A series of Masson pine experiment stands were established in Taijiang County of Guizhou Province.The stands included main technical processes of growing Masson pine plantations.The purpose of establishing the stands was to study the effects of different silvicultural techniques for growth of young Masson pine plantations.Based on the yearly measures of permanent plots of the stands for 8 years, and the statistical analyses of the measured data, the results showed that selection of different sites and seed origins, and planting density were the most important factors influencing growth of young Masson pine plantations among all main silvicultural techniques.Size of planting holes had more obvious effect on the growth of the young stands.Fertilization of the young stands had effect in a certain extent. Soil preparation way and young stand tending had no obvious effect on growth of the young plantations.Directive cultural techniques of growing the industrial Masson pine plantaions used in the trial area were preliminarily developed on the bases of above study.The techniques are as follows:Planting site lower, mid-lower and middle of mountain slopes, site index is above 16.Seed origin select seed origin of Gupeng and Tongmian in Guangxi Province.Planting density on middle quality site, building ~ timber : 1665 ~ 2500 tree/hm², pulpwood : 3330 ~ 4440 tree hm², fiber and chip board timber : 4995 ~ 6660 tree/hm².Soil preparation way spot preparation.Size of planting hole 40cm × 40cm × 25cm.Fertilizing young stand under the conditions of serious P deficiency calcium and magnesium phosphate used as base fertilizer, above 60g/hole (above 266kg/hm²); compound fertilizer used as topdressing, above 30g/hole (above 133kg/hm²).Young stand tending cut weeds and shrubs twice per year for 3 years.

The stand net productivity and biological cycle of nutrient elements in the 29-year-old plantations of Chinese fir on different rotations were studied.The results indicated that along with the increasing continuous plantations of Chinese fir, biomass of tree stratum from the second and the third planting decreased by 27.39% and 44.17%, their gross biomass of stand decreased by 26.43% and 41.78%, and their net productivity decreased by 21.20% and 24.41% separately, comparing with those of the first planting.The proportion of tree stratum making up the stand net productivity declined from 77.52%(the first planting) to 49.82%(the third planting).The nutrients accumulated in the undergrowth of the second and the third Chinese fir were higher than those in their tree stratum, but the first planting was an exception.Supposing that the nutrient uptake, retention, and return in the first planted Chinese fir stand were 100% separately, nutrients uptake by the second and the third plantings were 109% and 156%, nutrient attention 103% and 162%, nutrient return 117% and 149%, respectively.The order of the nutrient cycling rate were the second planting (0.493)> the first planting (0.460)>the third planting (0.439).

An evaluation on the shelter belts in a new oasis in Ulanbuhe Sands was carried out at the Dengkou County in western Inner Mongolia.The forest coverage in the study site increased from zero to 26.4% after the land development due to the establishment of shelterbelts.The result showed that:a) the crop yield per hectare inside the shelterbelts is 45.77% higher than that of outdside for wheat, 155.71% for seedsmelon, and 25.0% for beet; b) the new farmlands begin to gain at the sixth year after the establishment of shelterbelts, and all the investments can be take back at the tenth year with a profit of 22, 217 RMB Yuan; c) the annual sand-dust storm days inside the shelterbelts is 56.5% lower than that of outside, 56.8% for annual sand-blowing days, 63.9% for annual dust devil days, 6.5% for annual gale days, and 38.6%~63.2% for annual average wind velocity; d) there are 10 bacteria species in seven genera, 14 actinomyces species in one genus, and two fungus gnera in the developed land, while only four bacteria specie in four genera, eight actinomyces species in one genys, and no fungus in the desert lands; Comparing with the desert land, the soil salt content in the developed land is decreased by 31.6%, 13.6%, and 16.6% at soil layer Ⅰ (2 ~10cm), Ⅱ (10~30cm), and Ⅲ (30~100cm) respectively, and the pH is decreased by 0.88; e) the establishment of shelterbelts has greatly improved the habitats for wild animals and birds, which increased at a rate of 100%~400% in 1994; f) the human carrying capacity is increased by 33.1 times after the land development and the income per capita is 1356 RMB Yuan in the study year comparing to 98 RMB Yuan before the land development.

The origin and evolution of forest plant community in Daqinggou are explained based on the geology, geography, geomophology, soil, climate, vegetation material at ancient time and the relationship between present vegetation and related plant flora et al.The correlation coeffcient method and Fuzzy Clusteringis method were adopted to study the relationship between the plant community in Daqinggou and related plant flora.The results show that the climate conditions in large extent fluctuated from the Quaternary Period especially from Holocene leading to deterioration of deciduous broad-leave forest in Daqinggou, which survived only in special refuge area; The plant community in Daqinggou is significantly related with Changbai, Inner mongolia and Huabei plant flora.It shows that forest plant community in Daqinggou is a survived forest community type which was influenced by the long time climatic changes and the interaction of three plant floras.

