A preliminary study on in-stream large woody debris in broadleaved and Korean pine forest in Changbai Mountain, Northeast China

This study was conducted in Erdaobaihe River passing through the broadleaved and Korean pine forest located on the north slope of Changbai Mountain. In-stream large woody debris (LWD) in two segments of the river channel was investigated with base diameter, top diameter, length, and decay class. To study relationship between in-stream LWD and adjacent riparian forest, species of each log of LWD in segment 1 was identified, and the riparian forest was examined by setting a 32m?4 m quadrat consisting of twelve 8m?m small quadrats. The results showed that, in segment 1, in-stream LWD loading was 1.733 m3/100m or 10.83 m3hm-2, and in segment 2, it was 1.709m3/100m or 21.36 m3hm-2. In-stream LWD in decay class III and IV were accounted for a high proportion, which was different from that in the broadleaved and Korean pine forest, and the possible reason might be different decomposing velocities due to different decomposing conditions. Logs of LWD in stream and living trees in riparian forest declined as diameter increased, and it was in a reverse J-shaped distribution except logs of LWD in segment 1 in the first diameter class. Volumes of LWD in stream and living trees in riparian forest increased as diameter increased, and it was in a typical J-shaped distribution. Loading and species component of in-stream LWD were correlative to status of riparian forest to a certain extent, and there also existed difference. Comparing the correlation and difference was helpful to study on dynamic of the riparian forest.

Optimum Insecticide Doses Determination of Seed Oil of Three Botanicals Jatropha Curcas L., Helianthus Annus L. and Cocos Nucifera L. against Maize Weevil Sitophilus Zeamais Mots.

The insecticidal effect of four dosage rates of three botanicals namely Jatropha curcas, Heliathus annus and Cocos nucifera was tested on the maize weevil Sitophilus zeamais Mots.. This is done for the purpose of finding a replacement for conventional insecticides which has been found to be harmful to man. The seed oil was applied topically at the rate of 0.1, 0.2, 0.3 and 0.4 mL per insect. There were a total of 20 insects per Petri-dish. There were four replicates per treatment. Insect mortality was recorded on 12 hourly basis for 48 hours. The results of insects treated with all dosage rates of C. nucifera showed a significantly higher mortality when compared with the control. In the case ofH. annus, insect mortality ranged from 40-100, 70-100, 60-100 and 80-100% and for J. curcas the result ranged from 0.0-100, 40-100, 80-100 and 80-100% for rates of 0.1, 0.2, 0.3 and 0.4 mL, respectively, from 12 hrs to 48 hrs post application. The control experiment remained at 0% level throughout the period of the experiments.

Effect of Cement Dust Pollution on the Yield and Quality of Ficuscarica L. Fruits

The present study was carried out on Ficuscarica L. cultivated in the northwestern desert of Egypt. Plant materials （leaves and fruits） were collected from three polluted locations at a distance of 500-700, 1,000-1,250 and 3,000-3,500 m respectively away from the cement factory at EI-Hammam city, and a location of relatively clean air considered a control at 5,000-6,000 m away from this factory. The deposit cement dust washed from the surface leaf area of plant study was found to be 4.96, 4.21, 0.51 and 0.29 lag/cm2 at the four locations, respectively. Cement in more polluted locations increased mortality of young branches leading to a reduction in the height and yield of fig trees. The deposition of cement pollutants tothe loamy sandy soil of the present study alteredsoil chemical characteristics. The results showed that, biomass of fruits/tree, number of branches/tree and number of fruits/branch in polluted locations were significantly lower than those of the control one. Cement dust decreased leaf total chlorophyll content leading to a reduction in the economic yield （up to 50%）. Metabolic constituents （carbohydrates, proteins, amino acid and proline） and essential elements （Fe, Mg, Na, Ca, and K） were studied in two types of fruits on fig trees （mature and premature）. Thallium as a toxic metal was predicted in edible mature fruits, and the results showed that the concentration of thallium parts per billion （ppb） in polluted locations was significantly higher than those of the control one. The results revealed that fruits of fig plants at polluted sites showed quantitative and qualitative deteriorations.

Effects of Trifoliate Interstocks on Growth and Yield of Mexican Lime Trees

This study was carried out to determine the effect of 21 Citrus interstocks and the control Citrus macrophylla rootstock budded with Mexican lime （Citrus aurantifolia （Chistm.） Swingle） on growth and yield. Three types of mandarin and 13 trifoliate types including ＂C-35＂ and ＂Benton＂ used as interstocks, developed vigorous trees similar or more productive than the control. ＂Morton＂ and ＂Benecke＂ citranges, ＂Pomeroy＂ trifoliate trifoliate orange and the ＂Severinia buxifolia＂ interstocks showed a moderated effect on tree growth. Flying dragon （FDT） and Hiryu trifoliate oranges performed as semi-dwarfing interstocks. These interstocks reduced the tree height, canopy volume and surface area covered by the foliage on 25%-35%, 20%-30% and 20%-30%, respectively, compared to the control. While most interstocks surpassed the assigned area of growth （24 m2） in the 7th year, ＂FDT＂ and ＂Hiryu＂ did that at the 10th year. These semi-dwarfing interstocks produced up to 80 kg/tree per year. Most treatments recorded the highest production from the 8th to 10th year, except FDT and Hiryu, which showed the highest yield （130 kg/tree） from the 5th to 7th year. This study provides useful results to face the huanglongbing （HLB） problem using moderate or semi-dwarfing interstocks for Mexican lime orchards in high density plantations.

部门造林成为我国城市绿化一大亮点

近20多年来，仅中直、中央国家机关系统和解放军、武警部队等累计义务植树就达5．5亿株，成片造林5000多万亩。政府机关、企事业单位、社会团体等部门造林绿化，成为我国城市绿化工作的一大亮点。