Bark coverages on stem surfaces lead to premature death of saguaro cacti (Carnegiea gigantea). Bark coverages have occurred on surfaces of more than 50 species of tall, long-lived cacti throughout the Americas. This study analyzed data of bark coverages on 12 surfaces of C. gigantea. Among 1,149 saguaro cacti, from four sampling periods over 23 years, data of four independent algorithm programs were used to predict bark coverages and cactus death. On saguaros, bark coverage originates on south-facing surfaces and progresses to north-facing surfaces, prior to cactus death. For this population, bark coverages increased over time and 45% of all cacti were dead by the end of the 23-year study period. Validate Model and WEKA 3.8 predicted bark coverages with over 96% accuracy. Random Forest predicted cactus death with 99.6% accuracy and kNN predicted cactus death with 100% accuracy. Since trough surfaces occur after crest surfaces, trough surfaces were better predictors of bark coverages and cactus death. Cactus death was best predicted (above 99%) with north-right troughs with west-facing surfaces. Taken together, the four machine programs gave complimentary results and predicted (above 99%) both increased bark coverages from south-facing surfaces to north-facing surfaces over time and death of individual cacti over an eight-year period when north-facing right troughs had more than 80% bark coverages.

茎表面的树皮覆盖物导致仙人掌仙人掌（Carnegiea gigantea）的过早死亡。在整个美洲，超过50种长寿的高大仙人掌的表面已经覆盖了树皮。本研究分析了C. gigantea的12个表面的树皮覆盖数据。在23个年来的四个采样周期中的1,149个仙人掌仙人掌中，使用了四个独立算法程序的数据来预测树皮覆盖率和仙人掌死亡。在柱仙人掌上，树皮覆盖物起源于朝南的表面，并在仙人掌死亡之前发展为朝北的表面。对于这个人群，树皮覆盖率随着时间的推移而增加，到23年研究期结束时，所有仙人掌中有45％死亡。验证模型和WEKA 3.8预测树皮覆盖率的准确性超过96％。Random Forest预测仙人掌死亡的准确度为99.6％，kNN预测仙人掌死亡的准确度为100％。由于波谷表面出现在波峰表面之后，因此波谷表面是树皮覆盖率和仙人掌死亡的更好预测指标。预测仙人掌死亡的最佳方法（99％以上），表面朝西的北向槽中。综上所述，这四个机器程序给出了互补的结果，并预测（超过99％）随着时间的推移，从朝南表面到朝北表面的树皮覆盖率会增加，并且当朝北的右槽在八年时间内单个仙人掌的死亡树皮覆盖率超过80％。