Leucadendron argenteum: Difference between revisions

Silver tree
A young Silvertree at Kirstenbosch Botanical Gardens, Cape Town
Conservation status
Vulnerable  (IUCN 2.3)[1]
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
Order:	Proteales
Family:	Proteaceae
Genus:	Leucadendron
Species:	L. argenteum
Binomial name
Leucadendron argenteum (L.) R.Br.
Map of the extant population of Silvertrees in the Cape Peninsula
Synonyms[2]
Protea argentea L.

Leucadendron argenteum (Silver tree, Silver leaf tree,

The Silvertree is a striking

In addition there are two tiny outlying populations nearby, in Stellenbosch and Paarl (It has not yet been established for certain whether these are natural outliers, or were planted here in early Cape history).

Historically, the Silvertree was more widespread on Table Mountain, covering much of its slopes in shimmering silver forests. However, early demand for timber led to much of these forests being felled and now the Silvertree is a rare and endangered species.^[4]

Status and conservation

Table Mountain is perhaps the only place where these trees grow naturally, as the populations near Stellenbosch and Paarl (though conceivably natural) may have been introduced from Table Mountain.

In the face of urban development, inappropriate fire management, and invasive alien trees such as pines and gums, silvertrees have been driven from about 74% of their natural range.^[5] Mortality of these short-lived trees is negligible after a burn, but then increases to about 5% per annum. During a longer term absence of burns however, sudden die-offs may occur, even in a matter of hours. This is believed to be the combined result of (warm) berg winds and diseased roots which are weakened by Phytophthora root rot which inhibits their water absorption.

An estimated 40 to 50 percent of the extant native population burned in the fire of 26 to 27 January 2006.^[6] As recruitment of seedlings only occurs naturally after fire, this was a necessary stage in the life-cycle of this Fynbos species, and the population has recovered totally.

A major deterrent to propagation of the silver leaf tree is its short life span, as most don't live more than 20 years. This doesn't affect their conservation however, as fires rejuvenate populations on average every 15–20 years by killing the surviving adults and triggering the release of the canopy seed bank (in the cones), and germination of the soil seed bank. Seeds remain viable for at least 80 years. Juveniles take 5–7 years to flower and set seed, whereafter the populations are ready to burn again.

Heraldry

"[S]tylized twigs of the silver tree" [sic] appear in the arms of the South Peninsula Municipality of South Africa.^[7]

Wikimedia Commons has media related to Leucadendron argenteum.

Pictures

• 
  Silvertrees were driven to near extinction when their natural habitat was cleared for commercial pine plantations.
• 
  Silvertrees grow only in and around Cape Town, particularly on Table Mountain.
• 
  A large Silvertree near Rhodes Memorial
• 
  A young stand of Silvertrees on Devil's Peak, Table Mountain.
• 
  A Silvertree forest on the lower slopes of Devil's Peak
• 
  Partial removal of the invasive pine plantations allowed Silvertree forests to gradually return.
• 
  Silver tree leaves are soft and silky.
• 
  New growth detail
• 
  The silver leaf colour is due to their soft velvety hair
• 
• 
  Heavy cone of a female tree, which eventually opens to release the small, round nuts
• 
  Cone, seeds, leaf and juvenile plant

See also

• List of Southern African indigenous trees
• Peninsula Granite Fynbos
• Silwerboomkloof
• Rhodes Memorial
• Newlands Forest

References