1.08.00 - Silviculture for production of edible fruits
The Research Group on Silviculture for production of edible fruits is a group of researchers working on various aspects of silviculture where a main objective from the work carried out is to focus on the reproductive growth from trees. It has many linkages to other Research Groups in other Divisions.
State of Knowledge
Although the interest in forest edible fruits is even older than agriculture, since Palaeolithic times, forest management has been overwhelmingly targeted towards wood products. Currently there is a clear recognition, however, of the importance of non-forest products and ecosystem services from forests and concepts such as multiple-purpose forestry. In this context, there is an increasing interest in the silviculture for production of edible fruits which has to take into account operations that favour floral induction, enlargement of the inflorescence, flowering, pollination, fertilization and growth and ripening of fruits:
- Choosing appropriate genotypes for fruit production, possibly combined with timber production;
- Initial spacing and subsequent thinning can be vital for increasing seed production;
- Thinning criteria needs to incorporate information about tree fruit production;
- Pruning might be important to favour fruit production;
- When fruit production is the main objective special operations such as grafting might be considered;
- Fertilization might be important for fruit production;
Some trees have a fairly regular reproductive growth, so with a regular fruit production whereas others have a synchronous production of seed at long intervals concentrating their fruit production in masting years.
Two main groups of forest trees can be identified depending if they produce seeds enclosed in an ovary, Angiosperms, or if seeds are not included in an ovary, Gymnosperms.
Examples of forest tree Angiosperms from the temperate zone with interest for fruit or combined fruit and timber production are common walnut (Juglans regia), chestnut (Castanea sativa), wild service tree (Sorbus torminalis) and true service tree (Sorbus domestica). Common walnut many qualities that favour it as a valuable broadleaved tree including its rapid growth, the high value of its timber as well as its fruits, so numerous varieties have been selected for their fruit production. Walnuts planted in mixed stands, particularly with nitrogen-fixing species benefit from increased growth rates and improvement of tree form, combined with protection from frost damage and reduced weed competition. Cultivation of chestnut has traditionally been and important food source for rural populations. Chestnuts were cultivated for both fruit and timber production. Sorbus fruits are often used only locally (brandy and food), but probably possess a substantial potential for use in medicine.
As an example of forest tree Gymnosperms there are the Mediterranean stone pine (Pinus pinea) forests or plantations where silviculture is being carried out for the production of the pine cones and their seeds, the edible Mediterranean pine nuts or pignoli, a health and gourmet food. Around the Mediterranean sea, there are currently about 0.7 million hectares of stone pine-dominated forests, sparsely scattered from the Atlantic coast in Portugal to the shores of the Black Sea and Mount Lebanon. In recent decades, the planted area of stone pine has increased considerably throughout the Mediterranean, as well as a starting cultivation in Chile, Argentina, Australia and New Zealand, owing to the income anticipated by landowners based on the high prices paid for cones. Efforts are made to select best-performing clones in each agro-climatic zone for stone pine as a grafted orchard crop. The development of forestry, agroforestry, and orchard management guidelines are matter of ongoing research.
Similar to Mediterranean stone pine, there are other pine species with edible seeds, many of them with special implications for ethnobotany, cultural heritage and also a high potential for rural development based on local bio-resources. Some have great relevance on the world markets, especially the Chinese pine (P. koraiensis), the Chilgoza or Pakistani pine (P. gerardiana), the red cedar or Siberian pine (P. sibirica), as well as the American pinyons around the Great Basin and in Mexico (group P. cembroides, edulis, and others). These different pine nut species have very different tastes, dietary values, and processing qualities, thus they are, and must be recognised as different products, as issue of consumers' rights and food security. In the southern hemisphere there are also several Araucaria species with edible fruits, some of which are of major, but generally local importance.