We have developed a system with a remote control helicopter which monitors the status of land cover after hillside works. This system has linked a remote sensing technigue to a method of photogrammetry so as to exhibited the status of land cover in a three-dimensional space. The photographs shot from a remote control helicopter were colored and false-colored. As the scales of these photographs were not uniform and the camera carried on a remote control helicopter was a non-metric camera, the orientation theory derived by Okamoto. A were used to analysis these photographs. The random three-dimensional coordinates measured by photogrammetry are changed into three-dimensional grid data. Then image data analyzed from a false-colored photograph were matched to three-dimensional grid data. The conditions of land cover were classified into seven categories by multi-spectral analysis and showed in a three dimensional space in order to grasp the status of land cover after hillside works.

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Stand structure was investigated for all stems≥5cm diameter at breast height (dbh) of 0.92 ha plot in a mature Quercus serrata MURRAY stand near urban areas. Quercus serrata was the dominant species with accounting for 43.1% of all living stems and 71.5% of total basal area in the stand. Dbh distributions of major species showed each of normal, reverse J-shaped and L-shaped distribution. Eurya japonica dominated in the understory. Coppiced individuals with multiple stems from sprout origin and the non-coppiced individuals with single stem from seedling, origin were found for Q. serrata in the stand. The coppiced individuals accounted for 75% of the total living ones. Mean and maximum numbers of the stems per individual were 2.0 and 6, respectively. The mean dbh of coppiced individuals was as large as that of non-coppiced ones, but the mean base diameter of coppiced individuals was significantly larger than that of non-coppiced ones. The individuals with more numbers of stems and the maximum number of stems per individual increased as the base diameter increased. The height of coppiced stem and single stem increased with the dbh by reaching to the top. The age distributions of sampled coppiced stem and single stem showed the similar patterns with a mode at 35-40 years old. This suggests that the stand originated from nearly simultaneous emergence of sprouts and seedlings. Advance growth of Q. serrata were very few and the seedling survivorship of Q. serrata was low. Thus, the Q. serrata population will decline in the near future.

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Survival of trees planted in sandy regions, especially in semi-arid area, depends on laborious watering. The present report outlines green house and field experiments on a labor saving plantation by mingling water-absorbent polymer in beds.
The effects of mixing water-absorbent polymer in the bed soil were determined to be as follows:
(1) In case of sufficient and frequent watering, the mere presence of absorbent polymer is significant. In conditions of insufficient watering, mixing polymer at a higher component (examined at 0.05, 0.1 and 0.2% contents in weight) can stimulate seedling growth. The possibility of damage from too much mixing still remains, however. Research is needed to determine the maximum dose.
(2) In individual tests, the polymer showed better influence on seeding growth than fertilizer. The effects of fertilizer were strengthened by water holded in polymer.
(3) In the polymer mixed sand beds, the range of earth temperature are moderated, besides the expected increase in soil moisture available. These effects become stronger over time.
In the semi-arid sandy regions, a numbers of seedlings are withering away. The waterabsorbent polymer will be not expensive, if plantation was successful with a higher survival rate.

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[in Japanese]

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[in Japanese]

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