Review of theoretical and practical aspects related to genetic management of forest trees is presented. The implementation of international commitments on forest genetic diversity has been slow and partly neglected. Conservation of forest genetic diversity is still riddled with problems, and complexities of national legal and administrative structures. Europe is an example of a complex region where the distribution ranges of tree species extend across large geographical areas with profound environmental differences, and include many countries. Conservation of forest genetic diversity in Europe has been hampered by a lack of common understanding on the management requirements for genetic conservation units of forest trees. The challenge resides in integrating scientific knowledge on conservation genetics into management of tree populations so that recommendations are feasible to implement across different countries. Here, we present panEuropean minimum requirements for dynamic conservation units of forest genetic diversity. The units are natural or manmade tree populations which are managed for maintaining evolutionary processes and adaptive potential across generations. Each unit should have a designated status and a management plan, and one or more tree species recognized as target species for genetic conservation. The minimum sizes of the units are set at 500, 50 or 15 reproducing individuals depending on tree species and conservation objectives. Furthermore, silvicultural interventions should be allowed to enhance genetic processes, as needed, and field inventories carried out to monitor regeneration and the population size. These minimum requirements are now used by 36 countries to improve management of forest genetic diversity.
COBISS.SI-ID: 3490982
Dynamic conservation of forest genetic resources (FGR) means maintaining the genetic diversity of trees within an evolutionary process and allowing generation turnover in the forest. We assessed the network of forests areas managed for the dynamic conservation of FGR (conservation units) across Europe (33 countries). On the basis of information available in the European Information System on FGR (EUFGIS Portal), species distribution maps, and environmental stratification of the continent, we developed ecogeographic indicators, a marginality index, and demographic indicators to assess and monitor forest conservation efforts. We detected a poor coincidence between FGR conservation and other biodiversity conservation objectives within this network. We identified 2 complementary strategies: a species oriented strategy in which national conservation networks are specifically designed for key target species and a site oriented strategy in which multiple target units include so called secondary species conserved within a few sites. The network is highly unbalanced in terms of species representation, and 7 key target species are conserved in 60% of the conservation units. We performed specific gap analyses for 11 tree species, including assessment of ecogeographic, demographic, and genetic criteria. For each species, we identified gaps, particularly in the marginal parts of their distribution range, and found multiple redundant conservation units in other areas. The Mediterranean forests and to a lesser extent the boreal forests are underrepresented. Monitoring the conservation efficiency of each unit remains challenging; however, (2% of the conserved populations seem to be at risk of extinction. On the basis of our results, we recommend combining species oriented and site oriented strategies.
COBISS.SI-ID: 3506854
Vulnerability of individual conservation units (network of forests areas managed for the dynamic conservation of forest genetic resources) and the whole network to climate change using climate favourability models and the estimated velocity of climate change was quantified. Compared to the overall climate niche of the analysed target species populations at the warm and dry end of the species niche are underrepresented in the network. However, by 2100, target species in 33 65 % of conservation units, mostly located in southern Europe, will be at the limit or outside the species’ current climatic niche as demonstrated by favourabilities below required model sensitivities of 95 %. The highest average decrease of favourabilities throughout the network can be expected for coniferous trees although they are mainly occurring within units in mountainous landscapes for which we estimated lower velocities of change. Generally, the speciesspecific estimates of favourabilities showed only low correlations to the velocity of climate change of individual units, indicating that both vulnerability measures should be considered for climate risk analysis. The variation of favourabilities among target species within the same conservation units is expected to increase with climate change and will likely require a prioritization among cooccurring species. The present results suggest that there is a strong need to intensify monitoring efforts and to develop additional conservation measures for populations in the most vulnerable units. Also, our results call for continued transnational actions for genetic conservation of European forest trees, including the establishment of dynamic conservation populations outside the current species distribution ranges within European assisted migration schemes.
COBISS.SI-ID: 3780006
Forests damaged by large-scale natural disturbances often call for immediate regeneration through planting and sowing in order to provide all their functions as soon as possible. In this paper, planned and accomplished use of seed and seedlings in Slovenia for the years 2007 - 2011 is presented in addition to a case study based on restoration plans and needs of a regional forestry management unit - GGO Bled. Problems such as how to ensure sufficient quantities of species rich, genetically and ecologically suitable seed and seedlings for restoration of forests after large-scale disturbances are presented. Given the presented problems, proposals on how to ensure large enough quantities of appropriate seed and seedlings more easily are presented.
COBISS.SI-ID: 3578022
In the presented case study, we aim to understand the impact of an irregular shelterwood system (ISS ) on the genetic diversity of European beech (Fagus sylvatica L.) firstly by comparing managed stand to old growth beech forest and secondly by comparing two successive generations in both managed and old growth stands. Studies on European beech to date have not yet investigated the effect of ISS on its genetic diversity and have rarely addressed the effect of management on the genetic diversity of successive generations. The study was conducted in two mixed beech stands in Slovenia; the unmanaged Rajhenavski Rog old-growth European beech forest reserve and beech forest in Osankarica, managed according to ISS. All 140 sampled adult trees and saplings were genotyped at 16 nuclear microsatellite loci. ISS mimics genetic processes of the old growth rather well in the studied managed stand. The comparisons of diversity measures between managed and old growth stands did not reveal any significant differences between the two for any of the cohorts; the differences between the cohorts from the same stand were not significant. The observed significant shift in allele frequencies at four loci between successive generations could not be unambiguously attributed to management. Cohorts from the same stand had similar genetic structure, but six individuals from the managed stand formed a unique cluster. No convincing evidence of the effect of ISS on genetic diversity of the studied managed beech stand was found.
COBISS.SI-ID: 3946918