| The video clip above from the
Building and Fire Research Laboratory of the National
Institute of Standards and Technology illustrates what
happens when fire touches a dry tree. Within three seconds
of ignition, the dry Scotch pine is completely ablaze. At
five seconds, the fire extends up the tree and black smoke
with searing gases streaks across the ceiling. Fresh air
near the floor feeds the fire. The sofa, coffee table and
the carpet ignite prior to any flame contact. Within 40
seconds "flashover" occurs -- that's when an entire room
erupts into flames, oxygen is depleted and dense, deadly
toxic smoke engulfs the scene.
Wet trees tell a different
story. For comparative purposes, the NIST fire safety
engineers selected a green Scotch pine, had it cut in their
presence, had an additional two inches cut from the trunk's
bottom, and placed the tree in a stand with at least a 7.6
liter water capacity. The researchers maintained the Scotch
pine's water on a daily basis. A single match could not
ignite the tree. A second attempt in which an electric
current ignited an entire matchbook failed to fire the tree.
Finally they applied an open flame to the tree using a
propane torch. The branches ignited briefly, but
self-extinguished when the researchers removed the torch
from the branches. As NIST fire safety engineers say:
REMEMBER, A WET TREE IS A
SAFE TREE! |
