G. Schiller et al., POSTFIRE VEGETATION DYNAMICS IN A NATIVE PINUS-HALEPENSIS MILL. FOREST ON MT. CARMEL, ISRAEL, Israel journal of plant sciences, 45(4), 1997, pp. 297-308
Israel's largest natural Pinus halepensis Mill. forest is on the Mt. C
armel range and belongs to the distinct East Mediterranean genetic gro
up. Most of this forest is the result of invasion of abandoned fields
and grazing lands, resulting in a heterogeneous pine forest with an un
derstory of broad-leaf shrubs and trees. Species composition, vegetati
on cover, pine-stand structure, and pine genetic diversity of plots in
sites of known fire history, burned 5, 11, and 20 years ago, were stu
died with adjacent unburned sites forming a chronosequence. Except for
annual species, no species replacement took place during post-fire su
ccession. The main observed changes were in the cover of species and o
f plant life forms. The ratio of tree/dwarf-shrub cover was found to b
e linearly related to the number of years elapsed since the last fin.
Therefore, this ratio could serve as an index to determine the success
ional stage of Aleppo pine stands with unknown fire history. It is est
imated that 30-40 years are needed for full recovery of Aleppo pine st
ands after fire, depending upon site quality. The stands of post-fire
regeneration are of uniform age and are less variable in their structu
re than unburned stands. The genetic distance among the various Pinus
halepensis subpopulations was found to be very small; most of the gene
tic variability was due to within-subpopulations variability, with alm
ost no variability among subpopulations. Alleles that an typical of We
st Mediterranean P. halepensis populations or of P. brutia, were found
in mio post-fire subpopulations (stands), indicating pre-fire cross p
ollination between native Pious halepensis trees and trees in adjacent
pine plantations of foreign origin. The conclusion is that fin has li
ttle effect on species composition and on vegetation structure, but th
at it alters the Aleppo pine stand structure.