Research on the Influence of Temperature on Beech Crops Raised in Nurseries

摘要

A particularly important determining factor for the installation and development of seedlings during the early years is their ability to withstand deviations from the normal regime of the climatic elements. Beech seedlings have poor resistance to extreme climate changes. The development of seedlings during the first years can be strongly affected by extreme temperatures. During the research, it was noticed that the frosts which may occur during the second half of April and in early May, before foliation, can cause significant injuries to the plantlets. A large part of the beech seedlings appear in early spring, approximately 7 - 10 days before the foliation of beech trees. The effects of these frosts have also been felt in the nurseries located in the area of the Sovata Forestry, in the case of crops sown in the autumn of the previous year in the Isuica Nursery, situated at an altitude of 520 - 530 m, in the vicinity of S?c?dat Creek, and in the case of Solar II Nursery, situated in the village Campul Ceta?ii, at an altitude of 610 m. The latter nursery is neighbored by the trout farm from Campul Cet??ii to the south, by the secondary school to the west, by private residences and estates to the east and by the village road of Campul Cet??ii to the north. In both nurseries the emergence percentage of the crops at the end of April was over 90%. Based on the average number of seedlings emerged per area unit, the losses recorded as a result of the frosts from 3-4 May were, in the case of the Isuica Nursery, 89% on 10 May, reaching 97% towards the end of the month. Unlike in the Isuica Nursery, in the Solar II Nursery the losses due to the frost of 3 May were not uniform. The area that was least affected by frost was situated in the immediate proximity of the larch curtain and the secondary school building, where the percentage of losses did not exceed 2%. Moving away from the larch curtain, the percentage increased progressively, reaching, at about 24 m (on the diagonal of the plot), as high as 87%. This percentage was close to that of the (uniform) losses registered in the Isuica Nursery. Thus, the maximum protective effect was recorded up to a distance of about 9 km (0.75 H), where H represents the height of the larch curtain). From this distance, the protective effect exerted by the larch curtain (and the secondary school building with a height of 8 m) started to decrease. While at a distance of about 1 H, the percentage of losses was 17 %, at 1.5 H it reached 61 %, and at approx. 2 H it neared 90 %.