Championing changes in the forest.

To build on an idea by zoologist and author Richard Dawkins, imagine bringing all your direct female ancestors back to life. Line them up starting with you holding your mother's hand, your mother holding her mother's hand, and so on. Keep going for about 1.3 billion years worth of generations. We need to get back to when there weren't so many species in order to understand the complexity of dividing them up. Ultimately we're talking about trees here, but remember that all living things in the history of Mother Earth are seamlessly connected. So follow that ancestral line down, furry paw to scaly foot, amphibious foot to fin to tail to pseudopodia, flagella, and cilia. Don't laugh. These are your relatives I'm talking about.

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Now let's move back up through the generations but start with a different "daughter" than the one that led to you. This daughter's generational line runs parallel to your own ancestral line but is, shall we say, firmly rooted to the ground. This long-lost relative could be the hemlock you climbed as a kid. Or the redbud you planted in your yard. Or the big oak you nominated to be a champion tree.

To make sense of all your extended family, and to reflect as much biological reality as possible, we divide life up into species. Sometimes it's obvious where to draw the line. We all know a sycamore from a sequoia. But sometimes it's like drawing the line between two colors in the rainbow. Where does one stop and the other begin?

The modern scientific naming of plants began on May 1, 1753, with the publication of Species Plantarum by a man so famous that biologists the world over think of him when they see the letter "L." Carl Linnaeus named and described thousands of species, including more than 130 North American trees. Most of the rest of our trees were named and described soon after the first explorers arrived in a given region.

Then botanists began looking more closely at variations within particular species, hybridization, reproductive systems, microscopic morphology, and, eventually, gene flow and DNA. Often their findings caused them to redraw the lines between species.

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The last time AMERICAN FORESTS redrew the lines for the National Register of Big Trees was in the late 1990s with Elbert Little Jr., author of Checklist of United States Trees (Native and Naturalized). Little's 1979 publication, whch the Register uses, was a seminal work but, like most science, was only a snapshot of the limits of our knowledge at that time. Botanists have learned a lot since then.

It's time to make changes in the Register to reflect our improved but still imperfect understanding of where the lines should be drawn. The taxonomy of the 2008 Register will be completely updated, but this preview of some of the possible changes will give big tree fans an idea of what to expect, and a jump-start on finding champions among our long-lost cousins.

Oaks have always given botanists fits with their penchant for wanton hybridization, so it's no surprise that many proposed taxonomic changes involve Quercus species. A new species, Channel Islands scrub oak (Quercus pacifica), was described in 1994. It is a shrub or small tree found only off the southern coast of California on Santa Cruz, Santa Catalina, and Santa Rosa islands. This oak was long thought to be part of the coastal sage scrub oak complex, but it is actually more closely related to the blue oak.

Another Channel Islands endemic that might soon be an eligible member of the Register is the island live oak (Quercus tomentella). Found in moist canyons at lower elevations, this rare evergreen grows to at least 60 feet tall and 2 feet in diameter. As evidenced by fossils, it is a relic that retreated from the mainland long ago. It made a brief appearance in the Register in 1980 as a newly listed species without a champ, but apparently became the victim of a data entry error and is only now coming out of exile.

A more widespread species that could be added to the Register is the bluff oak (Quercus austrina), formerly treated as a variety of Durand oak (Quercus durandi), with which it is often confused. Look for specimens up to 75 feet tall in lowland forests from Mississippi to South Carolina.

At least six other oaks might make their presence felt among the Quercus already on the Register, although their rarity makes the nomination of a champion difficult by anyone not associated with them via conservation or research. The robust oak (Quercus robusta), Mexican oak (Quercus carmenensis), and lateleaf oak (Quercus tardifolia) are all restricted in the U.S. to the Chisos Mountains of Big Bend National Park, Texas. In 1992, a natural population of netleaf white oak (Quercus polymorpha), otherwise widespread in Mexico and Guatemala, was discovered in Val Verde County, Texas.

