Comparison of NPP model of natural vegetation among Miami model, Thornthwaite Memorial model, Chikugo model, Synthetic model and Beijing model has been done based on 125 sets of natural mature forest NPP data in China and 23 sets of NPP of natural vegetation obtained during IBP by Efimova, including forest, grassland and desert. The result shows that Chikugo model, Synthetic model and Beijing model can simulate NPP of natural forest, however, the two latter can simulate NPP of natural vegetation better in semiarid and arid areas than the former. The distribution of NPP of natural vegetation in China and its response to global warming are also presented in this paper. The NPP of natural vegetation in China increases from northwest to southeast, and will increase in different degrees under global climate change. The NPP of natural vegetation will increase more in moist area, and less in semiarid and arid areas. The limitation factor of NPP is the shortage of water.

The mixed plantation of poplar (Populus spp.) and black locust (Robinia pseudoacacia L.) is one of the successful mixed stands of nitrogen-fixing and non-nitrogen-fixing species on poor sandy sites along the river and besides sea in the north of China. The growth and yield of the mixture is briefly introduced in this paper. The soil amelioration and the interaction of mutual supplement of nutrient between tree species are mainly discussed in this paper. It shows that the yield improvement is mainly due to the soil nutrient amelioration (especially nitrogen nutrient) and the interaction of mutual supplement of N and P nutrient. The main reason of the soil nitrogen nutrient improvement is the high speed of litter decomposition and high ammonification and nitrification intensity because of the increased activity of soil microorganism. The interaction of mutual supplement of N and P nutrient between tree species is realized mainly through the mechanism that poplar trees can transfer phosphorus to black locust trees by root-contacting and black locust can transfer nitrogen to poplar trees also by root-contacting. The transfer intensity of N and P is very high. This kind of marvelous interaction between tree species in very important to the yield improvement in the young mixtures.

This paper deals with the results of a comparison study on mineral element (N、P、K、Ca and Mg) concentrations and their seasonal dynamics in needles collected from 15 introduced conifers. During a year at spring(30, April), summer (30, July), autumn (30, October) and winter (30, January), the current-year and one-year-old needles were collected from ten trees of each species. The needles from all ten trees were bulked into two composite samples according their foliar age for chemical determination. The results show that, there are significant differences in foliar nutrient concentration among 15 woody species planted at same site. The element concentration for all 15 species was following:N>K>Ca>P>Mg. The P, K, and Ca seasonal dynamic patterns in foliar concentration showed extremely similar for all species but the N and Mg exhibited higher differentiation among species. The results also indicated that the element concentrations and seasonal dynamics of each element had remarkable differences between two subgenus in Pinus.

According to the dynamic changes of the structure and function of water conservation forest ecosystems in Qilian Mountains, making studies on forest microclimate and hydrological effect. The result shows that the water conservation forest in Qilian Mountains not only has the function of blocking and storing precipitation,reducing temperature range,keeping more soil humidity,but also has the hydrological effect of soil and water-source conservation. The annual low flow runoff volume increased 28.87mm in forest coverage of 65 percent than of 32 percent, but annual flood runoff volume reduced 98.87mm. Water storage in forest soil is from 298.32mm to 391.93mm, but 182.09mm in glassland. The surface runoff seldem forms in forest land. The annual soil loss is 1793.9kg/hm² in grassland. Perennial and seasonal frozen earth make the runoff coefficient is 0.73 in frigid mountion area,the fewer evaporation is 156.54mm.Many years' monitoring data shows in Qilian Mountain the quality of stand is declining, the glacier is shrinking back,the runoff volume is reducing every year,the ecologic environment is worsening. So we suggest that government departments at different levels should think highly of the problem of ecologic protection in Qilian Mountains.

The major aim of this test is that the actual increment and main genetic parameter of the original high-quality stands were evaluated by testing progeny of Pinus yunnanensis, so as to examine "The Selection Method and Criterion of District (Western Yunnan) of The Original High-quality Stands of Pinus Yunnanensis". The authors adopted completely random district-group design to carry out the test in Guyong Forest Farm of Tengchong County in 1988. The results from the continous seven-year investigation show that the progeny of the original high-quality stands have the characteristics of straight tree-trunk, minor twinst degree of grain on wood, high growth increment, the actual increment of the tree height, DBH, volume of timber and twinst degree of grain reached respectively 37.49%, 65.60%, 219.84% and 269.57%, their genetic gain reached respectively 20.14%, 40.46%, 107.11% and 59.79%, their genetic gain reached respectively 20.14%, 40.46%, 107.11% and 59.79%. The data mentioned above have far exceeded 3% of tackling-key-problem check-up index of progeny genetic gain of original high-quality stands of pinus yunnanensis. The test feedback indicates that "The Selection Method and Criterion (western Yunnan) of the Original High-quality Stands of Pinus yunnanensis" is scientific and reliable.

