China is a country seriously affected by desertification it is the main content of combating desertification to protect the environmental resources forits sustainable development, to keep informed about the spatial and temporal changes of desertification for an effective implementation of macro control and management. For this purpose, the coverage of vegetation, the occupation ratio of bare sandy land and the soil texture are determined as three evaluation indicators of sandy desertification degree, depending on the configuration and ecotope of the earth surface. These 3 indicaltors show the productivity of a specific land from different aspects. A comprehensive mathematical model to evaluate sandy desertification degree was set up. According to the national conditions and the requirements of desertification monitoring by remote sensing, these evaluation indicators proposed in this paper audio-visual are, convenient and practical, which can be used not only to evalue the desertification degree of land but also to draw desertification distribution maps through visual interpretation on satellite images or on computer screen with digital imagety on pixel level. This monitoring and evaluation indicator system is testified to be applicable to classification and assessment on spatial distribution of desertification by using remote sensing and computer techniques after field investigation and verification in arid, semi-arid and dry affected sub-humid areas.

The climatic characteristics and the dustproof effect of agroforestry ecosystem are studied in Raoyang County, Hebei Province. The results shows that:(1) In sandy soil area, the dynamic and hydrological effect of the agroforestry system are remarkable, and it is the directive reason for reducing the falling the dust capacity. (2) The stronger the wind-protection ability is, the better the dustproof effect will be. Agroforestry system could reduce the transporting dust capacity effectively, and reduce the falling dust capacity by 20%~60%. (3) Wind-protection effect, turbulivity and soil moisture are the main factor which determine the falling dust capacity.

By means of both asymptotic stable and actual change process of coefficient variation of the diameter(CVD), the compatible CVD model is proposed so as to link three type models (whole stand, size class and individual tree) and better reflect the effect of thinning on forest tree differentiation in the stand. Taking Larix olgensis Henry as an example, the fittings and analyses are carried out for the compatible model, CVD dynamic model without thinning factors and diameter variance model. The result has shown that the compatible model has the best fitting precision among the three models. The compatible CVD model has many desired properties such as compatibility, invariance for projection length, and mechanism, and has clearer biological and mathematical meanings in parameters of the model. There are two conclusions in the description of CVD dynamic changes of thinned and unthinned even-aged stands in different thinning systems: 1) when stand is not thinned, the initial value of CVD determines the direction of CVD curve, if the initial value is higher than the tendency value of CVD, the CVD curve will decrease monotonously, conversely, the CVD curve will be monotone increasing. 2) Thinning intensity affects the speed towards to tendency value of CVD. The more the thinning intensity, the slower speed of tending to the tendency value of CVD and the longer the time needed.

This paper systematlly deals with the applied theory and method of angle measuring in volume growing estimation in permanent point sampling. A new estimator of basal area and volume increment is introduced by measuring reserved trees. Thus the new dynamic monitoring method of system is built based on the estimator.The results show that the methods suggested by author not only improve the traditional method but also eliminate the phenomenon of zero and jumping in the estimation of basal area and volume increment. Meanwhile the theoretical results also show the principle of methods no difference between varing angle ratio and measuring growth of reserved trees in Permanent point sampling.

A new method to store kiwifruit were applied and the physiochemical changes of kiwifruit during storage were studied. In a cold storage house, about 5t kiwifruit was sealed in each of polyethylene tents. There were two sleeves, from which gas could move in or out, at the opposite ends of every tent. A carbon molecular sieve nitrogen generator (CMSNG) was used to produce nitrogen from air, the nitrogen was piped into the tent through the in-sleeve, and the original gas in the tent was removed out through the out-sleeve. When the original gas in the tent exchanged completely by the nitrogen, the tent was sealed. Several days later, when the oxygen in the tents reduced to the lower limit or the carbon dioxide accumulated to the upper limit because of the respiration of kiwifruit, the tents were refilled with nitrogen from CMSNG as before to adjust the gas composition. The above operations were carried out regularly.The results showed that kiwifruit in the polyethylene tents has lower activities of EFE, amylase and polygalacturonase (PG) than the fruit in cold storage, so that the ethylene forming was inhibited, the rate of decomposition of starch and pectin substances was reduced, therefore the storage life was prolonged. In our experiments, when the kiwifruit was stored for 8 months in polyethylene tents, the rate of sound fruit was 92.3%~94.5%, but only 44% in cold storage in 5 months.Polyethylene tens have several virtues: (1)The gas composition was adjusted quickly as one tent with kiwifruit was piled up, (2)Each of tents in the storage house was a independent unit, kiwifruit in one tent was transported out of the storage house conveniently in need of commerce not to effect other tents, (3)The gas only inside of the tents was low in oxygen and high in carbon dioxide, the outside of the tents was of nomal atmosphere, so the changes of kiwifruit in the storage house could be check safely and easyly at any time, etc. Therefore the polyethylene tents storage was a suitable storage technique for kiwifruit preservation.

