I've noticed that in the pursuit of detecting illegal logging the subject of acoustic detection of chainsaws comes up a lot. But in every case of illegal logging the trees will have to be carried away of trucks. I can't seem to find any references to projects that are detecting the logging trucks along the roads, a similar problem I expect.

Is this being done anywhere? Is there any particular reason why focus is on acoustic detection of chainsaws as opposed to spotting the trucks before they chop down the trees ?