Investing in Koa Forest Plantations | Hawaii Forest IndustryHawaii Forest Industry Investing in Koa Forest Plantations Investing in Koa Forest Plantations April 2012 Hawai’i’s koa tree (Acacia koa) is a much beloved and venerated native tree which grows only in Hawai`i. For centuries Hawaiians have traditionally used the koa tree and its wood extensively to make objects ranging from canoes to personal ornaments. Its exquisite grain and endlessly varying colors make it one of the world’s most prized and expensive woods. Unfortunately, much of its native range has been converted to other uses, primarily grazing. The value of high quality koa lumber has created a strong demand for and pressure on the remaining koa forests. Planting koa trees to date has not kept pace with the use of the tree’s wood. This webpage is designed to encourage and inform potential planters and investors in koa plantations. Growing koa has numerous risks and pitfalls, however this gorgeous tree with its spectacular wood could be worth the risk if the planter or investor is fully informed. There is currently strong interest in growing koa both for conservation and utilization.

There has been substantial research conducted, which is ongoing, however there has been limited operational experience. The Hawai’i Forest Industry (HFIA) believes that growing koa is both environmentally and culturally the right thing to do and it can make financial sense, if the investor is well-informed on growing practices and very cautious with planting costs. 60-year old merchantable second growth Acacia koa tree. Ka`u, Hawai`i Island. Example of prime mature koa tree, naturally seeded. Note sprawling nature of branches. Forestry Investment 101 Millions of acres of timberland have been planted by or purchased internationally by Timber Investment Management Organizations (TIMOs) starting around 1980. The investors are primarily pension funds such as Hawai`i State Employee Retirement System and education trusts such as the Harvard Trust. As timber and timberland has become a well-known and accepted investment, and with billions of dollars in play, common methods of valuing these assets have become accepted. The most common metric is to calculate IRR (internal rate of return), which is similar to the interest rate on a bank account or bond.

Elements of this calculation are: Purchase price of the asset or planting cost of a new plantation; Costs to hold or manage; Income, normally from tree harvest. Income is the price of standing trees (stumpage) multiplied by volume of logs to be removed. Serious investors rely on current prices and do not speculate on future price changes; and The selling price of the asset, if any, at the end of the investment period. Return on investment is calculated like any other enterprise considering initial cost, cost to maintain, time elapsed, and return at the end. The University of Hawai’i College of Tropical Agriculture & Human Resources (CTAHR) has developed an excellent worksheet to input your own estimated variables for a situation or property of interest.8 In today’s world, investors look for an interest rate around 6%. In strong financial markets rates can climb to 8%. If your calculated rates on a proposed investment vary from this range by much, it is a good idea to check the assumptions. Note: Be careful, be informed. Globally there are bogus forestry investment schemes.7 Planting Koa It is difficult to forecast koa economic planting outcomes because koa has never successfully been grown in a plantation through to successful harvest.

However, it appears that with current koa pricing and careful attention to establishment costs, koa plantations can be economically viable. Spacing Typically trees are planted about ten feet apart, which will result in 440 trees per acre. Most of these planted trees will not survive to maturity. If a tree is planted 10 feet from the next tree, its branches can only grow out five feet until it is touching the next tree’s branches. Koa branches naturally grow much longer than this, giving koa its typical sprawling shape. Most of the planted trees will either die naturally or be crowded out by their neighbors. If this does not happen, they must be pre-commercially thinned by the grower. Otherwise growth will slow dramatically and few of the trees will reach usable size by the target harvest age. Typical growing prescriptions today call for stocking to be reduced to around 70 trees per acre (25 feet between trees) over time, so the remaining trees can grow large enough to be useable.2, 4, 5, 6 One-year-old koa seedling that received fertilization and both pre- and post-planting weed control.

Tree Planting Koa can be planted in areas cleared of competing brush and grass and free of any grazing animals. If grazing animals are present the trees will almost certainly suffer extensive damage or be killed. Koa appreciates a little fertilizer and is environment specific. Best results are from seed collected in the area to be planted. When seed cannot be obtained from the intended planting site, the seed source should be from a location with as many of the same characteristics of the intended site as possible. (eg. elevation, soil type, rainfall) Where to Plant Koa does best at elevation above 2,500 feet. While all koa are subject to rusts, wilts, and insects, those planted at low elevation are especially vulnerable and complete plantation losses can occur. Koa likes moist soils and climates but can grow (at slower rates) in very rocky soils. Koa trees are intolerant of frost but may survive. 2, 4, 5 Planting and Growing Costs Idol, Scowcroft et al.10 reports costs of $1,965 per acre ($4.91 per tree).

Forest Solutions, a privately owned forest management group, sets establishment plus maintenance at $2,300 per acre ($5.22 per tree) based on their experience. These costs are for planting 400 – 450 trees per acre plus two or three years of maintenance. This cost of establishment does not include fencing, which can substantially increase the cost. Maintenance Requirements Planted trees will require one or two weed control treatments plus one or two pre commercial thinnings before maturity. Pests The major diseases and pests that affect koa are “ Koa wilt ,” Fusarium SPP, Xylosandrus twig borers and the koa moth. Koa does not recover well from physical injury such as broken branches or insect injury to top buds. Losses may include complete plantation mortality and disfiguring trees, resulting in no commercial value for the investment.2, 4, 5 Acacia koa wilt disease. Koa mortality shown most likely caused by vascular wilt fungus Fusarium oxysporum. Acacia koa wilt stain. Typical stain caused by the vascular wilt fungus Fusarium oxysporum.

Growth Rates and Time to Maturity Measured growth rates of young natural stands and plantations are showing rates in maturing trees in the range of 150 to 250 board feet per acre per year. Forest land management should increase these “wild” yields, however but no data is available on such stands. Consensus between academics, forestry agency specialists and commercial foresters is that it is possible that there might be commercial use for koa trees as young as 35 years. The uncertainty stems from the fact that no plantation-grown koa trees have been grown to commercial maturity at this time. To test this hypothesis, the USDA Forest Service Pacific Northwest (PNW) Research Station and the Northern Research Station, University of Hawai`i, and the Hawai`i Forest Industry Association, with considerable contributions of time and equipment by saw miller Jay Warner, did a thorough technical analysis of lumber yields from logs harvested from three stands ranging in age between 31 and 36 in February of 2012. Results are not yet published, but three wood quality observations were made during the test: There is a high portion of unusable or very low value “sapwood” on the outside of the logs.

This wood is white, turning to dull yellow with brown flecks with aging. It is not recognizable as koa wood without a technical examination. There is no market currently for this wood. The logs yield some classic “koa look” lumber. Much of the lumber was an un-figured, un-distinctive brown color and included stain and other defects. There is no consensus yet on the market value of this type of wood. Results should be published soon and will be posted on this page. There is wide agreement among forestry professionals that a harvest age of between 45 -50 years should be achievable.1, 2, 3, 4, 5 Naturally seeded stands of koa can also do very well. The seed lives in the soil for long periods of time. Natural stands need soil disturbance so the trees can grow past grass and other competitors. Protection from grazing animals is also necessary. Natural stands often emerge very thick and can benefit from thinning and fertilization. A natural stand of thirty-year old Acacia koa. Kona, Hawai`i. Acacia koa tree in a fifteen-year old natural stand. Kapapala, Ka`u, Hawai`i.