The chemical composition of Chinese fir seeds from different geographic distribution sites and with the germination rate over 35% was studied. The results showed that the content of soluble carbohydrate, coarse protein, fat, and starch in the seeds was 40~70gkg^-1, 150~160gkg^-1, 230~260gkg^-1, 60~80gkg^-1, respectively. The content of N was the highest among the macroelements, wiich was 24~26gkg^-1.The order of the microelement contents in the seeds was Mn > Fe > Zn > Cu > Ni > Pd > Cd. The results may provide a scientific basis for the quality identification of Chinese fir seeds.

According to the bioassays of the two-year needles of damaged and undamaged Pinus tabulaeformis Carr. and the situation of Dendrolimus spectabilis Butler larvaes growth, development and reproduction fed on these two kinds of leaves, it was found that the chemical components in the leaves of damaged pine had significant changes. The concentrations of isoleucine, methionine, tyrosine, lysine increased, total amino acids and other several amino acids descended. The concentrations of soluble sugar, crude fat, tannins, alkaloid and the ratio of total sugar to total amino acids all rises. There were large changes in fatty acids, phenenes, terpenoids and mineral elements. The larvae fed on leaves of damaged trees had a 33.5% lower in herbivory, a 10% growth in mortality, and fecundity dropped. Damaged P. tabulaeformis showed a significant induced chemical defenses.

In this paper, the simple linear regression relations between population density of Aonidiella sotetsu (Takahashi) and percentage of withered stick and between percentage of withered stick and damage percentage of trunk firewood, multiple regression relation among covering percentage of crown canopy and annual precipitation and water conservation, multiple regression relation among covering percentage of crown canopy and annual precipitation and soil conservation, simple linear regression relation between covering percentage of crown canopy and water conservation percentage, simple linear regression relation between covering percentage of crown canopy and conservation percentage, critical data of water and soil conservation, critical percentage of crown canopy covering, damage percentage of water and soil conservation, damage percentage of crown canopy covering percentage and trunk firewood were studied.The results showed that the control threshold were 2.59, 15.02 and 27.44 head scale/cm², and at the same time the crown canopy coverings 70%, 80% and 90% respectively.

The research was carried out by investigating number of predators and predation capabilities along with mortalities of the pine bast scale (Matsucoccus liaoningensis Tang) inside sampling plot, and by applying the K-value graphic analysis method.It was found that the predation happened mainly on female imago, but seldom on egg sac.Among the predators, such as ladybug, lacewing, mite, stinkbug, ant and spider, the predation capability of ladybug ranks the highest, and the ant the second.The main predator species are ladbug Harmonia axyridis Pallas, Sticholotis punctata Crotch, Exochomus mongol Barovsky; ant Iridomyrmex anceps Roger, and Polyrhachis dives Smith.

