The vessel elements of rettan canes in 24 species of Calamus and Daemonorops genera have been described. Only simple perforation plates occur in C. thysanolepis Hance. All the other species have both simple perforationplates and multiple perforation plates,but the proportion of the vessel elementswith multipleperforation plates is small, and most of them occur in the periphery of vascuclar zone. In addition, a few spiral vessel elements withmultiple perforation plates have been observed. From the stem bark to thecentre, the width of vessel elements in metaxylem increases; the length ofvessel elements in most of the species shows an increasing trend and partspecies contrary, or no regular pattern.

With field experiment method, the regeneration conditions of Larix gmelini in primitive old-growth forest are studied. In mast year, the falling seed in old-growth forest amounts to 300-1000 seeds/m², the rank of differentforest types is listed as follows Ass. Alnus mandshurica,L. gmelinii>Ass.Betula fruticosa, L.gmelini > Ass. Herbage,L. gmelinii>Ass. Ledum palustre,L. gmelini. The emergence of seedling occurs mainly in June,the death predo-minately in July. In August the seeding amount has little change. Theseedling survive shows following sequencs: Ass. Betula fruticosa, L. gmelini>Ass. Ledum palustre, L. gmelini>Ass. Alnus mandshurica, L. gmelini >Ass. Herbage, L. gmelini. This order is mainly determined by soil surefacemoisture. If soil moisture is higher, the seedling of L. gmelini occurs moreabundantly.

The types and the characters of acoustic behaviors by larvae living in host timbers in the longhorned beetles, Nadezhdiella cantori (Hope) and Apriona germari (Hope), were studied. In larval living hosts, vibrational sounds areproduced by their feeding and crawling activities. In feeding sounds, the pulsetrain (PT) has higher amplitude but shorter lasting (about 60ms) of time, andthe maximum vibration frequency may reach to 700Hz. While in crawlingsounds, the PT has lower amplitude but longer lasting (100-300ms), and themaximum frequency is lower than 300Hz. The frequency analysis revealed thatthe feeding sounds are different between two species. The power-spectrum offeeding sounds in N. cantori consists of two peaks and the second one (MPF424+43Hz, n=13) takes the main part of signal energy. Though the spect-rum of feeding sounds in A. germari is also formed mainly by two peaks,the signal energy is given by the first peak (MPF=359+23Hz, n=16, timberⅠ; MPE=293+26Hz, n=24, timber Ⅱ) principally. Liited by detecting techniques, the characters of this larval produced solid-born sounds could notbe determined precisely here.

Forests insuration is a new kind of insuration in China. One of the questions is how to decide the insuration rate. The present paper, analysing the fire date collected in the areas of Fujian Province has given the Probabilitydistribution of the number and the area of forest fire. Mote-carlo method hasbeen used to simulate the number and the area of forest fire which will su-pposedly occur each year and a reasonable inauration rate has been determin-ed

Three species of willow——Salix turanica, S. caspica and S. triandraconstitute the principal foraging species for the beaver in Xinjiang. Investigations were designed to study the beaver's foraging strategy in fall in theBurgan River Reserve of Xinjiang. As predicted, beavers foraged fewer treesat increasing distance from the river's edge or the food cache and were moreselective to different size of trees. Beavers tended to cut farther in upperreaches than in lower reaches. Trees near the food cache were seldom cut.Trees in the 2.5-4.5cm category were preferred. As the distance from thecentral place increased, beavers tended to cut trees of 3.5-4.5cm in diame-ter. Large and small trees tended to be selected at any distances. It was notedthat the beaver usually cut in a spotty or "block cutting" way, producingdecided"foraging places". The cut density was correlated directly with thestand density. On the other hand, the rate of available trees cut was inverselycorrelated with the stand density. The oimum range for beaver's cutting was within 15m from the shore and between 40-120m from the food cache.When beavers cut away almost all the trees with no selectivity within reachof their activities, cut the largest trees heavily, or shift their winter burrowfrequently (1-2 years), it means that it is hard to carry the standing quan-tity of beavers for the habitat. Human activities were the primary factorswhich made the degeneration of the woods. Prohibitting from felling trees andgrazing is the key step in the beaver's conservation.

