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January 2000 |
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Pages 13-20
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PII:
S1146-609X(00)00107-7
Copyright © 2000 Éditions
scientifiques et médicales Elsevier SAS. All rights reserved.
Postfire, natural regeneration
of Pinus brutia forests in Thasos island, Greece
Ioannis A. Spanos
a, Evangelia N. Daskalakoub and Costas A. 
Thanos
, 
, b
a
Forest Research Institute of Thessaloniki, NAGREF, 570 06 Vassilika,
Thessaloniki, Greece
b Department
of Botany, University of Athens, Athens 15784, Greece
Received
3 June 1999; revised 3 December 1999; accepted 8 December 1999. Available online
4 April 2000.
Abstract
The natural, postfire
regeneration of Pinus brutia forests has been studied in two
40¯60-year-old forests of Thasos island, North Aegean sea, Greece,
burned in the summers of 1985 and 1989. Within the latter burned area
(5700 ha), forty experimental sites of various aspects and site index
values were established and successively monitored for 5 years, at 6-month
intervals. Pine seedling emergence took place late in spring (due to a long
drought in that particular year) but exclusively during the first postfire year.
By the end of the recruitment period (May 1990), mean pine seedling density was
considerably high (2¯6 seedlings.m¯2)
while a significant drop in the first summer was observed. Thereafter, a
relatively smooth decline was obtained and the density was almost stabilized to
about 0.6¯2 seedlings.m¯2 after
5 years: the kinetics of survival was found to follow a rectangular
hyperbola. Significant differences in seedling density values were detected
among site groups of varying aspect or site index: north-facing and index I
sites showed the highest density values while south-facing and index V ones the
lowest. Similarly, height kinetics showed a significant divergence among site
groups; again, the north-facing and the index I sites were the fastest growing.
Annual height growth showed a linear regression kinetics throughout the 5- (and
conceivably 9-) year-long postfire period of study, with a yearly increment of
17 cm. Starting at an age of 4¯6 years, an increasing
fraction of the sapling population became reproductive so that after
9 years a considerable portion (5¯15 %) had already
produced cones with fully germinable seeds.
Author Keywords:
Pinus brutia; pine forest; natural postfire regeneration;
seedling density; growth and survival
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