In the period from 1975—1976,the author made pathological and fungal investigations in forest in a region located below an altilude of 5,000 meters in Tibet,where a complete and comprehensive spectum of perpendicularly distributed forest was seen. Here is provided a very rare natural laboratory in the world,in which there exist very good conditions for the study of the ecological aspect of the rust.After a preliminary study the rust flora investigated contains 20 genera and we nomiate it the China-Himalayas rust flora. This rust flora is classified into 3 types in according to conditions of water and temperture:1) the plateau type.2) the temperate zone type.3) the sub-tropical zone type.Each type may be charaterized by any species belonging to it.The analysis that has been made shows that the region investigated has the following features:It is a place of origin for a new rust type,the rust flora in this region has affinities to those in other regions,thus it is possible for this rust flora to constitut a potential source of forest disease.

This paper deals with the provenance tests of three new clones of the Aigeiros Poplars,namely Populus deltoides cv.Ⅰ-63/51,P.deltoides cv.Ⅰ-69/55 and P.× euramericana cv.Ⅰ-72/58.The height and diameter of these new clones grew rapidly.Their increment was higher than that of the standard clones of Euro-American poplarⅠ-214.The height and diameter growth measured four years after planting average 15—17 m.and aboout 25—28cm.respectively.Their resistance to Melampsora rust and Marssonia diseases was appreciably high.In conclusion,these new clones are characterized by fastgrowth,high production and disease resistance and show a well promised development in the southern plain of the Yellow River.

By chemical methodes the trail-following compound,4-phenyl-cis-3-buten-l-01,was synthesized.The bioassays by four species of termites showed that the compound had good activity,and some mimic field bioassays were made.

This paper summed up the results of over five years investigation of the plantation-grown Sassafras tzumu Hemsl.in many sample areas.It is affirmed that the factors caused early senescence and lower production are:unsuitable site selection,overcrowded density of initial planting as well as tending and thinning out of time. For hill-land forestation of Sassafras tzumu Hemsl.in Chekiang,it is suited to be planted in the valleys and on the hillsides below 800—1,000m in altitude.It requires acid soil with pH 4.5—6.5,which is deep,loose in structure,moist but not waterlogged. Sassafras tzumu Hemsl.is extremly intolerant to shade,it prefers thin planting with a density below 600—900 plants/hectare. Large planting hole with deep turning is essentially important in preparing plantation for rapid growth of Sassafras tzumu Hemsl. In afforesting a mixed forest with Sassafas tzumu Hemsl.,it had better to select shade-tolerant,slow-growing species,such as Pseudolarix kaempferi Gord.or hardwood broad-leaved tree to compose the best multi-storeyed forest.

Intensities of photosynthesis of Chinese chestnut(Castanea mollissima Bl.)(trees and seedlings)were determined by colorimetric method under differend laboratory and field conditions,in the Shantung Pomology research institute. The treetments used were:foliar spray of essential elements to seedlings in sand culture experiments,and of some nutrient solution to mature trees;irrigation to roots or spray of water on leaves;Co₂ fertilization by increasing Co₂ concentration in the air,and application of certain growth hormones.Our results were,photosynthetic intensities of all the plants under treatments showed a higher rate than those of the controls.For example,photosynthetic rate of the seedlings in sand culture sprayed with 5% of P solution is 2.78 Co₂mg/dm²/hr.while that of the control(lack of P in sand culture)is only 2.38 Co₂mg/dm²/hr.similarly,rate of the trees under irrigation is 1.84 Co<_sub>2mg/dm₂/hr.with those of the control are 0.54 Co₂mg/dm²/hr. Among the chestnut varieties cultivated in this intitute,differences in photosynthetic intensities are also discernible.

