Tracking and Tracing
The difference is in direction & point in time:
To trace: follow the completed path backwards from its current point to where it began.
To track: follow the emerging path forwards from your starting point to wherever the thing currently is.
When you "trace" a cellphone call, you try to determine its origin... You go backward to the starting point.
When you "track" a cellphone, you monitor [the starting] location ... and follow it wherever it goes...
One of the most-often used traces is to find the origins of health problems like mad cow disease and tainted drugs and food. In Value Flows terms, that would start with the product that caused a health problem, and tracing back along the chain of resource flows to the source or sources of the product.