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.

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