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F. uhdei is a fast-growing, medium to large tree (up to 35-40 m tall and 1 m stem diameter) that grows naturally in mixed mountain forests from west-central Mexico to Guatemala and can become weedy in disturbed sites. The leaves are 15-30 cm long, compound and oppositely pinnate with 5-9 leaflets. A channeled leaf axis and a smaller (2.5-4 cm long) samara distinguish F. uhdei from its close relative F. americana. F. uhdei is sometimes referred to as an evergreen species but it is winter-deciduous in some regions. F. uhdei has been introduced to Hawaii, Puerto Rico and sub-Himalayan regions of India for watershed protection and timber production. It is also a popular street and shade tree in California, Arizona and Mexico. In the Central Valley and Bay Area of California, severe infestations by the ash whitefly Siphoninus phillyreae on F. uhdei have been reduced after the introduction of the parasitic wasp Encarsia partenopea (Gould et al., 1992).In its native range, F. uhdei has been selectively logged but it is not a prime timber species. In Chiapas, it has been grown in hedgerows for wood and fuel. In plantations, F. uhdei has high survival and rapid initial growth in favourable sites, but often exhibits uneven growth rates across sites, poor form and has a tendency to lodge. F. uhdei is relatively shade tolerant and can regenerate by coppicing (Walters and Wick, 1973). Stands can be established from seedlings or bare-root stock. In Hawaii, F. uhdei has higher growth rates in relatively deep soils derived from volcanic ash than in shallow, stony organic soils. Yields in Hawaii and Puerto Rico have ranged between 4.1 and 11.5 cubic m/ha/year.F. uhdei provides a valuable, medium density (0.5 g/cubic cm), pale brown wood with a straight grain and moderately fine texture (Shukla and Sangal, 1980). The wood has been used mainly for cabinet work, furniture, moulding and panelling, but it is also suitable for boat building, craftwood, flooring, interior trim, joinery poles, particleboards, pulpwood, plywood, structural sawnwood and veneer. It is easy to season, machine and finish but is susceptible to blue stain, Lyctus borers and termites. The sapwood is permeable to preservatives and the heartwood is moderately resistant. Uhdenoside, a secoiridoid dilactone isolated from leaves of F. uhdei, has potential applications in natural medicine (Shen et al., 1995).F. uhdei can spread into disturbed forest areas. In Hawaii, invasions have been recorded in the islands of Hawaii, Maui, Molokai and Oahu, and F. uhdei has been included among the most disruptive species to native ecosystems. Invasions are more intense on fertile soils and along streams (Harrington and Ewell, 1997). In some stands of F. uhdei, understorey vegetation is almost completely absent but stands with sparse canopies can harbour a profuse understorey of native and introduced species. |
