Integrating genetic and silvicultural strategies to minimize abiotic and biotic constraints in Brazilian eucalypt plantations
José Leonardo de Moraes Gonçalves, Clayton Alcarde Alvares, Antonio Rioyei Higa, Luciana Duque Silva, Acelino Couto Alfenas, James Stahl, Silvio Frosini de Barros Ferraz,
Walter de Paula Lima, Pedro Henrique Santin Brancalion, Ayeska Hubner, Jean-Pierre Daniel Bouillet,
Jean-Paul Laclau, Yann Nouvellon, Daniel Epron. Forest Ecology and Management
Organized forestry in Brazil began in the late 1960s, stimulated by a government policy which subsidized
afforestation programs from 1967 to 1989 to develop an internationally-competitive wood-based industry,
managed by the private sector. Currently, planted forests in Brazil total about 6.9 million ha, from
which 4.9 million ha is planted with eucalypt (around 25% of world plantation), 1.6 million ha with pine,
and 0.42 M ha with other species. Roundwood consumption of forest plantations totaled 170.1 million m3
in 2011, eucalypt plantation accounted for 80.6% of this total.
Most eucalypt plantations are managed in short rotations (6–8 years) and are established in regions
with water, nutritional and frost stresses of low to high degrees. Improving natural resources use efficiency by breeding and matching genotypes to sites and using
appropriate site management practices is a key challenge to sustain or increase productivity.
The wide range of eucalypt species and hybrids with different climatic and edaphic suitability associated
with the easy propagation by seeds and cloning allow the adaptation of plantations to various tropical
and subtropical regions in Brazil. The possibility of using eucalypt wood in a range of purposes has led
large and small enterprises to establish eucalypt forests for multiple uses. The desirable characteristics in
association with the accumulated knowledge on eucalypt silviculture encourage the use of this genus in
most plantations. The most important factors in the selective process for a genotype are wood characteristics,
productivity level, susceptibility to pests and diseases, drought tolerance, especially in tropical
regions (frost free), and frost tolerance in subtropical regions (mostly without water deficit). In regions
with pronounced seasonality and moderate to long drought periods, the planting of hybrid genotypes
predominates, propagated by cloning. Under subtropical conditions, the planting of single species predominates,
propagated by seed. Clonal plantations with interspecific hybrids have been fundamental
for eucalypt adaptation in regions under water and nutritional stresses. Given the rapid advances in eucalypt
breeding, regarding adaptation to water stress and resistance to diseases and pests, and the adoption
of clonal propagation techniques, genotypes are rapidly becoming obsolete and are replaced by more productive
ones after harvesting. Thus, the replanting of crops has become a common procedure after the
second half of the 1990s in Brazil.
This paper describes the basic requirements for integrating genetic and silvicultural strategies to minimize
abiotic and biotic constraints in eucalypt plantations.