Abstract
Non-native forest tree species have been introduced in Europe since the 16th century, but only in the second half of the 20th century the significance of the seed source origin for their economic use was recognized, resulting in the establishment of numerous provenance trials at a national, regional, European and International level, as those led by IUFRO. Breeding programs have also been launched in the continent for the most economically important species. Aim of this work is the formulation of provenance recommendations for planting of five non-native tree species in Europe (Douglas fir, grand fir, Sitka spruce, lodgepole pine and black locust), based on the information obtained from twenty countries, in the frame of the EU FP-1403 NNEXT Cost Action. The survey revealed that official and non-official national recommendations, based on provenance research results, have been elaborated and followed at a different level and extend for the above five species, but only for Douglas fir recommendations exist in almost all the participating to the survey countries. The compilation of provenance recommendations across Europe for each species is presented in the current work. Besides the recommended introduced seed sources, European seed sources are also preferred for planting, due to ease of access and high availability of forest reproductive material. European breeding programs yielding genetic material of high productivity and quality constitute currently the seed source of choice for several species and countries. Consolidation of trial data obtained across countries will allow the joint analysis that is urgently needed to draw solid conclusions, and will facilitate the development of ‘Universal-Response-Functions’ for the species of interest, rendering possible the identification of the genetic material suitable for global change. New provenance trial series that will test seed sources from the entire climatic range of the species, established in sites falling within and outside the environmental envelopes of their natural ranges, are urgently needed to pinpoint and understand the species-specific climate constraints, as well as to correlate functional traits to the seed origin and the environmental conditions of the test sites, so that the selection of suitable forest reproductive material of non-native tree species in the face of climate change can be feasible.
Highlights
Following the CBD [1] definition, the term ‘non-native species’ refers to “a species, subspecies or lower taxon, introduced outside its natural past or present distribution; the term includes any part, gametes, seeds, eggs, or propagules of such species that might survive and subsequently reproduce”, while according to FAO Global Forest Resources Assessment [2], and as accepted by Forest Europe (Indicator 4.4), the above definition is extended to those species having a potential to spread.In Europe, the first introductions of non-native tree species from other continents were carried out between the 16th and 18th century, mainly by botanists motivated by curiosity and botanical interest [3], in a time when knowledge on genetics and local adaptation was lacking
The responses obtained from twenty-six partner countries indicated that five nonnative tree species were the ones that attracted an extensive interest for testing and planting and were reported from five or more countries, namely Douglas fir, grand fir, Sitka spruce, lodgepole pine and black locust
Information on the geographic coordinates of the genetic trials established in Europe, as well as on the origin of the genetic materials tested within those genetic trials was provided by the representatives of the NNEXT Cost Action partner countries
Summary
Following the CBD [1] definition, the term ‘non-native species’ refers to “a species, subspecies or lower taxon, introduced (i.e., by human action) outside its natural past or present distribution; the term includes any part, gametes, seeds, eggs, or propagules of such species that might survive and subsequently reproduce”, while according to FAO Global Forest Resources Assessment [2], and as accepted by Forest Europe (Indicator 4.4), the above definition is extended to those species having a potential to spread (i.e., outside the range they occupy naturally or being able to occupy sites without direct or indirect introduction or care by humans).In Europe, the first introductions of non-native tree species from other continents were carried out between the 16th and 18th century, mainly by botanists motivated by curiosity and botanical interest [3], in a time when knowledge on genetics and local adaptation was lacking. The underlying processes or mechanisms that caused the observed variation were still unknown at that time and the introduction of non-native tree species reproductive material was not based on gene-ecological knowledge and genetic criteria. The use of reproductive material maladapted to the planting sites often resulted in extensive failures, as for example that of the interior variety of Douglas-fir in Central Europe [7]. Following such failures, the significant role of the seed origin for a successful introduction was increasingly recognized, resulting in the introduction of non-native species in a more organized way which considered the existing ecological and genetic knowledge (e.g., [8–10]). Non-native tree species have been utilized in Europe as an important timber [11], pulp [12] and biomass/energy [13] resource, as well as a source of non-timber wood products [14]
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