Douglas fir

Post Fire Early Winter Mixed Conifer Forest

The widespread mixed conifer forest in the hills of Santa Cruz County’s North Coast is drippy wet now, even between storms. Seventeen months ago, the CZU Lightning Complex Fire devoured tens of thousands of acres of mixed conifer forest just north of Santa Cruz. Now, there are thousands and thousands of stark blackened standing dead trees. There are also living and resprouting trees. The dead and the living conifers tower over a wet, glistening, vibrantly green, and lush understory. It is slippery and hikeable now, but as the trees fall and the brush grows up it will become impossible to explore until the next fire…a decade away.

The lush post fire understory of a mixed conifer forest. Above Davenport, CA December 2021

What is Mixed Conifer Forest?

Mixed conifer forest is our most common forest type. While it is true that we have patches of redwood-dominated forest and patches of Douglas fir-dominated forest, many areas have a mix of the two. At the larger scale, peering out of an airplane at 10,000 feet, all of the local forested landscape includes a mix of conifers – redwood, Douglas fir, knobcone pine, ponderosa pine, Monterey pine, and Santa Cruz cypress. Where Douglas fir and coast redwood co-dominate, this type of mixed conifer forest hosts a mix of plants and animals that are distinct to this habitat type. Low light levels from a high, dense canopy and a preponderance of difficult to digest resinous needles are important factors determining what else can live in this habitat type.

Flaming Bark

The mixed conifer forests burned unevenly in August of 2020. Douglas fir trees take a little coaxing, but coast redwood trees take real convincing, to burn. There are many more fire-killed Douglas firs than redwoods. During the last two fires, I watched both redwood and Douglas fir trees catch on fire. Fire seemed to race up Douglas fir trunks, spewing sparks and crackling away whereas redwood trunk flames were slower to move up the tree and was less sparky and noisy.

Unlike redwood, Douglas fir trunks are covered with sticky sap that ignites easily. I heard a story about a teenager that thought it would be fun use a lighter to light some sap on fire on the side of a tree and very shortly needed the help of the fire department to put out the flaming tree, which was threatening the family home.

Glowing Holes

For weeks after the initial fire storm, glowing spots throughout the forest decorated the night. Mostly, these were the smoldering stumps of trees that had died long before the fire. In the mixed conifer forest, there were many dead or dying madrones and tan oaks that had been shaded out. These hardwood stumps made for some hot holes that burned for days. Some smaller Douglas fir trees had also died before the fire, but they burned up quicker.  There are now quite a few treacherous holes making forest hiking more interesting.

Solanum sp, Nemophila sp, Claytonia sp., and more…all covering the post fire forest floor

Understory Greens

The rains have germinated 3” deep shag carpets of lush herbs and hydrated huge patches of shorter bright mosses below blackened tree trunks. Miner’s lettuce, phacelias, and weedy forget-me-nots make the carpet. In patches, taller plants like hedge nettle, blackberry, nightshade and many other plants add to the hillsides of bright green. Many areas are already dotted with white, pink, or purple blossoms brought on by the winter rains and encouraged by warm bright days between storms. A lot more sunlight hits the forest floor now. Where there are patches of live trees, the understory is less thick. In some places, the fire left small hillside meadows, without any trees at all.

The forest soil is still black and slippery with soot and ash. During each of my recent forest hikes, I have slipped and would have tumbled a long way were it not for my grip on the very strong 4’ tall redwood basal sprouts. The soil, in the hotter burned places where the understory herb seeds were destroyed, is covered by strikingly bright mosses littered by needles and small branches blown from the few remaining live trees somewhere uphill or up wind.

Post Fire Wildlife

The burning of the mixed conifer forests means more food for more birds: redwood and Douglas fir forests normally have few seed producing plants, but that’s changed now. In mixed coniferous forest, deer have little to eat; now, the forest floor is covered with deer food. It is easy to see the birds and easy to find the deer tracks. Sharp deer hooves, forming new trails, cut through mosses and lush hillside wildflowers, exposing forest soil. The tracks crisscross the steep hills, patches of tasty miner’s lettuce chewed off. I’ve been seeing deer beds of very flattened understory plants, mostly on level spots along old logging roads. Expect healthy coats on momma deer, more big antlered bucks and spotted big eyed deer twins navigating the hills on dainty legs this spring. Mountain lions prefer dark forest to move around, but they’ll be enjoying more food while the forest canopy grows back.

