Integration of Conservation Strategies of Plant Genetic ... - Genres

Seed stands are the major source of reproductive material in forestry. They are however only
of limited use for conservation of genetic diversity. There is no genetic information available,
no follow up of the single stand identity, no obligation to collect seed from many different
populations, no guarantee that local material is used locally. The only option is to guide
commercial seed collection in a way that many stands are included.
It is however a good practical solution to select some of the seed stands as conservation
stands and to have a thorough evaluation and utilization of these specific stands with a follow
up until plantation establishment. In situ methods are of course a main part of conservation
for forest gene resources but they must be supplemented by ex situ methods.
3.2 Ex situ methods
Ex situ methods are the main option for minor tree species and a necessary addition for major
species. Ex situ plantations are under the dynamics of natural selection and evolutionary
processes, however selection pressure may be different from in situ plantations if the
ecological conditions of the respective sites are very different. Therefore the selection of the
ex situ sites has implications on the efficiency of this method. It is possible to combine
selection and improvement with ex situ plantations.
Utilization is regularly only possible after flowering started, which may last some decades in
many tree species. However vegetative propagation is directly possible in some tree species
but more expensive.
Seed orchards are necessary for minor tree species and endangered populations of major
species, they are an additional option for major species if improved material from selection
is to be used. The comparatively intensive management excludes natural selection and reduces
dangers arising from fast environmental changes and catastrophes. Depending on the species
seed can be harvested soon, economically and - depending on the composition of the seed
orchard - with high or low genetic diversity. Compared to the options discussed above the
costs of seed orchards are comparatively high, since they are not integrated into regular forest
management operations. Due to the improvement, which is possible, and to the easier access
to seed they can be nevertheless economical for utilization.
Clonal archives have - as compared to seed orchards - the disadvantage, that a direct
utilization is not possible or much more expensive. Therefore they are more an intermediate
method until a sufficient high number of clones has been collected to establish a seed orchard.
Seed storage plays a major role under the ex situ methods in forestry with those species where
seed can be stored for long time. This is true for most forest tree species. It is an additional
security for in situ conservation stands, plantations and seed orchards and quarantees the
conservation of high genetic diversity with moderate costs. It is however a static conservation
method and sensitive to technical defects. Seed can be immediately used, however it is
exhausted after utilization.