The object of our study was aimed at seeking a series of techniques for selection of protection forests.Therefore the following functions were evaluated :productivity of the main protection forest, permeability capacity of the forest soil, water stablization index, maximum water storage petential of the soils, effective storage capacity and maximum water retainning potential of stands.Futhermore, a multi-step determination approach was utilized to determine the functions of the protection forests.On the base of this analysis, a total of 18 technique selection models were established for multi-function selection.The coincidence rate of these models determining the functions of forests with historical data were above 75.0%.

The contents, accumulation and distribution as well as biological cycles of 9 nutrient elements (N, P, K, Ca, Mg, Cu, Fe, Zn, Mn) were studied in four 16-year-old experimental Slash Pine plantations with different density at Lufeng Mountain Forestry Farm in Guangxi Autonomous Region.The results indicated as follows:the total nutrient elements accumulation of various Slash Pine stands amounted to 1273.83~1615.88kg/hm², of which stem occupied about 60 %.The nutrient retention accounted for 111.46~133.39kg/hm²·a, which is higher than that of either Chinese fir or Masson pine plantation.The nutrient return equalled to 90.43~105.09kg/hm²·a.Nutrient elements' turnover period is long while cycling rate is lower.The net production per ton needs 13.19~14.81kg nutrient.Obviously, the nutrient cycles mechanism of Slash Pine is characterized by high nutrient use efficiency with low cycling rate, so in management of Slash Pine plantation, the relation between forest utilization and forest land tending must be dealt with rationally in order to prevent forest land degrading.Of different density plantations, the 3200 tree/hm² one possessed the greatest net productivity, the largest amount of nutrient accumulation and uptake, as well as the highest nutrient use efficiency.

Selecting five clear cutting operation with different skidding methods and selective cutting operation of thirty percent intensity, this paper compared the change level of soil physical and chemical properties after harvesting.With the consideration of the affection of skidding volume and the area of skidding trials, it also revealed the disturbance degree of soil after different harvesting methods by means of principle component analysis (PCA).The results indicated that the disturbance degree of soil physical and chemical properties of clear cutting by walking tractor skidding was at the most, the order of the disturbance degree of others were as followings :clear cutting by dirt chute skidding > clear cutting by push cart skidding >clear cutting by high-lead cableway skidding >clear cutting by suspended cableway skidding >selective cutting by manual skidding.

The production of artificial seeds by encapsulating shoot tips or minibuds has received considerable attention in recent years.To accomplish conversion of the encapsulated shoot tips is one of the key questions in this area.In this paper some tests were carried out using the shoot tips of Eucaluptus camaldulensis as propagules in order to determine the effects of different kinds of auxin(NAA, IBA, IAA), shoot growth state, NAA in the encapsulation matrix and rooting pretreatment on their conversion.The results showed that NAA had a better effect on rooting of the shoot tips than IBA and IAA had.Shoot state was closely related to the conversion of encapsulated shoot tips.The vigor, healthy and tender shoot tips showed higher conversion rate after encapsulated.The problem of rooting and conversion for encapsulated shoot tips can not be solved with the method of adding NAA in the encapsulation matrix.The shoot tips was firstly pretreated on modified H rooting medium containing 2mg/L NAA, then the tip with the medium on its base was encapsulated with calcium alginate including modified H medium nutrition.This method significantly raised the rate of rooting and conversion of the encapsulated shoot tips 81.3 % rooting rate and 83.3 % conversion rate were obtained 2 and 3 weeks after they were cultured for germination respectively.