Fire Makes Beaches and Bonfires

Mostly, the forest floor is healing, and little erosion has been happening. The exception is where humans created roads during the early logging days. To create roads on hills, people carved uphill and dumped the soil they removed downhill. This is called ‘cut and fill’ road engineering. Sometimes the fill side buried logs and stumps which burned under these old roads in the recent fire. Now, the uphill scar is unstable in many places, the fire having destroyed the stabilizing plants. Between burned out fill sides and steep, less vegetated cut sides…there is lots of erosion. Throughout the fire, you can find large and small scallops of hillside slumping onto the old roads or downhill from the roads towards the creeks. Besides being activated post-fire, this legacy of disturbance is most evident now that you can better see the soil surface across the hillsides.

With the couple large storms we had, streams have been carrying soil and logs. Local streams are flowing with mud, as evidenced by the ocean’s big brown plume up and down the coast right after the last storm. That mud will sort out and the sand part will become our beaches- bigger beaches after fires? We’ll see.

One local stream was more black then brown for a while- probably because of ash and soot. Streams are also carrying logs. Judging from the scouring of streamsides, streams have been blocked by post fire logs (ever encounter the term ‘logjam?’); those blockages eventually give way and are swept downstream with great force, battering and baring stream banks downstream and far up their banks. Those logs become driftwood on the fire-augmented sandy beaches. That driftwood will become the bonfires for rocking all night parties that the Coastal Commission has just sanctioned by mandating the creation of 24-hour parking lots from Santa Cruz to Davenport. So, part of the post wildfire wildlife effects will be the noisy, blazing, smoky disturbance of whatever shorebirds were counting on nocturnal refuge on those once peaceful beaches. The CZU mixed conifer forest flames will carry on for human and non-human animals alike, for better or for worse.

Douglas Fir Forests

– this is another of my weekly posts reprinted from Bruce Bratton’s admirable weekly e-news publication at brattononline.com

According to tradition, people are hauling Douglas fir trees into their homes and decorating them for annual winter rituals. Some purchase dense, pruned trees, while others harvest spindly saplings from the woods (aka “Charlie Brown trees”). Soon, strings of lights cast needle shadows on the walls and ceiling, infants gurgle and sputter with delight, wide eyed at the beauty. The unique Douglas fir scent fills the air – a bright lemony pine smell. Hallways are festooned with ribboned Douglas fir garlands and people weave fir wreaths to decorate doors. In breaks between storms, on crisp cool days, we saunter into the forest, catching fresh fir scent moist with rain, sparkling in the foggy, low-angled sun rays.

Mouse Tales

Douglas fir is not a real fir- it’s a pseudo-fir, creating cones distinguished from genuine fir cones by having “the tail ends of mice” sticking out the cone. Check it out sometime- there really are what looks like two back legs with an accompanying tail poking out, so cones look like a bevy of mice are feasting on Douglas fir seeds.

The cone decoy seems to have worked, evolutionarily speaking. From Northern California though Canada, Douglas fir is the sole home of red tree mice. These mice live high in canopies and feed on only on needles. On huge branches among the complex old growth Douglas fir canopy, they maintain long lived, wickedly well-designed homes that include rooms with specific uses. If they aren’t careful while they are out harvesting needles, a spotted owl will eat them – red tree mice are a favorite and important food for this equally endangered bird. We’re apparently too far south for the red tree mouse- Santa Cruz is the near the southern end of Douglas fir’s range, and maybe there aren’t enough thick forests, or too frequent of fire, for these little critters.

Northward Ho!

Moisture-loving conifers have been retreating northward for a few thousand years, and Douglas fir may also be headed that way. There are layers of grand fir pollen up until just 15,000 years ago in the sediments of a pond in northern Santa Cruz County. The nearest grand fir is in Sonoma County, nowadays. South of here, if you look at the forest on either side of highway one south of Freedom Boulevard, you’ll see a few widely spaced straggly Douglas firs – those trees look like similar to those in the hills above Elkhorn. And that’s as far south as they go along the coast. But, north of there you’ll notice that they don’t appear to be having trouble making thick forests.

