Can we improve the health of our pine forests by managing tree investment in resistance traits?
The human interference in forest ecosystems has recently broken the equilibrium between trees and their enemies, increasing the frequency and intensity of sanitary problems. Factors such as global warming, the increases of movements of forest genetic materials throughout different countries and even continents, the reduction of the genetic diversity in breeding programs, or the decrease in resistance associated with the increase of productivity through breeding or silvicultural practices, predict an increase of the frequency and intensity of epidemic episodes in forest ecosystems. Range expansions of non-native pests and pathogens to new host plant species is also an extremely problematic consequence of global change. Given the difficulties of applying intensive management practices in forestry, searching for new environmentally-friendly and cost-effective alternatives for pest and pathogen management becomes essential.
Management of pine forest health has been traditionally focused on the control of pests and pathogens populations, mainly by means of phytosanitary chemicals and pheromones. Pine trees, however, have evolved extremely efficient defensive mechanisms that have allowed them to persist in earth for many millions of years despite the enormous pressure imposed by their multiple natural enemies. Recent investigations indicate that the expression of these defensive mechanisms is extremely variable both genetically and phenotypically. This huge variability opens the door for searching for new management alternatives focused on optimizing the resistance of our pine stands accordingly to the biotic risk to which they are exposed. In this communication, I present recent results about the sources of variation of resistance to pests and pathogens in Mediterranean pines, and discuss about the viability of exploiting this variability for enhancing pine forest health.