According to the theory of the least cost of timber skidding and transportation and the local facters of the northeast China, includding the forest resource, the natural condition and the forest roads, this research sets up ascientific method of planning forest roads, and a way of determining reasonableskidding distances and road separations. This paper makes the forest skiddingroad planning system more perfect and the theory of the forest road networkmore appliable.

This paper gives a detailed description of microscopic and ultrastructure and their effects on the permeability of the woods of Picea jezoensis var. komarovii and Abies nephrolepis. The abundent amorphous substances are depo-sited in the bordered pit membrances and the different layers of cell wall andaround the microfibrils of tracheids, that may be a main factor of the lowpermeability in heartwood of the two woods.

The result for analysing the relationship and structure between the forestry scientific and technological progress (FSTP) and forestry resources increase andeconomic crisis decrease finds that there are two kinds of means to increase forestresources by FSTP. One is by recovering forest resources, and the other is by decreasing forest resources consumption. The study also shows that "development","utilization", "conservation" and "storage" are four kinds of activities in FSTPctivities for forest resources increment. The system dynamical model hasbeen established according to the opinions metioned above, and the conclusionof model analysis points out that the effectiveness of FSTP is obvious whichis indicated by four index value of scientech level coefficiency, contributionto forest resources, investment return rate and benefit evaluation. Of which,the effectiveness of resources increase by refforestation way is much more obvious than resources increase by consumpationcontrol way. Among differentFSP activities, the effectiveness of conservation behaviour is the first, whilethat of development is the second, and utilization is the third.

Bursaphelenchus xylophilus and B. mucronatus were further confirmed to be two different species. The pathogenicity and the bursa forms of the twospecies evidently differ from each other, the bursa of the former species iseggshaped, while that of the latter species is flatmouthshaped. The physiological tests indicated that the two species couldn't mate with each other.Biochemical experiments showed that the former species esterase had three isoenzyme bands, and its relative electrophoretic mobilities (Rf) were 0. 42, 0. 45and 0.49 respectively, and that the latter species'esterase only had oneisoenzyme band and the Rf was 0.65. On the other hand, there were obviousdifferences between the two species about the distribution of fatty acids.

The gathering value size of the horizontal tesion coefficient (λ₀) of suspended condition of non-loading cable, which is based on the hypothetic conditions and its equation of the parabola theory, is founded the calculating formulaeof the main parameters of the design and fixing, is obtained by the study offorce analysis of non-loading suspended cable in this paper.

This paper studied the production and nutrient element contents of litterfall in Chinese fir plantation as well as its decomposition placed on the soil above ground and in soil underground in midmountain region of Laoshan,Tianlin county, Guangxi. The results indicate: 1. The mean annual litter in 17-19-year-old Chinese fir plantation is5.176 t·ha^-1 in Laoshan. 2. Total amount of nine nutrient elements of the litterfall returing to thesoil is 118.86 kg·ha^-1)·a^-1, in which N 39. 43, P 2. 02, K 7. 65, Ca 54. 80,Mg 11.68, Mn 3.07, Cu 0.05, Zn 0.12 and B 0.04 kg·ha^-1)·a·^-1 3. The decomposition of litterfall on the soil above ground is comparati-vely slow and the decay rates of the leaf, branch and fruit are 0.3308, 0.2062and 0.2358 g·g·^-1a^-1 respectively. 4. The rate of weight loss, the rate of translocation of nutrient elementsand the quantity of the various groups of microorganisms of the litterfall insoil undergound (20cm) are higher than that on the soil above ground.

