Annals of Forest Science

Table 5 PBRAVO model—validation statistics for the output stand variables simulated using as input data the first year of measurements in sample plots of 1,000 m²

From: A tree distance-dependent growth and yield model for naturally regenerated pure uneven-aged maritime pine stands in central inland of Portugal

	Year t ₁ (n = 32)				Year t ₂ (n = 30)				Year t ₃ (n = 28)
Variable	\( \overline{e} \)	\( a\overline{e} \)	\( {\sigma^2}p \)	\( {R^2}p \)	\( \overline{e} \)	\( a\overline{e} \)	\( {\sigma^2}p \)	\( {R^2}p \)	\( \overline{e} \)	\( a\overline{e} \)	\( {\sigma^2}p \)	\( {R^2}p \)
N					30.560	45.667	9,436.02	0.8283	47.229	64.043	11,689.69	0.809
G	−0.114	0.175	0.0489	0.999	1.961	2.109	12.384	0.8468	2.095	2.225	14.744	0.788
dg	−0.023	0.842	0.0348	0.998	0.374	0.751	0.806	0.9478	−0.010	0.973	2.201	0.829
\( \bar{h} \)	−0.021	0.933	1.2238	0.822	0.121	1.226	2.085	0.6889	−0.045	1.237	2.423	0.552
h _dom					−0.058	0.442	0.388	0.946	−0.037	0.713	0.886	0.866
V	24.926	24.926	197.148	0.962	38.207	38.207	892.248	0.866	38.702	38.702	938.467	0.830

\( \overline{e} \) model bias evaluated with the mean prediction errors, \( a\overline{e} \) model precision with the mean of the absolute value of the prediction errors, σ ² p prediction error variance, R ² p modelling efficiency computed with the prediction errors, N number of trees per hectare, G basal area per hectare, dg quadratic mean diameter at breast height, \( \bar{h} \) average height, h _dom dominant height, V total volume per hectare

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ISSN: 1297-966X

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