Save Plants: September 2018 Newsletter

Built to Burn

Southeastern US forests were once described as so extensive and dense that a squirrel could travel from the coast to the mountains without ever touching the ground. But historical accounts from early explorers, and other convincing evidence, clearly show that this region was actually more like a savanna – dominated by vast open meadows with scattered trees – for at least the last twenty thousand years. It was primarily the regular occurrence of fire that shaped this landscape, and many others of the continental US: they are ecosystems built to burn.

The general perspective on wildland fires in the early 20^th century was guided by the attitude of Smokey Bear, whose slogan, “Only you can prevent forest fires” led the national campaign to suppress all fires no matter where they occurred or how they started. Following Smokey – Bambi – the 1942 Disney film with its horrific forest conflagration scene, left no doubt on an entire generation that fire harmed nature.

But toward the later part of the 20^th century ecologists, land managers, and foresters slowly gained traction with the message that fire was an essential element for forest health and for the thousands of sun-loving wildflowers of the prairies, savannas, chaparral, and other fire-prone natural areas. Some ecologists went so far as to say that no single human modification of the environment has had more pervasive and widespread negative consequences for the ecological integrity of North America than the suppression of fire. Even Smokey Bear’s mantra changed to, “Only you can prevent wildfires.” But the damage was done – forests and other wildlands, over many decades, accumulated tremendous amounts of fuel, the human population built homes within huge tinderboxes, and many of the sun-loving herbaceous flora was shaded-out and declined to the point of imperilment.

Several CPC Participating Institutions hold the germplasm and work to recover the imperiled sun-loving herbaceous plants that reside in fire-dependent ecosystems, and at least half of North Carolina Botanical Garden’s 46 National Collection species are in some way reliant on fire. Of these, there are a few that particularly stand out.

Sandhills lily (Lilium pyrophilum), whose Latin specific epithet means fire-loving, is an obvious first choice! This strikingly beautiful rare denizen of the stream-heads and moist seeps of the Sandhills ecosystem in Virginia, North Carolina, and South Carolina, is not itself dependent on fire, but the longleaf pine ecosystem within which it resides is. So on a landscape scale, Sandhills lily loves fire, although it’s happy to avoid direct contact.

The Sandhills are dominated by longleaf pine (Pinus palustris), which is emblematic of this ecosystem and thus considered a flagship species, and a suite of mostly herbaceous plants adapted over the millennia to a one- to three-year fire frequency. These adaptations to fire include deep rootstocks, fire-resistant bark, and sturdy seeds that require heat or smoke to germinate.

East of the Sandhills, the wet pine savannas of the North American Coastal Plain are graced with over 1,800 endemic plants, a fact that prompted its recognition by Critical Ecosystem Partnership Fund as the world’s 36^th Biodiversity Hotspot.

Closer to home, and without the aid of bombs, the North Carolina Botanical Garden uses fire to help protect over 1,000 acres of nature preserves in the Piedmont Savanna. One of these is the Penny’s Bend Nature Preserve, adjacent to the state’s Plant Conservation Program preserves – all of which contain a treasure trove of rare and fire-dependent plants. The flagship species in these preserves is smooth coneflower (Echinacea laevigata), which, like much of the Piedmont savanna flora, was relegated to roadsides and rights-of-way through the decades of fire suppression.

About 20 years ago, NC Botanical Garden and Plant Conservation Program formed controlled burn crews who individually and together began resurrecting these fire-dependent species. Through careful fire management and select reintroduction, smooth coneflower and other rare plant populations are now thriving.

Beyond helping to revive rare plants, reintroducing fire has other benefits. Controlled burning maintains the overall “grassy” habitats necessary for regionally-declining ground-nesting birds such as bobwhite quail, whip-poor-wills, and meadow larks. Fire also reduces many plant pests, such as weevils that eat seeds. And wildlife and humans alike enjoy the significant decline of ticks where fire regularly occurs!

Yet it is sometimes difficult to recognize the importance of fire to natural ecosystems with the continuing incidence of megafires torching thousands of homes. In the best of all possible worlds, we would have thoughtful controlled burning for increasing ecosystem health, and humans would choose not to inhabit ecosystems built to burn. North Carolina Botanical Garden and its burn crew is working towards that ideal, providing burns where they can and educating the public on the importance of fire.

Adapting to the Recurring Threat of Wildfire

Timing is Everything

Their previous preparations helped the UCBG make quick work of the two populations, collecting seed from 122 individuals of one and 164 of the other in just a few hours before the long drive back to Berkeley. Quick does not mean easy. The collection was hazardous, collecting on a rocky roadside where car debris from recent accidents and rockslides are a semi-regular occurrence. The steep, rocky habitat made it difficult to collect evenly across the population. But they got what they could, and plan to bulk the seed in their nursery soon.

The two populations are separated at this time by a massive rock slide that closed Highway 140 for weeks, and necessitated the building of a single lane road on the opposite side of the Merced River and the erection of two one-lane bridges to bypass the destroyed road.

When Holly initially heard about the fire, she immediately thought of the clarkia – the uncollected seed of many still waving in the air, attached to the dry remains of the annual plants. Though the population should weather the fire well, the opportunity to collect would have been lost had the team not collected when they did – the road was closed for weeks after the collection and seed would have dispersed. It’s strange to think of a fire raging through an area you had just been walking through, of fire trucks and a swarm of firefighters occupying the space you had just been. But, for Holly, it was also a relief to know they had already secured seeds of the Merced clarkia.

Merced clarkia is just one of six clarkia species getting help from UCBG with their current USFWS project (coordinated by Valary Bloom and Josh Hull, USFWS Sacramento Office). The USFWS is funding their effort to conserve and increase the seed of clarkia species that are, as yet, not on the federal endangered species list, but are declining. Merced clarkia is threatened by big catastrophic events like fire and landslides, as well as poor road-side management – having been hit hard by roadside herbicide treatment a couple of decades ago. Other species are also susceptible to similar random events and other threats. All the targeted clarkias are to be maintained in conservation seed collections, along maternal lines (per CPC’s standards), and bulked to ensure there is enough seed to use when needed.

Having seed ready when it’s needed is, after all, what it’s all about. The Ferguson Fire is a good reminder of the importance of making conservation collections as soon as you can to make sure seed is obtained. Timing a seed collection can be difficult in general, but you never know when your target population may become inaccessible or even destroyed by any number of possible events.