No because when a tree catches fires bits of it break off and are carried on the wind and can travel further than any reasonably sized ditch.
There’s a lot of material that are attached to the forest trees. Some of it is bark; birch bark trees, for example, have very curly bark on them, and that can be carried up in the draft [or] the heat and then burned in the column of the fire. The wind carries it out in front and drops it down while it’s still burning. It can also be parts of a tree that get carried up because these things have tremendous winds.
When these fires get going, the wind’s interior can easily be 150 miles an hour. It’s not widespread, but they can rip out trees, they can carry a lot of big material, it’s lofted into the column of the fire, it’s burned very thoroughly and then it’s thrown out and it drops down and it could start another fire.
It’s burning up to water, but there’s such a tremendous column [of fire that] it’s carrying a lot of burning debris. The column usually leans out over the water. You can imagine the wind is pushing from behind, the surface is burning, but the column is tilted forward, and that column is carrying burning debris that gets deposited on the other side of the river, which starts spot fires and the fire keeps running.
Fires have been know to have jumped rivers and highways. There have been wildfires where it jumped over a kilometre out into lakes and took out islands that were a kilometre from the shore.
I had a neighbours trees catch fire once when they had a bonfire and the dry undergrowth caught fire, the speed these trees caught fire, the height of the flames was terrifying, fortunately there was good access for the fire brigade but for a while I thought my house was going to go up in flames.
The best thing you can do in such a situation is get out as quickly as possible.