Określanie wieku niektórych gatunków drzew ulicznych na podstawie wybranych parametrów dendrometrycznych

Trees are an important component of the urban landscape. Their aesthetics qualities and especially a positive impact on the environment translate into increased life quality of urban communities. From this point of view the aspect of trees’ growth in urban areas is an object of intensive research all over the world. The better the knowledge of factors and mechanisms affecting growth and development trees in urban areas, the more accurate is in example monetary evaluation of trees value and their effects on the environment (value of the retained stormwater, produced oxygen, assimilated CO2, retained pollutions of water, soil and air, reduction of heat islands, etc.). Research on the correlation of tree age, environmental factors and the growth of dendrometric parameters serve as a starting point for developing various computer programs enabling one to calculate the economic effect of trees on savings and expenditure of individual households, towns and cities. Results of tree growth research prove that savings resulting from the presence of trees in towns can be more than three times the cost of tree maintenance. Trees growth is with no doubt dependent on their age. This paper evaluates the possibility of determining tree age based simultaneously on dbh (diameter at breast height 1,3 m) and total tree height, using species most commonly growing along streets in Warsaw: common lime (Tilia cordata Mill.), common ash (Fraxinus excelsior L.) and horse chestnut (Aesculus hippocastanum L.). The first step of research was the identification and measuring of age homogenous trees populations growing in similar conditions (street side trees in Warsaw, excluding city’s downtown) for which planting ages were known (mainly from archive data). Next, multifactoral regression models were developed describing the growth of both parameters (dbh and height) over time. In the majority of cases, plotting tree age against diameter and height yielded a regression coefficient r value and determination coefficient r2 value above 0.9. For graphical interpretation of elaborated multifactoral model nomograms were applied. This kind of graph explains tree age based on both dbh and height of trees. Another aspect of the research was a verification. The resulting model was applied to unrelated groups of trees of known age. Mean bias values were established for each model. The difference between the actual age and mean age calculated with the model was less than ±15%. Presented model, although not meant for application to individual trees might be useful to determine the age of trees populations growing along streets and roads.