Genetic Variability Koa has highly variable genetics. Genetics can have great impact on wood quality, but is not yet well understood. Over time, genetics will be better understood and will present an opportunity for wood quality improvement. Two fifteen-year old trees with very different colors of heart-wood. Marketing the Crop Value of Harvested Trees – Example If typical plantation harvest ages settle out around age 45, this might yield gross volume of 9,000 board feet per acre (200 board feet per acre per year) before deductions for defect or sapwood. There is no reliable data for such deductions. Thirty-year old Acacia koa wood from Kona, Hawai`i Island. Note unusable white sapwood and heart stain. Current stumpage rates for mature koa are in the $4 per board foot range. No one knows whether the market will accept second growth lumber at the current price for the mature koa.

Using an optimistic assumption that second growth trees will garner today’s prices for the older koa, then net stumpage in this example would be $36,000 per acre--$82 for each of our originally planted 440 trees per acre or around $514 for each of the remaining crop trees. Poor form (eg. branchiness and multiple stems) limits the amount of volume that can be economically harvested from koa stands.11 An alternative strategy would be to make modest harvests periodically and allow some trees to grow larger and older.

A harvest of 1,000 board feet per acre once every five years starting at about age 35 would be sustainable, yielding perhaps $4,000 per acre once every five years.1, 5 Utilize the CTAHR calculator to use any assumption you care to make and find the economic yield.8 An example of current economics using one possible set of assumptions is located here: EXAMPLE KOA ECONOMICS Subsidies There are several attractive subsidy programs.1 The National Academy of Science in a report authored by representatives of Stanford, University of Hawai`i and Harvard indicates that a koa plantation without subsidies would be worth a net present value of $453 per acre, while with subsidies it could be worth $1,661 per acre. Incentive Programs for forest landowners in Hawaii can also be found here . Ongoing Research There are several organizations currently researching Acacia koa, including the University Of Hawai’i College Of Tropical Agriculture and Human Resources, the US Forest Service and the Tropical Hardwood Tree Improvement and Regeneration Center. Anyone interested in Hawai’i forestry as an investment should follow the efforts of these and other scientific organizations.

Koa (Acacia koa Gray), endemic to the Hawaiian Islands, is the second most abundant overstory species in upper elevation forests. It forms nearly pure stands in montane forests such as those on the slopes of Mauna Loa between approximately 4,000 and 7,00 Abstract : Acacia koa (koa), among the most prominent overstory species of native Hawaiian forests, is affected by a number of diseases, including those caused by rust fungi, wood rotting fungi, root infecting fungi, and diseases categorized as seedling blights, foliar infections, and vascular wilts. A number of fungi occurring saprophytically on koa substrates are also known. Symptoms of other apparent diseases and disorders of unknown origin, or whose cause has not been clearly demonstrated are often manifest as leaf spots or other foliar abnormalities. Endemic pathogens which have evolved with their host may be responsible for many of the heretofore observed disease conditions, and as such usually do not threaten koa populations. However, a condition tentatively referred to as koa decline, may represent an exception.

This condition is characterized by slow to rapid wilt and death of apparently healthy, vigorous trees of all ages occurring in more or less well defined disease centers. This phenomenon is particularly prominent in upper elevation koa forests on the slopes of Mauna Loa on the island of Hawaii. Other apparent decline problems on Oahu and elsewhere in the islands have been reported, some associated with insects. The relationship of these observations to the koa decline on the Big Island has yet to be determined, and the question as to whether "koa decline" represents a complex of disease conditions or can be more closely attributed to a single, specific cause requires further study. Koa (Acacia koa Gray), endemic to the Hawaiian Islands, is the second most abundant overstory species in upper elevation forests. It forms nearly pure stands in montane forests such as those on the slopes of Mauna Loa between approximately 4,000 and 7,000 feet (1,230 and 2,150 meters) (Whitesell 1990). Koa is distinctive in the formation of crescent-shaped phyllodes which in older trees assume the function of the pinnately compound true leaves produced in juvenile stages of development.

As an endemic tree, koa is of critical ecological importance, forming habitat for numerous native birds, insects, and other flora and fauna. As a nitrogen-fixing leguminous species, koa is thought to account significantly for the nitrogen content of otherwise nitrogen-poor volcanic forest soils (Whitesell 1990). Koa is also prominently represented in early Hawaiian legend and culture, and economically is considered the most valuable of the common native timber species. Koa wood, sometimes referred to as "Hawaiian mahogany," can be highly polished to emphasize its deep reddish coloration with wavy grain and is used for furniture, paneling, and such woodworking crafts as bowls and ukuleles. St. John (1979) recognized three distinct species as representing the genus Acacia in Hawai`i: A. koa Gray, A. koaia Hbd., and A. kauaiensis Hbd. Furthermore, within A. koa three varieties were recognized: A. koa var. koa, found on all major Hawaiian Islands; A. koa var. latifolia (Benth.) St. John (=A. koa var. hawaiiensis Rock) and A. koa var. waianaiensis St.

John restricted to the islands of Hawai`i and O`ahu, respectively. Although the current treatment of A. koa (Wagner et al. 1990) combines all of these forms within A. koa, the distinction among them is still apparently sufficient to delimit the host ranges of host-specific pathogens, such as the rust fungi. Reference to St. Johns classification is therefore useful to this discussion. Several observations of diseases and pathogenic fungi occurring on koa have been individually reported in the literature as they have been observed over the years (Raabe et al. 1981), or have not been formally published. It was of interest to assemble such published information, together with as yet unpublished observations of fungi and disease conditions of koa, to provide the basis for a discussion of the pathology of this pivotal species. Diseases Caused by Rust Fungi Rust fungi, members of the order Uredinales, are so called because of the often brownish to orange appearance of the spore masses. These fungi produce perhaps the most widespread and prominent diseases of koa, collectively referred to as koa rust.

Stevens (1925), originally described a single fungus, Uromyces koae Arth., as the cause of the disease, but five species of rust fungi, four of which are considered endemic and one indigenous, are currently recognized on koa (Hodges and Gardner 1984; Gardner 1991), each with distinctive symptoms. These include three species now placed in the genus Atelocauda: A. koae (Arth.) Cumm. & Y. Hiratsuka, A. digitata (Wint.) Cumm. & Y. Hiratsuka, and A. angustiphylloda Gardner, and two species of Endoraecium: E. acaciae Hodges & Gardner and E. hawaiiense Hodges & Gardner. Atelocauda koae occurs commonly on Acacia koa var. latifolia on Hawai`i. and on A. koa var. koa on Kaua`i, O`ahu, and Maui. It has not been reported on Moloka`i, nor has it been found on A. koaia anywhere.

Atelocauda koae is confined to young tissue, occurring most frequently on newly developing true leaves, phyllodes, and shoots of saplings, but also found on new shoots of older trees. It is evident as raised, powdery, brown leaf spots, 110 mm dia., occurring singly or in groups, on both leaf surfaces. Heavy infection, in which spots coalesce to form large, irregular powdery blotches, can cause severe distortion of leaves, shoots, and small branches, leading to stem deformation (Hodges and Gardner 1984; Chen et al. 1996). Atelocauda digitata is known from all major islands except Lana`i, although its presence on this island in upland forests would not be surprising. On Acacia koa var. latifolia, the conspicuous stages of this fungus cause "witches-brooms" up to approximately 15 cm tall, comprised of clustered, misshapen, abnormally thickened shoots developing from infected branches. The diseased tissue may be covered by powdery, brown spore masses which are easily rubbed off.

