How long before a new logging road shows up in satellite imagery?
A felled stand is easy to date. You see the gap, you check the harvest plan, you know roughly when the saws went in. A new access road is harder, and that's the problem if you're trying to catch unpermitted entry before the clearing starts.
The honest answer to "how long does it take" is: it depends on three things that have nothing to do with how good the satellite is. Revisit cadence, cloud cover on the day of the pass, and whether the pixel size is fine enough to pick out a two- or three-meter-wide track from the noise of shadow and leaf litter around it.
Revisit cadence sets the floor
If your monitoring area only gets imaged once a quarter, the floor on your detection lag is close to three months, even with a perfect sensor. A road cut the week after a pass sits unflagged until the next one comes around. That's the gap enforcement teams keep getting burned by: the road goes in, the skidder work follows a few weeks later, and by the time anyone looks at fresh imagery there's already a canopy gap to explain instead of a track to question.
A monthly scan narrows that floor considerably. It won't catch a road the day it's cut, but it closes the window from a season to a matter of weeks, which is the difference between an audit note and a cleanup after the fact. Cloud cover still pushes individual passes around. A socked-in month over a coastal or montane monitoring area can mean the usable pass lands late. That's a real constraint, not a technicality to wave away.
Why GSD matters more than people think
Ground sample distance, the size of the area one pixel covers, decides whether a new spur is actually visible once the imagery comes in. A skid trail or a single-lane access road is a linear feature a few meters wide. At 2-3 m GSD it often reads as a faint discoloration you can argue about. At 0.5 m or finer, the track separates cleanly from the forest floor around it: you can see the cut edges, the exposed soil, the branching pattern where a spur splits off the main haul road.
That resolution threshold is why road detection lags behind what people assume satellite monitoring can do. A sensor can revisit an area weekly and still miss a new track if the pixels are too coarse to resolve it from background texture. Cadence tells you when you'll get a look. GSD tells you whether that look is good enough to call something a road instead of a shadow.
What this means for a compliance window
For an auditor working a certification standard, the practical number isn't "how fast is satellite imagery" in the abstract, it's "how long between a new track going in and someone on my team seeing it in a dataset built to flag it." That number is a function of your scan's revisit interval plus however many days the processing and routing takes on top of it. A quarterly or ad hoc review cycle means roads can predate the clearing they lead to by months before anyone in the compliance chain sees them. A monthly cadence at sub-meter resolution means the lag is closer to the length of one scan cycle, track segments routed to your team as they appear rather than discovered retroactively when the canopy loss is already visible.
That gap, between a road appearing and someone with enforcement authority knowing about it, is the whole reason early warning on access routes matters more than catching the clearing itself. By the time canopy loss shows up, the operator has already made the call to go in. Logging Road Detection runs a monthly scan at sub-0.5 m resolution over a defined monitoring area and routes new track segments as they appear, so the track gets flagged while it's still just a track.
If unpermitted access is the thing you're trying to catch early, it's worth seeing what that scan would look like over your own monitoring area.