Jochen Kleinschmit¹, B. Richard Stephan², Fulvio Ducci³, Peter Rotach⁴ and Csaba Mátyás⁵

1. Niedersächsische Forstliche Versuchsanstalt, Abteilung Forstpflanzenzüchtung, Staufenberg-Escherode, Germany

2. Bundesforschungsanstalt für Forst- und Holzwirtschaft, Institut für Forstgenetik und Forstpflanzenzüchtung, Grosshansdorf, Germany

3. Istituto Sperimentale per la Selvicoltura, Arezzo, Italy

4. Professur für Waldbau, Abt. für Forstwirtschaft, ETH, Zürich, Switzerland

5. Department of Environmental Sciences, Sopron University, Sopron, Hungary

Forest inventories usually cover principal timber species, but they contain no or only scarce information concerning rare species. Most of the Noble Hardwoods belong to this group. They are scattered, and even at the local level, knowledge about the occurrence of the species is often missing. The knowledge of the present range of natural distribution is based more or less on random information. It is often better for state forest land than for private ownership. However, since the state forests usually have been managed intensively owing to the prevailing management rules which concentrated on economically important principal tree species, the habitats for rare species were more reduced than on most of the small, privately owned lands.

The knowledge of the present range of distribution and status of most of the rare Noble Hardwoods is based on general botanical knowledge, sometimes accompanied by local, more intensive studies, and on the individual knowledge of particularly interested foresters. In the following chapters the inventory requirements for these species will be discussed. We are aware that the situation is quite different from one country to another. Therefore we will concentrate more on the basic principles and procedures which have to be followed for inventories, depending on the degree of precision desired.

It is very important to differentiate the approach to inventories according to the frequency of a species' occurrence. For very rare species, every tree above a certain dbh (e.g. > 10 cm) has to be recorded, for more frequent species it may be regularly populations. However even in those species outstanding individuals should be registered. A minimum population size should be at least 20 individuals in reproductive age forming a mating unit.

The rarity of a species depends on its geographic range, its habitat specificity and its local population size. Several forms of rarity or frequency, respectively, can be distinguished according to Rabinowitz (1981) and Rabinowitz et al. (1986). The status of some tree species in Switzerland regarding their respective form of rarity is given as example in Table 1.

The lack of information is a limitation for conservation planning as well as for the use of a species. Data sources can be found from:

• literature

• forest inventories

• plant geographic information systems and maps

• habitat mapping

• files of forest tree breeding organizations

• files of nature protection organizations

• experience of local experts and foresters.

Table 1. Forms of rarity of some tree species in Switzerland

Since these sources do not give complete information, they have to be supplemented by inquiries and local inventories.

The inquiries, addressing foresters, forest owners, farmers and nature protection organizations, will give some additional information. They have, however, the weakness of depending on the local interest, the knowledge and the time of the addressed person.

Local inventories in cooperation with experienced local people give the most complete information. They are time-consuming and expensive. Combined procedures are possible and they allow concentration of efforts on the most promising points. However, even this information will not be complete for a larger area.

The most relevant information is location, health and threats, population structure including size of a stand or number of individuals, and genetic structure.

The aim is to identify locally the occurrence of the respective species, to register the site conditions (e.g. structure, profile and reaction of soil), ecological data (e.g. composition at shrub and herbaceous levels), the ownership, the possibilities for protection, and to code this information for an information system, which later on allows control and evaluation of the inventory results.

The geographical coordinates (latitude, longitude, Gauss-Krueger coordinates with seven digits, elevation above sea level) have to be as precise as possible. Global positioning systems (GPS) are an excellent support to locate and re-identify the position.

The area of the respective population or individual trees should be drawn on a map.

Climatic data (e.g. mean temperature, mean precipitation and their monthly distribution, snow cover) are important ecological information.

Descriptions of the type of location (field, forest, protected area) and ownership (public or private) are important and facilitate determining the possibility of in situ conservation. An identification code has to identify the specific object clearly, to prevent duplication and to enter all relevant information into an information system.

