Iranian Journal of Forest and Poplar Research
Year:2007 | Volume:15 | Issue:2 (28)|Papers Count:14

In order to access the best seed planting methods of oak (Quercus castaneifolia) for the complementary regeneration, the seeds of Quercus castaneifolia were planted by six methods of natural seeding, strip seeding along with scraping, partial seeding, seeding by drill, without destroying the soil structure (by shovel), strip seeding and control plot was selected .10 kgs of oak seeds were planted in the plots (100 m²) in random complete block design by four replications. Some characteristics including the germinated seeds percentage, urvival percentage, height and collar growth of seedlings were measured.Results show that based on ANOVA table, there is a significant difference (1%) among germinated seeds percentage in various planting methods. With regard to the mean comparison test (Duncan) the partial seeding method by the 88.73% of the germinated seed was better than other methods. There was a significant difference (1%) between the survival percentages of germinated seed. The partial seeding with the 85.67% of germinated seeds had the most survival percentage. Investigation on height and collar growth of seedlings showed that there is a significant difference among the seedlings height growth in various planting methods, whereas no significant difference could observed for collar growth of seedlings. Therefore, the partial sowing is a successful method for artificial regeneration of Quercus castaneifolia.

This paper aimed to study the frequency distribution of tree number, basel area and volume in the uneven-aged oriental beech which are importent factors for determining of equilibrium state. For this purpose, six sample plots each covering one ha (100*100m) were established in different beech stands of Neka region in Mazandaran province at the Caspian forests. All trees with dbh more than 7.5cm were measured and the number of trees in the first diameter class (N10), as well as number of standing and marked trees for cutting was assesed. The results showed that the N10 of the plots varied between 7 and 74 per ha. The mean annual diameter increment calculated to 2.7mm. The basel area varied between 26 and 42.7 m2ha-1 , while the volume varied between 388 and 509 m3ha-1. A combination of datas showed that the equilibrium state would be expected, where the comulative basel area of the stand varies between 21 and 25 m2ha-1 with a least N10 of 120 ha-1. Considering the red rot, the target diameter for harvesting of trees could be fixed between 80 and 85cm.

In order to estimate deforestation rate consider in Chaharzebar forests, with 10035 ha area in 34 km South west of Kermanshah, we studied aerial photographs of years 1955 and 1990 with the scale 1: 50000. Results of two methods are shown as follow:1– Sampling through dotted lattice: by average within a 35 years period of time, the forest areas has declined by 6% and the relative surface of 602 ha shows 0.16% decline (17.2 ha per year)2– Drawing and separating the forest areas by photographs: the decline forest area in this 35 year period is 641.6 ha which is 18.33 ha annually by average. On the other hand the non- forest areas have been increased. Deforestation rate in this region within 35 years is totally 5.95% and 17% annually.

Populus euphratica Oliv. distributed naturally in vast regions of Iran. Also it is a native species in arid and semi arid of the country. Geographical and climatical differences in P. euphratica sites affect on the morphological and genetical differences among the tree populations. Peroxidase isoenzyme analysis from leaf extracts of P. euphratica using polyacrylamid gel electrophoresis was conducted to determine genetical characteristics and differentiate individuals in eleven natural populations. Results of peroxidase activity patterns in 110 trees from 11 provenances showed differences among individuals. Peroxidase banding pattern showed three zones of activity. Cluster analysis of data based on bands frequency for 11 provenances showed the existence of three distinct major groups, group 1: Sarakhs, Khojir and Dezful; group 2: Dashly-borun, Malavi, Hamidiyeh, Gotvand, Manjil and Mahneshan; group 3: Gherekhlar. Also there was more genetic distance between Sarkhs and Gherekhlar sites in eastern and northern zones respectively.

In this research, the qualitative and quantitative characteristics of Oak (Quercus castaneifolia), Nettle tree (Celtis australis) and Walnut (Juglans regia) were investigated in experimental plantation.Two-years old seedlings of species were planted in separated groups in 4×4 meter spacing as a part of a research project “Group plantation of industrial fast growing trees” at 1983. Diameter at breast height (dbh), total height, crown and trunk height were measured in 2005. The results indicated that survival in 23-years old trees of oak was 73.2% and for nettle tree and walnut were 97.1, 85.7 percent, respectively. Mean height of oak, nettle tree and walnut were 19.67, 11.48 and 15.96 m, repectively. The annual height increment of oak, nettle tree and walnut were 81.9, 47.9 and 66.5 cm, respectively. The mean dbh were 26.7, 11.2 and 17.9 cm for oak, nettle tree and walnut. The volume was 287.9 m3ha-1 for oak, 39.4 m3ha-1 for nettle and 128.6 m3ha-1 for walnut. Volume increment was calculated 12.5 m3ha-1y-1 for oak, 1.6 m3ha- 1y-1 for nettle tree and 5.36 m3ha-1y-1 for walnut.