Removal of witches brooms is ineffective in controlling the disease since the fungus invades branch tissues systemically. From one to many brooms may occur in a tree. Less conspicuous stages of A. digitata occur as small, brown, raised sporulating pustules up to approximately 1mm in diameter on the surface of otherwise normal phyllodes. Occasionally such spots are surrounded by larger chlorotic spots, causing them to be more conspicuous. Atelocauda digitata kills branch portions distal to the broom, but entire trees are typically not killed by this fungus alone. On Acacia koa var. koa on Maui and O`ahu A. digitata produces hypertrophy of flower and shoot tissue, resulting in malformation, but it does not produce witches brooms typical of those on Acacia koa var. latifolia (Hodges and Gardner 1984). Atelocauda angustiphylloda is confined to Acacia koa var. latifolia and is limited in distribution on the island of Hawai`i, but visible in large koa trees on the upper Saddle Road.

This rust forms large (up to 1 meter tall) witches brooms comprised of hypertrophied but abnormally reduced, much narrowed phyllodes almost circular in cross section, giving a "shoe string" appearance (Gardner, in press). As with A. digitata, brooms are covered with powdery, brown spore masses. Although limited in distribution, large numbers of brooms (100+) may occur in certain mature, presumably susceptible trees. Host trees appear to tolerate infection by A. angustiphylloda, but loss of vigor and local tissue death may occur. Endoraecium acaciae, the most common of koa rusts, has been found on A. koa var. koa on Maui, Kaua`i, and Hawai`i, and on A. koaia on Hawai`i, Kaua`i, and Moloka`i. It has not been found on A. koa var. latifolia. This fungus produces conspicuous, profusely-branched brooms up to 30 cm long comprised of much reduced, flattened phyllodes covered with spore masses. In apparent contrast to other koa rusts, E.

acaciae may cause severe damage to the host, and heavy infections producing multiple brooms may kill the entire tree. Brooms of E. hawaiiense are similar to those of E. acaciae but are smaller, being seldom taller than 12 cm, and relatively inconspicuous. This fungus appears to be limited in distribution, having been found only at certain sites on O`ahu on A. koa var. waianaiensis and A. koa var. koa. An insufficient number of trees heavily infected with this fungus has been found to assess its potential for host damage. The two species of Endoraecium are further separated from one another by differences in spore morphology. Wind-distributed spores of the koa rust fungi are thought to be the principal means of long and short distance dispersal, although Leeper and Beardsley (1973) noted the possibility that the koa psyllid Acizzia uncatoides (Ferris & Klyver) [=Psylla uncatoides (Ferris & Klyver)] may at least in part account for short distance dispersal where populations of these insects are high.

Wherever koa rust diseases are observed, evidence can be found of variability in susceptibility to infection among neighboring individual trees. Koa breeding programs directed at selecting such resistance may be the most effective control approach for rust diseases. Wood-Rotting Fungi A number of diseases of koa caused by wood rotting, "higher" fungi (i.e., basidiomycetes) have been described. These fungi are characterized by external production of fleshy or woody fruiting bodies which are often conspicuous and indicate the presence of already well-established internal infection. Bega (1979) reported Phaeolus schweinitzii (Fr.) Pat., Laetiporus sulphureus (Bull. ex Fr.) Bond. & Sing. (=Polyporus sulphureus Bull. ex Fr.), and Pleurotus ostreatus (Jacq. ex Fr.) Kumm. for the first time in Hawai`i. These species, together with Armillaria mellea (Vahl ex Fr.) Quï¿½l.

and Ganoderma sp., were associated with deteriorating old-growth stands of koa on several thousand acres of range land in the Keanakolu, Halepiula, Spring Water Camp areas of Hawai`i Island at an elevation of 5,000 to 6,000 ft. (1,540 to 1,840 m). Wood-rotting fungi produce characteristic types of infection, such as brown cubical rot of heartwood produced by Phaeolus schweinitzii and Polyporus sulphureus, but positive field identification is usually possible only if the fruiting body is present. An exception, however, is A. mellea, which causes a stringy white root and butt rot of a wide range of woody hosts in Hawai`i and elsewhere, including koa (Laemmlen and Bega 1974; Raabe and Trujillo 1963), produces distinctive "shoe-string" rhizomorphs and mycelial fans under infected bark by which it may be identified.

Bega (1979) reported that the honey-colored fruiting bodies (mushrooms) of this species were not known in Hawaii; but fruiting bodies of a fungus agreeing with A. mellea in its previously described broad concept have now been found to be common in certain sites (G. Wong, personal communication). A new species of Phellinus, described as P. kawakamii Larsen, Lombard, & Hodges, recently was found on Acacia koa var. koa and A. koaia on Kaua`i (Larsen et al. 1985). The same species was also found on Casuarina equisetifolia L. on Hawai`i and O`ahu. This heartwood-decaying fungus produces white pocket-rot in its hosts and is characterized by a large fruiting body (to 70 cm wide, 20 cm thick) which is produced near ground level and may be obscured by leaf litter and thus easily overlooked. No fruiting bodies were found on koa during casual observations made in old-growth stands on O`ahu, Maui, and Hawai`i. However, internal decay typical of that produced by P.

kawakamii was found in a substantial number of stumps of A. koa var. koa trees salvaged following the 1982 hurricane, indicating that presence of fruiting bodies may not indicate the true incidence of disease in a stand (Larsen et al. 1985). Rather than killing their hosts directly, pathogenic heart and root-rotting fungi destroy timber usefulness and predispose trees to wind-throw and branch or stem breakage. Nelson and Wheeler (1963) reported that more than half of the large koa trees reported in the 1959-1961 forest survey were considered unmerchantable because of excessive wood rot. Other higher fungi associated with koa, either as saprophytes on dead material or as weak parasites, were reported earlier by Burt (1923). These include Schizophyllum commune Fr., a common wood inhabiting fungus of wide host range and world-wide distribution, where it occurs on dead parts of living trees and on hardwood slash. As an exception to its normal saprophytic activity, S.

commune was reported to cause wilting of planted 3-year old Acacia saplings in South Africa (Ledeboer 1946), but similar virulence on koa has not been documented. Fomes fasciculatus Burt was described as a new species on dead koa on Kaua`i, and F. hawaiensis Forbes in Lloyd was found on koa on Hawai`i, Kaua`i, Lana`i, and Moloka`i, but its pathogenic ability was not mentioned. Burt (1923) also reported the wood-rotting fungi F. australis Fr. on Kaua`i and F. fullageri (Berk.) Cke. (location not given) on koa. Although not classified among the higher fungi, wood-inhabiting fungi of the family Xylariaceae: Hypoxylon annulatum (Schw.) Mont., Nummularia guarantica Speg., and Xylaria rhopaliodes Mont. have been reported on koa (Stevens 1925). These genera produce dark, usually conspicuous stromata (fruiting bodies) visible on the bark of infected tissue.

The above genera are distinguished by the general morphology of their stromata: flat or cushion-like in Hypoxylon, cup-shaped in Nummularia, elongate or club-shaped and borne on stalks in Xylaria. Most members of the Xylariaceae are saprophytic or weakly parasitic, which is probably true of the species occurring on koa. Root Infections The ubiquitous "water mold" Phytophthora cinnamomi Rands, a root-infecting fungus favored by the oxygen-deficient conditions of water-logged soil, is known to attack a wide range of plant species. This pathogen was isolated from roots of koa, among those of a number of other forest species, in studies directed at determining its role in the decline syndrome of `ohi`a (Metrosideros polymorpha Gaud.) in Hawai`i (Kliejunas and Ko 1976). Koa was categorized with species considered "moderately tolerant" to the fungus (Kliejunas 1979), suggesting that Phytophthora root rot, while present under conducive soil conditions, usually was not a significant disease of koa.

