Friday, March 14, 2014

Leaves in the low light rainforest

How a plant gets established gives a fascinating insight to the role of seed , soil , timing of seed release . We can learn a lot for example from what grows where but we can also learn lots form shape colour and when and where things are likely or shown to happen . I had known for many years that Blackwoods (acacia melanoxylon ) which dominate the valleys in the southern fall of the Otways often grow from fern stems but only yesterday  realized  its probably the most common way they establish . This was confirmed this morning by correspondence from Paul who cultivates Ferns on the southern fall.
Lower slopes of the southern valleys have several  major constraints - high runoff , shallow soil and low light ( most of the time) tall eucalypts grow quickly on ridges as a result of Bushfires or sound regeneration practice which mimics this process.

  •  The fine dark green leaves are the first leaves of our most common rainforest tree, with the dark ones coming later when plant is fairly tall . Blackwoods have to develop in the very low light of the valleys and use the juvenile leaves and the sides of the fern (often) to get established and quickly grow above the fern .Blockout effect of the leaf arrangement of ferns and acacias leaves is amazingly similiar.
    Light capture is a big issue,
     esp on the southern fall . We have speculated too about the blue- green chlorophyll physiology and the shape /size of juvenile leaves. Parts of these valley communities are exempt from bushfire driven forces that drive most Australian forests with Northofagus being the classic example of a good survivor.A message from Paul "the blackwood seed falls from the treetop seed capule and lodges in the HOLLOW dry broken fern frond underneath the treefern circle canopy, the 100mm broken frond stub is still pointing up at an angle of 80 degrees, staying there until germination at a later time, which could be years later, the trunk grows over the stub enclosing the seed deep in the trunk". Blackwoods have a extremely hard seed covering which high acid in the situation would drive the germination- eventually and wonderfully . 

    Now for Northofagus - last time I asked, few had try to cultivate . But don't we just love those leaves too
    Now for Northofagus - last time I asked, few had try to cultivate . But don't we just love those leaves too   Copyright Emperors Academy March 14th 2014