جستجوی مقالات مرتبط با کلیدواژه « خشکه دار » در نشریات گروه « جنگلداری »

dead trees are one of the carbon pools in terrestrial ecosystems, which are one of the most important building components in forest areas. Measuring the amount of carbon storage in forest soil can be an important criterion and indicator in measuring the sustainability of an ecosystem. The aim of this study was to investigate the effect of dead trees on changes in soil carbon storage across an Altitudinal gradient of Qalajeh forest in Kermanshah province.

For this purpose, an area of Qalajeh forest with an altitude range of 1400-2100 meters above sea level was selected, the area was divided into seven altitudes classes with a difference of 100 meters. Then, at the level of each elevation class, one-hectare sample plots were implemented with three replications in order to estimate the amount of soil carbon storage in the areas containing the mentioned standing and fallen dead trees. In each sample plot, under the standing and fallen dead trees, healthy tree base and in the area without of tree cover (open space), each soil sample was taken from a depth of 0-20 cm.

The results showed that the amount of soil carbon storage in the dead trees areas (standing and fallen) was higher than the soil under healthy tree foundations as well as in the open area, and in general with increasing altitude soil carbon storage increased from sea level. So that the lowest amount of carbon storage (124 tons per hectare) was located in the altitude class of 1400-1500 and the highest (197 tons per hectare) was located in the altitude class of 2000-2100. Also, the results of correlation test showed that there is a significant positive correlation between the amount of soil carbon storage under the standing and fallen dead trees with altitude.

According to the results of this study, it can be said that in addition to their ecological functions, dead trees has an important role in soil carbon storage. Therefore, considering the importance and role of dead trees in relation to the amount of carbon storage and the process of its transfer to the soil layers, the process of harvesting and removal of these pools in these forests must be stopped and measures taken to This should also be considered.

Today, in near-to-nature forestry, biodiversity conservation, with emphasis on forests conservation, as a valuable genetic resource, has received much attention. Deadwood, as a habitat, plays a key role in diversity and abundance of saproxylic fungi in forest ecosystems. The uncontrolled exploitation, and the management programs applied in forests, have significantly reduced the deadwood volumes and diversity, jeopardizing diversity and abundance of saproxylic fungi. In this study, 29 saproxylic fungal species belonging to 15 families from the phylum Basidiomycota were collected from Asalem forest, Guilan province, northern Iran. The recovered species were identified based upon their morphological characters, using available identification keys. The results showed that the family Polyporaceae (31%) and the species Trametes versicolor (18.4%) have the highest abundance between other families and identified species, respectively. The importance of saproxylic fungi, introduction of deadwood, as a habitat and a key factor in biodiversity of saproxylic fungi in forest ecosystems, have also been discussed.

The impact of logging and tree harvesting on the ecological function and the future of Hyrcanian forests structure is a continuing debate topic. The information is currently available does not support firm conclusions about the impact of forest harvest intensity on forest structure and biomass. The present study aims to evaluate the effect of single-tree selection harvest intensity on biomass of hornbeam-Persian ironwood stand. For this purpose, information on all trees and dead trees were collected in 70 half-hectare plots. The 35 sample plots were in single-tree selection stands with three harvest intensities and the same sample plots were in control stand. Trees litter fall were measures from September to February and the storage of soil organic carbon was determined through organic carbon and bulk density. Then, tree biomass, litter biomass, dead tree biomass and total biomass were finally calculated. The results showed with increasing the rate of harvest intensity up to 13.5% the total biomass had rising trends, although harvest intensity had no significant effect on aboveground and belowground biomass and soil organic carbon. The aboveground biomass was higher in single-tree selection stand than control stand. The average of total biomass was 147 and 144 ton/ha in harvest and control hornbeam-Persian ironwood stands respectively and harvesting increased two percent of mean total biomass. The medium harvest intensity (3.6-9.5% of stand volume) was finally determined as appropriate selective logging intensity. The correspondence of litter biomass and dead tree biomass as bio indicator indicated that tree marking in the single-tree selection system was advisable.

In this study, a habitat of wild cherry (111 ha) in Mamji-Darasii in the province of East Azerbaijan, the city of Kalibar, was fully inventoried and all wild cherry trees were then counted and measured. Frequency of cherry regenerations was also calculated by establishing 23 0.1 ha ample plots. The results showed that 86.6% of the cherry trees were healthy and vital and their mean height, diameter at breast height and volume were 9.3 m, 12.6 cm and 0.08 m3, respectively. The highest and lowest frequencies were 10 and 25 cm DBH classes, respectively . Density, basal area and volume of cherry trees in stand level were calculated as 2.14 individual.ha-1, 0.032 m2.ha-1 and 0.17 m3.ha-1, respectively. There was no significant correlation between the quantitative characteristics of trees and slope but diameter, height and basal area of the cherry trees decreased with increasing the altitude. Most of the trees (62%) were found on the northeast-facing slopes. The trees were taller in the northeast directions and in terms of diameter, basal area and volume, trees in the eastern aspects had higher dimensions. A total of 53 dead trees were counted, of which 43 were standing and 10 fallen. They constituted 18.2% of total cherry trees. The regeneration rate of cherries was 36.1 individual.ha-1. The highest abundance of trees belonged to the hornbeam followed by oak Wild cherry with 3% abundance was in fourth place. To enhance and increase the density of wild cherries, slight opening of the canopy is necessary using appropriate silvicultural operations.