Other ubiquitous root-invading pathogens with wide host ranges, including the fungus Rhizoctonia sp. (Raabe et al. 1981) and the root-knot nematode Meloidogyne incognita (Kofoid & White) Chitwood (Raabe 1966), have also been found on koa, but the extent of any damage from these agents was not reported and presumed to be minimal. Seedling Blights Two species of the fungus Calonectria have been reported as causes of koa diseases. Calonectria crotolariae (Loos) Bell & Sobers, the pathogen causing collar rot of papaya (Carica payaya L.) seedlings, also caused a severe collar rot among a dense cover of koa seedlings reforesting a burned area in Kipapa Gulch in the Ko`olau Mountains of O`ahu (Aragaki et al. 1972). The disease caused a quick decline and collapse associated with signs of fungal growth and production of orange-red fruiting bodies near the soil line. Death occurred 2 days following onset of symptoms.

A slower decline also was observed among some seedlings, in which lower leaves became chlorotic and a progressive wilt led to seedling death in 7 days. Acacia melanoxylon R. Br. ex Ait. seedlings also were found to be susceptible when inoculated with the fungus from culture. Whereas the incidence of collar rot on koa seedlings was severe, it appears to have been a single event resulting from the coincident occurrence of several predisposing factors. Shoot blights caused by C. theae Loos were reported on koa and `ohi`a on O`ahu (Nishijima and Aragaki 1975). The disease, which also is known to occur on other species of Acacia, causes small dark spots on leaves and green twigs. Whereas artificial inoculation of koa seedlings resulted in considerable leaf drop, natural infection has been found only infrequently in Hawaiian forests and was not found to cause significant damage in these environments. Gardner (1980) reported a severe wilt disease of seedlings of Acacia koa var. hawaiiensis Rock (=A. koa var.

latifolia) caused by a specific form of the vascular wilt fungus Fusarium oxysporum (Schlecht.) Snyd. & Hans., designated F. oxysporum f. sp. koae Gardner. The disease appeared spontaneously among seedlings grown from seed collected in Hawai`i Volcanoes National Park, and the fungus was shown to be seedborne. Experimentally inoculated seedlings of A. koaia, A. confusa Merr. (Formosan koa), and A. simplicifolia Druce, the latter two introduced species, were also wilted by the fungus. Fusarium wilt diseases have been reported in a wide variety of agricultural and horticultural crops on a world-wide basis, where historically they have been of major economic importance. Foliar Infections Sutton and Hodges (1983) described a new leaf-spotting fungus, Gloeocoryneum hawaiiense Sutton & Hodges, on A. koa var. koa at Makaha Ridge on Kaua`i. Although G. hawaiiense originally was found on only two trees, both trees were heavily infected.

Leaves infected with this fungus have since been found on Maui (Gardner, unpubl.). The fungus appears as small, dark, spore-producing leaf spots (conidiomata), often arranged in short, more or less linear rows 30-120 mm long. Following maturity of the conidiomata, the immediately surrounding area becomes necrotic. Notwithstanding the severe leaf infection, the disease was reported to cause little apparent damage to the host itself. A leaf spot disease in which numerous (i.e., > 30 per cm2) dark, circular to oblong spots, 0.8 - 1.5 mm in diameter, on both phyllode surfaces was observed among koa trees planted in plots near Kahului, Maui (J. Tavares and D. Ogata, unpubl.). The spots, which sometimes coalesced to produce larger blotches, were associated with Alternaria alternata (Fr. ex Fr.) Keissl., although the role of this fungus as the primary cause of the disease is questionable and remains to be experimentally demonsrated. This fungus most often occurs as a saprophyte or a weak parasite on a broad range of plant hosts.

The dry conditions of the koa plots outside of their natural elevational range may have placed the trees under unnatural stress, predisposing them to infection. Alternaria alternata also was reported on koa leaves in Hawaii Volcanoes National Park, but a description of symptoms of infection was not included (P. H. Dunn and G. Baker, unpubl.). Stevens (1925) reported Lophodermium intermissum Starb. on presumably live koa at Wahiawa, O`ahu, and Pogues Ditch Trail on Maui. Species of Lophodermium may occur either saprophytically or parasitically, causing leaf spots containing dark, erumpent fruiting bodies. The Meliolales, or "dark mildews," are found primarily in tropical regions and are well represented in Hawai`i, occurring on a wide range of native species. The members of this well-defined group are closely allied with one another and have other characteristics in common with the powdery mildews (order Erysiphales) and the rust fungi.

Like the rusts, they are highly specialized, usually host-specific, obligate parasites (that is, they cannot be cultured on artificial medium but require living host tissue for survival). Most of the species of dark mildews occurring in Hawai`i are known only from endemic host species, and are themselves considered endemic (Stevens 1925, Goos and Anderson 1972). The dark mildews are conspicuous as black, more or less circular spots or blotches on leaf surfaces. The fungal colony, which may appear somewhat thick and velvety in texture, may occur as an isolated spot, or several colonies may coalesce to cover much of the photosynthetic area. The dark mildews are sometimes confused with another group of black fungi, the sooty molds, which occur superficially on plant or other surfaces and are not considered parasites. Meliola koae Stev. is recognized as the species occurring on koa (Stevens 1925, Goos and Anderson 1972). A second species, M. bidentata Cke., also was reported on koa by Raabe et al.

(1981) based on previously unpublished data from the files of the Department of Plant Pathology, University of Hawai`i at Manoa. The identity of this fungus appears questionable and should be confirmed through further collection. Petrak (1953), in his "Contributions to the Fungal Flora of Hawaii," listed a number of fungi associated with native plants, including the leaf-spotting fungus Mycosphaerella koae Petr., which he found on dry seed pods of koa at Kona (Hawai`i Island) and described as a new species. Although the original collection was associated with dead tissue, members of the genus Mycosphaerella are often parasitic and are known to cause serious leaf diseases of other hosts (Hanlin 1990). Other than the initial report by Petrak, no information apparently is available concerning occurrence of M. koae on koa, however. A number of apparent phyllode infections occur, some commonly, for which a cause has not been found. Although leaf-spotting fungi in such cases are usually suspected, sporulation or fruiting, which is necessary to identify such agents, has not been observed.

Of particular note among these symptoms is a prominent chlorotic (yellow) speckling which is frequently observed on A. koa var. latifolia. Until fungal agents of known pathogenicity are isolated as the probable causes, the possibility that such symptoms may also result from abiotic factors, such as physiological stresses or imbalances, must also be considered. Vascular Wilt Diseases As was indicated by the seedling disease caused by Fusarium oxysporum discussed above, pathogenicity and host range of the suspected causal agents of these diseases is most easily demonstrated experimentally on seedlings. However, vascular wilt diseases are typically virulent on all developmental stages of the host, where they cause rapid, irreversible wilting and decline. On older plants, the fungus systemically invades the vascular system and is contained within internal tissues during most stages of disease progression and is therefore not directly visible. In agricultural systems, development of resistant varieties has been relied on as the only practical control approach to a number of economically important vascular wilt diseases of crops caused by Fusarium and Verticillium. Genetic resistance is probably present in population of forest species as well, including koa, but has not yet been as well investigated or exploited.

