What Morels Taught Me About Floodplains

Sometimes the best lessons in restoration come from unexpected places.

A few hours in the floodplain can yield big results when the conditions are right!

Every spring, I become distracted. Not by fish. Not by restoration projects. Not by streamflow forecasts.

Morels.

Like many people in Idaho, I find myself scanning river corridors looking for one of spring's greatest treasures. And over the years, I've noticed something. The places that seem to produce the most morels often appear remarkably similar to some of the conditions we look to re-create in a project. That observation led me down a rabbit hole.

The Morel That Changed How I Look at Floodplains

The first Idaho morel I ever found wasn't in a burn scar, or deep in the mountains.

It was in a river restoration project.

I can't tell you exactly where, but it was in an area where we had recently reconnected a side channel to its floodplain. Spring runoff was beginning to recede, and I was walking the site when I spotted my first mushroom.

Then another.

And another.

Some were growing along the newly activated side channel. Others appeared along the access road the construction crews had used to move equipment in and out of the project area. At first, I was surprised. But the more I thought about it, the more it made sense. Both locations shared something in common.

They had recently been disturbed.

The side channel had been excavated and reconnected. The access road had compacted and disturbed the soil surface. Water, sediment, sunlight, and nutrients had all been redistributed. The conditions had changed. That was the moment I had a different perspective on morels.

I stopped hunting mushrooms and started hunting disturbance.

My daughter found these morels in subsequent years in the same location near the restoration site. If you find a hot spot, might as well keep coming back!

Looking Where Most People Don't

When most people think about morel hunting, they think about burn scars, and for good reason. Wildfires can produce incredible flushes of mushrooms, but floodplain morels are a different game entirely. They're quieter. More subtle. Less obvious.

Success often depends on reading the landscape. The best hunters aren't necessarily looking for mushrooms. They're looking for goldilocks conditions among a gradient:

• Moisture (not dry, but not too wet)

• Disturbance (not too recent, but also not a decade ago)

• Dips or swales in the topography (casting some shadow, but not too much)

• Duff (some leaf litter but not so thick they can’t crest the surface)

• Sparse grass (too much and they drown out the morel)

• Nutrient-rich soils (not just sand, but not clay either)

• Openings in a dense canopy (pockets of sunlight, but not all day)

  
  

These clues suggest a landscape is actively changing.

This old side channel may look unassuming, but if you were to blow this image up you’d see there are morels all over the place. I found about 20 morels from this patch of sandy duff, which probably hadn’t seen floodwater in several years. It felt like “Where’s Waldo”, but everything is brown!

If there is one habitat type that consistently gets my attention, it's mature cottonwood galleries.

It’s old floodplain forests with sandy benches above side channels. Partially open canopies with stressed or declining trees.

These places seem to produce morels year after year. Why?

Scientists are not sure, but morels appear to have a strong association with disturbance and transition. Not complete destruction. Not stability. Something in between — A place where the landscape is being rearranged. Where trees are aging, recruiting, or responding to changing conditions.

In other words, exactly the kind of environment found throughout functioning floodplains.

The Two Phases of Floodplain Morels

Over time, I've come to think of floodplain morel season as occurring in two distinct phases.

The first is what I think of as the Core Phase. This is the classic spring flush when snowmelt is underway. Spring rains are arriving. Soil moisture is high. Temperatures are warming. It can occur anytime in May, though I’ve found morels in April and June. The ingredients are straightforward: moisture, warmth, and the right habitat. Many hunters focus almost entirely on this phase because it is predictable and longer. 

But it's the second phase that I find most interesting, though harder to capitalize on.

I call it the Recession Phase.

This phase begins when runoff starts to drop and floodwater begins pulling back across the floodplain. If peak flow on the Big Wood River is typically middle of May to June 1, the recession phase happens shortly thereafter. 

For thousands of years, people around the world have practiced flood recession agriculture — planting crops in the moist, fertile soils left behind as floods recede. The annual floods deposit fine sediment and nutrients collected from across the watershed, creating productive growing conditions long after the water is gone.

Floodplains function the same way for morels (and many other living things).