Rock Scissors Paper (Douglas fir wins)

In the rush to capture the sun, Douglas fir quickly wins against all but the coast redwood around here. Look at most any of our majestic coast live oak forests, and you’ll see Douglas fir trees winding their flexible leaders between old oak branches. Play that forward, and those oak trees will be toast, shaded and outcompeted for water by these highly invasive conifers. Douglas firs are also invading coastal scrub and coastal prairie.

Pull ‘em Up, Chop ‘em Down

Kat Anderson reported to me documentation that tribal peoples have long pulled Douglas fir seedlings as part of their tending of oak groves. The tribal peoples took over from the tree-invasion prohibiting Pleistocene megafauna. Just north of here, a remarkable recent turn of events saw reintroduction of native people land stewardship with collaboration between the Amah Mutsun and State Parks. The Quiroste village site was once in a matrix of super diverse, well-tended coastal prairie framed by managed oak woodlands, but for the last hundred years, without stewardship, those systems succumbed to Douglas fir invasion. After careful planning, and with some controversy, the tribe and State Parks have been restoring the site by clearing Douglas firs…almost like the old days, but the trees got bigger and so it takes saws and a lot of work to remove them. With their work, the area is becoming more species rich and more fire safe.

Doug Fir, Associates

While coastal prairies and coast live oak forests are much more species rich, Douglas fir forests do have their own set of interesting species associates. Instead of tree mice harvesting Douglas fir needles around here, we get ants. Anywhere there are Douglas firs in the Santa Cruz Mountains, you’ll find 2’ tall piles of needles teaming with ants. These are Formica integroides, a mushroom farming ant, growing their fungi food in piles of Douglas fir needles. This needle harvesting critter forms armies of harvesters walking in long and sometimes wide lanes across and down human trails: watch out…don’t be rude by stepping on them!

Orchids also seem to like growing in Douglas fir forests. Also at its southern range limit, the gorgeous Calypso orchid has been documented with ephemeral populations at UCSC and near Davenport (both gone now), but has a somewhat famous large population under a north-facing Douglas fir forest in Butano State Park. Coral root orchids also seem to prefer Douglas fir forests. Curiously, ground nesting ‘yellow jacket’ wasps seem to key into coral root populations under Douglas fir. So, maybe look very carefully before walking off trail to get a closer look at the subtle but beautiful colors of coral root orchids.

Timber!

“Douglas fir doesn’t pay for itself to harvest.” That’s what local foresters tell me. By the time they do the timber harvest planning, go through the regulatory process, carefully fell the trees, trim and haul the few logs they find that aren’t damaged/diseased, mill and dry the wood, they can’t recoup their investment because someone elsewhere has produced a similar board, cheaper. The Pacific northwest and Canada, with more lax forestry regulations and healthier Douglas fir trees, are creating cheaper Douglas fir (and similar) 2x4s for sale. So, for many years, we’ve been growing some large Douglas firs on the area’s timber lands.

Then came the CZU fire…now, there are thousands of large and small standing dead Douglas fir trees: what should we do? If left, these trees will gradually fall over and create a Giant Fire Hazard. The next fire, spreading through those hundreds of acres of log piles, will be very intense, torching whatever trees tried to recover and scorching the soil badly. It will be a hot fire storm, to a great extent our fault.

Biomass Fuels?

If you have toured the CZU Lightning Complex Fire area, you have probably noticed piles and piles of logs. Burned up trees are dangerous to houses, roads, and power lines, so they must be felled and hauled away. “Away” is an odd word…mostly it means a landfill (another odd word). Ever throw something away? It is instructive to visit ‘away’ at the end of Dimeo Lane or near Buena Vista. We must find a new ‘away’ soon, but no one wants ‘away’ near their homes or over their groundwater. Piles of post fire logs will fill up landfills quickly, especially with more frequent fires. Why not use modern technology and turn those logs into electricity? There are new carbon-neutral, mobile wood-fired power plants that burn wood, make electricity, and create ‘biochar’ that has been shown to be a useful soil amendment for agriculture. Keep your fingers crossed that we might get one of these at one of our local landfills sometime soon. That way, when you throw something ‘away’ that can be safely burned, you’ll be making your own electricity and enriching agricultural soils.