Growth Characteristics of Robinia pseudoacacia (Linnaeus, 1753) Plantations After Applying of Agroforestry

Forest plantations with and without agroforestry practice are being analyzed. Biometric characteristics (mean height, stem volume, volume of construction timber and total volume) are better in the case of agroforestry with 2.11 m, 0.789 m3, 0.787 m3 and 0.878 m3 respectively. Concerning the biometric parameters of the crowns (length and width) the advantages are on the side of the plantations without agroforestry practice, which is explained by the lower planting density of the tree vegetation. In the comparative studies carried out on the variation curves of distribution of the diameters the majority of trees are in the thinner part of the mean tree diameter in both cases (60.8% for agroforestry and 54.7% without agroforestry). The comparative studies carried out on the variation curves of distribution of the heights show that the curves of height have approximately the same form and depend in certain degree of management activities. It is observed advantage of the plot with agroforestry in relation with the higher values of natural degrees of height and in much wider interval of natural degrees of thickness.The horizontal structure is also presented through the Stand Visualization System (SVS) program, which visualizes the graphical distribution of the plantations according to a previously made model in Microsoft Excel. Improvement of the soil quality in the plantation where agroforestry has been practiced is ascertained. The content of more resistant humic acids in the humus composition is higher for sample plot with agroforestry (1.45% against 1.02%), while the content of the more mobile and unstable fulvic acids is lower (0.65% against 0.92%). The results are a reason to recommend the application of agroforestry in the early stages of cultivation of acacia plantations, which is a highlighted advantage in relation with wood production in the future.