Cathay hickory has more flowers, but less fruit, a lower fruit set percentage, which is one of the problems in its production. Its female flowers have a long flowering period and a habit of waiting for pollination. A 4-year trialshows that its fruit set percentage might be increased by 40% or so by assistant pollination. With exroot nutrition, applying 0.3%B+0.3% urea and 0.3%B+0.3% P or K the fruit set percentage could be increased on an average by32.4% and 31.3% respectively compared with the contral. Chemicals and exogenous hormones which have remarkable and stable effect on fruit setpercentage during the flowering period are 0.02% CuSO₄ sprayed and 0.1-0.2% CuSO₄ brushed on the trunk, which increase the fruit set percentage by30.1-126.8% and 24.2-26.2% respectively compared with the control. Spraying 0.01-1.00ppm TRIA during the flowering and young fruit period andbrushing 10ppm TRIA on the trunk, the fruit set percentage could be increased by 8.7-16. 3% and 50% or so respectively. Brushin 5ppm NAA on the trunk and spraying 40ppm IAA during the flowering period could increase the fruit set percentage by 34. 8% and 42.2% respectively. The fruit sets of suchtrees which are in poor physiological status, could be increased by some agri-cultural measures, such as rootbreaking, barkcutting, girdling and stickingthe bark reversely, and so on, in an average of 29.4%, 32.1% and 36.7%respectively.

The trial was established in July 1986 and comprised of 10 provenances of E. nitens and 4 related species, E. globulus, E. maidenii, E. bicostata and E. viminalis. Local seedlots of E. globulus and E. maidenii were includedas contral. 4-year results indicated that there were significant difference between species and between provenances in the growth of height, diameter andvolume. Provenance from Federation Range (12401) has the heighest growthrate while provenance from Marshalls SPUR(15015)has the lowest. The volume of provenance 12401 was 2.5 times as much as that of 15015. At age 4,the volume of E. nitens was 23% and 45% larger than that of local E. globulus and local E. maidenii respectively. Bioclimatic analysis showed that E.nitens appeared to have great potential in plantation forestry in Yunnan-Gui-zhou plateau area. It would also be promising in the east part of Sichuan and the south Jiangxi and Hunan Province as well as south Jiangsu Province andnorth Zhejiang Province.

From 1987 to 1991 a survey on the rational stand density after one-time final thinning and the effect of deep soil tending orperation on the growth of Chinese fir plantation in fastgrowth phase was carried out in Dagangshanmountain, Jiangxi province. The result shows that the reasonable stand densityafter thinning should be kept at 1350 trees/ha or so on sites with a site indexof 16m in the hilly area; if a stand has a initial planting density above 2505trees/ha and no thinning afterward, it will be subjected to the risk of price.On sites with high quality class, the yield volume is maily determined by stand density while the deep soil tending has no significant effect, the increasedDBH growth by thinning is not detectable untill the second year since the DBHgrowth in the first year by thinning is not significent greater than that in theuntouched stands. It is expected that through one-time final heavey thinningthe rotation for Chinese fir can be shortened by 8 years on sites with highquality clas

The remainder left from tending and thinning of the halfmature forest and the young growth not only influence the forest hygiene, but also increases the fire denger rating. Based on a large number of experiments in Daxinganm ountain,the critical facters, which affect fire behaviour and harm growingtrees are the distance from the burning point to the growing trees, the burn-ing season, the piling size and moisture content of the remainder. The feasibility of burning treatment in winter is put forword in this paper.

The secretion regulation of pine gum of Chinese pine in deteriorated forest in Taihang mountain area was revealed. The Results show: the pine gumoutput has relations with the temperature in the forest, the DBH, the slopexposure, the dipping wood tapping time and so on. The temperature in theforest and the DBH are both positively correlative with the pine gum output;Using ordinary method, the pine gum output gotten from the shady and semishady slop is 14.7% and 13.9% higher than that from the sunning slop; Thepine gum output per tree using α-NAA is 19. 5% higher than that usingordinary method; The most suitable dipping time is at 7:00-8:00 am in Julyand August.