Aug 01

Social Distancing for Trees?

“But I moved to the mountain to live in the woods. If I do fire mitigation, I won’t have any trees left. I love the trees!”

It’s a common refrain I hear from people when the subject of fire mitigation comes up. Sometimes, I feel like the anti-Lorax. You know, the Dr. Seuss book, The Lorax, where the common refrain is, “I speak for the trees!”

A lot of mountain homeowners have a perception that wildfire mitigation is about clear cutting trees around their home. Wildfire mitigation is anything but.

In fact, creating effective defensible space makes for a healthier forest around your home, where trees and vegetation can thrive.

Think of it as social distancing for trees.

During the last several months, we’ve been hearing over and over that we need to restrict gatherings of people to small groups. Keep 6-10 feet away from others to keep the virus from spreading. Some of the same ideas on how to prevent Covid-19 from spreading apply to wildfire mitigation, especially in Zone 2.

Zone 2 is defined as 30-100 feet around your home. Zone 2 can be extended based on the topography around your house. A steep slope leading up to your house will draw fire quickly up the hill, what is commonly referred to as a “chimney effect.” Because of this, if your house has steep slope on any side, your Zone 2 will need to be extended to take this into account.

Social distancing for trees is most effective when employed in Zone 2. Grouping or clumping of 3-5 trees to create “tree islands” will help stop the spread of fire. Ideally, you should leave gaps of 20-30 feet between your groups to inhibit the spread of fire, but the minimum is 10 feet between the ends of branches.

The trees you choose for your tree clumps are important for the continued health of your forest. Ponderosa Pine trees do well in isolated groups as they are sturdy trees with deeper roots. As a former Park Ranger, I learned a lot about the ecology of the Ponderosa Pine forest. Prior to settlement of Colorado, we had naturally occurring fires burn at regular intervals in Ponderosa Pine forest. These low level fires would often singe the bark of the Ponderosa, but not destroy the tree. Even today, if you hike in the foothills, you may see these burn scars on mature trees.

Because of these fires, park-like stands were the norm with big open meadows between the trees. Ponderosa thrived in this environment due to lack of competition. However, after fire suppression took hold, our Ponderosa Pine forests became denser and denser, looking more like matchsticks. Less healthy, the Ponderosa became vulnerable to disease, like mistletoe and beetle infestations.

We often get asked about Mistletoe in trees. Mistletoe is a parasite that will take hold, damage and ultimately kill your trees. Mistletoe can often be seen as large bushy clumps on the tree’s branches. Unfortunately, once it takes hold, it is pretty much impossible to get rid of. However, by mitigating around your home, you can ensure younger trees will be less likely to get infested.


One tree that doesn’t do well in small clumps is Lodgepole Pine. Lodgepole are weak-rooted and extremely vulnerable to wind throw. Anyone who’s spent a winter in the foothills knows how our winds can gust and it’s often Lodgepole that comes down during these storms. When choosing trees to remove, Lodgepole should be first on your list because of this.

Other considerations when choosing trees to keep or remove is their age and health. Obviously, any dead trees should be taken down first. Then look for signs of stressed trees. If there’s a lot of sap on the trunk along with browning needles, it’s possible that beetles may have infested the tree. Double-trunked trees are likely to fail as well. At the “vee” of the two trunks, the trunk will start to develop rot and then split.

A healthy forest comprises both a mix of species and age. Sometime, during your assessment, you may discover species that were overlooked because of the density of the forst. During my assessment at my home in Nederland, I found limber pine on our property that I didn’t know were even there. Limber pine usually grows at higher elevation, but due to our north facing slope, three to four had taken hold there. I knew I wanted to try and give those trees a fighting chance to survive, so taking out some of the Lodgepole Pine seemed like a worthwhile sacrifice.

Ideally, the trees in Zone 2 will also include a mix of ages too. Like people, younger trees are able to defend against disease easier than older trees. Older trees will provide greater protection against wind throw. Including a bit of both makes sense in terms of long-term forest ecology. However, make sure to remove tiny, 2-4 foot trees growing underneath your mature trees. These are considered ladder fuels which can draw fire up into the crown.

Though many homeowners come into Wildfire Partners with a sense of trepidation, they are often surprised by the outcome of their mitigation efforts. Healthier trees, wildflowers, more wildlife and better views frequently are the result of your mitigation efforts.

“Wow, I can’t believe how much more light I have in my house. It doesn’t feel like the Black Forest anymore. And now we can even see Longs Peak from our great room!”

“I saw a herd of elk grazing behind our house!”

And as I look out my window, I can assure you, there are still plenty of trees to gaze upon.

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  1. wendell king
    August 5, 2020 at 2:50 am · Reply

    ‘social distancing for trees….’

    well written, well done.

    thank you


    • Jane Lewenthal
      August 6, 2020 at 4:01 am · Reply

      All of this is So consistent with what Wildfire Partners and SL fire department and an PhD in Ecology have advised me on our property for the past 27 years. 9 – 10 of these experts have advised me over the years and their advice has been consistent with these recommendations. There are photos of forests in natural condition in the late 1800s and modern day and they’re very different. Natural forests are Not full of trees that are spindly and crowded so close that they’re not able to grow in strength and majesty. More is not better!

      • Leslie Brodhead
        August 6, 2020 at 4:03 pm · Reply

        Jane, thanks for your very insightful comments.

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