Testing plantations were planted with clonal and seed progeny in 1983.Both of them are from the same plus trees.When the testing plantations were 12-year-old, the plantations height、diameter at breast height、height of trunk and volume have been tested.The result shows: 1. The coefficient of phenotypic variation of the clone is 76% greater than that of the family. The coefficient of genetic variation of the clone is 70% greater than that of the family; 2. According to being chosen of 20%, the genetic gain of clone is 128% higher than that of family.So the effect of plus tree clonal selection is better than that of plus tree family selection.

Genetic differentiation among three pine-stem rust fungi from China, i.e., Cronartium ribicola, C.flaccidum and C.quercuum, was assessed by random amplified polymorphic DNA(RAPD). Ten isolates(including an outgroup isolate)with different host and/or geographical origins were subjected to study. Pairwise similarity analysis was conducted on 51 RAPD loci detected by five selected primers. The result shown that although there were intraspecific variations, three rust pathogens were clearly separated as distinctive groups, thus justifying these traditional fungal taxa by using DNA data. Genetic relatedness between C.ribicola and C.flaccidum was closer than that between C.quercuum and either of the former two, this being consistent with the relationship reflected by disease symptom and telial-stage host range of these pathogens.High degree of intraspecific divergence was found between two C.flaccidum isolates which differ from each other in host specialization over their life circles, possibly demonstrating the genetic background underlying these two supposed formae speciales. Intraspecific variation was also found among C.quercuum isolates with different pine hosts, suggesting that the host specialization of C.quercuum in aceial stage as reported in Northern America may also exist in China. Evidences were also obtained that host adaptation, rather than geographic factors, is the primary force to drive genetic differentiation of the pine-stem rust fungi.

Nematicidal activity of aloperine, cytisine, N-methylcytisine and matrine Wilts bioas. Sayed by the agar medium method and the cotton.Ball method.The corresponding results by the tw.o methods showed that the nematicidal activity of aloperine was the strongest.Its log (1/ID₅₀)(mol/cotton ball) =8.67 was also the strongest in comparison with nematicidal activity of seven other quinolizidine alkaloids bioassayed by the same method in literature.A hypothesis that nematicidal activity of quinolizidine alkaloids is mainly determined by types of functional group pair and types of functional group in their molecular structures was proposed. Based on the hypothesis, the structures of alkaloids with strong nem aticidal activity were predicted.

Wetwood of poplars was distributed very widely and caused a serious damage in China.A fungus was frequently isolated from wetwood of stems and roots, which were collected from more than 20 Populus species in Hubei, Shandong, Hebei, Liaoning Provinces and Beijing City in 1995 and 1996.According to its morphological and cultural characteristics, the fungus was identified as Fusarium proliferatum(Matsushima)Nirenberg.The results of the laboratory and the field tests showed that F.proliferatum was a powerful pathogenic fungus, and an important pathogen of poplar wetwood disease.The observation with scanning electron microscopy indicated that membranes of vessel-to-ray pits were destroyed by F.proliferatum.The functions of bacteria and physiological factors in the course of wetwood development were discussed.

By polymerase chain reaction (PCR), the seasonal variation of the phytoplasmal amounts in mulberry tree was determined.It was demonstrated that the phytoplasma was unevenly distributed in the host.In stem, its amount increased during the growing season, which reached its peak in July and was undetected in winter; in leaves, the situation was similar to that in stem but the peak was in August.In roots, its amount was lower and hardly varied in all the year round.It was indicated that the seasonal variation of phytoplasma in mulberry trees was related to that of temperature.

In the present paper a new species, Bathythrix cilifacialis Sheng parasitizing in the cocoon of Pachynematus itoi Okutani (Hymenoptera: Tenthredinidae), with its biology is described and illustrated.Type specimens are deposited in the General Station of Forest Pest Management, Chinese Ministry of Forestry.Bathythrix cilifacialis Sheng, sp.nov. (Fig.)♀♂: Body 5.1~7.0 mm long. Fore wing 4.0~5.5 mm long. Face with very dense and long silver hairs, which are downward and press close to its surface. Clypeus with two strong teeth at apex. Malar space about 0.4 time (♀) and 0.3 time (♂) as long as basal width of mandible. Oral carina strongly raised behind the base of mandible. Antenna with 26~27 flagellar segments, in ♂ without tyloids. Basal vein of fore wing nearly parallels discocubitus. Nervellus distinctly reclivous, intercepted at lower 0.3. First segment of abdomen with almost parallel sides, 3.6~3.9 times as long as its apical width, spiracles at the midlle, without median dorsal carina. Second tergite a little longer than its apical width. Ovipositor straight. Ovipositor sheath 1.20~1.25 times as long as hind tibia. Black. front and midlle legs mostly yellow to yellowish brown. Tergite 2~4 redish brown.Holotype♀, Benxi (41°N, 123.8°E), Liaoning, Aug. 16, 1997. Sheng Maoling.Allotype♂, Aug. 20, 1997. Other data as the holotype.Paratypes: 2♀♀, Sep. 17~22, 1997. Other data as the holotype.This species is similar to Bathythrix. tenuis (Gravenhorst, 1829), but may be distinguished from the latter by: temple with shallow sparse punctures; antenna with 26~27 flagellar segments, ovipositor straight; tergite 2~4 redish brown.Biology: Adults occur in August~September, take cover beneath the fallenleaves, favor to drink water on the emergence day. It parasitize larva and prepupa in cocoon of Pachynematus itoi Okutani.

