Philip Larkin start­ed a poem that way, but it’s good advice for the For­est Ser­vice, too. We’ve long known that fire plays an impor­tant role in main­tain­ing forests, prairies and oth­er nat­ur­al ecosystems. 

A new set of stud­ies show that thin­ning forests with­out burn­ing makes sub­se­quent fires more dan­ger­ous:

Thin­ning forests with­out also burn­ing accu­mu­lat­ed brush and dead­wood may increase for­est fire dam­age rather than reduce it, researchers at the For­est Ser­vice report­ed in two recent studies.

The find­ings cast doubt on how effec­tive some of the thin­ning done under Pres­i­dent Bush’s Healthy Forests Ini­tia­tive will be at pre­vent­ing fires if the forests are not also burned.

Fires feed on the lay­er of duff that builds up on for­est floors, and thin­ning makes it eas­i­er for oxy­gen to get to a fire. Reg­u­lar burn­ing reduces the lev­els of duff, so that the fires are less intense. That means they kill few­er trees and are eas­i­er to con­trol in pop­u­lat­ed areas.

Fed­er­al pol­i­cy since 2003 has pushed thin­ning of forests as the major tool of for­est man­age­ment, and de-empha­sized pre­scribed fires. It was claimed that reg­u­lar thin­ning could con­trol fire fre­quen­cy and inten­si­ty, but it appears that the “healthy forests” plan is prob­a­bly mak­ing them less healthy.