scholarly journals The study of parent-regeneration relationships for wild cherry (Prunus avium L.) in Hyrcanian forests

2021 ◽  
Vol 67 (No. 7) ◽  
pp. 328-337
Author(s):  
Bahman Kiani ◽  
Kiyan Yegandoost

The regeneration of forest trees is affected by the presence, dispersion pattern and specifications of parent trees. These effects were investigated and modelled in hardwood forests in the north of Iran. To do so, at first, fifty plots, each with a total area of 0.1 ha, were identified. Four subplots with a radius of two meters were then stabilized in each plot. The height and the root collar diameter of all the cherry seedlings were measured. Likewise, the diameter, basal area, and distance from the plot centre were appraised in the parent trees. The correlation and regression analyses were performed to evaluate the effects and to construct the models, respectively. The results showed that there was a positive and significant relationship between the presence, abundance, mean diameter, and total basal area of parent trees and the presence and abundance of seedlings. The logistic regression showed that the models based on the mean diameter of parent trees and abundance of parent trees could significantly predict the presence of regeneration. Only in 10% of the sample plots was the regeneration recorded without the presence of a parent tree.  Due to the small number of established seedlings, while maintaining the existing parent trees, especially large trees, it is necessary to consider the proper management methods to promote and protect their regeneration. We recommend completing the natural regeneration of wild cherry by artificial regeneration and creating well-dimensioned canopy gaps.

2019 ◽  
Vol 19 (3) ◽  
pp. 274-278 ◽  
Author(s):  
Saba Fakhrieh Asl ◽  
Mehrnaz Pourvahedi ◽  
Ali Mojtahedi ◽  
Mohammad Shenagari

Objective:Helicobacter pylori is a Gram-negative bacterium which has a serious effect on up to half of the world’s population and has been related to different gastric diseases. The goal of this study was to assess the frequency of babA, cagE and cagA genotypes among H. pylori strains isolated from gastric biopsies of endoscopic patients in the north of Iran.Methods:The present study was performed on 90 strains of H. pylori isolated from patients with gastric diseases (Gastric ulcer (GU), Duodenal ulcer (DU), Gastritis (G), Non-ulcer dyspepsia (NUD) and Gastric adenocarcinoma (GC)). DNA was extracted from all isolated strains and PCR method was performed to detect the prevalence of babA2, cagE and cagA genes using specific primers.Results:Among 90 samples of H. pylori, babA2, cagE, and cagA genes were detected in 42.2%, 30% and 82.2% of strains respectively. The statistical analysis showed that the prevalence of cagA gene in GU, G, DU, and NUD was significantly higher than other genes. Moreover, cagA, and babA2 genes were significantly more prevalent in GC patients compared to cagE gene. Our isolates exhibited 8 distinct arrangements of virulence patterns. The occurrence of cagA (35.6%) was the most prevalent pattern followed by cagA/babA2 (20%) and cagA/babA2/cagE (14.4%).Conclusion:In summary, as first report from Guilan province in the north of Iran, we showed significant association between the presence of babA2, cagE, and cagA genes in different types of gastric disorders.


Author(s):  
Beheshteh Haghparast-kenari ◽  
Tooran Nayeri ◽  
Shahabeddin Sarvi ◽  
Mohammad Taghi Rahimi ◽  
Ehsan Ahmadpour ◽  
...  

Background: Soil-transmitted parasites (STPs) are significant intestinal parasites that infect humans and animals and impose considerable burdens on human society and animal husbandry industries. Therefore, the present study aimed to determine the prevalence of parasitic elements of soil samples collected from the north of Iran. Methods: A total of 256 soil samples were collected from public parks, public places, vegetable gardens, sand heaps, and shadow areas near houses in the north of Iran and examined using the sucrose flotation method. Results: Out of 256 examined samples, 131 (51.2%) ones showed parasitic contamination including larvae (43%), oocysts (14.1%), and different eggs (6.6%). According to the results, the most and least common parasites observed in the samples were larvae (43%), as well as Toxascaris leonina, and Trichuris trichiura (0.4%), respectively. Moreover, the most and least contaminated locations were sand heaps (62.5%) and shadow areas near houses (45.6%), respectively. Regarding cities, Behshahr (68.3%) and Sari (67.5%) had the highest contaminated soil samples, whereas Chalus (37.5%) showed the lowest contamination. On the other hand, rural samples showed more contamination, compared to urban areas (P< 0.05). Conclusion: The findings of the present study indicate that the overall prevalence of STPs in examined areas and highly contaminated soil samples can be considered as a potential source of human contamination particularly tourists with STPs.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tassiana Maylla Fontoura Caron ◽  
Victor Juan Ulises Rodriguez Chuma ◽  
Alexander Arévalo Sandi ◽  
Darren Norris

