Agriculture Reference
In-Depth Information
Fig. 3.1
Resprouting lignotuber of
Erica australis
from Portugal in the western Mediterranean
Basin. (Photo by P. Maia with permission from Prensa Cientı´fica S.A.)
burl be used to describe all woody swellings, genetic or induced. In most cases
lignotubers are initiated in the first year of development (Kerr
1925
; Wieslander &
Schreiber
1939
; Montenegro
et al.
1983
; Dodd
et al.
1984
; Molinas & Verdaguer
1993
; Del Tredici
2001
), although in
Eucalyptus
species there is apparently some
degree of flexibility in the timing of lignotuber initiation (Carr
et al.
1982
).
Lignotubers enhance the ability of resprouting individuals to persist indefinitely
on a site and preempt resources for considerable periods of time. The ability to
resprout over countless fire cycles (e.g.
Fig. 3.2c
) may allow individuals to persist
for hundreds if not thousands of years (Canadell & Zedler
1995
; Nicolle
2006
).
Epicormic resprouting occurs from dormant buds under the bark of scorched trunks
and canopy stems. It is very widespread in arboreal forms of the northern hemisphere's
Quercus
(
Fig. 3.3a
) and many other hardwood trees in both hemispheres. It is not
common in coniferous trees, but does occur in
Pinus canariensis
from the Canary
Islands and in
Pseudotsuga macrocarpa
, associated with California chaparral
(
Fig. 3.3b
). In the Western Cape of South Africa there is one fynbos arborescent
shrub,
Protea nitida
, that resprouts epicormically, as do most
Eucalyptus
in Australia
(
Fig. 3.3c
). Unlike basal resprouting that is tolerant of high-intensity crown fires,
epicormic sprouting in
Quercus
species is common when canopies are scorched
but may fail following high-intensity fires. However, some Australian
Eucalyptus
