Comparison of estimation methods to obtain ideal distribution of forest tree height

• Reliability and processing time for different estimation methods were compared.
• Integrated Absolute Difference (IAD) resulted of interest to select methods.
• The kernel functions method resulted the simplest using lowest calculation time.
• The method which needs less initial requirements was the kernel functions.

Yield tables are the most widely-used guides for establishing the management of forests with even-aged stands. The ideal or balanced curves determine the number and size of feet that should appear in a forest with certain characteristics. These curves have traditionally been defined and applied to uneven-aged stands, and relate diameter with number of stems. However it is also possible to construct similar curves to manage stands composed of even-aged units. This paper proposes and compares alternative methodologies, based on yield tables, for establishing distribution curves for height/number of stems for Pinus sylvestris L. Based on the yield tables for this specie, it can be seen that the “direct” methods correspond more closely to the original chart, but also require highly complex calculations. However, estimation methods based on the use of kernel functions are generally simpler and can produce similar results, with the correct choice of smoothing parameter.