. Development and evaluation of an even- and uneven-aged ponderosa pine/Arizona fescue stand simulator. Ponderosa pine; Forest management. BJBAG 1 = .05 .05 .05_. Diameter Class Size in Inches Figure 5-year mortality rate for even- and uneven-aged blackjack pine by diameter size class, MBA2 class, and even- and uneven-aged blackjack pine basal area growth (BJBAGl). During data collection, all trees were initially categorized by vigor class, and then those trees not cut on a plot were reclassified every 20 years (that is, at the start of every fifth growth period). An examination
. Development and evaluation of an even- and uneven-aged ponderosa pine/Arizona fescue stand simulator. Ponderosa pine; Forest management. BJBAG 1 = .05 .05 .05_. Diameter Class Size in Inches Figure 5-year mortality rate for even- and uneven-aged blackjack pine by diameter size class, MBA2 class, and even- and uneven-aged blackjack pine basal area growth (BJBAGl). During data collection, all trees were initially categorized by vigor class, and then those trees not cut on a plot were reclassified every 20 years (that is, at the start of every fifth growth period). An examination of the data available for modeling conversion indicated the following problems: 1. While growth, mortality, and ingrowth could be predicted every growth period, conver- sion from blackjack to yellow pine could only be predicted after every fourth growth period. This might cause the number of trees in each vigor class to change abruptly after every fourth growth period. 2. Cutting of blackjack trees between the reclassification times negates the utility of .the plot for predicting conversion because of the uncertainty of whether those trees cut would have converted or not. The plot and classification period combination without cutting are the first classification period of plot 62 and both periods of plot 61. 3. The conversion from a blackjack pine to a yellow pine is a slow but continual process, and therefore, the discrete classification of a tree as either blackjack or yellow pine is extremely subjective. This subjectivity can become a problem on long-term studies because the classification of vigor classes is done by different people with individualized critera for classification. An examination of the conversion rates for the first 20 years on plots 61 and 62, compared to the conversion rate on plot 61 in the second 20 years, shows that the rates differ considerably between the two classification periods. While it cannot be proved, it is likely this difference is due in par
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Keywords: ., bookcentury1900, booksubjectforestmanagement, booksubjectpondero
