Glossary

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Assisted migration

The human-assisted movement of populations and species outside their natural range to mitigate climate change. When climate changes, species have few options to survive: they either adapt to the new environmental conditions or they migrate to a site with appropriate conditions. Trees can both adapt an migrate but it might take several generations (centuries to millenia). The mismatch between climate change and trees adaptation and/or migration will have tremendous effects on forest growth and composition. Assisted migration helps trees to keep up with the changing environment and fulfills a variety of economic, ecological and social goals. For example, oriental beech (Fagus sylvatica subsp. orientalis (Lipsky) Greut. & Burd) has been proposed for assisted migration to replace drought-sensitive European beech (Fagus sylvatica L.) at critical sites. See our research on Oriental beech here and here.

Bulk seed collection

The process of collecting seeds without distinguishing by mother tree. This is common practice for many nurseries and forest institutions because it assures the genetic diversity of seed lots. For beech, it is usually done by placing a sheet on the forest floor and collect the seeds that fall on top of it. Manual shaking of branches by ropes, hooks, or the like from the ground or by climbers provides adequate impact to release mature dispersal ready fruits. For fir, although trees must be climbed for collecting seeds, the cones from different mother trees are mixed together. Seeds of different species can be easily distinguished but it can become problematic in case of hybrids presence.

Direct seeding

The process of sowing seeds directly in the place where they will develop into fully grown individuals. This is different from the most common practice of seedlings planting where nursery-grown seedlings are transplanted from the nursery to the final site. Direct seeding is a close-to-nature practice, resembling natural regeneration except for the fact that seeds are placed on the soil with human assistance after appropriate soil preparation. Direct seeding has several advantages compared to seedling planting:

  • there are no costs associated with seedlings grown in nurseries

  • it enables undisturbed root development of the seedling

  • it avoids the shock of transplantation

  • it promotes the optimal adaptation of the seedling to the site conditions

Genetic diversity

Each species is composed of individuals that have a unique code of DNA that is responsible for the expression of their distinct features, such as its development and growth, reproduction, susceptibility of diseases and environmental changes. A set of individuals that interbreed is called a population. Loosely speaking, a forest stand that is not managed could be considered a population. The genetic diversity of a population is a summary of the variation among its members in terms of their DNA. Most often, we cannot observe the whole DNA sequence of individuals (as they are very long and expensive to "read"), so instead, genetic diversity is approximated using so-called genetic markers. Genetic markers are short segments of the DNA that can be easily obtained for a large number of individuals.

Micro-garden approach

The micro-garden approach have been proposed by MyGardenOfTrees for the evaluation of species, provenances and mother trees. This approach can be regarded as distributed provenance trial because instead of using a few large test sites, it uses hundreds of small test sites. The main advantage of this approach is that many combinations of provenances (genetic origins) and site conditions (environments) are tested. Since the performance of provenances is evaluated across a wide-range of environments, findings can be generalized across large spatial scales.

The Nagoya Protocol

The Nagoya Protocol on Access to Genetic Resources and the Fair and Equitable Sharing of Benefits Arising from their Utilization (ABS) to the Convention on Biological Diversity is a supplementary agreement to the Convention on Biological Diversity.

It regulates (1) the access to genetic resources (e.g., it facilities access for companies and research institutions to genetic material from plants, animals and other organisms in provider countries) and the (2) the fair and equitable sharing of the benefits which result from the use of genetic resources.

The Nagoya Protocol on ABS was adopted on 29 October 2010 in Nagoya, Japan and entered into force on 12 October 2014. Detailed information about the protocol can be found here.

Provenance trial

Provenance trials are plantation experiments of trees that compare the growth of different seed origins at a common site. Provenance refers to a population of trees that come from a particular geographic location. Provenance trials have been used to showcase whether trees are adapted to their home environmental conditions. However, since these trials test each provenance only at one or at most at a few sites, their findings cannot be generalized to other sites than the site of the provenance trial itself.

Single tree seed collection

The process of collecting seeds preserving the identity of the individual mother trees. To make sure the identity of the mother tree is maintained, seeds are collected directly from the crown by climbers or shooting branches depending on the species. This practice allows to study the variation between individuals and is the preferred practice of scientists. This is because the knowing the mother tree of each seedling allows for the estimation of the trait variation that is due to genetic factors, the so-called heritability. Single tree seed collection usually requires more effort than the bulk seed collection, especially for broad-leaves, while for most conifers the collection is by single tree anyway.