This process of chipping logs to manufacture lumber is different from most other wood-cutting processes.The main characteristics of the former are that it not only requires to have a flat surfaces of the lumber,but also to have the appropriate sizes of chips;besides,it requires that the chips can not be deformed too greatly.In order to meet the above-mentioned requirements,mimicking the practical working conditions of chipping,we mounted the contricted chipping head on our reformed four side moulder to make the experiments in the cutting properties of the head. This article analyses the chipping kinematics,and on the basis of this analysis,it deals with the approximate formulars for calculating the thickneess and length of the chips.The width of the chips can be controlled by adopting grooving knives,the grooves positions of them are alternatively arranged on the head.For avoiding that the chips are deformed too greatly,we may increase the rake angle to 50°,and then it will cause the strength of cutting dges to decrease and the friction of the clearance surfaces of knives to increase.So long as a bevelled surface is ground on the clearance surface of each knife,the above-described faults can be eliminated.

1. The Sand-Block Method was adopted for the present for the tests of toxicity of water-borne preservative against wood fungi.The results of the toxicity of six formulation preservatives against Polystictus versicolor(L.)Fr.are summarized as follows: By the toxicity of Borax/Boric acid/Sodium fluorid/Chrome/Copper(i.e.B-B-F-Cr-Cu),B-B-F-Cr-Zn(Zine)and Zn-Cr-As(Arsenic),the threshold retention (T.R.3.0—4.0 kg/m³)were higher,while by that of Cu-Cr-As(T.R.1.5—3.0kg/m³)was found highest. As a result of leachability the toxicity of Zn-Cr-As and B-B-F-Cr-Ca appeared mostly higher than that of B-B-F-Cr-Zn.Their T.R.of the former two were 5.5—6.5kg/m³,but the latter was 6.5—11.5kg/m³.From among the T.R.of Cu-Cr-As (4.0—5.5kg/m³)was the highest. In regard to the toxicity and leachability(five days),the six formulation preservatives against Chaetomium globusum Kune.con be arranged in three groups:The toxicity of Cu-Cr-As belongs to the highest rank,that of B-B-F-Cr-Cu to the second,also these of B-B-F-CrZn and Zn-Cr-As belong to the third. 2. Using Sand-Block Method for the tests of toxicity of water-borne preservatives against termite(Reiculitermes speratus Kolbe)was the toxicity of B-B-F-Cr-Cu and Cu-Cr-As shown higher than that of Zn-Cr-As. 3. Six preservatives are not corrosive for iron.

It has been found that rosin amine can be prepared through a process of hydrogenation of resin acid nitrile,an intermediate product,which is obtained from rosin by introducing anhydrous ammonia in a flow rate of 90—100ml/min at 240—330℃ in the presence of ammonium tungstate as catalyst.The reaction is considered to be completed when acid value of the product is less than 5.Rosin nitriles can be purified through vacuum distillation.We conduct the hydrogenation of rosin nitriles by bubbling the gaseous hydrogen through a tube hydrogenator with alcohol as solvent and Raney nickle as catalyst,so that the initial pressure in hydrogenation could be lowered to 25kg/cm² other than 100—150 atm.and the temperature to 90—105℃ other than 120—150℃ as reported by other workers.After recovery of the catalyst and alcohol and vacuum distillation,the fraction obtained at 180—210℃/5mm Hg is rosin amine.A comparison of the main characteristics of the rosin amine prepared with that produced by the Hercules Co.is mad,and an ultrared spectrographical identification in also furnished.

The data of crow width and DBH for more than 500 stems above average tree pertaining to about one hundred temporary sample plots(area 200—500m)of different stand types are collected.Significance of difference among stand types are tested.Results of investigation indicates that relation between DBH and crown width is not effected the age of stand,stand-density and site condition.Thus:C_w=D/2.397+0.00254×D R=0.99 S=±0.15 The empirical equation of DBH and maximum stand density has been found as:N=25.95+23,961.17×D^-1 R=0.99 S=±37 Through trials of stationary thining experiments,a guide of optimum density for managing Larch plantation has been developed,which can be used as the technical criterion for controlling thinning intensity in practical use. The application of this guide and its effects are also described.