Variance analysis on 33 indices of anatomical, chemical, physical and mechanical properties of juvenile vs. mature wood of 10 species from plantation and 4 species from natural forest and plantation vs. natural forest of 4 species in China shows there is significance of differences between juvenile and mature wood in most species. Compared to mature wood, the growth ring width of juvenile wood is wider, the tracheid row is more, the length of tracheid is shorten, the diameter of tracheid is smaller, the microfibrillar angle is bigger, the wood density is smaller, the radial shrinkage is smaller, the ratio of tangential to radial shrinkage is bigger, the moisture diffusion coefficient is higher, the bending strength, elastic modulus of bending strength, compressive strength parallel to the grain, radial shearing strength parallel to the grain, radial cleavage resistance and toughness are smaller, and above 15 indices (46 %) have significant difference in statistics. This indicates that the juvenile wood and mature wood should be considered as 2 series with different properties in processing and using as structural material, and how to shorten the juvenile period and improve the properties of juvenile wood should be taken into account in cultivating forest for structural material.In order to compare the variance of wood from plantation vs. natural forest, the juvenile wood from plantation vs. that from natural forest, the mature wood from plantation vs. that from natural forest have been compared.Variance analysis on wood properties of plantation vs. natural forest of 4 species shows that there is no significance of difference between them in most properties except the following 4 properties (12 %) :compressive strength parallel to the grain of plantation is lower, ratio of trangential to radial shrinkage of plantation is bigger, moisture diffusion coefficient of plantation is higher, and cell wall ratio of plantation is smaller than those of natural one. This suggests that it is possible to cultivate wood with property similar to those of the wood from natural forest.

Water deficit is one of the most important environmental factors which limit plant growth, especially in arid and semiarid areas.Influences of water stress may be involved in many aspects on plant growth and development.Therefore, know ledge of these mechanisms in physiology, biochemistry, genetics and drought tolerance may assist in decision making in the future for drought resistance breeding.In this paper, we commented on and discussed some results obtained recently from extensive studies in the field in tree species, including influences on DNA transcription and expression, on PS Ⅰ and PS Ⅱ system, on stomata movement, on adaptation and response, on water use efficiency, mechanism of drought resistance, screening of drought tolerance index, and tolerance engineering.We presented our points in these aspects, especially in tolerance engineering.We presented our points in these aspects, especially in tolerance engineering and screening of effective traits by which selection is undertaken.

In order to understand the development and the achievements of ecological harvesting since establishment of The People's Republic of China, the author of this paper highly analyzed and summarized a lot of historical data.This paper was divided into three sections.The first section introduced ecological harvesting measures, such as cutting system and skidding system, regeneration methods, stump debarking, slash disposal etc.The second section introduced operational technical measures with highly environmental considerations.The ecological measures about the oprational organization and management were presented in the last section.

In view of property of environmental value of modern forestry management, this paper presented the system of forestry management types in China, which mainly includes natural reserves management, management of ecological forestry engineering, comprehensive management in forest areas and urban forestry management, etc.It also gave the classification of forest types based on the characteristics of environmental function of different forestry management types.Herefrom, this pater puts forward the system of evaluation indicators of environment function for different types of forestry management.

This paper studies a method to test the seed viability of Yunnan pine (Pinus Yunnanensis Franch) by the radiography with water as contrast agent.The results showed that the method can be used for rapidly testing seed viability in accordance with its germination percentage.The suitable procedure is as follows :The seeds were dried in a drier(30 ℃) with silica gel(SiO₂) for 5.5 hours after the seeds were soaked in water(25 ℃) for 24 hours and put on a germination medium for 24 hours.The internal structure of viable seeds can't been seen on its picture or slightly seen.Based on these dead seeds and viable seeds can be determined easily.

The adults of Apriona germari were fed in rooms with insecticides of benzoylphenol No.3 and triflumuron.The results showed that there was no obvious effect on the morphology of the internal reproductive system of the adult insects.The ultrastructure of the sperms of male A.gremari was observed and clearly defined by using electron microscope.Benzoylphenol No.3 can obviously decrease the sperm amount and cause sperm structure malformation, and there were no obvious effects on eating behaviour and life span, and some obvious effects were found on egg amount laid in the early stage of the adults, but there was no significant effect on the total egg amount laid.However, benzoylphenol No.3 and triflumuron treatments could decrease the egg incubation rates to 39.92 %~ 48.82 % and 74.33 %~ 100 %, respectively.