Magic Mulch Mountain

“The wood chips are smoking!” yells my 6-year-old.

“Ooo, they feel so warm!” comments my 10-year-old, hands thrust deep into the cozy embrace of wood chips. 

“Come climb Mount Everest!” entreats my 8-year-old, standing on another heap across the driveway. 

“I need shovel!” adds our 2-year-old son, always eager to dig.

My children are engaged in wood-chip wonder. A few times a year, 8- to 10-foot piles of chipped trees stand heaped in our yard, begging to be played with. Because it takes weeks to spread the thousands of pounds of wood chips across our yard — mounding it in neat rings around the base of trees, nestling it between plants — the kids enjoy a long runway of wood chip mountain play. However, the first few days are always the best because of the “smoke.” 

The smoke is actually steam generated by microorganisms that break down the wood and produce heat as a byproduct. This heat evaporates moisture in the freshly chipped wood, and when that warm, moist air meets the cooler air outside the wood chip pile, it creates steam. As a result, freshly chipped piles of wood can resemble a cozy cabin in the woods, emitting a steady plume from the top of the pile. This delights children and sometimes unsettles adults.

The wood chips aren’t simply a vehicle to fuel young imaginations. We regularly welcome them onto our property as mulch. Think of mulch as a big blanket that rests on top of the soil, protecting it from the sun and thereby reducing evaporation and improving water retention. Mulch can be organic (i.e., wood chips, grass, straw) or inorganic (i.e., rocks, gravel). Organic mulch is more complex because, like compost, it breaks down over time, adding nutrients to the soil. In the blanket analogy, mulch lays on top until it slowly wears out over time and needs to be replaced.

Mulch and compost are related, but different. While compost contains multitudes — a complex and dynamic amalgamation of microbial and nutrient diversity — mulch is more about supporting a diverse environment than actually being one.

We started mulching during one of Santa Barbara’s droughts. We are blessed with a dozen very large trees — redwoods, cedars, and pines — that lift our spirits every day but stress us out because of their seemingly insatiable need for water. We tried mulch to improve water retention in our soil, so that every precious drop of water our trees receive would be retained. 

After a local tree-trimming operation, Douglas Cicielo’s Tree and Arborist Service, dumped two mountains of wood chips in our Montecito yard, we set to work spreading it. Within four months we noticed a huge difference: When it did rain, we had literally no water runoff from our property; 2 inches below the wood chips seemed to be perennially damp; otherworldly Basket Stinkhorn mushrooms erupted from the soil. Someone else’s unwanted tree limbs had turned into our good fortune — soil with more life and better water retention. Our trees thrived, sending out bright green new growth we hadn’t seen in years.

And it’s free!

Tree trimming is a good business in Santa Barbara: We have an abundance of trees, some native, some non-native, some invasive, and most needing trimming. Every day, trees are trimmed and chipped, and tree-trimming companies have to pay to dump wood chips, so they are constantly in need of places to dump wood chips for free. It’s a perfect product market fit: Wood chips and your yard. 

Want chips?

Loads of wood chips vary in both volume and by species — oak vs. eucalyptus vs. pine, etc. If you’re interested in mulching your yard with wood chips, connect with a local tree trimming company or two about the volume you’d like and they will keep in touch when loads of that size become available. We admittedly use more wood chips than most. But you can mulch more moderately. And you can even do it without befriending a tree trimmer: An industrious friend of mine bought a small wood chipper and makes his own mulch. Or go the retail route: Garden centers sell a variety of mulch by the bag. Mulch your own way.

Mulch’s complicated cousin, compost:

While mulch and organic compost are related, compost is more complex and higher maintenance. So if you’re intimidated by compost — maybe reading Compost Doesn’t Have to Be So Gross will help — mulching can be a great place to start.