By urbanforestryassociates, Jan 3 2018 09:23PM
For the last few years, we have stayed very busy during the fire season assessing fire damaged trees around California. Often, we are forced to make decisions on tree removals much earlier than we'd prefer due to a variety of reasons out of our control. In most cases, the decision should be delayed for as long as possible. to give the tree the most time possible to do what it has evolved over thousands of years to do: recover from fire.
Whether or not a tree can be retained following a fire comes down to two basic questions 1) Is the tree stable in the short-term and 2) Will it recover a healthy, aesthetically pleasing canopy in a reasonable amount of time? Ideally, in a situation where money (or insurance) is not an issue, a tree would be initially assessed for stability and total mortality in the days and weeks following the damage. This would be looking at if the base or main crotches of a tree are burned out and if the bark is totally burned off, exposing the wood beneath. If neither of these is the case, the tree is left to make an attempt at recovery.
Much of the time, only a portion of the base of the tree is killed but there is still enough living vascular tissue to support a new canopy. This problem here is that the tissue over the necrotic area will no longer protect the structural wood of the tree from decay. The damaged bark could even act to conceal what becomes extensive, destabilizing decay in the future. The key words here are "in the future." A fire damaged tree could stand for many years before this necrotic area becomes an issue, if ever. The question then becomes - do I want to get another 5-10 years of enjoyment out of this tree or remove it while there is still someone around to pay the bill? It can be an emotional decision for some.
In the course of our work in these post-fire sites, we hear lots of opinions:
"Don't do anything for 6 months, then see."
"These are oaks, they'll be fine."
"There's no green left on the thing. Take it down."
"You've got to think about the beetles. Those things are gonna kill every tree here in 6 months."
Every tree is different and there is no golden rule but if you can see through the base of your tree, it should probably come down. If there is no bark left around the base of the tree, it should come down (though we have seen trees sprouting new canopies even when totally disconnected from their roots, don't let that fool you, it won't last). Many, if not most trees really do require an assessment from a qualified professional but if you can afford to wait, both in terms of risk and finance, do it. You might just get to keep what could be one of the few mature trees left in your area.