Patterns of seedling recruitment in West‐Mediterranean Quercus ilex forest influenced by canopy development

Quercus ilex (holm oak) coppice forests belong to the most representative communities in the western part of the Iberian Peninsula. Due to the high sprouting potential of holm oak after coppicing, the dynamics of recruitment of new individuals in existing populations has been largely over- looked. In these forests, the density of seedlings increases in old stands, as a result of the remarkable increase in the recruit- ment of 1-yr and 2-yr old seedlings, probably due to better environmental conditions for germination. Older seedlings show a tendency towards increasing survival under some degree of canopy closure, since their density appears to be higher just before complete canopy closure takes place. Nev- ertheless, the reduced growth of seedlings in older stands due to low light levels causes age distributions of holm oak seed- lings to change drastically, with saplings older than 15 yr becoming very unusual in these stands. Therefore, a bottle- neck of recruitment appears at this sapling stage and prevents vigorous regeneration just before thinning. Present conditions of genet density and management tend to prevent population renewal. Dynamics of the seedling bank reinforce the role of gap formation through small or large scale perturbations in population turnover.

[1]  J. Harper.  Population Biology of Plants , 1979 .

[2]  J. Canadell,et al.  Root biomass of Quercusilex in a montane Mediterranean forest , 1991 .

[3]  D. W. Smith,et al.  Oak Regeneration After Clear Felling in Southwest Virginia , 1986 .

[4]  Robert L. Johnson,et al.  Regeneration in Small and Large Sawtimber Sweetgum-Red Oak Stands Following Selection and Seed Tree Harvest: 23-Year Results , 1983 .

[5]  J. M. Espelta,et al.  Identificación de los anillos anuales de crecimiento de la encina (Quercus ilex. L.) , 1993 .

[6]  F. Romane,et al.  Quercus ilex L. ecosystems: function, dynamics and management , 1992, Advances in vegetation science.

[7]  C. Floret,et al.  Quelques remarques sur les taillis de chênes verts : répartition, histoire, biomasse , 1988 .

[8]  Zev Naveh,et al.  LANDSCAPE ECOLOGY: THEORY AND APPLICATION , 1983, Landscape Journal.

[9]  Charles D. Canham,et al.  Growth and Canopy Architecture of Shade‐Tolerant Trees: Response to Canopy Gaps , 1988 .

[10]  C. Augspurger.  Light requirements of neotropical tree seedlings: a comparative study of growth and survival , 1984 .

[11]  M. Tretiach.  Photosynthesis and transpiration of evergreen Mediterranean and deciduous trees in an ecotone during a growing season , 1993 .

[12]  J. Retana,et al.  Regeneration by sprouting of holm-oak ( Quercus ilex ) stands exploited by selection thinning , 1992 .

[13]  A. Larigauderie,et al.  The concept of stand senescence in chaparral and other mediterranean type ecosystems. , 1990 .

[14]  Lawrence K. Forcier.  Reproductive Strategies and the Co-occurrence of Climax Tree Species , 1975, Science.

[15]  C. Lorimer.  Development of the red maple understory in northeastern oak forests. , 1984 .

[16]  R. Bacilieri,et al.  Germination and regeneration mechanisms in Mediterranean degenerate forests. , 1993 .

[17]  Thomas R. Crow,et al.  Reproductive Mode and Mechanisms for Self-Replacement of Northern Red Oak (Quercus rubra) - A Review , 1988, Forest Science.

[18]  J. Ward.  Response of woody regeneration to thinning mature upland oak stands in Connecticut, USA , 1992 .

[19]  J. Terradas,et al.  The influence of summer and winter stress and water relationships on the distribution of Quercus ilex L. , 1992, Vegetatio.

[20]  M. Ducrey.  Quelle sylviculture et quel avenir pour les taillis de Chêne vert (Quercus ilex L.) de la région méditerranéenne française , 1992 .

[21]  Ecology of vegetative regeneration after coppicing in macchia stands in central Italy , 1992 .

[22]  Z. Naveh,et al.  12 – Effects of Fire in the Mediterranean Region , 1974 .

[23]  J. Keeley.  RECRUITMENT OF SEEDLINGS AND VEGETATIVE SPROUTS IN UNBURNED CHAPARRAL , 1992 .

[24]  M. Kimura,et al.  Seedling Growth Form of Oaks , 1989 .

[25]  J. Keeley,et al.  Reproduction of Chaparral Shrubs After Fire: A Comparison of Sprouting and Seeding Strategies , 1978 .

[26]  Paul S. Johnson.  Oak overstory/reproduction relations in two xeric ecosystems in Michigan , 1992 .

[27]  F. Rodà,et al.  Growth response of holm oak (Quercus ilex L) to commercial thinning in the Montseny mountains (NE Spain) , 1993 .