A molecular linkage map was constructed for P.deltoides Marsh × P.cathayana Rehd.based on random amplified polymorphic DNA (RAPD) markers.The mapping pedigree consists of three generations with the F₁ produced by interspecific hybridization between a P.deltoides female and a P.cathayana male.Three-hundred random 10-base RAPD primers were screened in amplification reactions using DNA isolated from parents P.deltoides, P.cathayana and their F₁ recombinant inbred population consisting of 4 lines.Of these primers, 180 revealed at least one polymorphic RAPD locus which can be used by mapping.This map identified 20 linkage groups spanning 1899.4 cM (110 RAPD markers) with an average distance of 17.27 cM between markers.Linkage groups ranged from 187.8 to 37.1 cM in length and included from 3 to 10 markers, respectively.This map should facilitate the identification of markers that "tag" genes for pest and disease resistance and other traits in poplar.This is the first genetic map for P.deltoides × P.cathayana and an important step towards the molecular breeding in poplar.

Lots of calli were.successfully induced by culturing the mature embryos of Taxus chinensis, Taxus chinensis var.mairei (Fujian) and Taxus chinensis var.mairei (Sichuan).The highest calli-inducing frequency was 95.7%, 98.4% and 91.7% respectively.The cellular and morphological observation revealed that somatic embryos at different growth stages could be produced from the calli which were cultured for some time under appropriate culture condition.For the above three materials, the largest number of somatic embryos per 100 calli was 127, 91 and 33 respectively.

This is a part of the cooperative project-studies on biological control of Tamarix insect pests between the Chinese Academy of Agricultural Sciences, Ministry of Agriculture, People's Republic of China and the Agricultural Research Service, Department of Agriculture, United States.Totally, 362 leaf-hoppers on Tamarisk and other plants were collected in Northw estern China from 1992 to 1994.Among them 4 species are new to science.The type specimens are deposited in the Insect Collections of Anhui Agricultural University.The new species are diagnosed as follows.1.Idiocerus kuohi Cai, sp. nov. (Fig. 1)Similar to I.ulmus Fang, but differs from the latter in the smaller size, the brownblack face and the form of aedeagus.♂: Length 3.0mm, incl. tegm. 5.0mm.Holotype ♂ (8059), Xinjiang, 15km NE Aksu, 11515km, 9 July 1992, Wang Ren & C.J. DeLoach, sweeping Elaeagnus angustifolia.2.Circulifer xinjiangensis Cai, sp. nov. (Fig. 2)Externally as C. obscurinervis Lindberg, but differs in the smaller size and the structure of aedeagus.♂: Length 2.0 mm, incl. tegm. 2.9 mm.Holotype ♂, Xinjiang, 84km SE Kashi, by Lake Potomogeton, 12364 km, 12 July 1992, Wang Ren & C.J. DeLoach, sweeping Halogeton giomeratus (Bieb.).3.Megalopsius tamaricius Cai, sp. nov. (Fig. 3)This new species can be distinguished from the know n species of the genus by its larger size and the male genitalia.Length ♂: 4.6 ~ 5.1mm, ♀5.0 ~ 6.1mm; Length incl. tegm ♂: 5.6 ~ 6.1mm, ♀6.3 ~ 6.5mm.Holotype ♂(7691), Xinjiang, 40km SW Aqal, 11684km, 10 July 1992, Wang Ren & C.J.DeLoach, sweeping Tamarix ramossisima.Paratypes 12 ♂♂ (7671, 7672, 7677-7681, 7683-7685, 7688) 6 ♀♀(7673-7676, 7689, 7690), same as holotype; 2 ♂♂(7668, 7669) 1 ♀(7667), same as holotype, 125km W. Koria (Kurie), 11081km, 9 July 1992, sweeping T. alongata, very few flow er; 1 ♂(7697) 2 ♀♀(7695, 7696), sweeping T. hispida var. hispida, old flowers; 1 ♂(7699), sweeping T. hispida var.karelini; and 2 ♂♂(7705, 7706) 1 ♀(7707), sweeping T.smyrnensis, flowering, same as the former; 1 ♀(7713), same as holotype, Qira (Cele) Desert Res. Sta., 12945 km, 13 July 1992, sweeping T. chinensis, flowering; 1 ♂(7715), same as the fomer, Turpan, Turpan Sand Dune Fix. Sta.Bot. Garden, 17 July 1992, sweeping T. arceuthoides, flowers; 2♂♂ (7718, 7719) 1 ♀(7717), Inner Mongolia, 14 km SE Wuyuan, by canal, 36790km, 16 July 1993, C.J. DeLoach, 20 sweeps T.austromongolia; 1 ♀(7736), Gansu, 33km S. Anxi, Anxi Natural Area, 40597km, 30 July 1993, C.J. DeLoach, 20 sweeps yellow seeding T. leptostachya; 3 ♀♀(7748-7750) 1♂ (7751), same as the former, 25km NW Dunhuang, 40820km, 1 Aug. 1993, T. karelinii; 2 ♂♂(7724, 7726) 2 ♀♀(7725, 7727), Ningxia, just N. Yinchuan at Pagoda, 38502km, 23 July 1993, C. J. DeLoach, 20 sweeps Tamarix sp.4.Tamaricella fuscula Cai, sp. nov. (Fig. 4)This new species is related to T. complicata Dworakowska, but can be separated from the latter by its larger size and the form of aedeagus.Length ♂: 1.5 ~ 1.7mm, ♀1.7 ~ 1.9mm; length incl. tegm ♂ : 2.1 ~ 2.8mm, ♀2.3 ~ 2.8mm.Holotype ♂(8015), Gansu, Minqin Botanical Garden, DCRI 39684km, 28 July 1993, C.J. DeLoach, 20 sweeps Tamarix gracilis.Paratypes 1 ♂(7961), same as holotype, 33km S. Anxi, Anxi Natural Area, 40597km, 30 July 1993, T. hispida; 1 ♂(7987), Xinjiang, Turpan Botanical Garden, 6 Aug.1993, 41843km, T. arcenthoides; 1 ♂ 3 ♀♀ (7920), Inner Mongolia, 43km S. Baotou, 37797km, 21 July 1993, T. austromongolica.