Centers of decline among koa stands in the Mauna Loa Strip region of Hawai`i Volcanoes National Park have been observed for a number of years (Gardner, unpubl.). Some such centers are apparently no longer active or are progressing slowly within mature stands in which a number of older trees have died. On the other hand, well-defined centers of decline are obviously active among otherwise vigorous stands of koa in the Mauna Loa Strip, in which pre-senescent trees of all ages, including saplings, are rapidly dying. Symptoms of the decline point to Fusarium wilt as a possible cause (Gardner 1980). Fusarium agreeing with the description of F. oxysporum f. sp. koae has been isolated from diseased trees at these sites, cultured and shown to be virulent to inoculated healthy seedlings (Gardner 1980; unpubl.). However, lack of consistent recovery from older trees to date suggests the need for more thorough investigation before definite conclusions can be drawn.

In 1994 a Fusarium isolate, associated with wood discoloration, was recovered from branch sections of a mature, dying koa tree, marked by progressive thinning of the crown, at a homestead on Mt. Tantalus, O`ahu. Pathogenicity of the isolate was subsequently demonstrated in inoculation tests of koa seedlings (Gardner and E. Yoshino, unpubl. data). Because decline caused by vascular wilt organisms may be rather nondescript, without overt evidence of the causal agent, death of isolated, individual trees such as this possibly occur more commonly than is currently recognized. Koa Decline Addressing the subject of koa decline, Laemmlen and Bega (1972) reported that, according to aerial surveys in 1954, 67,000 acres of koa and `ohi`a forests occupying approximately 600,000 acres on the island of Hawai`i were in slight (<20% dead trees) to severe (60% dead trees or more) decline.

In 1965, the affected areas had increased by 10,000 acres, and the severely affected portions had increased from 5,000 acres in 1954 to 14,000 acres, with more recent ground surveys indicating a steadily deteriorating situation. The decline was characterized as a rapid wilt and death of trees and/or a slow progressive decline causing a thinning of foliage with many dead twigs, followed eventually by complete defoliation and death. The most severely affected forest was on the slopes of Mauna Kea at an elevation of 750-1,700 m. Laemmlen and Bega (1972) mentioned several possible causal or contributing biotic agents, including the fungi Armillaria mellea, Phytophthora cinnamomi, and Diatrype princeps Penz. & Sacc.; the insects Xylosandrus compactus Eichoff (black twig borer) and Plagithmysus bilineatus Sh., a native wood-boring beetle, together with the activities of wild pigs and other mammals (presumably rats).

Damage to young koa by stripping of bark from limbs and trunks has been documented as an apparently common phenomenon, with up to 54% of trees sampled in 4- to 6-year-old stands in the Laupahoehoe and Waiakea areas on the island of Hawaii affected (Scowcroft and Sakai 1984). Whereas in this study complete girdling by such bark removal was rare, injury has been observed in the Mauna Loa Strip region of Hawaii Volcanoes National Park in which girdling, presumably caused by rats, resulted in the death of branches of older trees. Such effects result in conspicuous browning and wilting of foliage and may be confused with disease symptoms, such as those generally attributed to koa dieback (Gardner, unpubl.). Abiotic factors such as changes in soil drainage were also suggested as possible contributing factors. Although Laemmlen and Bega (1972) indicated that quantitative and qualitative studies of the decline were to be initiated, the original scope of the work became separately focused on the prominent ohia decline phenomenon (c.f. Hodges et al.

1986), with little emphasis on koa. The extent to which a vascular wilt disease may be operative in the forest decline syndrome described by Laemmlen and Bega is not known, but the high degree of host-specificity characteristic of the wilt Fusaria suggests that such a disease would not fully account for a general decline of forests including both koa and `ohi`a and possibly other species. Nonpathogenic Fungi Associated With Koa In addition to the above-described diseases and disease conditions of koa, and of fungi which under favorable conditions may cause, or contribute to, koa disease, a number of fungi have been reported associated with koa tissue as saprophytes. Petrak (1952) described as new species two stromatic fungi found on dead koa branches on Mt. Tantalus: Diaporthe sheariana Petr. and Thyridaria koae Petr. Fungi also have been found existing on leaf surfaces but causing no apparent harm to the plant. Members of the genus Pestalotia are frequently isolated from diseased tissue, but their role as pathogens is questionable. Humicola brevis (Gilman & Abbott) Gilm.

and species of Pestalotia, including P. angusiana M. B. Ellis, P. breviseta Sacc., and P. stevensonii Peck have been found on apparently healthy koa phyllodes in Hawaii Volcanoes National Park (G. Baker, unpubl.). A number of other more or less common fungi, including Cylindrocephalum (=Chalara) sp., Cylindrocarpon sp., Cylindrosporium sp., Epicoccum purpurascens Ehrenberg, Papulospora sp., Sporotrichum laxum Nees, Stachybotrys atra Corda, and Triscelophorus monosporus Ingold also have been reported on koa leaves (phyllodes) or leaf litter (Goos 1978; G. Baker and P. H. Dunn, unpublished records in the University of Hawaii Department of Botany). Whereas some saprophytic or epiphytic species are more or less generalists, capable of subsistence on a wide variety of substrates, others show some degree of specificity.

In a study to determine the association of fungi with leaf surfaces of three endemic trees, koa, `ohi`a, and olapa (Cheirodendron trigynum (Gaud.) Heller. ), Baker et al. (1979) found a large number of fungi on leaves of ohia, but significantly fewer on koa phyllodes and leaves of olapa, which were not as widely sampled. They concluded that the smooth phyllode surfaces of koa retained spores poorly. Stoner et al. (1975), listed a large number of fungal species in surveys of soil of root zones of native vegetation types, including A. koa var. hawaiiensis, of the Mauna Loa region of Hawaii Volcanoes National Park. Conclusions Whereas a considerable number of fungi and other possible disease agents (i.e., nematodes) are associated with koa, relatively few of these currently cause diseases of significance to the general well-being of native Acacia in Hawaii.

Outbreaks such as the above-described seedling collar rot caused by Calonectria crotolariae are locally devastating, but, because they depend on a coincidental occurrence of several conditions favorable to disease development, are observed only rarely. Many wood rotting fungi, while probably more prevalent than published reports indicate, are most prevalent in older, senescent or presenescent trees, often hastening, but not causing, their decline. Among the exceptional diseases which may impact otherwise vigorous, actively growing trees are those caused by rust fungi and agents responsible for the koa dieback observed in the Mauna Loa Strip area of Hawaii Volcanoes National Park. The rust fungi attacking koa are relatively well understood and all are thought to be native species, closely related to one another, having evolved in close association with their hosts (Hodges and Gardner 1984). While infection causes branch flagging, with heavy infection by Endoraecium acaciae resulting in some apparent death of koa, and timber quality may be affected by distortion of the terminal development of young trees infected with Atelocauda koae, rust diseases are not considered threatening to koa populations.

Perhaps the most ominous threat to koa, from the standpoint of disease, is the koa decline syndrome, currently prevalent and well defined in the Mauna Loa Strip region of Hawaii Volcanoes National Park. As stated above, although the presence of Fusarium oxysporum f. sp. koae has implications, the extend to which this fungus contributes to the decline is not known. Likewise, the relation of decline in this location to other, more incidental death of koa trees elsewhere throughout the islands, is not known. Perceived increases in frequency of such deaths may be a result either of increased awareness of koa itself or reflect an actual disease situation. Research directed at elucidating these problems is anticipated. Literature Cited Aragaki, M., F. F. Laemmlen, and W. T. Nishijima. 1972. Collar root rot of koa caused by Calonectria crotalariae. Plant Disease Reporter 56:73-74. Baker, G., P. H. Dunn, and W. S. Sakai. 1979. Fungus communities associated with leaf surfaces of endemic vascular plants in Hawaii.