Rooting and early growth of four poplar clones belonging to different species planted at plastic vases were examined after applying pre-rooting treatments combinations to dormant cuttings. Treatments included 3 cutting length (15, 20 and 25 cm) and soaking period (0, 2 and 4 days) that carried out in a randomized complete block design layout with 3 replications and investigated during spring of 2006. Significant differences in both rooting percentages and growth attributes were shown between clones after 12 weeks of growth. After the period we have measured height, leaf number, leaf weight, root length, root number, root weight, stem weight, total weight and percentage of root weight/ total weight as rooting success. The results indicated that cuttings planted without soaking had the lowest rooting success, at less than 12% on 4 days soaking. Cuttings planted with 15, 20 and 25 cm length have revealed 29, 42 and 35 percentages of rooting success, respectively. Cuttings planted with 0, 2 and 4 days soaking have shown 31, 32 and 43 percentages rooting, respectively. For optimal rooting of Populus caspica we recommend using 25 cm cuttings, soaked for 4 days in water, but for P. euphratica we suggest using 20 cm cuttings without soaking. Regarding the P. alba 58/57 we recommend using 25 cm cuttings and soaked for 4 days in water.

In order to determine the germination rate of Tilia platyphyllos Scop. seed an investigation was carried out in the open field of Natural Resources Faculty of Noor, Tarbiat Modares University (north of Iran). In 0.5 m 2 plots and under the shelter, the stratified seeds which were being germinated were sown in 1.5 and 3 cm soil depths and irrigated every day and every two days. The results revealed that contrary to sowing depth, irrigation affected the germination rate. Treatments combination of “Daily irrigation-3 cm sowing depth” and “two-day irrigation-1.5 cm sowing depth” produced the highest and the lowest germination rates, respectively. In each treatment combination, accumulative germination rate enhanced less than one week and did not change afterwards. Generally it can be stated that if for seedling production, Tilia platyphyllos stratified seed (with vernal sowing) is used, treatment combination of “daily irrigation-3 cm sowing depth” (together with shelter), compared to other treatments combination, will produce higher germination rate. This is while that a shelter ensures growing well. The better response can be achieved by earlier sowing (early spring) of germinating seeds. Next investigations will prove this important.

It is a fact that excessive traffic of machines on natural sources and agricultural fields increases soil compaction. The study of soil compaction requires determination of the stress state of soil. A transducer was designed to measure normal pressure in six predetermined directions. The pressure transducer composed of six sensing units and a core. The Data Acquisition System used in this research consists of a data logger, a printer and a recorder. The data collected were used to determine shear stresses which in turn can be utilized for calculation of soil stress state. The change in soil density due to the excessive traffic can be calculated by these data.

Slenderness coefficient of trees, defined as the ratio of total height to diameter at breast height (DBH), is frequently used as resistance index of trees to wind throw. By measuring DBH and total height of 1379 trees, the relationships between slenderness coefficients and trees DBH were investigated for five major tree species in a broadleaved Hyrcanian forests of Iran, Kheyroudkenar-Noshahr, including beech (Fagus orientalis Lipsky), hornbeam (Carpinus betulus L.), maple (Acer velutinum Boiss.), alder (Alnus subcordata C.A.M.) and oak (Qercus castaneifolia C.A.M.). Tree slenderness coefficients were found to be negatively correlated with DBH. The graphical results indicated that about 75% of the sampled trees had a slenderness coefficient lower than 80 and the range of variation is between 20 to 173. The most of difference among the slenderness coefficients of tree species were found in diameter class below 30 cm. Maximum slenderness coefficients observed in the valleys and northern aspects, while minimum in karstic phenomenons and southern aspects. No correlation was found between tree slenderness coefficients and stand density.

The decision on the tree scale constitutes smallest and the most concrete scale of decision in forest management. All decisions concerning of the forest trees (cut, selection of species, etc.) are often found on the basis of the technical and economic considerations. The tree economic model is a valuable tool which integrates all the economic considerations to help all decisions on the tree scale. The determination of the future value of the various species, the exploitation diameter and the amplitude of the damage to trees could be evaluated by the tree economic model. The tree economic model also makes it possible to study the effect of various factors (diameter, method and density of exploitation) on the tree future value. Moreover, as the stand is a whole of trees, the tree economic model could be transformed into a stand economic model. In spite of the importance of the tree economic model, there is only a little research on this topic. In this article, on basis of Faustmann economic model, a tree economic model is presented. In order to present certain examples of application of the proposed model, we used the necessary data from simulation of the corresponding models calibrated in the case of the beech in the North-East in France. This study shows that the optimal exploitation diameter of the good quality trees of the beech in the irregular stand with average productivity (7.5 m3/ha) is 70 cm. Moreover, the application of the model in the calculation of damage to a tree of 25 cm shows that the calculated damage is more than ten times higher (36 Euros) that its market value (3 Euros). Indeed, the damage to a future tree is higher than its market value because of his higher value at financial maturity.