Dipterocarpaceae

DipterocarpaceaeBy:Krisnavimala

NatashaLee Yian Ping

ShahidaYaashiniSyafiqah

TROPICAL FOREST SYNERGY.• Members of the canopy tree family Dipterocarpaceae dominate • Southeast Asian tropical forest. • Consist of 16 genera, over 500 species

– Malay peninsula- 9 genera, 155 species• In some parts of Borneo, dipterocarps constitute as much as

– 70% of the canopy tree biomass– 80% of the tallest tree canopy trees

• Many dipterocarp species reproduce in a spectacular but irregular manner called • ‘mass-fruiting’: production of large numbers of single seed fruits once every 3 to 4 years, with very little seed

production in the intervening periods.

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• More than 50 dipterocarp tree species dispersed seed within 1-to-2 month period every 3 to 4 years during ENSO events.

* ENSO: El-Nino-Southern Oscillation– A period change in the atmosphere and ocean of tropical

pacific region.– a warm surface current that usually appears around

Christmas in the Pacific off Ecuador and Peru and disappears by the end of March, but every two to seven years it persists for up to 18 months or more

• The density of dipterocarps in Southeast Asian is commercially and ecologically important.

• Commercial logging of timbers as valuable source of plywood• Harvested dipterocarps constitute of the global plywood trade

Dipterocarpus(Keruing)

• Basal quarter of fruit fused into calyx tube• 2 calyx lobes enlarged into wings but a few

species not• Thin cotyledons• First pair of leaves opposite• Leaves plicate, and remaining corrugated even

after being expanded

Hopea (Merawan)

• 32 species• Fruit with two of the calyx lobes expanded

into wings• Cotyledons fleshy• Hypocotyl elongated• First to leaves opposite, but sometimes the

first 3 leaves and rarely the first 4 are ni a whorl instead

Parashorea (Gerutu)

• 3 species of tree• Unwinged with one cotyledon very large• Cotyledon divided into 2 hemispherical lobes• The large cotyledon forcing the fruit wall apart• The smaller cotyledon remaining adherent to

one of the lobes of large cotyledon

Shorea (Meranti, Balau)

• 57 species of trees• Fruit with 3 of the persistent sepals developed

into wings• Cotyledons fleshy

JOURNALS

TEMPORAL AND SPATIAL PATTERNS OF MASS FLOWERINGS ON THE MALAY

PENINSULA• Trees of the family dipterocarpaceae are widely distributed in lowland rain forests of the Southeast Asian tropics.

• This region has little seasonal weather variation, but yet the dipterocarps have a unique rhythm of reproductive phenology known as mass flowering/general flowering.

• There is evidence that some meteorological cues, including – prolonged drought – strong solar radiation – tree nutritional status – abnormal temperature

triggers floral induction in dominant canopy trees

TEMPORAL PATTERN OF MASS FLOWERING• report:

– flowering occurs in the 2nd quarter on the malay peninsula and in eastern borneo

– fourth quarter in south sumatera and western borneo– in contrast, flowering occurs in both the 2nd and 4th quarters on

the malay peninsula. • Why???

– Annual pattern of rainfall and minimum temperature in this region.

– Strong relationship between mass flowering and ENSO period • Borneo• Eastern malay peninsula

– Triggered during the absence of El Nino episodes in the focal forest. • El Nino episodes generally decrease rainfall but increase

average temperatures on the malay peninsula.

PHYLOGENY GENE IN SHOREA AND ITS CLOSELY RELATED GENERA (DIPTEROCARPACEAE)

• Incongruence of the Placement of Neobalanorcarpus Between Nuclear And Chloroplast Phylogenies– Neobalanocarpus Heimii was origionally described as

a species of Ballanocarpus and is confined to the Malay Peninsula

– Produces timber of good quality (Known as “chengal”)

– Rather close to Hopea by leaf morphology and wood anatomy

• The unique characteristic:– Linear anther in the flower and sub-equal short

woody fruit sepals• Obsure both generic and sectional affinity• Interesting features:• Irregular segregation of chromosome during

meiosis • 1st hypothesis:• Could have derived via hybridisation between

the ancestral lineage leading to white meranti of shorea and that leading to Hopea

• 2nd hypothesis:• Gene duplication also a potential cause of

phylogenetic incongruence• Occurred in stem lineage of clades I to VI• If it is true, at least 4 independent gene losses at

specific positions are necessary to explain the topology.

• Conclusion: – Favors the hypothesis of the hybrid origin of

Neobalanocarpus because:• Its cytological• Confusion about its affinity to Hopea and Shorea

VERTERBRATE RESPONSES TO SPATION TEMPORAL VARIATION IN SEED PRODUCTION OF MAST-FRUITING DIPTEROCARPACEAE

Bornean dipterocarps: an ideal study system about germination and reproduction of dipterocarp.

• Reasons: – Dipterocarp mast fruiting is more extreme (longer intervals, tighter fruit drop

and strict mast fruiting) and is more highly synchronized (across hundreds of species and widely dipersed sites).

– Rapid germination is concurrent with fruit fall and optimal periods for germination can be precisely quantified

– Sympatric dipterocarp species possess seeds that vary greatly in mass.– Reproductive adults of many species occur across diverse soil types along an

altitudinal gradient and at many levels in the forest strata– Dipterocarp species are insect pollinated stagger flowering times among

species groups that share pollinations and the communitywide reproductive response includes species andgenera that do not share pollinators.

• Dipterocarp seeds are exclusively wind or gravity dispersed. Dipterocarp mast fruiting does not involve complex interactions of vertebrates that destroy some seeds but also provide dispersal services. Unlike:– Temperate oaks (Quercus)– Some pines (Pinus)– Beech (Fagus)

• Dipterocarps are not subjected to conflicting pressures to produce seeds to maintain disperser populations. Dipterocarp seeds are eaten only by predators that impart directional (negative) selection, rather than the more complex web of relationships (positive and negative) found in temperate communities.

Phylogeny of the tropical tree family dipterocarpaceae

• Origin and phytogeography of dipterocarps:• 1st hypothesis:– Dipterocarps originated on the Eurasian plate,

possibly in the Malesian region, and migrated westward towards south Asia and Africa.

– Based on the assumption that the high species diversity of dipterocarps found in the far east is associated with the origin of the family.

• 2nd hypothesis:– Suggested that dipterocarps originated in

Gondwana. – One clade, comprising the sub- families

Monotoideae and Pakaraimoideae, extended its range westward from Africa to south America.

– The other clade, the subfamily Dipterocarpoideae, migrated eastward through the Deccan plate, entered the Eurasian plate, and diversified in the Far Eastern region.

THE END…