Mycologia 71:272-292. Bega, R. V. 1979. Heart and root rot fungi associated with deterioration of Acacia koa on the island of Hawaii. Plant Disease Reporter 63:682-684. Burt, E. A. 1923. Higher fungi of the Hawaiian Islands. Annals of the Missouri Botanical Garden 10:179-189. Chen, W.-Q., D. E. Gardner, and D. T. Webb. 1996. Biology and life cycle of Atelocauda koae, an unusual demicyclic rust. Mycoscience 37:91-98. Gardner, D. E. 1980. Acacia koa seedling wilt caused by Fusarium oxysporum f. sp. koae, f. sp. nov. Phytopathology 70:594-597. Gardner, D. E. 1991. Atelocauda angustiphylloda n.

sp., a microcyclic rust on Acacia koa in Hawaii. Mycologia 83:650-653. Gardner, D. E. Additions to the rust fungi of Hawaii. Pacific Science. In press. Goos, R. D. 1978. Occurrence of Triscelophorus monosporus in upland sites on Oahu, Hawaii. Mycologia 70:188-189. Goos, R. D., and J. H. Anderson. 1972. The Meliolaceae of Hawaii. Sydowia, Annales Mycologici Ser. II. 26:73-80. Hanlin, R. T. 1990. Illustrated genera of Ascomycetes. The American Phytopathological Society Press. St. Paul, Minnesota. Hodges, C. S., Jr., and D. E. Gardner. 1984. Hawaiian forest fungi. IV. Rusts on endemic Acacia species. Mycologia 76:332-349. Hodges, C.

S., Jr., K. T. Adee, J. D. Stein, H. B Wood, and R. D. Doty. 1986. Decline of ohia (Metrosideros polymorpha) in Hawaii: A review. General Technical Report PSW-86. Berkeley, Calif.: Pacific Southwest Forest and Range Experiment Station, Forest Service, U. S. Department of Agriculture. Kliejunas, J. T. 1979. Effects of Phytophthora cinnamomi on some endemic and exotic plant species in Hawaii in relation to soil type. Plant Disease Reporter 63:602- 606. Kliejunas, J. T., and W. H. Ko. 1976. Dispersal of Phytophthora cinnamomi on the island of Hawaii. Phytopathology 66:457-460. Laemmlen, F. F., and R. V. Bega. 1972. Decline of ohia and koa forests in Hawaii. (Abstract). Phytopathology 62:770.

Laemmlen, F. F., and R. V. Bega. 1974. Hosts of Armillaria mellea in Hawaii. Plant Disease Reporter 58:102-103. Larsen, M. J., F. F. Lombard, and C. S. Hodges, Jr. 1985. Hawaiian Forest Fungi. V. A new species of Phellinus (Hymenochaetaceae) causing decay of Casuarina and Acacia. Mycologia 77:345-352. Ledoboer, M. S. J. 1946. Schizophyllum commune as a wound parasite: A warning to wattle growers. Journal of the South African Forestry Association 13:39-40. Leeper, John, R., and J. W. Beardsley. 1973. The bioecology of Psylla uncatoides in the Hawaii Volcanoes National Park and the Acacia koaia Sanctuary. Island Ecosystems IRP. U. S. International Biological Program. Technical Report 23.

13 pp. Nelson, R. E., and P. R. Wheeler. 1963. Forest resources in Hawaii. Hawaii Department of Land and Natural Resources, Honolulu. 48 pp. Nishijima, W. T., and M. Aragaki. 1975. Shoot blights of ohia and koa caused by Calonectria theae. Plant Disease Reporter 59:883-885. Petrak, F. 1952. Ein Beitrag zur Pilzflora von Hawai. Sydowia Annales Mycologici 6:363-371. Petrak, F. 1953. Beitrï¿½ge zur Pilzflora von Hawaii. Sydowia Annales Mycologici 7: 381- 409. Raabe, R. D. 1966. Check list of plant diseases previously unreported in Hawaii. Plant Disease Reporter 50:411-414. Raabe, R. D., and E. E. Trujillo. 1963.

Armillaria mellea in Hawaii. Plant Disease Reporter 47:776. Raabe, R. D., I. L. Conners, and A. P. Martinez. 1981. Checklist of plant diseases in Hawaii. College of Tropical Agriculture and Human Resources, University of Hawaii Information Text Series 022. 313 pp. Scowcroft, P. G., and H. F. Sakai. 1984. Stripping of Acacia koa bark by rats on Hawaii and Maui. Pacific Science 38:80-86. St. John, H. 1979. Classification of Acacia koa and relatives (Leguminosae): Hawaiian plant studies 93 (Hawaii). Pacific Science 33:357-367. Stevens, F. L. 1925. Hawaiian fungi. Bernice P. Bishop Museum Bulletin 19. Honolulu, Hawaii. 189 pp. Stoner, M. F., D. K. Stoner, and G. E. Baker. 1975.

Ecology of fungi in wildland soils along the Mauna Loa Transect. Island Ecosystems IRP. U. S. International Biological Program. Technical Report 75. 102 pp. Sutton, B. C., and C. S. Hodges, Jr. 1983. Hawaiian forest fungi. III. A new species, Gloeocoryneum hawaiiense, on Acacia koa. Mycologia 75:280-284. Whitesell, C. D. 1990. Acacia koa Gray. Pp. 17-28. In: Silvics of North America: 2, Hardwoods. R. M. Burns and B. H. Honkala, technical coordinators. Agriculture Handbook 654. USDA Forest Service, Washington, D. C. Hawaiian Plants - Koa Habitat: Sea level to 6,000 ft The Koa tree is one of the tallest trees in Hawai'i, often reaching several hundred feet in height.

The reddish-orange and brown wood is prized for many products and was used by the Hawaiians to build canoes - many of which were built from a single, straight Koa trunk. The trees can reach a diameter of over 10 ft and are resistant to salt water, making them perfect for boat building. Koa leaves are unusual in that the juvenile plants first leaves look totally different than a mature plant. The top Koa picture on this page shows the typical crescent shape leaves of a mature plant, while the picture just under it shows the leaves of a seedling. You can easily see that the immature leaves are not only different but are also compound leaves while the mature leaves are not compound. The mature Koa leaves are flat and strong. Dry leaves can be very slippery to walk on as they tend to resist water. The flowers of the Koa are small yellow and puffball like. The Koa tree is a protected tree in Hawai'i. Because the wood is so prized for all sorts of uses it is now illegal to kill any living Koa tree, and only dead trees may be used for any type of woodworking.

You can find Koa all over the Big Island, but huge stands of Koa are easy to find in the Volcano area, including Bird Park and the National Park itself. The Koa In Ancient Hawaiian Medicine Both the bark and the crescent leaves were used in various medicinal preparations including birth control. Koa - Acacia koa Koa Large tropical tree world-renowned for its beautiful red-orange-brown wood, often used in fine furniture. Seed Availability Seeds are not available for the Koa. Please visit our seed store to view current selections. Seeds were last available in April 2015. Description Large tree to 100-120ft. Koa grows native in mid elevation rain forests. Hardiness It can survive cooler temperatures and the occasional frost. Growing Environment Does best with lots of rainfall throughout the year. Propagation By seeds. Uses One of the most beautiful woods in the world, koa wood is expensive and used in furniture and woodworking. Native Range Native to the Hawaiian Islands.

