Table 3.

Comparison of street trees common lime, common ash, and horsechestnut age classes known and calculated age with multifactorial nonlinear regression model.

Common lime			Common ash			Horsechestnut
Age class number	Actual age^{^z} (years)	Calcult. age^{^y} (years)	Age class number	Actual age (years)	Calcult. age (years)	Age class number	Actual age (years)	Calcult. age (years)
1	7	7.2	1	10	8.0	1	16	17.8
2	18	21.9	2	16	18.0	2	22	27.6
3	25	27.9	3	20	21.0	3	25	26.9
4	34	35.2	4	26	29.1	4	30	36.0
5	34	35.2	5	43	43.5	5	38	33.5
6	36	42.2	6	45	45.3	6	58	59.4
7	53	49.8	7	80	81.2	7	60	67.3
8	58	59.4
9	75	66.7
10	85	79.5
Mean bias (%)		3.9	Mean bias (%)		1.8	Mean bias (%)		9.5

↵^zThe actual age of trees taken from historical records or/and tree rings number (Pressler borer).
↵^yAge calculated with developed multifactorial regression model applied on trees’ dbh and height of each species taken from the control group.
dbh = diameter at breast height.