The mapleleaf oak (Quercus acerifolia), recently elevated to full species from a variety of Shumard oak, has only been found at six sites in the Magazine and Ouachita mountains of Arkansas, and totals only a few hundred individual trees. The Cedros Island oak (Quercus cedrosensis), of Cedros Island and mainland Baja California, was discovered in 1995 to be growing just north of the border in the San Ysidro Mountains, where it is known from only four sites.

One sterile Sonoran oak (Quercus viminea) has been found in the U.S., at Red Mountain, Santa Cruz County, Arizona. However, no specimens have been located since so it don't look for it to be added to the Register anytime soon, but with global warming, big tree hunters may not have long to wait.

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The thorniest problem (pun intended) in the taxonomy of North American trees is undoubtably Crataegus, the hawthorns. Various named species have been produced by rampant hybridization, changes in chromosome number, and asexual development of seeds. But to make matters far worse, several hair-splitting taxonomists at the beginning of the 1900s described numerous species on the basis of minute differences, like the color of the anther, the pollen bearing part of the stamen. This resulted in more than 1,100 named hawthorn species in the continental U.S.!

Most of this taxonomic nightmare was created by a former director of the Arnold Arboretum at Harvard, Charles Sargent, who described an astounding 700 species of Crataegus. That's about as many species as all the other native trees in mainland America combined!

Fortunately, by 1979 the taxonomic "lumpers" (those who lump together similar species) had gained the upper hand over the "splitters," (those who classify minor species variations as separate trees) and had whittled the number of hawthorns down to the 35 native species recognized in Little's Checklist and in the current Register. But the tide has turned. American Forests has not yet decided how to deal with "the Crataegus problem," but be forewarned: the USDA's Plants Database, the Integrated Taxonomic Information System, and The Nature Conservancy's NatureServe all cite the North Carolina Botanical Garden's Synthesis of the North American Flora as the primary authority for their own lists. A strict following of the Synthesis would add more than 100 hawthorns to the Register.

One other addition to the Register will likely be the recently naturalized African sumac. Introduced to Tucson in 1925, and subsequently widely planted as an ornamental, this native of South Africa is now invasive along desert streams and washes in Arizona.

Slightly balancing all these potential additions to the Register are a number of trees under consideration to be dropped. The Macdonald oak, the only oak in the current Register to have never had a champion, shares the same distribution as the new Channel Islands scrub oak. No coincidence there. It is now known to be a hybrid between Channel Islands scrub oak and valley oak. The Kearney sumac, another empty throne species, could be dropped because it does not reach tree size, at least not in the United States.

A minimum of three full species might be deleted from the Register because they have been lumped with another species. The Carneros yucca, Florida chinkapin, and Hinds willow are now what taxonomists call synonyms (no longer accepted names) of Faxon yucca, Allegheny chinkapin, and sandbar willow. Other trees you might soon have to forget about include the following varieties that are no longer recognized: Black Hills spruce, Arizona smooth cypress, northwestern paper birch, Florida elm, Florida elder, Simpson stopper, and Deering Tree-cactus. Of course, any current champions of these delisted species will be stacked up against champions of the species they are lumped with. So some may be able to change their name and still keep their place in the Register.

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There will be many other differences in the 2008 Register, but they will not have any bearing on which trees you should size up. Only the names will be changed to protect the taxonomic integrity of AMERICAN FORESTS. Many varieties will be elevated to full species status, which means they'll have their own separate heading in 2008. These include intermountain and Colorado bristlecone pines, redbay, silkbay, swampbay, pignut hickory, Alaska paper birch, and 14 varieties of oak (all current varieties in the Register except Bigelow and Durand oaks). A few full species will be demoted to mere varieties: southern and eastern redcedars, speckled and mountain alders, and Torrey and fewflower vauquelinias.

