Since climate change projections contain many uncertainties and are normally unable to predict the direction and magnitude of change at the small scale needed by forest managers, some understanding about the functioning of the target forest should be obtained before a robust management strategy can be applied. Structure and regeneration patterns are related to key ecosystem processes which, on the other hand, can be modified by silvicultural treatments. In this research, the structure and recruitment dynamics of two stands with different histories of management were investigated in the southern limit of the range of Pinus nigra subsp. salzmannii (Southeast Spain). We described forest structure and facilitation effects by forest canopies and nurse shrubs, and quantified the processes affecting each stage of regeneration (dispersed seed, first year seedling and second year seedling) in different microhabitats. Forest structure was more complex in the stand scarcely influenced by human activities. Juniperus communis shrubs seemed to facilitate the establishment of tree saplings. Most seedlings died of desiccation during their first summer. At best, 190 out of 10,000 emerged seedlings survived the first summer. In light of these results, the possibilities of applying close-to-nature forestry in the study forests and other aspects of silviculture under a frame of adaptive forest management are discussed.
References
[1]
Lovelock, J. The Revenge of Gaia; Penguin Books: London, UK, 2006; p. 175.
[2]
IPCC. Climate Change, Fourth Assessment Report; Cambridge University Press: London, UK, 2007; p. 255.
[3]
Millar, C.I.; Stephenson, N.L.; Stephens, S.L. Climate change and forests of the future: Managing in the face of uncertainty. Ecol. Appl. 2007, 17, 2145–2151.
[4]
Linares, J.C.; Tíscar, P.A. Climate change impacts and vulnerabilitity of the southern populations of Pinus nigra subsp. salzmannii. Tree Physiol. 2010, 30, 795–806.
[5]
Noss, R.F. Beyond Kyoto: Forest management in a time of rapid climate change. Conserv. Biol. 2001, 15, 578–590.
Herrera, C.M. Topsoil properties and seedling recruitment in Lavandula latifolia: Stage-dependence and spatial decoupling of incluential parameters. Oikos 2002, 97, 260–270.
[8]
Gómez-Aparicio, L. Spatial patterns of recruitment in Mediterranean plant species: Linking the fate of seeds, seedlings and saplings in heterogeneous landscapes at different scales. J. Ecol. 2008, 96, 1128–1140.
[9]
Linares, J.C.; Carreira, J.A.; Ochoa, V. Human impacts drive forest structure and diversity. Insights from Mediterranean mountain forest dominated by Abies pinsapo (Boiss.). Eur. J. Forest Res. 2011, 130, 533–542.
[10]
Linares, J.C.; Tíscar, P.A.; Camarero, J.J.; Ta？qui, L.; Vi？egla, B.; Seco, J.I.; Merino, J.; Carreira, J.A. Tree growth decline on relict Western-Mediterranean mountain forests: Causes and impacts. In Forest Decline: Causes and Impacts; Jenkins, J.A., Ed.; Nova Science Publishers Inc.: Hauppauge, NY, USA, 2011.
[11]
Rey, P.J.; Alcántara, J. Recruitment dynamics of a fleshy-fruited plant (Olea europaea): Connecting patterns of seed dispersal to seedling establishment. J. Ecol. 2000, 88, 622–633.
[12]
Rees, M.; Mangel, M.; Turnbull, L.; Sheppard, A.; Briese, D. The effects of heterogeneity on dispersal and colonization in plants. In The Ecological Consequences of Enrironmental Heterogeneity; Hutchings, M.J., John, E.A., Stewart, A.J.A., Eds.; Blackwell Science: Oxford, UK, 2000; pp. 237–266.
[13]
Puerta-Pi？ero, C.; Gómez, J.M.; Valladares, F. Irradiance and oak seedling survival and growth in a heterogeneous environment. Forest Ecol. Manag. 2007, 242, 462–469.
[14]
Gómez-Aparicio, L.; Zavala, M.A.; Bonet, F.J.; Zamora, R. Are pine plantations valid tools for restoring Mediterranean forests? An assessment along abiotic and biotic gradients. Ecol. Appl. 2009, 19, 2124–2141.
[15]
Gómez-Aparicio, L.; Zamora, R.; Gómez, J.M.; Hódar, J.A.; Castro, J.; Baraza, E. Applying plant facilitation to forest restoration: A meta-analysis of the use of shrubs as nurse plants. Ecol. Appl. 2004, 14, 1128–1138.
