In order to asses the air pollution effects on forests, the laboratories involved in the ICP Forests Program must use analytical methods that allow to obtain comparable results for the precipitation samples parameters (pH, conductivity, alkalinity, SO 4 2-, NO 3 - , NH 4 + , Cl - Ca2+, Mg2+, Na + , K + ). In the framework of the project “Analytical Quality Control and Assessment in the Mediterranean Basin (AQUACON)”, each year are organized intercomparison exercises using simulated water samples. The chemistry laboratory of the Forest Research Station Campulung Moldovenesc participated to these exercises in 1996, 1997 and 1998. The analytical methods used and the results obtained are presented in this article. It can be concluded that from the total of 110 results ( 10 for each parameter), 8 1 (74 %) registered deviations less than 20% and 29 (26 %) exceed this limit. The most frequent accepted results (deviation less than 20%) were obtained for pH, Na + , conductivity and Mg2+, SO 4 2-, NO 3 - . The lower precisions were obtained for Cl - K + and Ca2+. For K + and Ca2+ we didn’t use the methods recommanded by the Manual ICP Forests and for Cl - we used an alternative method. In order to verify the precision of our methods and results, our laboratory will continue to participate to intercomparison exercises organised by laboratories certificated at European and international level.

Research made in the atmospheric deposition monitoring program have shown a great variability in the mineral ion content of rainwater samples, especially in samples took under the stand canopy. To prove that the litter in the samplers can influence the results of analysis of samples, it was organised a bifactorial experiment (contact time and the nature of litter) with each factor repeated 3-6 times. In distillate water were placed different amounts of litter, with the contact time of 3 to 30 days, after which were analysed with conventional methods. The obtained results led to following conclusions: (1) in small quantities of litter, the influence of litter on results of analysis was insignificant, (2) in high concentration of litter (1-2 g/l) the errors were of 20-30 % in K and N-NH 4 concentrations, while in the concentrations other ions the error was 5- 20 % from the annual mean concentration and (3) in very large quantities of litter (>5 g/l) the sample concentration can increase with values of 20-80 % from the annual mean concentration. The largest values can be encountered in K and N-NH 4 and the minimum values in Na

This paper presents a likehood model for estimating the risk of windthrow by extreme value analysis. We use the Gumbel model for modelling the catastrophic windthrow at the European level through that we can estimate the probability to appear wind damage with k intensity in a t time period. The return period of a wind damage with an intensity above 1 million m 3 is 3.6 years, and above 10 million m3 is 8.5 years

This part of the paper analyses the elements of particular elicoidal motion of prunning planer. There are remarks regarding velocities and acceleration field, elements which influence them (trunk ray, α0 angle, motion step (p), taper of trunk, a.s.o.) and their effects to stabile working of the machine and quality of prunning. The graphics highlight motion characteristics of artificial prunning planer.