Ilie Covrig

Research on the Variation of Light Intensity Across Surfaces with Beech Seedlings Planted after the Application of the Progressive Felling Treatment

Abstract The research we have undertaken seeks to clarify some aspects concerning the specific characteristics of aforest microclimate. Spot measurements were carried out for 12 hours/day, on certain days that are typical for the period of vegetation and, respectively, for the period of vegetative rest. Measurements regarding the intensity of light were conducted across surfaces where progressive felling had been applied. The research findings about the light regime are presented below: 1. Surfaces subjected to the progressive felling treatment I - seeding fellings that create cut block sites in the mature stand canopy u. a. 74 B, UP III, Nirajul Mic, the Sovata Forestry. In these regeneration areas appear noticeable changes of the light regime, caused by the intensity of the fellings, the size of the cut block sites and the position of each cut block site sector. Thus, in clear cut block sites, having an elliptical shape of 0.5 H3 X 0.75 H*, in which seedlings have not yet been planted, the amount of light that reaches the soil surface, in relation to the open field solar radiation, is approx. ¼ - 1/3 in the eastern and southern sectors, 2/3 in the central sector and, respectively, 2/5 - ½ in the western and northern sectors. In the case of elliptical cut block sites, with diagonals of 1.0 H X 1.5 H, we have found some variations, in the sense that the eastern and the southern sectors receive, at ground surface, approx. 1/5 - 2/5 of the light from an unforested area, the central sector receives a little over 2/3, while the western and the northern sectors receive 4/5 -1/1 of the light from an unforested area, which is also the area with relatively maximum light availability. 2. Surfaces subjected to the progressive felling treatment II - fellings for expandingcut block sites UP VI, Valea Soveții, u.a 127,the Sovata Forestry. Thus, in an elliptical cut block site (1.0 H X 1.5 H) from UP VI, u.a. 127, at1 p.m.,when the sky was overcast, 50% of full light reached the eastern sector, 40% reached the southern sector, approx. 80-90% reached the center of the cut block site, and 75-85% of the amount of light from an unforested area reached the western and the northern sectors at soil surface level. Forest ecosystems are characterized by a great capacity of solar radiation absorption. As a result of selective processes of absorption, reflection and transmission, carried out at the level of the “active surface”, the light regime inside the forest presents a series of distinct features. Light intensity decreases from the top of the canopy to the ground. The decrease is accentuated in the canopy and much slower in the space underneath the canopy, all the way to the ground. Thus, while an average of 66-67% is recorded at the level of the canopy (2/3 of full light), underneath the canopy it reaches 9% (under 1/10 of full light) and only 6-7% of the light from an unforested area is recorded at ground level. Differences are found from one measurement point to another, within the same level, as a result of the foliage structure and the different thickness of the foliage mass located above the measurement point.

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

Abstract 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 Săcădat Creek, and in the case of Solar II Nursery, situated in the village Câmpul Cetaţii, at an altitude of 610 m. The latter nursery is neighbored by the trout farm from Câmpul Cetăţii to the south, by the secondary school to the west, by private residences and estates to the east and by the village road of Câmpul Cetăţii 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 %.

CONSIDERATION THROUGH REGENERATION OF FOREST FROM NORTH-WEST OF TRANSILVANIAN PLAIN

In forests from north-west of Transilvanian plain the tendencies to obtain regeneration of rammels naturally through specifically treatments applies of this purpose. Owing to rammels un-evenly and of stationary conditions, executions of regeneration cuts under economical pressure except the fructify of basic species, this thing could be practically impossible happen upon all three regeneration types (natural, artificial or mixed). The idea is to use in regeneration process, rammel with natural origin by seed, regardless of high, conditioned by apart to the valuable species and do not present injuries. Perfectly could be to harvest wooden mass according to fruition of principal’s species trough extraction of trees wealthy mature, when is the maximal growth and to realize natural regeneration of resulted surfaces without the necessity of afforestation intervention. This thing could be possible especially according to regeneration spruce firs and beech’s situated in stationary favorable conditions. In studied period (1997-2001), in these rammels succeed natural regeneration percentages around 70 %, and even more, but not in all situations cause also in stationary conditions when the cuts where executed after the fruition of principal species. This paper work propose to analyze the meted situations on Forest Department from Cluj-Napoca according to rammel regeneration establish the necessary measures through vitalize this activity.