It's not really autumn with the Talisay

Abe V Rotor

Talisay (Terminalia catappa) is a highly deciduous tree changing its crown at least twice a year - one at the onset of summer and the other at the start of amihan season in the Philippines when cold winds from Siberia arrive. The leaves turn bright yellow, orange, red to purple before they fall off from the tree. It is more pronounced in November to December than in summer months.

Typically deciduous trees shed their leaves starting in autumn and become leafless throughout winter. It is different in the tropics. Thus we see that the talisay is not an indicator of the arrival of Autumn or Fall just like the deciduous trees in the temperate region. In the first place we do not have the distinct four seasons of the year.

Its deciduous characteristic must be a carryover of a primitive biological cycle dictated by ancient genes. Which means that its distant ancestor must have been indigenous in the temperate region, and has undergone a number of biological phenomena, namely -

• Acclimatization through plant introduction by natural means, and later, by human activities.
• Speciation or the development of new species deviating from their ancestors under a new environment.
• Continental drift, slow movement of land masses from their original latitude and longitude.

Expression of the ancient gene of deciduousness is carried to this day by many "migrants" like narra, tanguili, fire tree, dapdap, and many others.

Talisay trees do not lose their leaves all at the same time -

some are early and others late, like in this group of trees
at UST. Talisay is highly resistant to drought, salinity, and
apparently to pollution. It ventures up to the shoreline
and estuaries, and can grow at high elevation, too.

Closeup of a talisay sapling. Old and young leaves alike respond
to deciduousness. The shoot becomes dormant, leaving the tree
almost bare for several days. By some precise biological signal new
leaves grow and make a new crown for the tree - fresh green at first,
becoming deep green and luxuriant. The thick and broad canopy
which remains to the next fall earns the tree its name, umbrella tree.

Dead leaves pile under the tree, or they are swept by wind and
water to other places, forming mulch to retain soil moisture
and help prevent forest fire by preventing the growth of weeds.
They also sustain the needs of beneficial organisms, consequently
converting them into compost, and fertilizing the tree and
nearby plants. Through the years soil is built layer after layer
on the forest floor. This is important in the formation - and stability
of a multi-storey tropical rainforest. Deciduousness of many
species of forest trees, particularly the dipterocarps, is key to
high biomass production and biological diversity. The
tropical rainforest has the highest biological diversity of all
ecosystems in the world.

Living with Nature 3, AVR 2009 (All Right Reserved)