As floodwaters spread across a valley bottom, they redistribute moisture, organic matter, and sediment. When the water recedes, it leaves behind a landscape rich in nutrients and holding just enough residual moisture to support new growth.

The hydrograph starts dropping. The floodplain begins drying. And in the right places, morels emerge.

This is often when I start focusing my attention on side channel and main channel margin surfaces that remain moist but aren't saturated.

This morel popped up to say hello on the fringe of a very modest overflow channel.

What This Has to Do with Restoration

As stated earlier, I've realized that many of the river features that attract my attention as a restoration practitioner also attract my attention as a morel hunter.

Abandoned side channels.

Relict floodplain benches.

Beaver-influenced wetlands.

Riparian islands.

Avulsion margins.

Areas where water used to flow. Places where the river is still leaving fingerprints on the landscape. These are transitional environments — neither wetland nor upland. Neither chronically disturbed nor completely stable. They're ecological edge habitat. And edge habitats are often where biodiversity thrives. In ecological theory this is referred to as the Intermediate Disturbance Hypothesis. 

The Intermediate Disturbance Hypothesis (IDH) is an ecological concept proposing that local species diversity is maximized when ecological disturbances such as fires, floods, or grazing occur at moderate frequency and intensity. It suggests biodiversity peaks at a "sweet spot" balance between competitive exclusion and harsh survival conditions.

At first glance, mushrooms and river restoration seem unrelated, but both are responding to the same underlying processes. When we reconnect a floodplain, create side channels, or improve floodplain access, we're not just creating fish habitat. We're restoring the physical processes that generate ecological diversity.

Fish respond.

Birds respond.

Insects respond.

Plants respond.

And sometimes, perhaps years down the road, mushrooms respond too. One of the challenges in restoration is identifying where these opportunities exist. Morels offer a unique lens through which to think about that question. In a way, morels can serve as a reminder of what functioning floodplains do best: they create opportunity. Not for one species, but many. 

Here’s a goldilocks situation that morels love: sparse grass, a thin duff layer, and a sandy floodplain bench. 

Identifying Potential Spots

The Blaine County GIS Map Services is a great place to start. Here you can see land use information and parcel ownership, to make sure you’re hunting for morels in a publicly accessible location. One tool I use for both prospective restoration sites and morel sites is the Big Wood River Atlas HAWS (Height Above Water Surface) map. Instead of showing absolute elevations (like a standard topographic map), a HAWS map calculates the vertical distance of the land surface relative to a nearby water body's water level. This helps to visualize which areas could be submerged as flooding occurs, where there has been historic river avulsions, and identify floodplain side channels and ponds. In our work, it’s a very useful tool to understand the river’s historical flow paths but also identify channelized stretches of river that would benefit from reconnection to historic features. 

As a morel hunter, I also rely on this tool to map out adventures, by targeting old avulsions and side channels. Dark green channels and edges of teal are a good place to start. Once I find those, I turn off the HAWS layer and look for mature cottonwood forests in the vicinity.

Figure 5. This HAWS map illustrates a color gradient that represents how high a surface is relative to water surface in the Big Wood River. Teals and greens represent at or close to the water surface elevation, whilst reds and whites would be considered upland areas that are unlikely to get inundated. 

A Different Way to See a Floodplain

To be successful involves slowing down. Way down. Morel hunting is a good reminder each spring to go slow and pay attention in each moment. The floodplains are full of surprises if you look closely.  

Today, when I walk a floodplain looking for morels, I'm really looking for evidence of a living river. The side channel that carried water last month. The sediment deposited during runoff. The beaver pond holding groundwater. The cottonwood stand bouncing back from flooding a few years ago. The access road, bank edge, or floodplain bench that was recently disturbed.

The mushrooms are just clues.

What they're really pointing toward are the processes that created them. And that's one of the reasons I find floodplain morels so fascinating. They're often a product of disturbance, hydrology, nutrient cycling, and ecological succession working together. The same ingredients that create productive floodplains. The same ingredients that support healthy rivers. And the same ingredients we try to restore.

Because sometimes the best restoration indicators aren't found in a monitoring report.

Sometimes they're hiding beneath a cottonwood tree, waiting for someone to notice what the river has been doing all along.