جستجوی مقالات مرتبط با کلیدواژه « direct seeding » در نشریات گروه « جنگلداری »

This research aimed at studying the seedling emergence and survival rate of Pistacia atlantica, Acer monspessulanum and Amygdalus orientalis by direct seeding in Dalab forests of Ilam with two aspects and five seeding positions (nurse type). For this purpose, six sites were selected in the north- and south-facing slopes with the same altitude. In each site, one transect was established perpendicular to the slope, and the seeding positions including “tree”, “shrub”, ‘bush”, “rock” and bare spaces, by observing three replicates were determined. At each seeding position, 12 holes were dug and the seeds of the mentioned species were planted. The number of seedlings during the spring and summer of 2018 and 2019 years was counted. According to the results, the number of seedling of P. atlantica decreased in the second year compared to the first year and in summer compared to spring. The highest percentage of holes with seedlings of P. atlantica was found in northern aspect and under tree crown and next to the rock. The highest percentage of holes with A. monspessulanum seedlings was under tree crowns and shrubs. A. orientalis did not react to any of the examined factors. The most and least share of the seedling emergence were belonged to P. atlantica and A. monspessulanum, repectively. It was concluded that the rate of seedling emergence changes under the effects of aspects and seeding positions, so to increase the emergence rate of seedlings, it is better to sow in the field in more suitable seeding position in any aspect.

In this study, the rate of seedling emergence from direct seeding of Brant`s oak (Quercus brantii Lindl.) and wild pistachio (Pistacia atlantica Desf.) in Dalab forests of Ilam in two altitude and five regeneration establishment positions during two years 2018-2019 was examined. For this, six sites were selected at an altitude of 1400 and 1550 m above sea level with the same aspects. In each site, a transect was implemented perpendicular to the slope, and on it regeneration establishment positions including “under tree crown”, “under shrub”, ‘under bushes”, “next to the rock” and bare spaces, observing three replicates were established. At each regeneration establishment position 12 holes were dug. In the dug holes, the seeds of the mentioned species were planted in the winter of 2017. The number of green holes and the number of emerged seedlings were counted during the spring and summer of 2018 and 2019 years. The results showed that the effect of sampling year, sampling season, altitude, regeneration establishment position and interaction effect of altitude and regeneration establishment position on the percentage of green holes is significant. The percentage of green holes decreased in the second year compared to the first year and in summer compared to spring. The highest percentage of seedling emergence was at lower altitudes and under tree crowns. The performance of Stones and bushes was better than shrubs which ranked after tree crowns. It was concluded that if seed sowing is done according to the natural pattern of regeneration, successful results can be hoped for.

Today, Zagros reforestation is more than ever felt due to human presence and its destructive activities. To do this requires observing the scientific principles of silviculture. Of essential restoration activities in these forests can be mentioned the seed planting of indigenous species within their range of development. In this regard, the present research was conducted with the aim of investigate the germination and emergence status of Quercus persica, Pistacia atlantica and Acer cineracens seeds planted in Dalab Ilam forests in 2018. For this, three sites on the northern slope and approximately the same height of 1380 to 1410 meters above sea level were selected. In each site, three trees were considered for each of Q. persica, P. atlantica and A. cineracens species. Under each tree, three holes were drilled between the trunk and the end of the crown for each crown side, and a total of 12 holes. In drilled holes under the trees, the corresponding seeds were planted in the winter 2017. The results of the sampling in the spring 2018 showed that the seeds of Q. persica had the highest emergence rates (22%). The seeds of P. atlantica gained the second rank in terms of germination and emergence (18%). The seeds of A. cineracens had the lowest amount of emergence (0.3%) and the number of emerged seedlings was rare. The highest occurrence rate of Q. persica seedlings was on the northern side of tree crown (32%) and in for P. atlantica was on the southern (32%) and western (30%) sides of the tree crown. The highest rate of seedling emergence of Q. persica (48%) and P. atlantica (51%) was found at nearest distance to tree trunk. Despite planting the seeds of these three tree species in the same conditions in terms of topography, position under the crown and distance from tree trunk, similar results were not obtained which the reason of this can be attributed to their seed characteristics such as seed size and seed vigor.

The present study was carried out with considering the problem of Quecus castaneifolia (C.A.Meyer) natural regeneration in Caspian forests and the key rule of light and vegetation competition (with dominant species of grass) in growth and establishment. For this target, homogenous, sound acorns were collected from a mature tree and directly sown in an open area of Caspian plain forest, Noor region (15 m a.s.l.). The experimental design was based on factorial and completely randomized blocks with cleaning treatment (weed removal, weed competition or control) and light treatment (full light and 40% shade). To make a shadow, the wooden network with 100 cm in height was applied. Results at the end of third growth season revealed that under weed competition, height growth, collar diameter and number of branches of Q. castaneifolia seedlings were significantly decreased but survival did not differ. With increasing light intensity, number of branch was significantly increased, but no significant difference obtained in survival rate, height growth and collar diameter growth. Survival did not decrease from 86.4% in competition with weed and from 90.6% in full light. It is deduced that growth and establishment of Q. castaneifolia in open areas, like in shaded places, has been successful. So, it can be suggested that direct seeding of Q. castaneifolia is a suitable method for restoration of degraded and non-regenerated areas in some lowland forests of northern Iran. In these conditions to reduce competition in early years it is better to use weeding practices around the seedling following direct seeding.