High-grading effects on Scots pine volume and basal area in pure stands in northern Spain

A yield model for formerly high-graded Scots pine stands in a transitional climatic area in northern Spain has been developed. High grading practices were used broadly during the last decades. In the past years, the silvicultural system has switched to a conventional even-aged system. A modeling approach is used to understand the effects of high-grading on basal area and dominant height. The equations are calibrated to be used in non high-graded stands and in previously high-graded stands when the silvicultural practices are switched. Dominant height and linear models were used to calibrate the original multiplicative model. With these models the effect of high-grading practices upon forest yield was studied. Standing volume decreased due to high-grading over 26% as the rotation age increased in a medium productivity class. The total volume reduction at rotation age was 18%.