Tree Biology

A hemlock tree, planted in a yard 14 years ago, died suddenly. The homeowner left town with the tree apparently healthy and returned two weeks later to find the tree had lost all its needles. On inspection, all the above-ground parts of the tree were dead. We excavated the tree with an Air Knife to see if there were below-ground signs or symptoms that might indicate the cause of death. We found extensive injury to the cambium, phloem and xylem below the ground level of the tree.
 

Stem of a dead hemlock showing extensive injury.

What caused all this damage? Read more for the solution.

A huge, stinky flower is blooming again in San Francisco's Conservatory of Flowers. The flower, which can be as much as 10 ft. tall when it opens, is the second largest flower in the world, and smells of a combination of rotting meat and sweaty socks. The corpse flower, also known as the titan arum, Amorphophallus titanum, is from Sumatra also home to the world's largest flower Rafflesia, Rafflesia arnoldii (spectacular pictures are here). Once thought to be closely related, recent DNA analysis places Rafflesia in its own family and order, while the corpse flower is in the Arum family, Araceae. The common name, corpse flower, is a direct translation of the Indonesian name, bunga bangkai.

Large stinky flowers are adapted to attract pollinators, just like sweeter flowers. However, in this case, the pollinators are probably flies and beetles that are attracted to rotting meat or vegetation (the pollination guild of corpse flower has not received much scholarly attention). A brief article on pollination in Amorphophallus is on the Aroid Society web site. The smelly compounds have low volatility, and these plants have the remarkable ability to generate a substantial amount of heat during flowering. This heat serves to increase evaporation of the smelly compounds. The way that flowers heat themselves to release odors was extensively studied in voodoo lily by the Indonesian-born botanist Bastiaan J.D. Meuse. Bastiaan discovered that salicylic acid, an important regulatory compount in plants, triggers the heating of arum flowers. Bastiaan passed away in 1999 after a prolific and distinguished career.

Update: "Big Bucky", a corpse flower at the University of Wisconsin, is getting ready to flower for the first time since 1991.

In the Pacific Northwest, bigleaf maple is a highly valued wood for musical instruments and furniture, especially if it is figured. Figured wood includes bird's eye, ripple and other patterns which make the wood exceptionally beautiful. More often than not, trees with figured wood are gnarled, decayed or have other defects that lessen their value as sawlogs, but dramatically raise their value in the specialty wood market. Figure in trees is often the result of very subtle growth abnormalities. The shifting of cambial cell divisions by small angles between years of growth results in ripple patterns. Bird's eye is the result of the growth and division of trace buds beneath the bark. Burls, which usually contain highly figured wood, may result from virus or fungal infections. The physiologic and genetic factors that cause figures wood are not known. A gallery of great photos of figured wood is at Jim Mattson's lab at Simon Fraser University. Jim and his colleagues are investigating the genetic causes of wood figure, in hopes of being able to propagate trees with a high probability of producing figured wood.

The price paid for this high-value wood is high enough that timber rustlers are a major problem. The Seattle Post-Intelligencer tells us that maple theft is rampant in towns and rural areas around Seattle. Since woodoworkers will often pay hundreds of dollars for a single board of figured wood sufficient to make a guitar, thieves have substantial motivation for their deeds. A single pick-up truck load of good figured wood can fetch $5,000, not bad for a day's work. Or a night's work, since the trees are sometimes taken while a homeowner sleeps.

A new Washington state law will require that transport of figured or specialty wood be accompanied by a permit. The permit must be signed by the land owner where the wood was harvested. Until the new law takes effect in July, law enforcement authorities have to prove that the wood was stolen.

The real problem here is that wood is a commodity, whose origin is unknown to the end user. Once a log is sawn, the identity of the wood product is lost. All over the world, illegal logging ranging from huge forests in Borneo to individual trees in Washington brings a flood of illicitly obtained wood to the market. As long as there is no systematic effort to track the origin of the wood, many of the wood products we buy will come from illegal operations. Third-party certification programs, such as Smartwood, provide a trusted chain-of-custody system that allows the origin of wood to be tracked. Woodworkers and consumers have a moral obligation to avoid the use of illicit wood, but this message does not seem to have penetrated the wood market sufficiently. Considerably more consumer education is required before guitars like the Gibson Les Paul Smartwood guitar becomes the norm in the marketplace.