The Lower Saxony Forest Research Institute, Department of Forest Tree Breeding Escherode (Germany), uses an 11-digit code (see Annexes):

• digits 1 to 3 for tree species identification

• digits 4 and 5 for year of first registration

• digits 6 to 8 are current numbers for a stand within the year

• digits 9 to 11 are current numbers for single trees within the year.

It would be desirable to agree on a minimum common identification code for the Noble Hardwoods Network.

The vitality of a particular unit is relevant for conservation decisions. The following information is necessary and should be registered.

• Diseases or attacks by fungi, insects, etc. The periodic epidemics of insects or other organisms can be decisive for the health of a tree population. Recording historical information about this aspect is important.

• Damage by deer, especially in natural regeneration.

• Site degradation (drainage, soil erosion, emissions).

• Adaptation to local environment (to be judged by vitality).

• Plantations of hybridizing species or cultivars in the vicinity. Their presence can be a limiting factor and can affect the survival of a pure species population and its further evolution.

• Competition by other species.

• Logging operations (e.g. clear-cutting might eliminate a population).

This includes the botanical identification, the size of the population (stand = more than 20 individuals in reproductive age within pollination distance thus forming a mating unit), the structure (pure stand, mosaic or single tree mixture in mixed stands, even-aged or uneven-aged stands, or populations outside of forests) and the regeneration status of the species. The maximum distance between individual trees depends on the pollination vector. The frequency of occurrence at local and regional levels, the occurrence of varieties or hybrid forms (especially the occurrence of hybrids between closely related species) and the potential for seed collecting (including stand quality) are relevant information. Additional information about: origin, stand history (old forest site, stand type), silvicultural status (competition, survival without human interference, thinning methods), type of regeneration (generative or vegetative), and dendrometric characters (height, diameter, length of trunk, form) can be important and should be registered.

All the information described above can be collected locally. Information on the genetic structure needs additional efforts with field testing, laboratory work, etc. Relevant information includes morphological, phenological, biochemical or molecular genetic (isoenzymes, DNA) traits.

Introgression between species or cultivars, which is important in Noble Hardwoods, can be judged from morphological traits only, if the material is grown ex situ under equal experimental conditions.

This type of species inventory has a precondition that at least a rough knowledge of the local occurrence of a species is available. It is, however, an important condition for well-founded gene conservation planning.

The genetic structure of Noble Hardwoods populations can change according to ecological succession. Therefore, phyto-ecological traits or other indicators can be useful in order to define different situations, e.g. regarding subspecies, varieties, races, etc.

A good inventory is the basis for the knowledge about species in a region. It has been shown that in particular the knowledge of local people (e.g. foresters, forest owners, nature conservationists) can contribute significantly to the inventory. Personal contact can create and promote interest in activities to conserve these species. A part of this work has to be formalized to obtain comparable results. In Annexes 1 and 2 the inventory sheets of the Lower Saxony Forest Research Institute, Department of Forest Tree Breeding are given as an example for such a formalization. This may serve as standardized information which can be directly entered into a database.

The main problems for wide application are time and money. If we take the resolution of the Rio Conference and the European Ministerial Conferences in Strasbourg, Helsinki and Lisbon seriously, we have to invest time and money. Noble Hardwoods are important components of mixed hardwood forests, their regular management can increase the biodiversity of forests and the economic return from these forests as well. The best conservation of these species is their regular, sustainable use in forest management. To be able to do this, we require reliable inventory data. Therefore, more efforts are necessary to obtain these data.

Rabinowitz, D. 1981. Seven forms of rarity. Pp. 205-217 in The Biological Aspects of Rare Plant Conservation (H. Synge, ed.). Wiley, New York.

Rabinowitz, D., S. Cairns and T. Dillon. 1986. Seven forms of rarity and their frequency in the flora of British Isles. Pp. 182-204 in Conservation Biology: the Science of Scarcity and Diversity (M.E. Soulé, ed.). Sinauer, Sunderland.