[16]
Herrera, C.M.; Jordano, P.; López-Soria, L.; Amat, J.A. Recruitment of a mast-fruiting, bird-dispersed tree: Bridging frugivore activity and seedling establishment. Ecol. Monogr. 1994, 64, 315–344.
[17]
Lindner, M.; Maroschek, M.; Netherer, S.; Kremer, A.; Barbati, A.; Garcia-Gonzalo, J.; Seidl, R.; Delzon, S.; Corona, P.; Kolstr？m, M. Climate change impacts, adaptive capacity, and vulnerability of European forest ecosystems. Forest Ecol. Manag. 2010, 259, 698–709.
[18]
Smith, D.M.; Larson, B.C.; Kelty, M.J.; Ashton, P.M.S. The Practice of Silviculture: Applied Forest Ecology; Wiley: New York, NY, USA, 1997.
[19]
Stephens, S.L.; Millar, C.I.; Collins, B.M. Operational approaches to managing forests of the future in Mediterranean regions within a context of changing climates. Environ. Res. Lett. 2010, 5, 024003.
[20]
Spittlehouse, D.L.; Stewart, R.B. Adaptation to climate change in forest management. BC J. Ecosyst. Manag. 2003, 1, 1–11.
[21]
Drever, C.R.; Peterson, G.; Messier, C.; Bergeron, Y.; Flannigan, M. Can forest management based on natural disturbances maintain ecological resilience? Can. J. Forest Res. 2006, 36, 2285–2299.
[22]
Martín-Fernández, S.; García-Abril, A. Optimisation of spatial allocation of forestry activities within a forest stand. Comput. Electron. Agric. 2005, 49, 159–174.
[23]
Cayuela, L.; Hódar, J.A.; Zamora, R. Is insecticide spraying a viable and cost-efficient management practice to control pine processionary moth in Mediterranean woodlands? Forest Ecol. Manag. 2011, 261, 1732–1737.
[24]
Tíscar, P.A.; Linares, J.C. Pinus nigra subsp. Salzmannii forests from Southeast Spain: Using structure and process information to guide management. In Pine forests: Types, Threats and Management; Frisiras, C.T., Ed.; Nova Science Publishers Inc.: Hauppauge, NY, USA, 2011.
[25]
Richter, K.; Eckstein, D. The dendrochronological signal of pine trees (Pinus sp.) in Spain. Tree-Ring Bull. 1991, 51, 1–13.
[26]
Linares, J.C.; Tíscar, P.A. Buffered climate change effects in a Mediterranean pine species: Range limit implications from a tree-ring study. Oecologia 2011, 167, 847–859.
[27]
Sánchez de Medina, A.; García-Abril, A.; Grande, M.A. Los Pinares de Pinus nigra Arn. en Espa？a. In Los Pinares de Pinus Nigra Arn. en Espa？a: Ecología, uso y Gestión; García-Abril, A., Grande, M.A., Eds.; Fundacion Conde del Valle de Salazar: Madrid, Spain, 2005; pp. 1–54.
[28]
Tapias, R.; Climent, J.; Pardos, J.A.; Gil, L. Life histories of Mediterranean pines. Plant Ecol. 2004, 171, 53–68.
Alejano, R.; Martínez, E. Distribución de Pinus nigra Arn. subsp. salzmannii en las sierras Béticas. Ecologia 1996, 10, 231–241.
[31]
McElhinny, C.; Gibbons, P.; Brack, C.; Bauhus, J. Forest and woodland stand structural complexity: Its definition and measurement. Forest Ecol. Manag. 2005, 218, 1–24.
[32]
Tíscar, P.A. Capacidad reproductiva de Pinus nigra subsp. salzmannii en relación con la edad de la planta madre. Investig. Agrar. Sist. Recur. Forest. 2002, 11, 357–371.
[33]
Siles, G.; Rey, P.J.; Alcántara, J.M.; Ramírez, J.M. Assessing the long-term contribution of nurse plants to restoration of Mediterranean forests through Markovian models. J. Appl. Ecol. 2008, 45, 1790–1798.
[34]
Tíscar, P.A. Condicionantes y limitaciones de la regeneracion natural en un pinar oromediterraneo de Pinus nigra subsp. salzmannii. Investig. Agrar. Sist. Recur. Forest. 2003, 12, 55–64.
[35]
Zar, J.H. Biostatistical Analysis; Prentice Hall Inc.: Englewood Cliffs, NJ, USA, 1984; p. 600.
[36]
Legendre, P.; Legendre, L. Numerical Ecology; Elsevier: Amsterdam, The Netherlands, 1998.
