The aim of the study in the Loveh forest was to compare two cases of sampling with the sample plots of constant area (lO-are) and the sample plots of the variable area (Relascope) considering the parameters of statistical precision and the measuring required time. The quantities for the parameters such as measuring time, number in hectare and basal area in hectare have been compared with the quantities measured by the complete enemuration. The following results rave been obtained: The required time for the complete enemuration in the measured area (116 hectares) has been equal to 17842 minutes, in the case of sampling with the 10-are sample plots to 2879. 30 minutes, and in the case of sampling with the variable sample plots to 2433.9 minutes. The actual mean of the number in hectare (measured by complete enemuration) equals 323.8 and in two eases of sampling with sample plots of constant area and the sample plots of variable area is equal to 321.8 and 292.9 respectively which - in both cases - the confidence limit calculated for the parameters of the number in hectare involve the actual mean of the number in hectare. The actual mean of basal area in hectare is equal to 28.08 square meters and in the two cases of sampling is equal to 28.61 and 21.82 square meters respectively. In the case of sampling with the 10- are sample plots, the calculate confidence limit for the parameter of basal area in hectare involves the actual mean. However, in the case of sampling with the sample plots of the variable area, the above confidence limit doesn't involve the actual mean. Lack of precision measuring with the relascope in the Loveh forest can be seen in the intense understory of these forests by the bush and shrub species which prevent us from seeing to the diameter of the breast height. In addition, the topographical position of the area in some parts has prevented precise measuring by the relascope. Generally, the sampling with the sample plots of the constant area, compared with the two cases above mentioned sampling, has been closer to the reality and more suitable for the measuring of the forest.

This paper presents the results of an elimination trial with 9 spieces, varieties and provenances under rainfed condition six years after astablishment in Kheyroud forest area of Nowshahr Mazandaran (North of Iran).The altitude of area is 450 meters above sea level and has a cool and very humid climate with about 30 days dry seasons. The results of 6 years (1990 - 1995) studies showed that:- Seqouia sempervirens (seed collected from Nowshar nursery) was the most promissing species.- According to survival and growth rate following are primissing species respectively:Pinus taeda (origin D.S.A), Cryptomeria japonica (seed collected from Kelardasht nursery), Pinus nigra var. calabrica (origin south France).

In 1963, Norway spruce stand (Picea abies) stablished in Ladjim forest region (in the north of Iran). The afforestation was done with five years old seedling (with Yoguslavian origin) about 45 hectar area.In order to study the growth and yield of stand, final stage inventory was done as randomly systematic sampling with 20 percent intensity. Diameter and height's growth models were selected by analysis of quality and quantity data and other results of stand in 35 years old have shown as follow: 1- Volume increment is 4.5 m and also the current volume increment is 6.5 m. 2- Volume in pure area is 114 sylve and the best site it 150 sylve per hectar. 3- Height mean is 14.5 m and height increment is 42 cm. 4- The D.S.H. of stand is 17.5cm and the average of diameter increment is 5mm. 5- At present, number of lost trees is 75 percent of seedling.

A preliminary field trail was conducted in Karaj area in 1998 to examine the efficacy of some chemicals in preventing fire blight blossom, infections on pear trees. The bactericidal effects of these chemicals plus streptomycin as a check were performed on KB medium using replica plating method. streptomycin (200 ppm) and starner (300 ppm) with 23 & 14mm inhibition zones showed respectively the most protective activities against E. amylovora.In field trail, 12 years old pear trees (cv. Duchesse d'Angouleme) with heavy natural infections were pruned before treating with four chemical compounds i.e. Bordeaux mixture (1%), starner (300 ppm), aliette (3 g/l) and copper oxychloride (3 g/l). The reperiment was conducted in complete randomized blocks design with 3 blocks and 2 replications per treatment in each block. The trees were sprayed 4 times at 6-7 day intervals at different bloom phenology i.e. bud swollen stage, 5%, 50% bloom and full bloom. Two weeks after treatments, the number of diseased blossoms (strikes) per tree in all treatments including non-treated check were counted. The disease incidence (number of infected strikes/tree) was significantly reduced in all treatments as compared to non-treated control. There was no significant difference among the treatments at 5% level by DMRT. Yet starner with %46.3 disease reduction ranked first among the other four applied chemicals.

Ecological capabilities (environmental characteristics such as soil, slope and its direction, microclimate and elevation which shows potential of forest) of Iranian conifers forests were evaluated. As such, cypress "Cupressus sempervirens", forest sites in Hasan-Abad, Chalus and Zarringol, Gorgan were studied. For this evaluation trees distribution, natural regeneration and vegetation were considered.After obtaining the maps of slope, geographical aspect, elevation and soil, the ecosystem unit's maps were drawn. Inventory was performed in 2500m2 sample plots. For analysis of data, basal area, trees distribution in trunk diameter classes, number of trees per hectare, height curve, biodiversity indices and regeneration were prepared. The results show that Hasan-Abad cyprees forest is an unevenaged forest which has some problems in natural regeneration over the past 30 years. However, zarringol cypress forest has a good natural regeneration from the conservation point of view. Cypress is compatible with calcic soils but the sandy soil has not a suitable capability for this species. The best site situation for this species is north geographical aspect, with elevation less than 700m, low slope and soil deeper than 1m. On the contrary the worst situation for cypress is south geographical aspect, high slope, with shallow soil and elevation over than 700m.

In order to study the using of stratification inventory method for volume estimation in Kheyroodkenar forest, the cost and precision of systematic random sampling and stratification method were compared in Patom and Namkhaneh districts. First, the forest, based on crown density, was stratified on aerial photographs and then inventoried with systematic random sampling method. Also the time used in aerial photographs lab for stratifying the photos and in the field for measuring the sample plots were recorded. After stratification and measurement, the time-cost and precision of each method were calculated. The numeral values of precision2xTime -cost (E2%xT) were used to compare these two methods. The results showed that the stratification.