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Institute for Forestry and Game Management, 1560 Hoeilaart, Belgium

During the last decades, forestry in Europe has shown a growing awareness of the high importance of a specific group of tree species known as Noble Hardwoods. The acknowledgement of their eminent silvicultural, economic and/or ecological values led to their upgrading from a former status of ‘minor’ species.

Out of this awareness arose a major concern to safeguard the existing resources of these species (isolated individuals, relict populations, small-scale homogeneous stands). Because one can not protect what one does not know, substantial efforts have been needed, in the first place, to identify the still existing resources.

Furthermore, the gene conservation programmes, set off in different European countries, very rapidly urged for an effective characterization of these resources once they had been identified. In this way a varying set of criteria, techniques and traits was developed and applied in each country, aiming at:

• determination of wild forms vis-à-vis cultivated and hybrid forms (e.g. wild apple)

• assessment of the levels of (genetic) diversity within the entities

• characterization of diversity between geographically disjunct entities.

The EUFORGEN Noble Hardwoods Network provides a mechanism for monitoring the practices currently used throughout Europe for such evaluation of genetic resources. In order to carry out an overview of the current evaluation methods and practices in different countries, a questionnaire was chosen as the most appropriate way to gain good information from all the participating countries (see list of Participants).

It was agreed to classify the different traits used for evaluation of Noble Hardwoods genetic resources into four categories: morphology, phenology, resistance characteristics and biochemical/genetic traits.

The received information was rearranged into a fairly limited number of tables representing the individual Noble Harwood species. The aim is to provide each member of the Network (and other scientists concerned) with a guide indicating where to search for additional information in order to compare, complete, refine and/or optimize their own evaluation techniques.

The purpose of this task is certainly not to produce one uniform methodology for the evaluation of Noble Hardwood species in all countries. The form of the questionnaire used for conducting this survey allowed for obtaining well-balanced and standard information. However, one should keep in mind that putting the available information into a fixed questionnaire inevitably entails a certain loss of information which does not fit into the presented form and can not be comprehended in the following overview tables (Tables 1-16).

Some similarities and common features between the different countries could be observed:

1. For all species considered, the evaluation of genetic resources is most often done on the basis of morphological and phenological traits, as these are readily observable and do not require any sophisticated equipment (Fig. 1). Exception is made for the Ulmus species, for which tolerance/susceptibility to the Dutch elm disease is adopted as a major distinctive characteristic used.

1. Morphological observations most often focus on leaves and fruits/seeds (Fig. 2). Among all phenological traits observed, flushing and flowering appear to be the most important ones (Fig. 3).

Fig. 1. Relative importance of evaluation techniques.

Relative importance of evaluation techniques.

Fig. 2. Relative importance of morphological traits.

Relative importance of morphological traits.

Fig. 3. Relative importance of phenological traits.

Relative importance of phenological traits.

Table 1. Acer pseudoplatanus

A = lamma shoots; B = buds.

Table 2. Acer campestre

A = lamma shoots; B = buds.

Table 3. Acer platanoides