Disturbance related vegetation dynamics differs with Azorean mountain forest communities, where each tree species has its own regeneration strategy. Knowledge of the spatial distribution of tree species may help us to generate hypotheses on the relation between disturbance, regeneration and spatial organization and on the possible underlying ecological mechanisms. In view of this, we asked the following questions regarding the spatial pattern of tree species: What is the spatial distribution of saplings and adults? Are there any spatial associations or exclusions between saplings and adults of the same and different species? To what extent do the disturbance regimes and regeneration strategies of each species explain its spatial pattern? Six 225 m2 (15 × 15 m) plots were placed in each of three different forest types in three Islands (Pico, Terceira and Flores). Patterns of tree individuals were analysed through Morisita’s index of dispersion (Iδ) and Iwao ω index. With the exception of Laurus azorica and Frangula azorica, saplings are in most cases aggregated. Erica azorica is the only species whose adults are aggregated at short distances. Spatial distribution is mostly random for the other species. At short distances, few strong associations or exclusions were detected. Pioneer species such as Juniperus brevifolia tend to be more aggregated due to their dependence on gaps to germinate and recruit new individuals. In fact, increasing disturbance and gap size enhances the regeneration of J. brevifolia. Primary species tend to be randomly distributed in part due to their strategy of forming seedling-sapling banks. Spatial pattern of tree species is largely explained by disturbance regimes and regeneration strategies of each species. However, factors such as habitat related patchiness, competition and dispersion limitation may also explain many of the observed patterns.
Anand, M. and A. Langille. 2010. A model-based method for estimating effective dispersal distance in tropical plant populations. Theor. Popul. Biol. 77: 219–226
Langille A. , 'A model-based method for estimating effective dispersal distance in tropical plant populations ' (2010 ) 77 Theor. Popul. Biol. : 219 -226 .
Arévalo, J. R. 1998. Organización espacial y temporal de la Laurissilva de Anaga — Tenerife, Islas Canarias. Ph.D. Dissertation. Universidade de La Laguna, Departamento de Parasitologia, Ecologia e Genética. La Laguna. Canary Islands.
Arévalo, J. R. and J. M. Fernández-Palacios. 2003. Spatial patterns of trees and juveniles in a Laurel forest of Tenerife, Canary Islands. Plant Ecol. 165: 1–10.
Fernández-Palacios J. M. , 'Spatial patterns of trees and juveniles in a Laurel forest of Tenerife, Canary Islands ' (2003 ) 165 Plant Ecol. : 1 -10 .
Bell, T., R. P. Freckleton and O.T. Lewis. 2006. Plant pathogens drive density-dependent seedling mortality in a tropical tree. Ecol. Lett. 9: 569–574.
Lewis O.T. , 'Plant pathogens drive density-dependent seedling mortality in a tropical tree ' (2006 ) 9 Ecol. Lett. : 569 -574 .
Boll, T., J. C. Svenning, J. Vormisto, S. Normand, C. Grández and H. Balslev. 2005. Spatial distribution and environmental preferences of the piassaba palm Aphandra natalia (Arecaceae) along the Pastaza and Urituyacu rivers in Peru. Forest Ecol. Manage. 213: 175–183.
Balslev H. , 'Spatial distribution and environmental preferences of the piassaba palm Aphandra natalia (Arecaceae) along the Pastaza and Urituyacu rivers in Peru ' (2005 ) 213 Forest Ecol. Manage. : 175 -183 .
Brokaw, N. V. L. 1982. The definition of treefall gap and its effect on measures of forest dynamics. Biotropica 14: 158–160.
Brokaw N. V. L. , 'The definition of treefall gap and its effect on measures of forest dynamics ' (1982 ) 14 Biotropica : 158 -160 .
Busing, R. T. 1998. Composition, structure and diversity of cove forest stands in the Great Smoky Mountains: a patch dynamics perspective. J. Veg. Sci. 9: 881–890.
Busing R. T. , 'Composition, structure and diversity of cove forest stands in the Great Smoky Mountains: a patch dynamics perspective ' (1998 ) 9 J. Veg. Sci. : 881 -890 .
Clark, D. A. and D. B. Clark. 1984. Spacing dynamics of a tropical rain forest tree: evaluation of the Janzen-Connell model. Am. Nat. 124: 769–788.
Clark D. B. , 'Spacing dynamics of a tropical rain forest tree: evaluation of the Janzen-Connell model ' (1984 ) 124 Am. Nat. : 769 -788 .