The numbers of bamboo stem at different ages and the diameter at breast hight (DBH) which are the elements for measuring a tree, the standing bamboo amount in a bamboo stand, and the environment of the bamboo stand were investigated in 1330 bamboo high yield plots collected from the bamboo production areas in Nanlin mountains.Taking the bamboo stem yield of a timber stand and the shoot production of a bamboo shoot stand as the dependent variables, the following yield models were established. For timber stand Y₁ =-62695.245 +6.5413N +7012.5195D +8.4548X₁ +11.0870X₂ +14.1520X₃+8.9969X₄ +14.5156X₅ For shoot stand Y₂ =697.5569 +0.2052N +1.8514D -0.6414X₁ +1.2493X₂ +0.7636X₃ +0.3790 X₄ -0.8833X₅ Eight restricted conditions were suggested in combination with the need of production, these models were used to optimize age structure of bamboo stand under different quality, density, site condition and level of management.The results showed that the models could increase yield of bamboo and shoots significantly.

Based on the growth yield model system of masson pine plantation established already the productivities of various site indexes (14 ~ 20) were analysed, suitable cultivation objectives of various site indices was determined.According to the differences in cultivation objectives, sites and cultivation measures, a lot of cultivation types for building timber were given.The stand quantitative, technical and economic mature ages of various cultivation types were calculated, then rational cutting ages of various site indexes were determined.The results showed that the cutting age determined in this paper was shorter 4 ~ 12 years than that being used, and that IRR was raised 3%~ 9%.The relations between cutting age and site, cultivation objectives, silvicultural condition (planting density, thinning), economic condition were studied.The quantitative, technical and economic mature ages reduced with the raising of site index, with thinning times increase, the quantitative mature age of the lower planting density stand increase, but technical mature age reduce.The economic mature age reduce with the discount rate increasing, while discount rate raise 1 %~ 2 %, the economic mature age reduce for 1 year, otherwise, the economic mature age put off about 1 year.

The leaf abaxial epidermis micromorphologic characters of Liriodendron reciprocal cross hybrids and parents were observed under scanning electron microscope (SME).The results are as follows :Liriodendron chinense (Hemsl.) Sarg.and minus crossing F₁ have obviously papillar cell in abaxial epidermis, that of L.tulipifera Linn.and plus crossing F₁ is flat. Stomatal density of L.tulipifera Linn.and plus crossing F₁ are much denser than that of L.chinense (Hemsl.) Sarg.and minus crossing F₁.There are no significant differences in abaxial epidermal waxy ornamentation and stomatal apparatus form between hybrids and parents.Reciprocal cross hybrids have larger stomatal apparatus opening than parents′.

The biological features of flowering were studied in 26 superio rindividual male Ginkgo biloba trees selected from 5050 male trees in Taian and Tancheng of Shandong Province. These superior male trees possess the features of florescence long, a large number of pollens, and high vitality of pollens, etc.The results of analysis of correlation and variance showthat the florescence prolong swith raising elevation, but numbers of microstrobil per short shoot (sh.sh.) decrease evidently.The maximum number of short shoots per meter of long shoot (l.sh.) is 45.There is a significant positive correlation between the length of short shoot and the microstrobil numbers per short shoot.The flowering percentage of short shoot of 3-year-old segment is the highest, amounting to 96 %.The maximum microstrobil per sho rt shoot is 6.45, the maximum anther per microstrobil is 58, the maximum pollen grain per anther is 23000.There are 650000 pollen grains in per microstrobil averagely.the pollen productivity of No.14 tree is 6.83 %.A 45-year-old male tree can yield 165g pollen.The mean vitality of pollen reaches 92 %.Seed production percentage is 90 %after pollination, the percentage of embryo in seeds is more than 91 %.