[37]
STATISTICA for Windows [Computer Program Manual]; StatSoft, Inc.: Tulsa, OK, USA, 1999.
[38]
Adaptation of Forests and People to Climate Change—A Global Assesment Report; Sepp？la, R., Buck, A., Katila, P., Eds.; IUFRO World: Vienna, Austria, 2009; Volume 22, p. 224.
[39]
Franklin, J.F.; Spies, T.A.; van Pelt, R.; Carey, A.B.; Thornburgh, D.A.; Berg, D.R.; Lindenmayer, D.B.; Harmon, M.E.; Keeton, W.S.; Shaw, D.C.; Bible, K.; Chen, J. Disturbances and structural development of natural forest ecosystems with silvicultural implications, using douglas-fir forests as an example. Forest Ecol. Manag. 2002, 155, 399–423.
[40]
Molino, F. Los Coleópteros Saproxílicos de Andalucía. PhD Dissertation, University of Granada, Granada, Spain, 1996.
[41]
Staudhammer, C.L.; LeMAY, V.M. Introduction and evaluation of possible indices of stand structural diversity. Can. J. Forest Res. 2001, 31, 1105–1115.
[42]
López-Soria, L.; Castell, C. Comparative genet survival after fire in woody Mediterranean species. Oecologia 1992, 91, 493–499.
[43]
Coll, L.; González-Olabarria, R.; Mola-Yudego, B.; Pukkala, T.; Messier, C. Predicting understory máximum shrubs cover using altitude and overstory basal área in different Mediterranean forests. Eur. J. Forest Res. 2011, 130, 55–65.
[44]
Herrera, C.M.; Jordano, P.; Guitián, J.; Traveset, A. Annual variability in seed production by woody plants and the masting concept: Reassessment of principles and relationship to pollination and seed dispersal. Am. Nat. 1998, 152, 576–594.
[45]
Castro, J.; Gómez, J.M.; García, D.; Zamora, R.; Hódar, J.A. Seed predation and dispersal in relict Scots pine forests in southern Spain. Plant Ecol. 1999, 145, 115–123.
[46]
Sánchez-Gómez, D.; Valladares, F.; Zavala, M.A. Performance of seedlings of Mediterranean woody species under experimental gradients of irradiance and water availability: Trade-offs and evidence for niche differentiation. New Phystol. 2006, 170, 795–806.
[47]
Allen, C.D.; Macalady, A.K.; Chenchouni, H.; Bachelet, D.; McDowell, N.; Vennetier, M.; Kitzberger, T.; Rigling, A.; Breshears, D.D.; Hogg, E.H.T. A global overview of drought and heat-induced tree mortality reveals emerging climate change risks for forests. Forest Ecol. Manag. 2010, 259, 660–684.
[48]
Linares, J.C.; Camarero, J.J.; Carreira, J.A. Competition modulates the adaptation capacity of forests to climatic stress: Insights from recent growth decline and death in relict stands of the Mediterranean fir Abies pinsapo. J. Ecol. 2010, 98, 592–603.
[49]
Linares, J.C.; Camarero, J.J.; Carreira, J.A. Interacting effects of changes in climate and forest cover on mortality and growth of the southernmost European fir forests. Glob. Ecol. Biogeogr. 2009, 18, 485–497.
[50]
Zamora, R.; Hódar, J.A.; Matías, L.; Mendoza, I. Positive adjacency effects mediated by seed disperser birds in pine plantations. Ecol. Appl. 2010, 20, 1053–1060.
[51]
Matías, L.; Zamora, R.; Mendoza, I.; Hódar, J.A. Seed dispersal patterns by large frugivorous mammals in a degraded mosaic landscape. Restor. Ecol. 2010, 18, 619–627.
[52]
Gómez-Aparicio, L.; Valladares, F.; Zamora, R. Differential light responses of Mediterranean tree saplings: Linking ecophysiology with regeneration niche in four co-ocurring species. Tree Physiol. 2006, 26, 947–958.
[53]
Schütz, J. Opportunities and strategies of transforming regular forests to irregular forests. Forest Ecol. Manag. 2001, 151, 87–94.
[54]
Mendoza, I.; Zamora, R.; Castro, J. A seeding experiment for testing tree-community recruitment under variable environments: Implications for forest regeneration and conservation in Mediterranean habitats. Biol. Conserv. 2009, 149, 1491–1499.
[55]
Castro, J.; Zamora, R.; Hódar, J.A.; Gómez, J.M. Use of shrubs as nurse plants: A new technique for reforestation in Mediterranean mountains. Restor. Ecol. 2002, 10, 297–305.