The Cimbicid sawfly Cimbex japonica Kirby is a newly occurred pest in China. In recent years it has caused serious damage to Ulmus pumila in the central part of Shanxi Province. The generation is annual with adults on the wing in early May. No adult male occurred. Each female can lay about 50 eggs. The eggs are laid singly on the edge of the leaf under the upper surface. The feeding peak of the larvae is from mid -May to mid -June. When its larva is full-grown, it goes into the litter or into the furrows in the soft soil 2~3cm in depth, makes a elliptic dark brown cocoon and there spends the winter, changing to a prepupa. Pupation takes place in mid -April. The pest was 90 % or over controlled by Cyhalothrin(Karare) at 3000 × dilution during the peak of the larval eclosion in mid -May. In mid -April, before the emergence of the adults, digging out the cocoons from the soil under tree crowns and then burning them was also very effective against the pest.

We extracted DNA from 20 infected plants and their healthy counterparts collected in China, amplified the phytoplasma 16S rDNA fragments by nested PCR.The primer pair R16F2/R16R2 amplified a 16S rDNA fragment (about 1.2kb) from each DNA sample prepared from 20 infected tissues but not from any DNA sample extracted from healthy tissues. We purified the nested PCR products and connected it into T-vector for storage.The 16S rDNA fragments amplified were compared through RFLP analysis. Based on the similarity of RFLP patterns, these 20 phytoplasmas could be classified into 4 distinct 16S ribosomal RNA groups, corresponding to: Aster yellows (Paulownia witches'-broom, Hackberry witches' - broom, Periwinkle witches'-broom, Fernleaf hedge bamboo witches'-broom, Hibiscus fasciated disease, Chinaberry tree witches'-broom, Chinese thorny bamboo witches' -broom, Tobacco witches' broom, Banana bunchy top, Everg reen chinkapin witches'-broom, Willow yellows, Mulberry yellow dwarf disease, Mulberry dwarf disease); Ash yellows(Cherry fasciated disease, Jujube witches'-broom); Peanut witches' -broom (Stylosanthes gracilis H. B. K. witches'-broom, Groundnut witches' -broom, Stylosanthes guianensis cv. Witches' - broom) and clover proliferation (Bishopwood witches'-broom, Cinnamon yellows).

The Hainan Island is rich in polypore resources. More than 3500 specimens of poly pore were collected from this Island. After identification, they can be divided into 13 families, 54 genera, and 312 species. Among them 6 species are new to science and 15 are new records in China, 24 genera and 162 species are new records in Hainan Island. The resources and the environment of the polypore fungi in this area are briefly dealt with. The Hainan Island polypore fungi species can be divided into the following four ecological types: the first type is the polypore fungi of evergreen monsoon rain forest, the second is the polypore fungi Tropical rain forest, the third is the polypore fungi of tropical semi-deciduous monsoon forest and the fourth is the elfin woodland.