42 isolates of Marssonina brunnea collected from different poplars in Jiangsu, Henan, Shandong, Beijing, Shaanxi and Jilin Provinces of China were studied with the morphological markers, characteristics of colony growth culture, pathogenicity and hyphal anastomosis grouping.No significant difference was found on the morphological features of conidia (shape, mean dimension, size and septum location).Morphological features could not be used to study the specialized forms or isolates within the Marssonina brunnea, but could identify the spices of Marssonina brunnea.Five isolates from the poplar or Section Leuce possessed the characteristics of faster colony g rowth, dark reddish conidiosorus production on PDA medium, germinating only one germtube, mostly pathogenic to P. tomentosa and slightly pathogenic to P.×euramericana I-45, P.canadensis, P.cathayana and P.simonii by artificial inoculation in vitro.The thirty-seven isolates from the poplars of Section Aigeiros and Section Tacamahaca, however, had the characteristics of slow ly colony radial growth and yellowish-green conidiosorus production, germinating 1 ~ 5 mostly 2 ~ 3 germtubes, usually pathogenic to P.×euramericana I-45 and P.canadensis, also pathogenic to P.tomentosa, P. cathayana and P.simonii.The test of hyphal anastomosis showed that hyphal anastomosis developed between isolates from the poplar of Section Leuce, and between isolates from poplars of Section Aigeiros and Section Tacamahaca, but could not develop between isolates from the poplars of Section Leuce and isolates from poplars of Section Aigeiros or Section Tacamahaca.The five isolates from the poplar of Section Leuce were placed in one group and the thirty-seven isolates from the poplars of Section Aigeiros and Section Tacamahaca in the other group.These two groups were similar to the two specialized forms reported by Li (1984) and He et Yang (1991).

More than 2500(87 species) birds were netted and 2410 birds(80 species) were banded in Longqingguan, Weishan County, Yunnan Province (25°18′N, 100°21′E).Most of them were netted by night, only 22 birds (10 species) were netted by day.The ratio of adult to young and female to male is about 1:2 and 2:1 based on the aging of 1138 birds and sexing of 839 birds.Total of 94 species were netted and 2942 birds (87 species) banded combined with the banding results of 1995 and 1996.The most important birds are red-throated flycather (Ficedula parva), oriental tree pipit (Anthus hodgsone) and red-tailed shrike (Lanius cristatus) according to the important value (IV). The relation between the birds number netted every night and the weather conditions was discussed.

The larch needle brown rust (Triphragmiopsis laricinum(Chou)Tai) is a common larch fungal disease in the east of Jilin Province, China. The Larch (Larix olgensis) stands infected in the first year generaly grow normally, but in the second year they are affected seriously, the growth loss increases greatly in the stand infected lasting 2 years or over 2 years. Regresion equation was developed to predict disease index (X) and volume losses of growth/hm²(Y):Y=1.94/1+e^{5.49337-0.06893X}. The injury index was defined as 35. The equation of the economic threshold was developed to describe the relations among standing volume price(C), the efficiency of control (Q) and the cost of control (E):1.94C[1/1+e^{5.49337-0.06893X}-1/1+e^{5.49337-0.06893(1-Q)X}]-E=0.The equation of forecasting the mean disease index was:Y=5.185+3.2596X₁-0.42105X₂+0.08627X₃±6.9(Y:mean disease index, X₁:mean temperature in May of the current year, X₂:mean relative humidity of the current year, X₃:mean precipitation in September of the last year).

Cecidomyia weni Jiang was firstly found in a Pinus tabulaeformis Carr. seed orchard in Xingcheng, Liaoning Province in 1987. It is bivoltine. The larvae mainly feed on the first year cones causing serious injury. Male inflorescences also can be damaged. Its larvae drop to the ground and pupate, then overwinter in cocoons in the litter. At least three species of parasitic natural enemy are found, including Capellia coni Yang, pyrethroid and phosphoramidate are effective to control the adult of C.weni Jiang.