AbstractDegraded Amazonian forests can take decades to recover and the ecological results of natural regeneration are still uncertain. Here we use field data collected across 15 lowland Amazon smallholder properties to examine the relationships between forest structure, mammal diversity, regrowth type, regrowth age, topography and hydrology. Forest structure was quantified together with mammal diversity in 30 paired regrowth-control plots. Forest regrowth stage was classified into three groups: late second-regrowth, early second-regrowth and abandoned pasture. Basal area in regrowth plots remained less than half that recorded in control plots even after 20–25 years. Although basal area did increase in sequence from pasture, early to late-regrowth plots, there was a significant decline in basal area of late-regrowth control plots associated with a decline in the proportion of large trees. Variation in different forest structure responses was explained by contrasting variables, with the proportion of small trees (DBH < 20 cm) most strongly explained by topography (altitude and slope) whereas the proportion of large trees (DBH > 60 cm) was explained by plot type (control vs. regrowth) and regrowth class. These findings support calls for increased efforts to actively conserve large trees to avoid retrogressive succession around edges of degraded Amazon forests.


2016 ◽  
Vol 12 (2) ◽  
pp. 117-124
Author(s):  
Judit Sárándi-Kovács ◽  
László Nagy ◽  
Ferenc Lakatos ◽  
György Sipos

Abstract During a regular survey of declining forests in 2011, sudden dieback symptoms were observed on scattered wild cherry trees (Prunus avium) in a mixed deciduous forest stand, located in the flood plain area of the Rába River, in northwest Hungary. In this study, we correlated both soil conditions and presence of Phytophthora spp. to dieback of cherry trees. Two Phytophthora species, P. polonica and P. plurivora, were isolated from the rhizosphere soil of the dying trees. By contrast, only P. polonica was recovered from the necrotic tissues of symptomatic roots. Stem and root inoculation tests on cherry seedlings showed pathogenicity of both species, although P. polonica proved to be more virulent. This is the first report of natural infections of P. polonica.


2007 ◽  
Vol 242 (2-3) ◽  
pp. 419-430 ◽  
Author(s):  
S.P. Vaughan ◽  
J.E. Cottrell ◽  
D.J. Moodley ◽  
T. Connolly ◽  
K. Russell

2005 ◽  
Vol 35 (3) ◽  
pp. 610-622 ◽  
Author(s):  
EH (Ted) Hogg ◽  
James P Brandt ◽  
B Kochtubajda

Trembling aspen (Populus tremuloides Michx.) is the most important deciduous tree in the North American boreal forest and is also the dominant tree in the aspen parkland zone along the northern edge of the Canadian prairies. Since the 1990s, observations of dieback and reduced growth of aspen forests have led to concerns about the potential impacts of climate change. To address these concerns, a regional-scale study (CIPHA) was established in 2000 that includes annual monitoring of forest health and productivity of 72 aspen stands across the western Canadian interior. Tree-ring analysis was conducted to determine the magnitude and cause of temporal variation in stand growth of aspen at the scale (1800 km × 500 km area) encompassed by this study. The results showed that during 1951–2000 the region's aspen forests underwent several cycles of reduced growth, notably between 1976 and 1981, when mean stand basal area increment decreased by about 50%. Most of the growth variation was explained by interannual variation in a climate moisture index in combination with insect defoliation. The results of the analysis indicate that a major collapse in aspen productivity likely occurred during the severe drought that affected much of the region during 2001–2003.


2010 ◽  
Vol 40 (12) ◽  
pp. 2427-2438 ◽  
Author(s):  
Md. Nurul Islam ◽  
Mikko Kurttila ◽  
Lauri Mehtätalo ◽  
Timo Pukkala

Errors in inventory data may lead to inoptimal decisions that ultimately result in financial losses for forest owners. We estimated the expected monetary losses resulting from data errors that are similar to errors in laser-based forest inventory. The mean loss was estimated for 67 stands by simulating 100 realizations of inventory data for each stand with errors that mimic those in airborne laser scanning (ALS) based inventory. These realizations were used as input data in stand management optimization, which maximized the present value of all future net incomes (NPV). The inoptimality loss was calculated as the difference between the NPV of the optimal solution and the true NPV of the solution obtained with erroneous input data. The results showed that the mean loss exceeded €300·ha–1 (US$425·ha–1) in 84% of the stands. On average, the losses increased with decreasing stand age and mean diameter. Furthermore, increasing errors in the basal area weighted mean diameter and basal area of spruce were found to significantly increase the loss. It has been discussed that improvements in the accuracy of ALS-based inventory could be financially justified.


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