When Linnaeus erected the pine genus, Pinus, he included hemlocks, firs, and spruces. Later botanists kept the pines in Pinus but moved the hemlocks to Tsuga, the firs to Abies, and the spruces to Picea. Similar generic reshufflings are still taking place and could soon affect the names you see in the Register. Incense-cedar could move from Libocedrus to Calocedrus; giant chinkapin from Castanopsis to Chrysolepis; saguaro from Cereum to Carnegiea; Key tree-cactus from Cereus to Pilosocereus; smokethorn from Dalea to Psorothamnus; and you could just see the bumelias (Bumelia), willow bustic (Dipholis), and false-mastic (Mastichodendron) join each other in Sideroxylon.

Finally, some changes in common names might also be in order. "Digger" is an old pioneer term derisively used to label California Indians for the way they obtained some of their food (roots and bulbs), and so the digger pine could become California foothill pine. However, look for most of the potential common name changes in the trees of Florida where Little often used the Latin genus as part of the common name instead of the more colorful, and truly vernacular, names currently in use. New names could include Lancewood (Florida nectandra), great leadtree (great leucaena), Florida clover-ash (Florida tetrazygia), greenheart (coffee colubrina), princesstree (royal paulownia), fevertree (pinckneya), and Florida toadwood (Florida cupania).

If change makes you feel unstable, join the botanists. Unless you want to wait decades or centuries until all the data are in, we must accept that taxonomists' current standards for the relationships of all our very distant arborescent cousins is the best that can be done at this time. New information, discoveries, and opinions will cause more changes in the future.

But look on the bright side. A sassafras (Sassafras albidum) is still a sassafras (Sassafras albidum), pines are still in the genus Pinus, and you may no longer have to ponder the difference between Hinds and sandbar willows. Best of all, there are probably more than 900 species of hawthorns that won't be in the 2008 Register.

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Photojournalist Whit Bronaugh lives in Eugene, Oregon.

RELATED ARTICLE: IN WITH THE NEW, OUT WITH THE SYNONYMS?

A preliminary list of tree species that you might see added or deleted in the 2008 National Register of Big Trees.

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Species potentially added: you may need to start looking for a big one of these!

Common Name        Scientific Name      Location

Island oak         Quercus tomentella   Channel Islands, Calif.
Channel Isl.       Quercus pacifica     Channel Islands, Calif.
  scrub oak
Cedros Island oak  Quercus cedrosensis  San Ysidro Mountains, Calif.
Mapleleaf oak      Quercus acerifolia   Magazine & Ouachita mtns., Ark.
Bluff oak          Quercus austrina     lowlands of Miss. to S. Carolina
Mexican oak        Quercus carmenensis  Chisos Mountains, Texas
Lateleaf oak       Quercus tardifolia   Chisos Mountains, Texas
Robust oak         Quercus robusta      Chisos Mountains, Texas
Netleaf white oak  Quercus polymorpha   Val Verde County, Texas
African sumac      Rhus lancea          Ariz.

Species that might be deleted: if so, save your tape measure for something else!

Common Name         Scientific Name       Reason Deleted

Kearney sumac       Rhus kearneyi         only a shrub in the U.S.
McDonald oak        Quercus macdonaldii   hybrid
Black Hills         Picea glauca var.     grouped w/white spruce
  spruce              densata
Arizona smooth      Cupressus arizonica   grouped w/Arizona cypress
  cypress             var. glabra
Florida elm         Ulmus americana       grouped w/American elm
                      var. floridana
Florida chinkapin   Castanea alnifolia    grouped w/Allegheny chinkapin
Northwestern paper  Betula papyrifera     grouped w/paper birch
  birch               var. subcordata
Deering             Cereus robinii        grouped w/Key tree-cactus
  tree-cactus         var. deeringii
Hinds willow        Salix hindsiana       grouped w/sandbar willow
Simpson stopper     Myrcianthes fragrans  grouped w/twinberry stopper
                      var. simpsonii
Florida elder       Sambucus canadensis   grouped w/American elder
                      var. laciniata
Carneros yucca      Yucca carnerosana     grouped w/Faxon yucca
Hawthorns (many)    Crataegus species     nationwide, mostly in the East