What are the genetic consequences of forest management on beech?

The way in which genetic variation is distributed within tree populations is essential for them to adapt to environmental changes. The spatial distribution of genetic variation within a population can be altered by natural and human-induced disturbances.

Photo: Beech stand, Central Appennines, Italy. Credit: Bioversity International/B.Vinceti

A recent paper published by scientists from the FORGER project highlighted that if we properly assess the fine-scale distribution of genetic variation in forest species, we will be in a better position to preserve forest genetic resources through appropriate forest management, especially in the face of climate change.

The study by Piotti et al. focused on a widespread European tree species, beech (Fagus sylvatica L.), comparing cryptic within-population genetic structure of forest tree stands under different disturbance levels.

Contrarily to what was previously thought, the presence of a complex within-population structure, organized around subpopulations that may be highly intermingled, is emerging as a common characteristic of forest tree populations. Few studies have investigated the genetic consequences of forest management at such a fine scale so far, and have generated contrasting results among different species. However, such species-specific responses to forest management can arise because experiments need to be replicated on properly sampled plots from managed and unmanaged forests in order to draw general conclusions.

This study shows that despite the variety of conditions explored, a large proportion of within population genetic variation is due to the existence of different subpopulations in all plots, and that disturbance is a relevant factor in determining differences in the complexity of within-population genetic structure. Moreover, a general reduction in the complexity of the genetic structure was observed in managed vs unmanaged forest plots.

The results of the work by Piotti et al. indicate that detecting even subtle changes in the within-population genetic structure can provide early signals of the consequences of forest management on genetic variation.

Text by B.Vinceti based on the paper Within-Population Genetic Structure in Beech (Fagus sylvatica L.) Stands Characterized by Different Disturbance Histories: Does Forest Management Simplify Population Substructure? By Andrea Piotti, Stefano Leonardi, Myriam Heuertz, Joukje Buiteveld, Thomas Geburek, Sophie Gerber, Koen Kramer, Cristina Vettori, Giovanni Giuseppe Vendramin

Read the full article in PLoS ONE