This research was carried out in an unmanaged (934) and a managed (923) comportments of the Shafaroud region of northern old- growth beech forests of Iran. Gap characteristics such as gap area, gap fraction, gap frequency per hectare, DBH of gapmakers, frequency of gapmakers per gap and decay class of gapmakers were measured. Results showed that gap fraction of managed and unmanaged gaps were 13.5% and 9.06%, respectively. There were significant differences in frequency distributions of gap areas, DBH and gapmaker per gap between two study sites. Spatial pattern of gaps was random for both areas in 25m radius and beyond this distance aggregate pattern was determined. Based on this research, decrease of number of gap per hectare and increase of dead wood frequency and volume should be implemented in the next management practices.

Forest decline is an important and complicated phenomenon that happened in most world oak forests. This research aims at the determination of mortality rate, the volume of deadwood, and also the designation of the ecological factor affecting these mentioned parameters in Tange Alamdar, Behbahan. To do so, a 50 hectares oak forest was selected and 30 systematic randomized sample plots (25 Are) were established in this site. Within each sample plot, mortality rate, deadwood volume in different classes (coarse and fine dead wood), slope, elevation, landform, and terrain shape indexes, and aspect were recorded. Pearson’s correlation coefficient and one-way ANOVA were used for data analysis. The result indicated that standing dead tree, fallen dead tree, and fine woody debris volume were 7.01, 15.21, and 0.039 m3 ha-1, respectively. Persian oak mortality rate in the studied site was 57 percent and the highest rate belonged to the 10-15 cm d.b.h class. The high rate of mortality had no correlation with elevation and aspect. Also, deadwood volume and number in the different studied groups had no significant correlation with physiographical features. A high level of mortality rate in all of the diameter classes might imply that mortality is not the result of aging but some kind of disturbances. One of the possible reasons for low fine woody debris volume could be related to human disturbances. Overall, reforestation should be considered in the studied site to decrease the mortality rate.

The aim was to investigate the relationship between macrofauna biodiversity with quality or decay grade of beech logs deadwood and some environmental factors in the East Hyrcanian forests. 108 fallen beech dead woods have been selected for this purpose that have appropriate frequency in four decay classes, three diameter classes from 10 to 100 cm and three classes of altitude above sea level from 250 to 900 m. The macro fauna samples were collected in the field under dead wood skin and inside wood with a knife and hand sorting. The total macro fauna observed belonging to 7 classes, 10 orders and 27 families. The results showed that two orders Coleoptera and Geophilomorpha, two families Lumbricidae and Arionidae and two genus Julus and Octotemnus had the highest and lowest macro fauna frequency respectively. Richness and diversity of macro fauna have decreased with increasing altitude above sea level. Dominance indices were decreased with increasing the dead wood quality (decay stage class) while richness and diversity were increased. Slope and elevation, were introduced as the most important environmental factors that controlled macro fauna biodiversity of fallen beech dead wood.

Deadwood is widely recog­nized as an extremely important structural and functional component of forest communities. Therefore, understanding its role and dynamics are important to improve forest management strategies in both managed and unmanaged forests. The aim of this study was to analyze the qualitative and quantitative characteristics of dead trees in the mid-succession stage in intact mixed oriental beech (Fagus orientalis Lipsky) forests of Kheyrood,, Mazandaran province. Three one-ha sample plots were laid out in compartment 310 of Gorazbon district, in which a number of quantitative (diameter at breast height≥7.5cm and height) and qualitative (species, type of deadwood (log or snag) and decay class) characteristics were recorded. Our results indicated the mean volume of deadwood of 37.8 m3 ha-1. In addition, common hornbeam (Carpinus betulus L.) possessed the highest frequency (64%) of the deadwood among the species. The frequency and volume proportions of logs were 74.7% and 69.3%, respectively, and the maximum amount of deadwood was observed in the large timber size (50-75 cm). As conclusion, forest management planning should pass an adequate attention to succession stage and the amount of deadwood to guarantee the health, long lasting productivity and sustainability of forest ecosystem.

