The observations on the effect of some sand-fixing plants,which were Salix flavida Chang et Skv.,Artemisia halodendron Turcz.,Lespedeza bicolor Turcz.,Caragana microphylla Lam.,and Hedysarum mongolicumTurcz.,on sandy soil were made.It was observed that sand movements was stoped efficiently by these plants.The velocity of wind within the plantations was greatly reduced so that soil erosion became rather weak and lots of litter was accumulated on the ground under the plants.There were the greatest quantity of litter accumulated in the plantation of S.flavida with 3.5—3.9 tons per hectare and the least in the plantation of A.halodendron with 0.31 tons per hectare. It could be seen clearly on the texture profile that the mechanical structure of the top layer and the volume weight became finer and lighter respectively.The nutrient condition of soil was much improved with marked increases in humus and some nutritional elements such as nitrogen and potassium,especially in the content of potassium obviously increased. Tree plantations should be established within 2 or 3 years after dunes stabilized by the plants mentioned above and a little attention should be paied to the espacement,which could be designed larger than the normal.

In the present paper an attempt was made to introduce Kalman's Linear Filtering and to apply it to the continuative forest inventory.Two estimated values of the linear filtering were used to estimate the changes of forest resources.One was the difference between two elements of flitering vector,i.e,flitering difference;the other was the difference between two estimators on two occasions.The former was more accurate than the latter,but the latter,is more suitable for maintaining the two estimators to be consistent.In addition,the formula of linear filtering,which was used in the various SPR projects of continuative forest inventory on the two occasions,was given and some associated problems were also discussed based on the results of forest inventories made in a forestry bureau of Jilin Province.

To examine the effects of species and disposition of trees on absorbing sound of various frequencies an experiment of reducing noise by trees was conducted in the reverberative room by using saplings. In the experiment 6 species of trees and 9 different ways to dispose the saplings were tested.It was found in the result that all of species and disposition had the founctions to absorb sounds but broadleaved species were more effective than coniferous especially.on the sound waves in higher frequency.

Longiculcita vinaceella abstractella Roesler.is an important insect pest of Aleurites spp in Fujian,Guandong,zhejiang,Hunan and Kweizhou provinces and also in Guangxi Zhuang Autonomous Region.The larvae infest the leaf,terminal bud,flower-bud,ovary and husk of young fruit,causing a considerable damage to these plants,and frequently leading to the death of the seedling. In the field the insect's generations are overlapping.It has seven generations each year in North Fujian.Winter is passed as pupae within its own thin concoons on the fallen leaves of the Aleurites,The adult moths begin to appear in early March next year,and they are most abundant in late March to early April.The moth needs supplemental nutrients after emergence.It hides during the day in shaded places and mating and oviposition take place at night.The eggs are laid singly on the underside of the leaves and the average number of eggs laid by per female is 70 to 392.The newly hatched larvae usually feed side by side on the underside of the young leaves and only the upper-epidermis will remain.Larvae over 3 instars usually spin silk threads binding several leaves together,and they consume entire leaf except the larger veins.The first generation lavae population reach maximun in early May.At maturity they attach themselves to leaves to pupate. The important natural enemies of the insect are Microplitis sp,Xanthopimpla sp,Hyposoter sp and Thomisus lebefactus. For control,the following methods are recommended: 1. Cleaning of field in early winter,to eliminate the overwintering pupae. 2. It is very effective to spary with Fenitrothion,Phoxim,Dipterex(Trichlorfon), Dichlorvos,Dimethoate etc. 3. Dichlorvos used as smoke "741" was found to be effective against 2nd-3rd instar larvae.

To explore the relationship between the characteristics of urea resin adhesive and its bond property,the authors make a study on the rule of precipitation temperature of urea resin.The relationships between precipitation temperature and condensation degree of urea resin and its bond property have been found. It is suggested that the precipitation temperature is a characteristic index which reflects composition of condensation products in urea resin and is possible to presuppose the bond property.

This paper has reported systematically on the wood ultrastructure of Pinus massoniana Lamb.It includes:bordered pits,microfibrillar orientation in the different layers of cell wall,warty layer and crystals.It is the first report on the occurrence of crystals in the pit chambers and on the inner layer of secondary wall or warty layer of tracheids and the lumen of ray parenchyma cells of this pine.These crystals are formed as a result of fungal metabolism of wood all along the hypha.Since the hyphal strands penetrate into the parts as above, crystals can also be found there.This means that anatomists can not classify the crystals as a normal structure to be useful in identifying this pine.This paper has pointed out the difference of pit structure between the sapwood and heartwood,earlywood and latewood,a evidence of the primary structure of torus,the permeability of wood is easier in sapwood and latewood than in heartwood and earlywood,and their causes are indicated too.On the surface of the layer S₂ appearing some random orientation of microfibrils,the author considers that may be the connected layer from S₂ to S₃ or the outer surface characteristics partially on the layer S₃.The sections treated with 0.25% sodium hypochlorite for partially delignification,the warty layer on the inside of tracheid lumen looks like decreasing in quantity and size clearly,and sometime it is not easy to be seen under TEM.