Condit, R., P. S. Ashton, P. Baker, S. Bunyavejchewin, S. Gunatilleke, N. Gunatilleke, S. P. Hubbell, R. B. Foster, A. Itoh, J. V. LaFrankie, H. Seng-Lee, E. Losos, N. Manokaran, R. Sukumar and T. Yamakura. 2000. Spatial patterns in the distribution of tropical tree species. Science 288: 1414–1418.
Yamakura T. , 'Spatial patterns in the distribution of tropical tree species ' (2000 ) 288 Science : 1414 -1418 .
Crawley, M. J. 1997. The structure of plant communities. In: M. J. Crawley (ed.), Plant Ecology, 2nd edition. Blackwell, Oxford. pp. 475–531.
Crawley M. J. , '', in Plant Ecology , (1997 ) -.
Dias, E. 1996. Vegetação natural dos Açores. Ecologia e sintaxonomia das florestas naturais. Ph.D. Dissertation. Universidade dos Açores. Angra do Heroísmo.
Dias, E., R. B. Elias and V. Nunes. 2004. Vegetation mapping and nature conservation: a case study in Terceira Island (Azores). Biodivers. Conserv. 13: 1519–1539.
Nunes V. , 'Vegetation mapping and nature conservation: a case study in Terceira Island (Azores) ' (2004 ) 13 Biodivers. Conserv. : 1519 -1539 .
Elias, R. B. 2007. Ecologia das florestas de Juniperus dos Açores. Ph.D. Dissertation, Azores University, Angra do Heroísmo.
Elias, R. B. and E. Dias. 2004. Primary succession on lava domes on Terceira (Azores). J. Veg. Sci. 15: 331–338.
Dias E. , 'Primary succession on lava domes on Terceira (Azores) ' (2004 ) 15 J. Veg. Sci. : 331 -338 .
Elias, R.B. and Dias E. 2009a. Gap dynamics and regeneration strategies in Juniperus-Laurus forests of the Azores Islands. Plant Ecol. 200: 179–189.
Dias E. , 'Gap dynamics and regeneration strategies in Juniperus-Laurus forests of the Azores Islands ' (2009 ) 200 Plant Ecol. : 179 -189 .
Elias, R.B. and Dias E. 2009b. Cyclic patch dynamics in a Macaronesian island forest. Community Ecol. 10: 25–34.
Dias E. , 'Cyclic patch dynamics in a Macaronesian island forest ' (2009 ) 10 Community Ecol. : 25 -34 .
Elias, R.B. & Dias E. 2009c. Effects of landslides on the mountain vegetation of Flores Island, Azores. J. Veg. Sci. 20: 706–717.
Dias E. , 'Effects of landslides on the mountain vegetation of Flores Island, Azores ' (2009 ) 20 J. Veg. Sci. : 706 -717 .
Fangliang, H., P. Legendre and J. V. La Frankie. 1997. Distribution patterns of tree species in a Malaysian tropical rain forest. J. Veg. Sci. 8: 105–114.
Frankie J. V. , 'Distribution patterns of tree species in a Malaysian tropical rain forest ' (1997 ) 8 J. Veg. Sci. : 105 -114 .
França, Z., J. V. Cruz, J. C. Nunes and V. H. Forjaz 2003. Geologia dos Açores: uma perspectiva actual. Açoreana 10: 11–140.
Forjaz V. H. , 'Geologia dos Açores: uma perspectiva actual ' (2003 ) 10 Açoreana : 11 -140 .
Gratzer, G. and P. B. Rai. 2004. Density-dependent mortality versus spatial segregation in early life stages of Abies densa and Rhododendron hodgsonii in Central Bhutan. Forest Ecol. Manage. 192: 143–159.
Rai P. B. , 'Density-dependent mortality versus spatial segregation in early life stages of Abies densa and Rhododendron hodgsonii in Central Bhutan ' (2004 ) 192 Forest Ecol. Manage. : 143 -159 .
Grubb, P. J. 1977. The maintenance of species richness in plant communities. The importance of the regeneration niche. Biol. Rev. Camb. Philos. Soc. 52: 107–145.
Grubb P. J. , 'The maintenance of species richness in plant communities. The importance of the regeneration niche ' (1977 ) 52 Biol. Rev. Camb. Philos. Soc. : 107 -145 .
Haase, P. 1995. Spatial pattern analysis in ecology based on Ripley’s K-function: Introduction and methods of edge correction. J. Veg. Sci. 6: 575–582.
Haase P. , 'Spatial pattern analysis in ecology based on Ripley’s K-function: Introduction and methods of edge correction ' (1995 ) 6 J. Veg. Sci. : 575 -582 .
Hardy, O. J. and B. Sonké. 2004. Spatial pattern analysis of tree species distribution in a tropical rain forest of Cameroon: assessing the role of limited dispersal and niche differentiation. Forest Ecol. Manage. 197: 191–202.