The process of gathering the log-shape data by the way of log image processing was involved in this study. The steps taken in image processing and algorithms used in each step were experimented and compared. The results indicated, it is suitable for log image processing to use the following steps, and the final coordinates are log-shape parameters:Image Dithering→Geometrical Correcting By Daulity-Quadratic-Polynomial And Double Linear Interpolation→Piecewise Linear Graylevel Transformation→Bilevelizing Noise-Eliminating By Intelligent High-Pass Filter→Edge-Extracting By Robert Operator→Coordinate Extracting

A variety of simulative experiments on the discoloration behavior of catalpol, paulownin and sesamin separated from methanol-water extractive of Paulownia wood (Paulownia elongata S.Y.Hu) were conducted under different conditions. The results indicate that the color change of catalpol is mainly affected by acidity, while the discoloration of paulownin and sesamin are caused by both radiation and oxygen. The variation of temperature and humidity also have effects on the discoloring of catalpol. The color change of Paulownia wood is a result of a combination of all the factors. A tentative mechanisms of discoloring reaction were figued out.

The micro- and ultramicro-structures in stems of Calamus simplicfoius Wei.C.tetradactylus Hance and Daemonorops margaritae (Hance) Bece were observed with EM.The surface, epidermis, cortex, vascular bundles and parenchyma in the middla section of rattan were detailed in this paper. It comes to the conclusion that the structural characteristics of rattan will be help for classification, identification and selecting species.

The paper inverstigated the effect of intermittent flood upon the wood physical and mechanical properties of Taxarlium ascendens.The results are as follows:Annual rings width、latewood percentage、shrinkang、basic specific gravity and main mechanical properties of Taxodium ascendens wood under intermittent flood are smaller than those of wood without intermittent flood, but shrinkage differences of wood is bigger than that.The T-test valves indicated that there no significant differences between wood under intermittent flood and without intermittent flood in annual rings width and shrinkage differences.there are significant variances in other physical and mechanical properties.

White translucent gloosy mucilaginous embryogenic callus was induced from mature zygotic embryos of loblolly pine on callus induction medium containing 2, 4-D and BA. Embryonal suspensor masses were formed from embryonic callus cultured on DCR medium supplemented with 2, 4-D, IBA and BA. Early stage somatic embryos developed into late stage somatic embryos on the high osmatic press medium. Late stage somatic embryos developed into cotyledonary somatic embryos on the medium containing ABA, PEG and activiated charcoal. Cotyledonary somatic embryos can germinate and develop furture intergeneration plant when they were isolated and cultured on a hormone-free DCR medium. The highest frequency of plantlet regeneration from somatic embryos is 18.4%.

The toxicity analysis of tebufenozide against Dendrolimus punctatus was studied.The rlesuhts showed that in laboratory tebufenozide(24%)could kill the 3rd instar pine caterpillar with the average mortality of 100.00%, 94.20%, 99.20%, 78.30%, 85.50%and 79.10% respectively when it was diluted with water to 120, 70, 35, 14, 7 and 3.5 mL/kL.In the forest of Pingle County, Guangxi Zhuang Autonomous Region, the average mortality were 93.47%, 91.55%, 85.52%and 70.32% respectively when tebufenozide was diluted with water to 120, 80, 60 and 40 mL/kL.In Pingle County, Guava Zhuang Autonomous Region, at the Same concentration of tebufenozide as mentioned above, the average mortality were95.79%, 92.91%, 76.93%and 74.94% respectively.Data analysis checked by LSR test showed that the differences were quite significant between treatment and control

By means of the statistical method of forest economics and establishment of calculating index system, through quantification of the ecological and economic benefit values, the total value of ecological and economic benefit of the grassland shelterbelts on the Korqin Sandy Land, was objectively evaluated. It was shown that the total effect coefficient of the shelterbelt system on sandy grassland was 4.57, and the total effect coefficient of ecological benefit 42.85, the total effect coefficient of economic benefit 3.29. The transformed value of ecological benefit was 470.79 yuan/hm² annually, and the annual income of economic benefit 770.72 yuan/hm² in the grassland shelterbelt system on the Korqin Sandy Land. By arranging the basic indexes of ecological and economic benefit in order of its importance it indicated that priority should be given to ecological benefit in the desertificated and semi-desertificated areas on the Korqin Sandy Land.