Determining the age of streetside trees with diameter at breast height-based multifactorial model

摘要

This article evaluates the possibility of determining tree age based simultaneously on diameter at breast height (dbh) ( 1.3 m [4.3 ft]) and total tree height using common lime, common ash, and horsechestnut species. The first step was the identification and measuring groups of trees growing in similar conditions (streetside trees in Warsaw area, Poland) in which planting ages were known (mainly from archives). Next, multifactorial regression model was developed describing the growth of both tree 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 r(2) value above 0.9. For graphic interpretation of elaborated inultifactorial models, nomograms were applied. This kind of graph allows explaining tree age based on both dbh and height of trees. Another step was 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 groups of trees growing along streets and roads.