Sonké B. , 'Spatial pattern analysis of tree species distribution in a tropical rain forest of Cameroon: assessing the role of limited dispersal and niche differentiation ' (2004 ) 197 Forest Ecol. Manage. : 191 -202 .
Hoshino, D., N. Nishimura and S. Yamamoto. 2001. Age, size structure and spatial pattern of major tree species in an old-growth Chamaecyparis obtusa forest, Central Japan. Forest Ecol. Manage. 152: 31–43.
Yamamoto S. , 'Age, size structure and spatial pattern of major tree species in an old-growth Chamaecyparis obtusa forest, Central Japan ' (2001 ) 152 Forest Ecol. Manage. : 31 -43 .
Ishikawa, Y., P. V. Krestov and K. Namikawa. 1999. Disturbance history and tree establishment in old-growth Pinus koraiensis-hardwood forests in the Russian Far East. J. Veg. Sci. 10: 439–448.
Namikawa K. , 'Disturbance history and tree establishment in old-growth Pinus koraiensis-hardwood forests in the Russian Far East ' (1999 ) 10 J. Veg. Sci. : 439 -448 .
Leithead, M. D., M. Anand and L. Deeth. 2009. Asynthetic approach for analyzing tropical tree spatial patterns through time. Community Ecol. 10: 45–52.
Deeth L. , 'Asynthetic approach for analyzing tropical tree spatial patterns through time ' (2009 ) 10 Community Ecol. : 45 -52 .
Li, L., H. Zhongliang, W. Ye, H. Cao, S. Wei, Z. Wang, J. Lian, I. Sun, K. Ma and F. He. 2009. Spatial distributions of tree species in a subtropical forest of China. Oikos 118: 495–502.
He F. , 'Spatial distributions of tree species in a subtropical forest of China ' (2009 ) 118 Oikos : 495 -502 .
Manabe, T., N. Nishimura, M. Miura and S. Yamamoto. 2000. Population structure and spatial patterns for trees in a temperate old-growth evergreen broad-leaved forest in Japan. Plant Ecol. 151: 181–197.
Yamamoto S. , 'Population structure and spatial patterns for trees in a temperate old-growth evergreen broad-leaved forest in Japan ' (2000 ) 151 Plant Ecol. : 181 -197 .
Martinez, I., T. Wiegand, F. González-Taboada and J. R. Obeso. 2010. Spatial associations among tree species in a temperate forest community in North-western Spain. Forest Ecol. Manage. 260: 456–465.
Obeso J. R. , 'Spatial associations among tree species in a temperate forest community in North-western Spain ' (2010 ) 260 Forest Ecol. Manage. : 456 -465 .
Matsuda, Y. and N. Hijii. 1998. Spatiotemporal distribution of fruit bodies of ectomycorrhizal fungi in an Abies firma forest. Mycorrhiza 8: 131–138.
Hijii N. , 'Spatiotemporal distribution of fruit bodies of ectomycorrhizal fungi in an Abies firma forest ' (1998 ) 8 Mycorrhiza : 131 -138 .
McDonald, R. I., R. K. Peet and D. L. Urban. 2003. Spatial pattern of Quercus regeneration limitation and Acer rubrum invasion in a Piedmont forest. J. Veg. Sci. 14: 441–450.
Urban D. L. , 'Spatial pattern of Quercus regeneration limitation and Acer rubrum invasion in a Piedmont forest ' (2003 ) 14 J. Veg. Sci. : 441 -450 .
Miyadokoro, T., N. Nishimura and S. Yamamoto. 2003. Population structure and spatial patterns of major trees in a subalpine oldgrowth coniferous forest, central Japan. Forest Ecol. Manage. 182: 259–272.
Yamamoto S. , 'Population structure and spatial patterns of major trees in a subalpine oldgrowth coniferous forest, central Japan ' (2003 ) 182 Forest Ecol. Manage. : 259 -272 .
Morisita, M. 1959. Measuring the dispersion of individuals and analysis of the distributional patterns. Memoirs of the Faculty of Science of Kyushu University, Series E 2(4): 215–234.
Morisita M. , 'Measuring the dispersion of individuals and analysis of the distributional patterns ' (1959 ) 2 Memoirs of the Faculty of Science of Kyushu University, Series E : 215 -234 .
Rivas-Martínez, S., T. Díaz, F. Fernández-González, J. Izco, J. Loidi, M. Lousã and A. Penas. 2002. Vascular plant communities of Spain and Portugal. Addenda to the syntaxonomical checklist of 2001. Part II. Itinera Geobot. 15(2): 433–922.