Additional Pictures Biochemical Characterization of Acacia koa for Commercial Value and Ecological Attributes - UNIV OF HAWAII Source: UNIV OF HAWAII submitted to BIOCHEMICAL CHARACTERIZATION OF ACACIA KOA FOR COMMERCIAL VALUE AND ECOLOGICAL ATTRIBUTES Sponsoring Institution National Institute of Food and Agriculture Project Status MOLECULAR BIOSCIENCES & BIOSYSTEMS Non Technical Summary Acacia koa (koa) is the most valued timber wood of Hawaii. Koa wood products are highly valued for their attractive qualities in grain and color. The depletion of koa from native and remnant forests has resulted in the harvest of lower quality wood. In some parts of Hawaii koa forests are heavily infested with Fusarium wilt. This research will develop scientific methods for identifying biochemical qualities associated with wood color and disease resistance. Furthermore, identifying non-wood products as functional foods with neutraceutical properties will create a new paradigm for koa forestry as a value-added production system. Animal Health Component nutraceuticals Goals / Objectives 1) Identification of flavonoid profiles of Acacia koa (koa). 2) Determination of the effects of flavonoids of A. koa in disease resistance.

3) Characterization of neutraceutical properties of phyllodes of A. koa. Project Methods 1. Identification of flavonoid profiles of A. koa. From at least five healthy koa trees, basal bark and phyllodes will be collected. Subsequent to collection, all samples will be freeze-dried and stored at -20C in order to preserve chemical composition for further preparations. Flavonoid contents will be analyzed using methods described by Johnson et al. (1997). 2. Determination of the flavonoids of A. koa in disease resistance. The experiments of this objective will be designed to identify and monitor biochemicals, which promote healthy growth and production of koa. A bioassay will be performed to identify chemical compounds that inhibit growth of Fusarium and Cylindrocladium (Calonectria) isolates from wilt-symptomatic koa. The crude extracts of juvenile sapwood and HPLC-purified fractions from both resistant and sensitive accessions of koa will be assayed for antifungal activity. A Fusarium isolate collection taken from individual koa trees showing symptoms of wilt disease will be used for this assay. 3.

Characterization of neutraceutical properties of the phyllodes of A. koa. The experiments of this objective will be designed to identify biochemicals with potential human health benefits. Collections will be made from 3-5 year-old koa trees established as germplasms on the islands of Oahu, Maui and Hawaii. Mature green phyllodes will be collected. Subsequent to collection, all samples will be freeze-dried and stored at -20C in order to preserve chemical composition for further preparations. The crude extracts and total purified phenolics from mature green phyllodes will be assayed for antioxidant activities. To verify that koa phyllodes are safe for human consumption, standardized in vitro assays will be performed to determine toxic effects of crude phyllode extracts on human hepatic cell lines. HepG2 cell line, a human hepatocellular carcinoma cell line, will be purchased from American Tissue Culture Collections. Progress 11/01/05 to 09/30/08 Outputs OUTPUTS: Acacia koa (koa) is a valuable tree legume endemic to the Hawaiian Islands. It is an ecosystem dominant tree in the forests of Hawaii and is a source for high-value timber.

It is also considered to be an important canopy tree that provides watershed and habitat for other endemic species of Hawaii. In natural forests, large phenotypic differences among island types of koa are observed in seed size and shape, pubescence, phyllodes width and curvature, floral morphology and pigmentation, retention of juvenile leaves, and branch bark color. Microsatellite markers for studying genetic diversity in koa had not yet been developed. The aim of this research was to develop and use microsatellite markers to characterize koa in the Hawaiian Islands. Genomic DNA fragments of sizes 300-1000 bp were cloned and sequenced following enrichment for microsatellite motifs by PCR using seven oligo repeat primers in separate reactions. Among 96 sequences analyzed, 63 contained unique microsatellite motifs flanked by variable sequences. A dual PCR method involving a primer walking step was used to develop 15 primer pairs. Another 16 primer pairs were developed directly from the variable sequences on both sides of the microsatellite motifs within the same fragment. These 31 primer pairs were tested on 172 koa plants representing eleven populations collected from four of the major Hawaiian Islands.

Nine of the primers that identified polymorphic microsatellite loci and three that detected unique alleles exclusively in some populations were used for genetic diversity studies of koa. Cluster analysis and multidimensional scaling of the allelic phenotypic data revealed that koa from Kauai formed a clear distinct group from those of the neighboring islands of Oahu, Maui and Hawaii. The oldest of the four islands, Kauai, also had the most diverse populations of koa. PARTICIPANTS: Rudolph Fredua-Agyeman Daniel Adamski Richard Liao Clifford Morden Dulal Borthakur TARGET AUDIENCES: Researchers on Acacias PROJECT MODIFICATIONS: Not relevant to this project. Impacts The microsatellite markers developed in this study will be useful in koa breeding and improvement programs in the future. Many trees in plantation koa forests die due to wilt disease within a few years of plantation. In recent years, some koa provenances have been identified that appear to be resistant to wilt disease. In some crops, microsatellite loci linked to disease resistance have been identified after analyzing a large number of samples from disease resistant and susceptible plants.

Microsatellite loci linked to genes conferring resistance to wilt disease may be identified and used as selectable markers in future koa improvement programs. The markers developed in this study may also be used to determine if the extent of genetic diversity in various koa plantation forests is similar to that found in the existing natural koa forests. These markers may be also useful for distinguishing koa from other acacias. Publications Fredua-Agyeman R, Adamski D, Liao RJ, Morden C, Borthakur D (2009) Development and characterization of microsatellite markers for analysis of population differentiation in the tree legume Acacia koa (Fabaceae: Mimosoideae) in the Hawaiian Islands. Genome (in press). Fredua-Agyeman R (2008) Development and characterization of microsatellite markers for analysis of population differentiation in the tree legume Acacia koa. PhD dissertation submitted to the University of Hawaii in December 2008.

Pp120 Progress 10/01/06 to 09/30/07 Outputs OUTPUTS: Acacia is a non-monophyletic genus encompassing over 1350 species. It is classified into three subgenera, Acacia, Aculeiferum, and Phyllodineae. A. koa and A. koaia are classified in the subgenus Phyllodineae, which also contains the largest number of species within the genus Acacia. A. koa and A. koaia have been debated to be two separate species based on morphological characteristics and habitat. Differences are evident in both phyllode size and shape, as well as seed alignment within the pod. The distinguishing features that differentiate A. koaia include narrow pods with longitudinal seeds, shorter phyllodes, and denser wood. Additionally, A. koaia usually grows in drier and more open habitats than A. koa, although a few populations have been found in mesic habitats. These differences may or may not be sufficient to define them as different species, with some scholars suggesting that subspecies classification is more appropriate.

One of the objectives of this investigation was to apply molecular approaches to resolve discrepancies in this classification. Koa phyllodes were collected from the Big Island of Hawaii and Kauai. Sampling included representatives of koa based on morphological distinctions. Genomic DNA was extracted from these samples and used to amplify the ITS regions of nuclear ribosomal DNA with Acacia-specific primers for simple sequence repeats (SSRs) in nested PCR. Purified PCR products were then sequenced to determine the placement of A. koa within the genus phyllodineae. A. koa is closely related to the Australian acacias, and shows high homology with A. melanoxylon. Additionally, genotyping of polymorphic microsatellite loci was carried out to determine possible hybridization between koa populations. Allele variation was determined in koa for 8 microsatellite markers using total alleles found, mean number of alleles for polymorphic locus (AP), and unique alleles not found in other populations. The three populations surveyed were those displaying morphological characteristics of A. koa, A. koaia, and a hybrid type with mixed characteristics.

