Modeling size-density trajectories of even-aged ash (Fraxinus excelsior L.) stands in France. A baseline to assess the impact of Chalara ash dieback

Table 2 Parameter estimates and statistics of Eq. (1) fit to the ash experimental stand data with the constraints of alignment of the inflection points parallel to the maximum size-density line

Parameter	Treatment	Observed value^†	Estimate	Std. error	t value	P value
a	all	–	13.57	0.106	128.1	< 0.01^‡
b	all	–	−1.54	0.019	−81.6	< 0.01
a₁	all	–	13.03	0.061	213.4	< 0.01
N₀ (trees ha⁻¹)	900	927	922^¶	7.524	122.5	< 0.01
	1100	1109	1106	8.307	133.1	< 0.01
	1200	1169	1199	23.486	51.1	< 0.01
	1600	1572	1586	14.246	111.3	< 0.01
	7000	7158	6881	459.827	15.0	< 0.01
	8000	8225	8131	118.086	68.9	< 0.01
	80000	82494	91215	1867.844	48.8	< 0.01
Residual std. deviation = 0.0167; df = 145

ISSN: 1297-966X