A permanent sample plot with an area of 6 ha is located on mid elevation of the Neka-Zalemrood forest, south of Sari in northern Iran. After fencing the plot, a metal tag indicating tree number was installed on each tree. A full calipering was conducted, which was followed by measuring the diameter at breast height (DBH) and height of selected trees. Forest structure, proportion of dead wood, and proportion of tree species were studied for a period between 2006 and 2012. Results of the inventory of the total 2375 trees in 2012 showed three storeys and an uneven-aged structure in Fagus orientalis-Carpinus betulus forest type. Further results included mean tree number of 389 ha-1, mean basal area of 43 m2ha-1, mean stand volume of 538 m3ha-1, and De' Liocourt factor of 1.38. Dead trees accounted for 3.1% of the total tree number and 5.7% of the stand volume. Comparison between the two inventories (2006 and 2012) showed that beech trees gained a higher proportion among the tree species in almost all diameter classes, while hornbeam lost more of its presence in the diameter classes. Amongst the DBH classes

The establishment and survival of seedlings is one of the main objectives of forest management which ensures continues production. The aim of this article is the investigation of dead trees effect on beech and hornbeam seedlings in Masal's forests. For this reason, 30 dead trees were selected, and the control trees were selected in four aspects around the dead trees. They were the same as dead trees in terms of species and diameter. In general, 30 and 120 sampling plots were taken around dead trees and control trees, in respectively. The quantity and quality (crown equality, multi trucks and verticality) of seedlings were recorded. In addition, the volume of dead trees were assessed by measuring their diameter and height, and also their decay classes were investigated. According to the results, abundance of seedlings doesnt significantly differ among decay and canopy coverage classes, whereas dead tree's diameter classes significantly effect on seedlings abundance. The forked seedlings were significantly higher than other forms of stem growth. Abundance of seedlings, in terms of quantity and quality (the forked) around the dead trees, showed significant differences with control trees. Based on the finding of this research and the overall impact of dead trees on regeneration, it is recommended that large dead trees be considered as a seedbed in the management of natural regeneration in the forest stands.

Understanding and our knowledge about mixed beech stands development play key role in managing forest stand in the close to nature ways. There are differences in amount and quality of coarse woody debris reported from beech stands in the north of Iran. This research try to answer this questions: how amount and quality of coarse woody debris affected by stand development stages? So 30 one hectare sampling plots randomly were chosen in main three stand developmental stages and all coarse woody debris had been measured. Results showed that the volume of CWD followed the general “U-shaped” temporal trend: the highest in the Volume transition stage (42.2 m3 ha-1), lowest in the volume accumulation (12.8 m3 ha-1) and intermediate in the Volume growing up stage (27.8 m3 ha-1). Amount of oriental beech coarse woody debris was (log, snag and stump) significantly higher in three stages. Amount of beech volume, logs, size class III and decay class I and IV significantly differ among the three stages. Our results revealed that stand development have effect on the distribution of CWD among three stages.

Knowledge of the stand condition and the gradual replacement of tree species in different development stages and phases provide appropriate information related to the close to nature treatments. Stem exclusion phase is one of the important development phases in the forest stands development. The aim of study was to analyze the characteristics of dead trees in the stem exclusion phase in the less disturbed forests of Kheyrood, northern Iran. Three sample plots were laid out in this stem exclusion phase and some properties such as diameter, height of all standing and dead trees, as well as the decay stage of dead trees were recorded. Results showed the maximum amount of mortality was observed in the 10 cm diameter class (N = 125). The proportion of snags was 39% while 61% of dead trees were recorded as log. The average volumes of standing and fallen dead trees were 31 and 69 percent, respectively. Oriental beech as dominant tree species made up 47.2 % of decaying trees following by hornbeam (36.1%) has a significant contribution in dead wood pool in this phase. Results of comparing trees mortality showed form, size, and decay class of dead trees were significantly different and the most of the dead trees was observed in the early decay stage, in small diameter class, and in form of snag. Determining of the mortality rate and the quality and quantity of dead trees in this phase of the forest stands development can be applied as guidance in forest tending interventions..

Deadwood is commonly known as an essential structural and functional element in forest communities. Thus it is important to understand its role and natural dynamics to improve the forest management strategies in both managed and unmanaged forests. This study analyzed both qualitative and quantitative characteristics of deadwoods asindicatorsof stand developmental stages in the unmanaged forests of Kheiroud in Mazandaran province, northern Iran. Three sample plots were established in the initial, optimal and decay stages, in which attributes such as diameter at breast height, height of all standing and dead trees as well as the decomposition stage of dead trees were recorded. Results showed differencesin the amount of deadwood per ha as well as in volume, type andsizeofthe coarse woody debris (CWD) in all the three stages. The frequency of snags was higher than logs in initial and decay stages, whereasthe proportion of logs was greater than snags in the optimal stage. Moreover, maximum and minimum volume ofthe CWD was observed in the initial and optimal stages. Amongst the species, beech returned the highest number and volume of deadwood in all three stages. In addition, the entire deadwood showed diameter

