Plant Adaptations and Strategies to Fire

I had to “cook” these cones on my stove on a setting of 8 for over ten minutes to get them to open and shed their seeds. Unopened ones in the middle are for context. In nature, fire is what opens these cones and exposes the seeds.

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On a recent hike, I spotted a red squirrel cache of new lodgepole pine cones. Each cone was tightly sealed and I recalled that many lodgepole cones are serotinous, meaning that they require high heat in order to open. That heat is generally from a fire, and the doghair thick stands of young lodgepole pines that sprouted after the Yellowstone fires of 1988 are a testament to the efficacy of this tactic, often referred to as a seeding strategy. I grabbed a handful of cones and took them home to see if I could force them to open on my stove. The results are in the accompanying photo.

In our area, as in many areas, plants and even plant communities are adapted to and shaped by fire. There is no single strategy—plants have found various ways to either avoid destruction by fire or to utilize fire to grow and disperse across the landscape.

The seeder strategy, like that followed by the lodgepole pine, is to produce lots of seeds and preserve them so that they are ready to take advantage of the excellent growing conditions that follow a fire—lots of freed-up nutrients and little competition for space and sunshine. These plants are already native to the area and may increase dramatically after a fire.

Resistant plants, another fire adapted strategy, are ones that can actually survive light to moderate fires. They are likely to have thick bark like a Douglas fir or ponderosa pine, and deep roots. They also have the habit of shedding lower branches which effectively limits fire-climb upward.

Other plants take a completely different tactic. They sacrifice the above ground parts, but can resprout new growth from trunks, branches or underground roots. Many shrubs, like chokecherry, serviceberry, willow, and bitterbrush, are sprouters (often called re-sprouters) as are quaking aspens, Rocky Mountain maples, and Gambel’s oak.

There are some plants that do not mix well with fire and only thrive when the plant community is mature and naturally fire resistant. Sometimes called avoiders, these species are generally thin-barked and shallow-rooted, making them susceptible to fire. Examples include western red cedar, western hemlock, and white fir, all valuable lumber species. Sagebrush is another “climax” avoider species that does not play well with fire.

There is one other category, and that is the invader. These are usually non-native plants that may be at low numbers pre-fire. Just like the native seeders, they find the disturbed area a perfect place for them and will often proliferate at an amazing/alarming rate of speed, often dominating the burned area before natives can get established.  One example of an invader is cheatgrass, a native of Eurasia. When a fire races through a sagebrush habitat, cheatgrass often permanently replaces it. Other invaders include: Canada thistle, musk thistle, and knapweed. Fireweed  is an example of a native invader. However, fireweed is an early successional plant, yielding to others plants over time.

Fire has created these interesting strategies among plants and it also plays a huge role in how plant communities are shaped and maintained. In the West, shade intolerant aspen communities only thrive when periodic fire removes canopies of evergreens. Without fire, many aspen stands across the West have been lost or severely suppressed.

Some grasslands, mature pine forests and oak savannahs are maintained by fire as well. Periodic low-intensity fire sweeps through these environments often enough to eliminate encroaching shrub and tree seedlings, but leaving mature trees alone. At the same time, it recycles nutrients thus fertilizing the grasses.

Surrounding the neighborhood where I live are tens of thousands of acres of native forest that has been protected from fire for generations. So much so that the forest has become a dangerous tinderbox. Thankfully, the Forest Service has recognized this fact and has spent the past five or more years addressing the problem. Interestingly, they are using techniques that mimic much of what a low intensity fire would do—they are thinning the standing trees, cutting off the bottom limbs of remaining trees, and gathering up dead trees and branches on the forest floor and creating piles that are burned during the winter months.

There are two things that such work cannot mimic though. First is the nutrient recycling and understory rejuvenation that a fire creates. Second, fire helps to keep forest pests at bay—thinning and forest clean-up does not do that.

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Help Idaho Wildlife

When we traveled across the state in October 2017, most of the vehicles we saw using the wildlife management areas did not have wildlife plates. Buying wildlife plates is a great way for non-hunters and hunters alike to support wildlife-based recreation like birding.

C'mon folks, let's help Idaho's wildlife by proudly buying and displaying a wildlife license plate on each of our vehicles! 

See below for information on Idaho plates. Most states have wildlife plates so if you live outside Idaho, check with your state's wildlife department or vehicle licensing division for availability of state wildlife plates where you live. 

And tell them that you heard about it from Nature-track.com!

Wildlife License Plates

Idaho Wildlife license plates provide essential funding that benefits the great diversity of native plants and wildlife that are not hunted, fished or trapped—over 10,000 species or 98% of Idaho’s species diversity. Game species that share the same habitats (such as elk, deer, antelope, sage-grouse, salmon, trout) also benefit from these specialty plates.

No state tax dollars are provided for wildlife diversity, conservation education and recreation programs. Neither are any revenues from the sale of hunting or fishing licenses spent on nongame species. Instead, these species depend on direct donations, federal grants, fundraising initiatives—and the Idaho Wildlife license plates.

Both my vehicles have Bluebird Plates. I prefer the bluebird because the nongame program gets 70 percent of the money from bluebird plates, but only 60 percent of the money from elk and trout plates - 10 percent of the money from elk plates supports wildlife disease monitoring and testing programs (to benefit the livestock industry) and 10 percent from cutthroat plates supports non-motorized boat access.

Incidentally, in 2014, the Idaho Legislature denied the Department of Fish and Game the ability to add new plates or even to change the name of the elk and cutthroat plates (very specific) to wildlife and fish plates, a move that would have allowed for changing images occasionally and generating more revenue. It would seem that they believe that we Idahoans don't want a well funded wildlife program.

I think it is time we let the Legislature know that Idahoan support wildlife funding and that we would like to see these generic plates come to fruition.