# Create a simple four-taxon tree with branch lengths:
tree <- ape::read.tree(text = "(A:1,(B:1,(C:1,D:1):1):1);")
# Set root age as 20 Ma:
tree$root.time <- 20
# Now prune taxon A:
pruned_tree <- ape::drop.tip(phy = tree, tip = "A")
# Show that drop.tip has not updated the tree's root time:
pruned_tree$root.time
# Use the function to fix the root time:
pruned_tree <- drop_time_tip(time_tree = tree, tip_names = "A")
# Show that the root time is now fixed (19 Ma):
pruned_tree$root.time
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