Based on the practical needs of wood production,this paper discusses the supporting structure of curved segment on conveyer in theory.With the use of inner superhigh guide rolling support structure,the problem of serious wear has been solved,and the curved conveyer runs steadily.Through theoretical analysis,the principal parameters,such as radius of curve,inclination angle of guide slot,superhigh of inner rail and tensional calculation etc.,have been determined rationally,thus a concrete theoretical basis is provided for design of the curved conveyer.

It is in general reviewed in this paper that,with a ration-wide,the achievements of establishing shelterbelts had been gained since the founding of new China and some main patterns in which shelterbelts were set up in the different parts of the country. This paper in detail assesses the critical techniques to establish shelterbelts,with emphases on the project,silviculture,thinning,regeneration and negative effect on agricultural crops.In addition to the activity of protecting crops from the harmful weather,the ecological and social benefits of shelterbelts are also discussed with some examples.

The frequency of lignotubers on the seedlings of Eucalyptus tereticornis Sm.was studied.There are indications that lignotubers occur in all populations within the range of the species,but the lignotuber frequency varies significantly among the populations with an average value of 83.5 percent.Compared with E.camaldulensis and also E.amplifolia,the lignotuber frequency of E.tereticornis is much higher.

In order to evaluate site quality for afforestation in the arid region of loess covered by low woodland and shrubs mainly consisting of Caragana korshinskii Kom.a quantitative method was employed.Based on the quantification of critically ecological factors as independent variables,which affect the growth of trees,a deterministic mathematical modle was established to predict fresh weight of C.korshinskii at the age of four years through multiple regression analysis.Thus the fresh weight above ground can be used as criterion to evaluate the site quality before starting afforestation.

The Landsat MSS imagery has been applied in many research and production areas and the astonishing results have been obtained.In the meantime,with the deepened and widened development of the Remote Sensing technique,more requirements are proposed regarding the quality of MSS imagery for solving the impressing problems in research and operation.What is the potential of this kind of imagery?What is its prospect? These are the inevitable questions in regard to the capability research of the Landsat MSS imagery. At present,a great deal of articles deal with general discussion about the applicability and interpretation potential.It is the first time,however,that a quantitative statistic analysis of the spatial and spectral resolution of this kind of imagery in terms of the construction of the pixels is made,which may provide a basic reference for the evaluation of the potential and applicability of the imagery.

Based on the effect of natural defoliation of pest insects on the growth of poplar tree,an artificial defoliation has been made to observe the influence of this treatment on poplar tree's growth.The results obtained are as follows: 1. There was no significant effect of artificial defoliation 25% and 50% on the growth in diameter and in height,as compared with the control.However,a defoliation of 75% and 100% resulted in the decrease of 21.2% and 50.8% in diameter and 20.5% and 44.7% in height of the tree tested,respectively. 2. The average amount of leaves eaten by a single Clostera anachoreta (Faby.) from the first generation to the fourth generation was 15935mn²,8184mm²,10226mm²,14168mm²,respectively.

The oleaster leaf-spot caused by Septoria argyraea Sacc.is a discase of oleaster tree which is an important nitrogen fixation woodly plant.Some nodules exist on its root,which can fix the nitrogen from air.As more the leaf spots produced the damages are resulted.The number of nodules appeared to be correlated to the serious grave of the disease.Experiment shows that the damages produced by the disease are: Lowing the number of the nodules. Weakening the activity of N-fixation of the nodules. Decreasing the growth race as well as the Nitrogen content of the plant. Because of the disease,infected plant are 3—6 times less than normal plant in dry weight,3—16 times in number of nodules,21—100 times in centent of the nitrogen fixation.

The effect of Dendrolimus punctatus Walker caused defoliation on the growth of Pinus massoniana Lamb and Pinus thunbergi Parl is studied. A empirical formula is derived;management index=larvae density when 50% crown totally defoliated/6.83 It is not nesessary to make a control decision until the larvae density per tree exceed the management index. A atable based on a significant coefficient between breastheight diameter and foliage biomass is shown.From this table,one can find out the management index conveniently if only he measures the breastheight diameter of tree.

The wear of knife during the veneer-peeling procedure is a serious problem.Besides mechanical wear of the knife,acetic acid and polyphenols in the sap may also react with the knife and corrode it.According to the theory of electricity-chemistry corrosion,anew method "Veneer is peeld under the acting of electricity applied directly" has been designed and the wear of knife is reduced.