Seasonal changes in the nutritive composition concerning the food plants and the damage in the apple orchards by Japanese serows in Otobe, Morioka, Iwate Prefecture

We examined the damage of apples caused by the Japanese serows and analyzed the nutritive composition of the food plants as well as considered the food selection of the Japanese serows depending on the seasons. The two orchards in Otobe, Morioka, Iwate prefecture and Mt. Koujinyama which is close to them were set as the study area. The damage ratio among the all apple leaves were recorded after reviewing them in the two apple orchards. We estimated the amount of damage by multiplying the damage ratio of the apple leaves and the number of damaged trees. We also analyzed the amount of moisture, ash content, crude fat, crude fiber, and crude protein of the leaves of apple and Japanese kerria, which had been collected from June to November, with the rules so as to estimate NFE (nitrogen free extract). We applied the single regression analysis to compare the amount of damage in the apple orchard A and the nutritive composition of Japanese kerria leaves as well as the amount of damage in the apple orchard B and the nutritive composition of apple leaves. As the vegetation survey, 50 quadrats were set up in Mt. Koujinyama and the coverage of each plant was recorded. It verified the most significant damage caused by Japanese serows in the apple orchards was the feeding damage of apple leaves. The amount of damage in June was the greatest, and it decreased thereafter. To obtain the values from a regression equation by specifying the amount of damage in the apple orchard B as dependent variable (Y) and the ratio of crude protein of the apple leaves as independent variable (X), its simple linear regression formula was calculated as followed: Y=0.086X-0.055 (R**2=0.72, t=3.20, S.E.=0.28, p=0.03). It proved that the Japanese serows intrude into an apple orchard and feed apple leaves when their nutritive value is much better than any other plants in the mountain