Statistical information prove that in the last 50 years the damages caused by snow in forests (especially in the coniferous forests) significantly increased. The research aims are to propose an holistic analisy of the snow damages in forests and for the management of the risk. A better knowledge of the risk can reduce of the impact of catastrophic damages as much is possible and restore the damaged forests in such way so that further catastrophes may be limited in their extent and effects. The main causes of the occurrence of snowdamages are: (a) the structural modifications of forest landscape under human activities, through extension of the artificial coniferous plantations; (b) climatic changes with major effects, represented by the catastrophic rainfalls in short time (1-3 days) in the same region. When these are liquid, the catastrophic floodare are registered and when the precipitation are in snow-form, snow-damages in hilly forests or avalanches in high mountains are registered too. More than 10 catastrophic snow-damages have been reported in the last 20 years in Europe. In some regions, snow and wind damages represent more than 40-80 % of sustained cut in 10 years, with severe effects on the forest management and wood market. In comparison with the wind damages, snow damages are more dangerous, because appear, generally, in young stands, and the management of damaged stands is more difficult and risky. In forests, snow damages are examined in relation with the geographical and meteorological conditions: (a) identification of the natural parameters in different region of Romania for the evaluation of natural risk to snow damages; (b) meteorological and climatological factors which determine snow damages in forests (determinant factors); evaluation of the risk on the basis of determinant factors - probabilistic model; (c) identification of the predisposant and incitant factors in snow damaged forests and quantification of their influence; (d) development of the methods and mapping criteria for the prognosis of risk to snow damages; (e) production of the methods for snow risk analisys and the specific management of stands; (f) rationalization of the financial and human efforts with an increase of the forest stability. The results are the based on the autor's experience in the research and evaluation of four catastrophic snow damages in Romania (1977, 1979, 1993, 1996). Some proposals for the evaluation of stands stability to snow and for the snow risk mapping of the Romanian territory have been developed in recent years.

In the framework of ICP Forests, within the period 1997-1999, the concentrations of Na and Mg in precipitation samples collected in open field and under the wood canopy were determined in the laboratory of ICAS Campulung by atomic absorption spectrophotometry, using a spectrophotometer produced in Romania in 1980. The concentrations of Ca and K for the same period and samples were determined by flame ionization, using an apparatus produced in Est Germany in 1970. Beginning with 2000 untill 2004, the concentrations of the four metallic ions were determined only by atomic absorbtion spectophotometry, using a spectrophotometer produced in USA in 1975 and donate to the laboratory of ICAS Campulung by INRA Nancy. In order to provide the comparability of the results obtained in time, the detection limits obtained were compared and 38 samples were analysed in parallel with the specific apparatus used within the two periods of mesurements. The detection limit was the same for Mg, but much lower for Na (twice), K (tree times) and Ca (ten times) with the apparatus used in 2000-2004 than that used in 1997-1999. The lowest deviations were obtain for Mg (< ∓ 20%) and Na ((< ∓ 30), because for these ions was used the same method (atomic absorption spectrophotometry), but different apparatus. For K and Ca were used different methods (flame ionization and respectively, atomic absorption spectrophotometry) and apparatus, so the deviations were higher ( up to ∓ 100 and respectively up to ∓ 40%).

The sustainable management of the forests must accomplish both main functions: conservation of the production capacity and the ecological service of the socio-economical activities nearby. This functions are produced by every specific stand at different level. For these evaluation, some parameters are used: diversity, stability and the forest continuity. First (Cd) is computed as function of the diversity of species (Cd1), of forest types (Cd2) and of the age structure (Cd3) (formule 4). The stability index (Cst) is computed as function of Cst1 - the stability coefficient of the stands with reduced resilience to disturbance factors and Cst3 of the stand with high resilience; p1, p3 - percentage of the stands in classes of resilience 1 and 3 (formule 5). The continuity index (Cc) depends by Ci - the weight of the silvicultural treatment and pi - percentage of forest area managed with the treatment i. On the basis of these indices, is computed the degree of acomplishing of the function (formule 6). The results permit evaluation of the intensity of the function, as follow: 100-150 - very weak, 160-250 - weak, 260-350 - medium, 360-450 - good and 450-550 - very good. The methos is easy to use based on the data from forest management plans (FMP). Computed for different periods (every 10 years the FMP are revised), the method permit a good evaluation of the forest management quality to assure the sustainable ecological services of the forests.

The paper presents to the Romanian readers a state of art regarding the main aspects of the phenology, based on a wide sources of scientific literature, both foreign and Romanian. Thus, it is performed a general view of the phenology development - including historical aspects, activity of the main (European) national and international networks. A short history of the Romanian phenology - from the first known references until present - both about the phenology of the cultivated and forest species - as the programme of observations are coordinated by National Meteorological Administration (A.N.M.) and Forest Research and Management Institute (I.C.A.S.), respectively - is presented too. The must important aspects of data collecting and processing - i.e. influence factors, methodologies used, phenology and remote sensing, the use of modelling in phenology - are resumed. A special attention received the relationship phenology - climate change, as a new and useful application of the present and historical phenological records.