In Italy the palebark pine (Pinus leucodermis Antoine) forms natural populations present in Calabria and Lucania at the borderline between the two regions on calcareous soils and litho-soils. The surface range is about 5700 hectares, distributed in four natural groups of vegetation, two Apennine areas (Alpi, Spina -Zàccana, Pollino) and two coastal areas (Palanuda-Pellegrino, Montéa). In the mountain areas the species becomes exclusive and shows resistance to climate harshness at high elevation, ability to colonise ecologically difficult sites, aptitude and specific reliability to artificial spreading. The experimental plan, carried out without any repetition because technically unfeasible in the area, estimated three input variables: plastic bag-grown S2F2 and bare-rooted seedlings S2T2, inter-distance on the terrace (0.5m, 1m, 1.5m), elevation a.s.l. (1400m, 1550m, 1700m). 4 yrs old seedlings, one half plastic bag-grown and one half bare-rooted, were transplanted in autumn in each site on 24 terraces (4x3x2) handmade in summer. Each sampled area was made up of four adjacent terraces for an overall length of 184 m. Transplanting operations were completed in December and an enclosure was set up to protect the plantation from grazing. As a whole, the experimental areas was shaped as a rectangle. Additional terraces, carried out in the lower part, were planted with bare-rooted Austrian pine and Silver fir seedlings at an inter-distance of 1m and provided the direct comparison with the same thesis of palebark pine. Maintenance practices were undertaken in June and in July of the first and second year to eliminate weeds and shrubs along the terraces. The mensurational surveys were carried out in 1982-1983-1987-1994-2007-2009. The quite complete mortality of Austrian pine and Silver fir transplants in 1983-84 made impossible any further comparison among the species. The statistical analysis was applied at yrs 1, 12 and 27 from the plantation and concerned the following dependent variables: survival rate, height to diameter ratio, taper ratio. Over the time-intervals 1982-1983, 1982-1994, 1982-2009, results showed: (i) the higher survival rate (95.5%) and height to diameter ratio at the major elevations and at the wider interplanting distances with plastic bag-grown seedlings; (2) the same system accounted for increasing the taper ratio as compared with the bare-rooted system. Mean diameter is 9.8 cm, mean height is 5.29 m at the age of 27 in the 18 test areas. The first fruiting appeared at the age of 16-18 years.
S. Avolio (Thu,) studied this question.