Shorea | |
---|---|
![]() | |
Shorea roxburghii | |
Scientific classification![]() | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Rosids |
Order: | Malvales |
Family: | Dipterocarpaceae |
Tribe: | Shoreae |
Genus: | Shorea Roxb. exC.F.Gaertn. (1805) |
Synonyms[1] | |
|
Shorea is agenus of about 47species of mainlyrainforest trees in the familyDipterocarpaceae. Thetimber of trees of the genus is sold under the common nameslauan,luan,lawaan,meranti,seraya,balau,bangkirai, andPhilippine mahogany.[2]
The tallest documented tropicalangiosperm is a 100.8 m (331 ft)Shorea faguetiana found in theDanum Valley Conservation Area, inSabah,Malaysia (Borneo). In Sabah'sTawau Hills National Park, at least five other species of the genus have been measured to be over 80 m (260 ft) tall:S. argentifolia,S. gibbosa,S. johorensis,S. smithiana, andS. superba.[3] Borneo is also the hotspot ofShorea diversity with 138 species, of which 91 areendemic to the island.[4]
The majority ofShorea spp. are general flowering species, which is an event occurring at irregular intervals of 3–10 years, in which nearly all dipterocarp species together with species of other families bloom heavily.[5] General flowering is thought to have evolved to satiate seed predators[6] and/or to facilitate pollination.[5] Both explanations apparently hold merit.[7] Flowering is thought to be triggered by droughts that occur during transition periods fromLa Niña toEl Niño.[8] The magnitude of a flowering event is suggested to be dependent on the timing of the droughts associated with the El Niño southern oscillation cycle, with the largest events occurring after an interval of several years with no flowering.[8]
Shorea spp. areinsect pollinated. A variety of insects have been identified as pollinators, with species within the sections ofShorea sharing the same insect pollinators. Flowering within a section is sequential within one habitat and species association to prevent competition for pollinators.[9]
Seed predation and mortality have an impact on the reproduction process of dipterocarps such asShorea. In Singapore,crab-eating macaque andmoth larvae are known seed predators.[10]
Shorea fossils (linked with the modernsal,S. robusta, which is still a dominant tree species in Indian forests) are known from as early as theEocene ofGujarat,India. They are identifiable by theamber fossils formed by theirdammar resin.[11] Other fossils include aMiocene-aged fossilized fruit from the same region; this fruit most closely resembles the extantS. macroptera of theMalay Peninsula.[12]
The genus is named after SirJohn Shore, the governor-general of theBritish East India Company, 1793–1798.
Shorea spp. are native toSoutheast Asia, from northernIndia toMalaysia,Indonesia, and thePhilippines. In westMalesia and the Philippines, this genus dominates the skyline of thetropicalforests.
Of the 148 species ofShorea currently listed on theIUCN Redlist, most are listed as beingcritically endangered.[13] Some concerns exist regarding the IUCN's listing of dipterocarps, as the criteria used to assess the level of threat are based mainly on animal population characteristics. This is thought to overstate thethreat assessment, when applied to long-lived, habitat-specific organisms such as trees.[4]
IUCN red list category | Number of species |
---|---|
Extinct | 1 |
Critically endangered | 102 |
Endangered | 34 |
Vulnerable | 3 |
Least concern | 6 |
Data deficient | 2 |
Not evaluated | ~48 |
Many economically importanttimber trees belong toShorea. They are sold undervarious trade names including "lauan", "lawaan", "meranti", "seraya", "balau", "bangkirai", and "Philippine mahogany". The "Philippine mahogany" sold in North America is not a truemahogany at all, but a mixture of woods from the genusShorea.
Other products fromShorea spp. include dammar andillipe. Dammar is a resin collected from a variety of species. It varies in colour among the different taxonomic groups.Shorea wiesneri is listed in many websites as an important source of dammar;[14] however, this appears to be either a trade name or asynonym.[15][16]
Borneo tallow nut oil is extracted from the egg-shaped, winged fruit ofShorea species.[17]