C. F. Keil and Franz Delitzsch on 2 Samuel 18:8

2Sa 18:8

The conflict extended over the surface of the whole land, i.e., the whole of that region (the Chethib נפצות is not the plural נפצות, which would be quite unsuitable, but is most probably a noun, נפצוּת ,nuon a, signifying bursting asunder, or wild flight; the Keri נפצת is a Niphal participle, fem. gen.); “and the wood devoured more of the people than the sword ate on the same day.” The woody region was most likely full of ravines, precipices, and marches, into which the flying foe was pursued, and where so many perished.