Penas A. , 'Vascular plant communities of Spain and Portugal. Addenda to the syntaxonomical checklist of 2001. Part II ' (2002 ) 15 Itinera Geobot : 433 -922 .
Rumeu B., M. Nogales, R. B. Elias, D. P. Padilla, T. Resendes, A. F. Rodríguez and E. Dias. 2009. Contrasting phenology and female cone characteristics of the two Macaronesian island endemic cedars (Juniperus cedrus and J. brevifolia). Eur. J. Forest Res. 128: 567–574.
Dias E. , 'Contrasting phenology and female cone characteristics of the two Macaronesian island endemic cedars (Juniperus cedrus and J. brevifolia) ' (2009 ) 128 Eur. J. Forest Res. : 567 -574 .
Self, S. 1976. The recent volcanology of Terceira, Azores. J. Geol. Society London 132: 645–666.
Self S. , 'The recent volcanology of Terceira, Azores ' (1976 ) 132 J. Geol. Society London : 645 -666 .
Souza, A. F. and F. R. Martins. 2002. Spatial distribution of an undergrowth palm in fragments of the Brazilian Atlantic Forest. Plant Ecol. 164: 141–155.
Martins F. R. , 'Spatial distribution of an undergrowth palm in fragments of the Brazilian Atlantic Forest ' (2002 ) 164 Plant Ecol. : 141 -155 .
Szwagrzyk, J. and M. Czerwczak. 1993. Spatial patterns of trees in natural forests of East-Central Europe. J. Veg. Sci. 4: 469–476.
Czerwczak M. , 'Spatial patterns of trees in natural forests of East-Central Europe ' (1993 ) 4 J. Veg. Sci. : 469 -476 .
Takahashi, K., K. Homma, V. P. Vetrova, S. Florenzev and T. Hara. 2001. Stand structure and regeneration in a Kamchatka mixed boreal forest. J. Veg. Sci. 12: 627–634.
Hara T. , 'Stand structure and regeneration in a Kamchatka mixed boreal forest ' (2001 ) 12 J. Veg. Sci. : 627 -634 .
Tanouchi, H. and S. Yamamoto. 1995. Structure and regeneration of canopy species in an old-growth evergreen broad-leaved forest in Aya district, southwestern Japan. Vegetatio 117: 51–60.
Yamamoto S. , 'Structure and regeneration of canopy species in an old-growth evergreen broad-leaved forest in Aya district, southwestern Japan ' (1995 ) 117 Vegetatio : 51 -60 .
Taylor, A. H. and C. B. Halpern. 1991. The structure and dynamics of Abies magnifica forests in the southern Cascade Range, USA. J. Veg. Sci. 2: 189–200.
Halpern C. B. , 'The structure and dynamics of Abies magnifica forests in the southern Cascade Range, USA ' (1991 ) 2 J. Veg. Sci. : 189 -200 .
Taylor, A. H., S. W. Jang, L. J. Zhao, C. P. Liang, C. J. Miao and J. Huang. 2006. Regeneration patterns and tree species coexistence in old-growth Abies-Picea forests in southwestern China. Forest Ecol. Manage. 223: 303–317.
Huang J. , 'Regeneration patterns and tree species coexistence in old-growth Abies-Picea forests in southwestern China ' (2006 ) 223 Forest Ecol. Manage. : 303 -317 .
van der Meer, P. J., F. J. Sterck and F. Bongers. 1998. Tree seedling performance in canopy gaps in a tropical rain forest at Nouragues, French Guiana. J. Trop. Ecol. 14: 119–137.
Bongers F. , 'Tree seedling performance in canopy gaps in a tropical rain forest at Nouragues, French Guiana ' (1998 ) 14 J. Trop. Ecol. : 119 -137 .
Wolf, A. 2005. Fifty year record of change in tree spatial patterns within a mixed deciduous forest. Forest Ecol. Manage. 215: 212–223.
Wolf A. , 'Fifty year record of change in tree spatial patterns within a mixed deciduous forest ' (2005 ) 215 Forest Ecol. Manage. : 212 -223 .
Yu, H., T. Wiegand, X. Yang and L. Ci. 2009. The impact of fire and density-dependent mortality on the spatial patterns of a pine forest in the Hulun Buir sandland, Inner Mongolia, China. Forest Ecol. Manage. 257: 2098–2107.
Ci L. , 'The impact of fire and density-dependent mortality on the spatial patterns of a pine forest in the Hulun Buir sandland, Inner Mongolia, China ' (2009 ) 257 Forest Ecol. Manage. : 2098 -2107 .