The present paper deals with diapause of Eotetranychus populi (Koch).The results show that E.populi expresses diapause with fertile female adults, and it grows under long light (above 13 hours light per day) and produces diapause under short light (below 11 hours light per day). The threshold of photoperiod inducing diapause is at 12 hours light.The larva, protonymph are sensitive to photoperioodic changes, but the adults and eggs are not.Lower temperature (below 21℃) promotes the incidence of diapause and higher temprature (above 25℃) restrains it when they are subject under the photoperiod of 10 hours per day.

Forest fire management economics is a science which studies how to manage and control forest fires with application of economics and by making use of other economic resources, and brings into maximum play the integrated forest benefits.The paper defines the concepts of forest fire management economics, analyzes the characteristics, research objects and research contents, and describes basic research methodologies of the forest fire management economics.The study on the forest fire management economics will produce important significance in enhancing the level of national forest fire management and formulating objectives of scientific forest fire management in China.

Contents of major chemical components of 9-year-old Eucalyptus urophylla trees with 5 different fertilization treatments were determined.Based on the obtained data, law of effects of fertilization treatments on contents of wood chemical components were analyzed and discussed in detail.Results show that fertilization treatments have no significant effects on the contents of cellulose and lignin, but have extremely significant effects on contents of extractives and pentosan.Fertilization treatments can significantly improve the contents of cold-water extractives, hot-water extractives, 1% NaOH extractives and pentosan.And the larger the amount of the fertilizer applied, the higher the content of pentosan.

In order to clarify the rules of humidity conditioning function of interior wall materials, the temperature, relative humidity and logarithm of absolute humidity in a box (20cm×20cm×30cm), which was constructed of steel plates and lined with an experimental material on its floor, were measured at a certain time when its ambient temperature was changed from 20℃ to 33℃.The experiments showed that the logarithm of h was represented approximately by a linear equation of temperature T, and the degree of humidity conditions could be evaluated by the slope (b) of the equation.The b values were used to classify the tested interior wall materials such as plywood, particleboard, fiberboard and so on.The value b of linden plywood tended to increase nonlinearly with the increasing ratio of the area (A) occupied by the wall material to the volume (V) of the steel box (A/V).The value b of linden plywood covered with polyurethane coating was about 2/3 of the uncovered.At the beginning of the rise of the ambient temperature, the different changing tendency of relative humidity was observed between wood-based materials and synthetic of inorganic ones.

One of the basic characteristics of tropical forests is their diversity of tree species and the diversified morphological and architectural traits of the tree species. The study of architecture is an important aspect of the research for structural diversity of tropical tree species. This paper gives a brief account of the development of the science of architecture of tropical trees. The manners of tree formation and the major elements of architecture are described. Main classification elements for architecture of tropical trees include the following: developmental sequence of different parts of the trees, manners of meristem activity, manners of extension growth, and patterns of branching, etc. The dynamics of structure and morphology are implicated in the concepts of tree architecture and architectural model. 23 basic architectural models were recognized by tropical botanists according to elements of architecture. We concisely described the major characteristics of the 23 models. And their similarity and dissimilarity are illustrated in the key and series of illustrate figuers mainly developed by Halle et al. None study on architecture of tropical trees has been conducted in China till now. We expect that this review would stimulate more researches in this field in China, a country with tropical forests in its southern part. This review affords references for further study of architecture of tropical trees in China.

The growing rate curve of young forest has one valley and two peaks and the boundary (the valley point)is in the first and second decade of July.The increments in early stage and on sunny slope are greater than that in the later stage and shady slope respectively.The young trees are more sensitive to water condition than thermal one. The reaction process needs about 10 days.The combined effect of water and heat on the growth is very strong.High temperature can limit the tree growth.The difference of growth between different or ientations of slope is due to different water and thermal conditions.The tree growth on the shady slope is better than that on the sunny slope in weibei loess plateau.

To predict the seed yield of Masson pine (Pinus massoniana Lamb.), a model via visible female cones, immature cones or mature cones in crown, a model via the most informative section of crown, and a model via cutting cones were established on the basis of the number of female cones, immature cones and mature cones after systematic sampling. Each way for modelling had its own merit, but all the three were verified easy, accurate and highly applicable.