structural:expansion, quality:corruption, linguistic:paraphrasing, structural:reformatting
Genetic diversity in forestry

The provenance of forest reproductive material used to plant forests has a great influence on how the trees develop, hence why it is important to use forest reproductive material of good quality and of high genetic diversity. More generally, all forest management practices, including in natural regeneration systems, may impact the genetic diversity of trees.

The term genetic diversity describes the differences in DNA sequence between individuals as distinct from variation caused by environmental influences. The unique genetic composition of an individual (its genotype) will determine its performance (its phenotype) at a particular site.

Genetic diversity is needed to maintain the vitality of forests and to provide resilience to pests and diseases. Genetic diversity also ensures that forest trees can survive, adapt and evolve under changing environmental conditions. Furthermore, genetic diversity is the foundation of biological diversity at species and ecosystem levels. Forest genetic resources are therefore important to consider in forest management.

Genetic diversity in forests is threatened by forest fires, pests and diseases, habitat fragmentation, poor silvicultural practices and inappropriate use of forest reproductive material.

About 98 million hectares of forest were affected by fire in 2015; this was mainly in the tropical domain, where fire burned about 4 percent of the total forest area in that year. More than two-thirds of the total forest area affected was in Africa and South America. Insects, diseases and severe weather events damaged about 40 million hectares of forests in 2015, mainly in the temperate and boreal domains.

Furthermore, the marginal populations of many tree species are facing new threats due to the effects of climate change.

Most countries in Europe have recommendations or guidelines for selecting species and provenances that can be used in a given site or zone.