European mixed forests: Definition and research perspectives

Bravo-Oviedo A., Pretzsch H., Ammer C., Andenmatten E., Barbati A., Barreiro S., Brang P., Bravo F., Coll L., Corona P., Den Ouden J., Ducey M.J., Forrester D.I., Giergiczny M., Jacobsen J.B., Lesinski J., Löf M., Mason B., Matovic B., Metslaid M., Morneau F., Motiejunaite J., O’Reilly C., Pach M., Ponette Q., Del Rio M., Short I., Skovsgaard J.P., Soliño M., Spathelf P., Sterba H., Stojanovic D., Strelcova K., Svoboda M., Verheyen K., Von Lüpke N., Zlatanov T. (2014) European mixed forests: Definition and research perspectives. Forest Systems. 23: 518-533.
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Doi: 10.5424/fs/2014233-06256

Resum:

Aim of study: We aim at (i) developing a reference definition of mixed forests in order to harmonize comparative research in mixed forests and (ii) briefly review the research perspectives in mixed forests. Area of study: The definition is developed in Europe but can be tested worldwide. Material and methods: Review of existent definitions of mixed forests based and literature review encompassing dynamics, management and economic valuation of mixed forests. Main results: A mixed forest is defined as a forest unit, excluding linear formations, where at least two tree species coexist at any developmental stage, sharing common resources (light, water, and/or soil nutrients). The presence of each of the component species is normally quantified as a proportion of the number of stems or of basal area, although volume, biomass or canopy cover as well as proportions by occupied stand area may be used for specific objectives. A variety of structures and patterns of mixtures can occur, and the interactions between the component species and their relative proportions may change over time. The research perspectives identified are (i) species interactions and responses to hazards, (ii) the concept of maximum density in mixed forests, (iii) conversion of monocultures to mixed-species forest and (iv) economic valuation of ecosystem services provided by mixed forests. Research highlights: The definition is considered a high-level one which encompasses previous attempts to define mixed forests. Current fields of research indicate that gradient studies, experimental design approaches, and model simulations are key topics providing new research opportunities. © 2014 Ministerio de Agricultura Pesca y Alimentacion. All rights reserved.

Llegeix més

Viewing forests through the lens of complex systems science

Filotas E., Parrott L., Burton P.J., Chazdon R.L., Coates K.D., Coll L., Haeussler S., Martin K., Nocentini S., Puettmann K.J., Putz F.E., Simard S.W., Messier C. (2014) Viewing forests through the lens of complex systems science. Ecosphere. 5: 0-0.
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Doi: 10.1890/ES13-00182.1

Resum:

Complex systems science provides a transdisciplinary framework to study systems characterized by (1) heterogeneity, (2) hierarchy, (3) self-organization, (4) openness, (5) adaptation, (6) memory, (7) non-linearity, and (8) uncertainty. Complex systems thinking has inspired both theory and applied strategies for improving ecosystem resilience and adaptability, but applications in forest ecology and management are just beginning to emerge. We review the properties of complex systems using four well-studied forest biomes (temperate, boreal, tropical and Mediterranean) as examples. The lens of complex systems science yields insights into facets of forest structure and dynamics that facilitate comparisons among ecosystems. These biomes share the main properties of complex systems but differ in specific ecological properties, disturbance regimes, and human uses. We show how this approach can help forest scientists and managers to conceptualize forests as integrated social-ecological systems and provide concrete examples of how to manage forests as complex adaptive systems. © 2014 Filotas et al.

Llegeix més

Uncoupled spatiotemporal patterns of seed dispersal and regeneration in Pyrenean silver fir populations

de Andres E.G., Camarero J.J., Martinez I., Coll L. (2014) Uncoupled spatiotemporal patterns of seed dispersal and regeneration in Pyrenean silver fir populations. Forest Ecology and Management. 319: 18-28.
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Doi: 10.1016/j.foreco.2014.01.050

Resum:

Silver fir (Abies alba) reaches its southwestern distribution limit (rear edge) in the Pyrenees, where it forms highly fragmented populations threatened by drought-induced die-off. Therefore, we need a better knowledge of regeneration patterns and processes (seed production and dispersal, regeneration niche) of such rear-edge stands to assist their long-term conservation. Seed rain patterns were studied in two structurally contrasting sites: an even-aged pure stand (Las Eras) and an uneven-aged mixed silver fir-beech (Fagus sylvatica) stand (Gamueta) over 8 and 12. years, respectively. Seed production experienced a greater synchrony in years of high seed production than when crops were low, suggesting masting behavior in both sites. Seed inverse modeling methods resulted in dispersal curves differing between sites, with estimates of mean dispersal distances of 9.9 and 21.5. m for the pure and mixed stands, respectively. Long-term sampling of seed dispersal and production was complemented with an analysis of silver fir regeneration niche. Seed and seedling patterns were spatially uncoupled, emphasizing the relevance of microsite filtering of regeneration. Understory light environment was the main factor explaining seedling emergence and mortality. Our study provides a mechanistic basis and a methodological approach for understanding the colonization ability of Pyrenean rear-edge silver fir stands and similar tree populations. © 2014 Elsevier B.V.

Llegeix més