Three kinds of poplar clone wood, poplar 72(Populous ×euramericana cv. I-72/58), poplar 63, (P. deltoides cv. I-63/51) and poplar 69 (P. deltoides cv. I-69/55), growing in three different beaches of the Yangtse River (river beach, islet beach and lake beach) with three different planting densities (3m ×4m, 4 ×5m and 5m ×6m) were selected as the testing materials. The relationships between wood properties and quality of veneer and plywood were studied.The results show that in wood anatomical properties of poplar 72, poplar 63 and poplar 69, the variance of veneer thickness is very significantly related to the fiber width, the proportion of vessel and fiber at 0.01 level is significantly related to the fiber length, the thickness of cell wall, the ratio of cell wall to cell cavity, the ratio of cell cavity to cell diameter, the length of vessel and the proportion of ray at 0.05 level.The ratio of lathe check of veneer is very significantly related only to the diameter of cell cavity at 0.01 level, but not related to other anatomical properties. The gluing strength of plywood is very significantly related to the fiber length, the fiber width, the diameter of cell cavity, the thickness of cell wall, the radio of cell wall to cell cavity, the vessel length, the diameter of vessel in tangential, the microfibril angle and the proportion of vessel and ray at 0.01 level, and is significantly related to the proportion of fiber at 0.05 level. In wood chemical properties (pH value, acid and alkali buffer) of poplar 72, poplar 63 and poplar 69, the variance of veneer thickness and the ratio of lathe check of veneer are not related to chemical prperties, but the pH value of sapwood is significantly related to and the pH value of heartwood and the average pH value of sapwood and heartwood are very significantly related to gluing strength of plywood at 0.01 level, respectively. In wood physic-mechanical properties of poplar 72, poplar 63 and poplar 69, the variance of veneer thickness and gluing strength of plywood are not related to physic-mechanical properties, but the ratio of lathe check of veneer is very significantly related to the modules of elasticity at 0.01 level and is significantly related to the wood density in air-dry at 0.05 level.

Polycarboxylic acids and inorganic salts are used as esterification agents and catalyst, respectively, in our research on wood crosslinking reaction. This new crosslinking system is composed of the reagents of non-formaldehyde series and it is soluble, poison-free and pollution-free.The characteristics and parameters (esterification degree, carbonyl ratio and crosslinkage degree) of esterification between wood and polycarboxyic were determined by FTIR ¹³CNMR spectra in this paper.

The yellow green hard callus is the best embryogenic callus, which obtained from the stem tip of Populus alba ×(P. davidiana ×P. simonii) ×P. tomentosa on the induced medium (MS+KT0. 1mg·L^-1 +2, 4-D 0.05mg·L^-1) after 10 days culture. Its formation frequeny of adventure buds, adventure roots and somatic embryos ane 100 %、19.4 % and 13.3 % respectively on the differentiated medium (MS + KT 0.3mg·L^-1). Org ans and somatic embryos are all derived from the surface layer of calli. The somatic embryogenesis is very similar with the zygote embryogenesis. The esterase isozymes and soluble protein bands of various calli are very different.

Using the sample survey, this paper presents the results of a research on the fruit yeild, seeds hidden under ground, and number and distribution of seedlings. The results show that cones of Sabina vulgaris are mainly distributed within 3 metres around the centre of bush of S. vulgaris. There are usually 1506 seeds under the bush of S. vulgaris, but their fine seed rate are only 25.84 per cent. Although 3~9 seedlings per square metres distributed averagely under S. vulgaris bush at the moist interdune low lands and the foot of sand dune where ground water table is 40~60cm, water content in surface soil 16.7 %, and the depth of litter layer 1~3cm. These seedlings are usually 1~3-year-old and their natural regeneration is difficult. The seedlings of S. vulgaris always regenerate at moist bottomland where some plants such as Salix cheilophila bushes are growing, the bottomland has seasonal water, and the surface soil water content is about 30 %.The ages of these seedlings are different and their natural regeneration is easy. The seeds are spread mainly from the bush of S. vulgaris to the sand by the sand run-off. and then spread to other bushes by wind, run-off, birds, of animal.

Certain dose of aloperine was injected into the basal trunk of 6~7 years old healthy Black pine, Pinus thunbergii in the late June or early July. In the preventive test one week or two weeks after the injection of aloperine, in the therapeutical test one week or two weeks before the injection, an inoculation was received by each test tree with pine-wood nematodes, Bursaphelenchus xylophilus (Steiner et Buhrer)Nickle. Results were checked in the late March of the following year. Recovery from the disease was ascertained by resin exudation and growth and survival of the lead shoots. In the preventive test at the doses of 0.042, 0.124g/tree, the survival rates of the test trees were 43 %, 68 % respectively. In the therapeutical test at the doses of 0.042, 0.21g/tree, the survival rates were 50 %, 93.8 % respectively. The survival rates of control trees of the two tests were 30 % and 20 % respectively. Aloperine is the first natural compound, the effects of which in controlling the pine wilt disease have been confirmed in the field tests. Aloperine dosage used in the future practice of controlling pine wilt disease, its toxicity to human and tree, production cost and perspective in practice were discussed.