Stump sprouting of Eurya japonica within a current year of the cutting was examined atcutover plots cut in 1987 and 1988, in a Quercus serrata stand and at a clear-cut area cut recently. Ratio of sprouted individuals to total cut ones was lower when the cutting was done in Augustthan in June in the plots of the Quercus site, indicating that the sprouting of Eurya japonica isinfluenced by cutting seasons. Individuals in the age of 5 to 20 years old possessed relativelystrong sprouting ability compared with other aged ones, although growth conditions beforecutting might influence their sprouting ability.(Base diameter) ² × height of the individuals beforecutting was used as estimates representing the amount of below-ground biomass which mightindicate that of reserved substances, resulting that there was no distinct relationship between thenumber of sprouts and these values. For each sprouts, there were significant positive allometricrelations between sprout length and, stem and leaf dry weights, respectively. The coefficients ofrelative growth were nearly equal between two sites with different light condition. Althoughmean number of sprouts was nearly equal at both sites, mean sprout length was larger at thesite with better light condition, indicating that the growth of sprouts is largely influenced bylight condition. There might be a negative relation between the mean sprout length and thesprout density within a individual.

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Straw checker-board is one of lateral barriers against drifting sands established to guard the road and railway through the semiarid sandy region in China.
This article describes some investigations in the functions of the straw checker-board (A) adopted on the sea side road in Tottori Pref. Japan, and compares those efficiencies with an alternative checker-board (B) structured with straw mats of poor flexuosity and poor wind passability.
By A sand deposition progressed leeward indeed. But by B sand deposition initiated in the central part and expanded both leeward and windward.
Ultimate rise of sand surface averaged within B was approximate to the height of the structure designed (30 cm). By A, creeping of sand surface layer depressed the effective height of the structure to half.
Lateral variations in wind velocity measured at 50 cm high above the sand surface showed that B brings an accerelated region above the windward front.
However, ratios of wind velocity in the medium of the structures and on the unaffected part showed that the B reduces wind velocity more than A at 30 to 50 cm high above the sand surface.

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The effects of water stress on the morphological and phenological aspects of leaf production of seedlings of five tree species, namely Pinus densiflora, Quercus glauca, Zelkova serrata, Caragana korshinskii and Hedysarum scoparium, growing in plastic pots with Vermiculite under four levels of soil moisture contents were studied for 3 years. Dry conditions increased the length and decreased the weight of pine needles. Both the number and the size of leaves and the stomatal density of Q. glauca did not show any relationship with soil moisture contents. In the case of Z. serrata, the amount of leaves per tree decreased and the mean size of individual leaf became small with the water stress, but the stomatal density increased. C. korshinskii had stomata on both sides of the leaf and the water stress increased the stomatal density. The water stress affected the period of new leaf elongation and the time of defoliation of Q. serrata, C. korshinskii and H. scoparium.

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Emergence and survivorship of Quercus serrata seedlings were followed periodically on the forest floors with intact and experimental treatments, for three years (1988-1990), in a mature Q. serrata stand with developed understory of evergreen shrubs (e.g. Eurya japonica) near urban areas. Treatments were with and without litter layer after the understory cleared. Relative illuminance on the floor was increased by clearing the understory. The greatest number of new seedlings emerged on the floor without litter layer and understory. Seedling emergence on intact floor was delayed about one month. Every early emerged seedlings had a lower initial mortality, and the survivorships were best compared with other later emerged ones. Survival rate of current seedlings was significantly the lowest in the intact floor. Survival rate of one-year seedlings was the highest on the floor with litter layer and without understory, and was the lowest on the intact floor. No seedlings survived on the intact floor at the time after three years following their emergence. More branched seedlings occurred on the floor without understory. Survival rate of branched seedlings was significantly higher than that of unbranched ones. It was concluded that Q. serrata seedlings could not establish on the floor with developed understory, but the understory clearing provided favorable conditions for their survival in the Q. serrata stand.

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Estimating method for effect of tree root on a slope stability wasinvestigated. Large scale (30×30×30 cm) direct shear tests for rooted soil and pull-out testswere made using same shear apparatus and giving test conditions. Comparing those testresults, a new model that can infer the reinforced shear strength of roots from the pull-outstrength was developed. Simulated reinforced strengths by the model could coincide thoseobtained by the shear tests very well. Pull-out test is considerably easy and practical even inforest fields. The pull-out strength reflects influences of slope conditions and intact rootmorphology. So, it gives extremely worth information in a field. The model should beimproved to apply actual forest slope stability problems.

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