Populations with hybrid phenotypic characteristics had the most total alleles (49), highest AP (6.1), and most unique alleles (12). A. koa had a higher AP (5.4) than the rare A. koaia (4.8). Using eight different microsatellite loci, 65 total alleles were observed, among which 26 were common to all, three were unique to A. koa, one was unique to A. koaia, and 12 were unique to the hybrids. Thirty-seven of these alleles were common between A. koa and A. koaia, whereas the numbers of common alleles between A. koa and the hybrids, and between A. koaia and the hybrids are 30 and 29, respectively. Thus, there is more commonality between A. koa and A. koaia than between either of them and the hybrids. It seems likely that natural cross pollination between A. koa and A. koaia gave rise to the hybrid, which evolved as a distinct new type through natural selection for several thousands years in the isolated environments of the Hawaiian islands. PARTICIPANTS: 1. Daniel Adamski (Graduate Student) 2.

James Leary (Graduate student) 3. Sandro Jube (Graduate Student) 4. Rudolph Fredua-Agyeman (Graduate Student) 5. Nick Dudley, Forest Scientist, Hawaii Agriculture Research Center 6. Mel Jackson, Biochemist, Hawaii Agriculture Research Center 7. Ricelle A. Acob, Junior Researcher, Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa 8. Dulal Borthakur, Professor, Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa Collaborators Robert L. James (Plant Pathologist, U.S. Forest Service) Mike Robinson, Department of Hawaiian Home Lands (contact: Tel: 1-888-943-4335; email: merobi@hilo.net) Richard Wass, U.S. Fish and Wildlife Service, (Contact: Tel: 808-933-6915 ext. 23; email: richard_wass@fws.gov) Training and Professional Development 1.

Daniel Adamski, James Leary and Rudolph Fredua-Agyeman and Sandro Jube are trained on genetic characterization of trees. Daniel Adamski is writing his MS thesis on A. koa. 2. Undergraduate student Richard Liao received molecular biology methods through this project. TARGET AUDIENCES: Ranchers, conservationists, and land managers from the islands of the State of Hawaii who are involved in koa plantations are the target audience of this project. PROJECT MODIFICATIONS: Contrary to our expectations, we did not find a positive correlation between biochemical profiles of the koa pants with resistance to wilt. Therefore, we had to change some directions of the project. We concentrated genetic characterization of koa populations using microsatellite markers. Impacts Maintaining a supply of high quality koa is integral to the forest industry in Hawaii. The selection of high quality and disease resistant accessions will provide opportunities to successfully establish koa plantations in the future. Assessment of genetic variability will help maintain and select superior genotypes for breeding program.

Publications Adamski DA, Fredua-Agyeman R, Leary JK, Dudley N, Borthakur D (2007) Taxonomic classification and genetic diversity of the nitrogen-fixing tree legumes Acacia koa and Acacia koaia, based on microsatellite markers. Poster number 41, presented at the 20th North American Symbiotic Nitrogen Fixation Conference, held at Marquette University, Milwaukee, WI, on July 10-14, 2007. Adamski DA, Fredua-Agyeman R, Leary JK, Dudley N, Borthakur D (2007) Taxonomic classification and genetic diversity of Acacia koa and Acacia koaia, based on microsatellite markers. Poster number 9, presented at the 20th CTAHR Symposium, held at University of Hawaii, on April 5-6, 2007.

Progress 10/01/05 to 09/30/06 Outputs In a preliminary trial, we used HPLC protocols to differentiate phytochemical extractions from three koa heartwood samples: (i) light blond, (ii) medium brown, and (iii) dark red. In this trial, polyphenolic profiles from each of the koa wood samples were generated at 280 nm. We found that as wood color progresses from light to dark, the profile changes markedly. Two peaks appear consistently throughout the three profiles at 8.9 min and 12.0 min. However, they increase in peak height and area as wood color intensifies, with the 8.9 min peak doubling in peak height from light to medium, and by 9.2 fold, from light to dark. These are likely candidate marker peaks for potential wood color prediction. The remainder of the peaks observed in the light and medium koa extracts are in relatively trace amounts.

In contrast, the profile of the dark koa extract shows 5 major peaks including 8.9 and 12.0 min, but also including major peaks at 16.2, 31.8 and 38.6 min. Consequently, the latter three peaks may prove to be specific to dark wood color. This preliminary trial demonstrates that our HPLC protocol is very useful in characterizing wood color in koa and should be useful for characterizing sapwood phytochemical profiles. In a follow up study, ten samples of koa were supplied by James Leary in the form of shavings from the softwood and heartwood portions of five koa branches representing 5 different wood color intensities. These samples were collected from native stands on the island of Kauai. The polyphenolic contents corresponding to wood color was not evident in these samples. There could be a number of reasons for this, including differences in the age of the wood samples this time compared with those samples analyzed last time, or differences in the wood curing/drying process. One exception is the peak eluting at 36 minutes.

This peak generally appeared to increase with a darkening of wood color, and so may be a chemical marker in these samples. Sapwood samples did not exhibit any significant polyphenolic content when subjected to HPLC at 280nm (not shown). The same heartwood samples were subjected to HPLC analysis with UV detection set at 365nm, specific for flavonol compounds. From these results there is no discernible pattern relating flavonol content with wood color. Sapwood samples were also ana;yzed for polyphenolic content and flavonol content. These data are not shown. No discernible peaks were observed in the sapwood samples; either polyphenolic or flavonol. Conclusions: The results of this study show that relating polyphenolic content and flavonol content may not be as straightforward as first thought. There are a number of wood preparation methodologies that need standardizing in order to make this comparison more valid. The samples from the earlier study, where a correlation was easily demonstrable were much older than the samples seen here. It is also possible that polyphenolics and flavonols are not correlated to wood color at all. Other compound classes may be better markers.

Impacts Koa wilt is a serious epidemic infecting many of the native koa forests and plantations in Hawaii. Fusarium oxysporum f. sp. koae as the main causal organism. Infection by this pathogen causes a vascular wilt disease that can be lethal to both young seedlings and mature trees Several other Fusarium species (i.e. F. solani) have also been routinely isolated from diseased koa seedlings and trees as well and may also contribute to the disease etiology. Furthermore, other pathogenic fungi, such as Calonectria ilicicola (= C.crotalaria; anamorph = Cylindrocladium parasiticum) and C. indusiata (= C. thea, anamorph = Cylindrocladium theae) which cause collar root rot and shoot blight, may also contribute to koa wilt. Field trials using different koa families suggest that genetic disposition can confer resistance to this disease in nature. In order for the koa forest industry to survive, it will be necessary to select for resistant accessions to be used in plantations. Juvenile koa are most susceptible to mortality from Fusarium wilt (Anderson 2002).

Thus resistant accessions may have anti-fungal compounds accumulated within the young sapwood. Most recently, our team has identified seed families that appear to confer disease resistance. For this next fiscal year we will be focusing our attention ongenerating new information related to this success. Publications

Question: The Koa tree (Acacia Koa) is native and popular in which island group?
Answer: Hawaii