Abstract
A simple method for evaluating the acorn yield of Quercus serrata was developed and tested. This simple method of evaluation, classified the yield qualitatively according to descriptive criteria assessed by direct observation of the tree canopy. A quantitative standard was also established to determine whether trees had fruited, and, if so, to estimate whether the crop yield would be above or below average. The fruiting of 392 Q. serrata trees were examined simultaneously in two ways: (A) by several unskilled observers using the simple evaluation method, and (B) by a forest researcher employing the established method based on the average number of acorns on the terminal 50 cm region of the branches. The results obtained using these two methods (which were summarized into 3 levels) were in agreement for 75% of the trees, when the data from individual observers using method (A) were compared with method (B), although the simple evaluation method (A) had a tendency for underestimation. However, when the largest value from the multiple observers was used, the concordance rate with (B) improved to 86% and the evaluation bias was also eliminated. The results of the study indicate that the newly developed, simple evaluation method, when used by several unskilled investigators simultaneously, produces a reliable assessment of the acorn yield and is suitable for monitoring acorn crops in practice.