The purpose of this study was to investigate and analyze quantitative and qualitative amount of dead wood in a natural untouched Fagus oreientalis forest of permanent research plot of Shast klateh by 16 ha. For this purpose all the standing and fallen dead woods، based on species and the degree of decay، with a diameter higher than 7. 5 cm، were measured. The results of this study showed that the mean diameter at breast height، soil، the number and volume of standing live trees per acre in that certain Forest stand were 39. 5 cm، 33. 2 m، 287 m and 472 of the base respectively. While the mean diameter، number and volume per acre of total dead wood were 49. 5 cm، 27. 7 dead woods and 45. 4m3. ha، respectively. Hornbeam with 58. 2% was of the maximum N/ha dead wood (standing and fallen)، while beech with 61. 2 was of the highest volume having dead wood. The results also showed that less than 30 cm diameter class with 16. 9N. ha allocated highest contribution and diameter class (70-55 cm) with a 2. 75 allocated minimum number of dead wood. In the case of volume per hectare dead wood، diameter classes greater than 75 and less than 30cm، with 32. 5 and 1. 8 have comprised maximum and minimum V. ha، respectively. 61. 5% of the total N/ha of dead woods included fallen dead wood and 28. 5% was standing dead wood. Fallen dead wood with 35. 7m3. ha (about 78. 7%) of the total amount of dead wood allocated to itself. The overall results of the study showed that dead wood allocated about 9 percent of the number and volume per hectare of live and standing stand.

Due to their significance for carbon sequestration and ecosystem management، information on decay dynamic of deadwood and its total decay time are of great importance to ecologists and forest managers. This study was conducted in Kheirud forest of Nowshahr to study the decay process of beech and hornbeam deadwood. Therefore، 72 beech and hornbeam dead trees were randomly selected. For each sample tree، information on species، diameter، decay classes and slope gradient were recorded. The cubic cut samples with 5 cm length، width and height in two perpendicular aspects were taken from each decaying stump. 30 and 16 years of decaying time were shown to be needed for 95% dry mass of dead beech and hornbeam logs، respectively. In addition، the required periods for passing through all stages of decay for beech and hornbeam dead trees were 27 and 21 years، respectively. A strong relation (R2=0. 8) between density and decay stage of dead trees was indicated. Therefore، the density of dead wood was concluded to significantly decline with increased decay stage in both species.

Awareness of the impact of forest various management methods on forest regeneration is necessary for forest maintenance and sustainable development. Gaps occurs in the forest canopy when trees dry out and die. Canopy gaps have great importance in forest ecosystems and increase the forest biodiversity by establishment of new species and development of natural scenery. This study aimed to investigate the effect of canopy gaps size and dead trees on natural regeneration in control compartment of the Experimental Forest Station of Tarbiat Modares University (Aghozchal district). Therefore، after an initial forest survey and determination of canopy gaps location، plots of 400m2 were sampled in the canopy gaps and adjacent to the existing dead trees and seedlings in the plots were studied in two separate parts: short (50cm height) seedlings. Also، species، number of dead trees، quality status (decay class) and destruction status of canopy gaps were recorded. The results showed that maximum and minimum number of dead trees based on the size of canopy gap was in very large group and small group respectively، and based on decay class is related to class 2 and 4. Logs become much more frequent than snags and the highest and lowest frequency of logs was beech and alder respectively and in contrast، for snags was alder and beech respectively. In comparison with other species، beech has the highest frequency in both parts of natural regeneration. Thus the presence of dead trees in the forest has a significant impact on the natural regeneration and forest biodiversity، high attention should be given for the important role of dead wood in order to achieve forest sustainability.

The permanent plot, with 6.1 ha area, is located on mid-elevation of Hyrcanian forests at district 3 of Section 5 in Neka-Zalem Roud forest project. After fencing the border of the area, a metal number tag was installed on each tree. The full census inventory method performed and in each diameter class, ten trees were measured for preparing of tree height curves. Tree frequency in height classes (or crown layers) was obtained in the basis of: the diameter classes in each height stage, tree frequency in diameter classes and relationship between tree diameter and height. Forest structure, dead trees (snag and log) and damaged trees (hollow and broken), and rate of them within the stand were analyzed. Results showed that the stand consists of uneven-aged Beech-Hornbeam (Fagus orientalis-Carpinus betulus) with three layers. De Liocourt factor of stand is 1.27; diameter and height regression is fitted with S form model. The ratio of Beech height increment is higher in ages before reaching to 45 cm dbh. Hornbeam trees have higher height increment speed in younger stages in competition to beech. Damaged trees contain 10 percent of the stand volume, of which one-third is hollow trees, one- third broken trees and the rest are snag and log.