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Table 7 PBIRROL model—distance-independent version—validation statistics for the stand variables simulated using as input data the first year of measurements in sub-sample plots of 500 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 = 30)

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

 

8.667

8.667

1,039.540

0.981

12.857

12.857

1,635.979

0.972

G

1.129

1.220

0.595

0.981

0.659

0.889

1.201

0.983

dg

0.402

0.430

0.086

0.985

0.233

0.333

0.211

0.983

\( \bar{h} \)

−0.004

0.384

0.277

0.963

−0.089

0.442

0.333

0.954

0.094

0.853

2.765

0.631

\( \bar{{c}} {r} \)

0.016

0.046

0.003

0.580

−0.017

0.041

0.002

0.575

0.094

0.853

2.765

0.631

d dom

 

0.553

0.611

0.206

0.979

 

h dom

−0.023

0.345

0.241

0.969

\( \bar{t} \)

0.930

3.513

19.758

0.662

0.973

3.473

20.112

0.667

V

6.424

8.229

82.125

0.980

14.725

15.953

189.192

0.941

9.766

16.180

358.155

0.935

  1. \( \overline{e} \) 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, \( \bar{c}r \) crown ratio, h dom dominant height, d dom dominant diameter, \( \bar{t} \) mean age, V total volume per hectare
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Annals of Forest Science

ISSN: 1297-966X