New Topical Collection on “Establishment of second-growth forests in human landscapes: ecological mechanisms and genetic consequences”

This special issue gathers articles (see references below) arising from the ERA-NET BiodivERsA3 research project “Unraveling the Potential of Spontaneous Forest Establishment for Improving Ecosystem Functions and Services in Dynamic Landscapes (SPONFOREST)”.

SPONFOREST addressed two major ecological research questions :
1) How do new forest patches establish within fragmented landscapes?
2) Which consequences has the establishment process for the genetic and phenotypic diversity of new forest patches and for their functionality at ecosystem level ?

The researchers studied 5 very diverse rural landscapes of Southwestern Europe located in France and Spain. Their results show that the growth mechanisms of secondary forests are highly complex and highly dependent on the context in which they are established.

Among the various results, the researchers observed that reforestation favours the defragmentation of pre-existing forests and the proliferation of new plots, in forested and non-forested landscapes respectively, whereas it is not associated with a decrease in landscape diversity.  The diversity and heterogeneity of unmanaged secondary forests favours the diversity of herbivorous insects in fragmented landscapes. They are also less sensitive to periods of drought and the “wild” character of these unmanaged forests, with trees of various ages and their unsystematic exploitation, could help to improve their resistance to a warmer and drier climate.

The regrowth of spontaneous forests is a widespread reality throughout Europe and beyond. Understanding this phenomenon is essential to exploit their potential to improve the management and conservation of European landscapes in a context of climate change that is increasing tree mortality in Europe.

An Opinion paper by Arndt Hampe, Raquel Alfaro-Sánchez and Irene Martín-Forés accompanies the set of contributions to this special issue and illustrates the great complexity and context dependence that characterise the establishment and expansion of second-growth forests. European rural landscapes are being transformed at an unprecedented pace following rapid socio-economic and environmental changes that involve both continued intensification and widespread abandonment in different parts of the area. Spontaneous forest regrowth is a reality across Europe that implies risks and opportunities for stakeholders, administrations and society as a whole. A proper biological understanding of the phenomenon is a prerequisite if we wish to fully exploit its potential as a highly feasible, nature-based solution.

Spontaneous reforestation can represent a very cost-efficient and politically feasible tool to foster multifunctional, diverse landscapes when active management is not possible.

SponForest Topical Collection articles :

Ruiz-Carbayo H., Pino J., Bonal R. et al. Insect herbivory in novel Quercus ilex L. forests: the role of landscape attributes, forest composition and host traits. Annals of Forest Science 77, 32 (2020). https://doi.org/10.1007/s13595-020-00934-4

Palmero-Iniesta M., Espelta J.M., Gordillo J. et al. Changes in forest landscape patterns resulting from recent afforestation in Europe (1990–2012): defragmentation of pre-existing forest versus new patch proliferation. Annals of Forest Science 77, 43 (2020). https://doi.org/10.1007/s13595-020-00946-0

Alfaro-Sánchez R., Valdés-Correcher E., Espelta J.M. et al. How do social status and tree architecture influence radial growth, wood density and drought response in spontaneously established oak forests?. Annals of Forest Science 77, 49 (2020). https://doi.org/10.1007/s13595-020-00949-x

Villellas J., Martín-Forés I., Mariette S. et al. Functional distance is driven more strongly by environmental factors than by genetic relatedness in Juniperus thurifera L. expanding forest stands. Annals of Forest Science 77, 66 (2020). https://doi.org/10.1007/s13595-020-00973-x

Gerzabek G., Oddou-Muratorio S., Hampe A. Recruitment of a genotyped Quercus robur L. seedling cohort in an expanding oak forest stand: diversity, dispersal, and performance across habitats. Annals of Forest Science 77, 78 (2020). https://doi.org/10.1007/s13595-020-00979-5

Lamonica D., Pagel J., Valdés-Correcher E. et al. Tree potential growth varies more than competition among spontaneously established forest stands of pedunculate oak (Quercus robur). Annals of Forest Science 77, 80 (2020). https://doi.org/10.1007/s13595-020-00981-x

Opinion paper :

Hampe A., Alfaro-Sánchez R., Martín-Forés I. Establishment of second-growth forests in human landscapes: ecological mechanisms and genetic consequences. Annals of Forest Science 77, 87 (2020). https://doi.org/10.1007/s13595-020-00993-7