dogs (Pã0.05). However, dogs that completed a 708 km race 5-days prior to the IHC had a significantly higher IS than dogs that were deconditioned and those that were conditioned but unraced. These results suggest that the workload of an exercise challenge is a factor in post-exercise changes in IS but that exercise conditioning has little impact on IS in Alaskan sled dogs.

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