Site quality assessment of degraded Quercus frainetto stands in central Greece

Site quality assessment of degraded Quercus frainetto stands in central Greece

The potential yield of a site is measured by site index, which is defined as the dominant height of a stand at a base age. A site index model for site quality assessment of Quercus frainetto (Hungarian oak) stands in central Greece was developed using a base age of 50 years. Data were collected from...

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Published in:IForest (Viterbo) Vol. 8; no. 1; pp. 53 - 58
Main Authors: Kitikidou, K, Milios, E, Tsirekis, E, Pipinis, E, Stampoulidis, A
Format: Journal Article
Language:English
Published: Potenza The Italian Society of Silviculture and Forest Ecology (SISEF) 01-02-2015
Italian Society of Silviculture and Forest Ecology (SISEF)
Subjects:
Age
Bias
Forest management
Guide Curve Method
Hungarian Oak
Oak
Quality assessment
Quality control
Quercus frainetto
Regression analysis
Regression models
Root-mean-square errors
Simpson’s Paradox
Site index
Site Quality
Timber
New Zealand
Greece
New York
United States > US
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Summary:The potential yield of a site is measured by site index, which is defined as the dominant height of a stand at a base age. A site index model for site quality assessment of Quercus frainetto (Hungarian oak) stands in central Greece was developed using a base age of 50 years. Data were collected from 39 temporary sample plots of 10 x 10 m. Linear regression models widely used in site index studies were fitted to height-age data. The adjusted coefficient of determination (R2adj), root mean square error (RMSE), bias, coefficient of determination for the prediction (R2pr) and residual plots were used for the choice of the best-fitting model. The best model was H = -0.231+0.251A-0.001A2, where H is the predicted height at age A. The guide curve method was adopted in constructing the sites curves, with the chosen model as the guide curve. Based on this curve, the study area was divided into three site quality classes (I to III), with class I representing the best and class III the poorest. Also, the presence of a Simpson’s paradox in these analyses is discussed. The results showed that a 50-year-old stand in the study area attained an average dominant height of about 11, 8 and 6 m on site quality classes I, II and III, respectively. The Hungarian oak stands of the present study can be considered very low productivity stands.
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ISSN:1971-7458
1971-7458
DOI:10.3832/ifor1069-007