The center of the spruce log should be brighter except for the bottom right pixel. Precisely, it should be #70522e instead of #614b2e.
The dark rings of the jungle log miss a darker color appeared on other logs. Using planks as the reference, it should be #785437.
The mangrove log has a more serious problem. Like the jungle log, its dark rings only contain 2 colors. In addition, its color correspondence between the log and the planks is different from others. The attachment shows it. (Above: what it should be, below: what it actually is)
The dark color on the right side of the outer ring of the cherry log should be brighter, #dd9d97 instead of #cd8580.