Different variables were classified in this work keeping in mind full compatibility with FRA 2000 definitions and classifications. In the following a comparison is made between FRA 2000 and definitions used in PFDB.
Most planted forest data in references were given by countries. Especially gross areas and annual or periodic planting rates were in some countries given more exactly by regions. Only such observations were used where regions (=sub-national units, SNU) were the same as those used in FRA 2000. In many cases rotation lengths and mean annual increments were given for individual tree species or genera without any area definition. Class General was used in those cases.
FRA 2000 presented gross areas of forest plantations and annual planting rates in 2000 by eight tree species, genera or groups:
• Acacia spp.
• Eucalyptus spp.
• Hevea spp.
• Tectona grandis
• Other broadleaves
• Pinus spp.
• Other coniferous
• Unspecified
Besides those the same information was collected but not presented in FRA 2000 by five other species or genera:
• Casuarina spp.
• Dahlbergia sissoo
• Gmelina arborea
• Mahoganies
• Terminalia spp.
In PFDB tree species were recorded at the accuracy they were given in the literature on the level of one of the following:
• Tree species
• Genera
• Broadleaves
• Coniferous
• Unspecified
Latin names were used in the identification but also common names were derived if possible for each species.
The ownership of planted forests was classified in PFDB as:
• Public
• Private corporate
• Private smallholder
• Unknown
By combining Private corporate and Smallholder –classes the same classification as in FRA 2000 was derived.
The purpose of the planted forests was classified in PFDB as:
• Industrial, roundwood
• Industrial, pulpwood or fiber
• Industrial, biomass
• Industrial, not specified
• Non-industrial, fuelwood
• Non-industrial, environmental protection
• Non-industrial, recreation
• Coppice
• Unknown
By combining the four Industrial classes and three Non-industrial classes the same classification as in FRA 2000 was derived (Industrial, Non-industrial). The more exact classification was used mainly when filling the growth data into PFDB. The class Coppice was used in Mean annual increment and Rotation length data only.
Forest action classification was used when filling planting rates as:
• Afforestation
• Reforestation
• Both
• Unknown
In most cases forest land use action was not mentioned.
Reliability of planted forest data source was classified into thee levels:
• High
• Medium
• Low
The classification was the same as in FRA 2000. Usually only original sources could have highest level of reliability. If information was based on other sources within the reference used, this original source was also listed. Reliability classification was based on the subjective consideration and previous knowledge.
Reference year meant the year to which a single gross and/or net area observation was connected and included also the planting area of that particular year.
Gross area was the total planted area was the planted area as stated from official institutions (FAO 2001a) in the reference year. It could be a grand total of a country, of sub-national unit, of individual species, of genera, of purpose or of ownership. The definition of gross area was similar to that of FRA 2000.
Net area was planted area that had clearly announced to be actual existing plantation area, established successfully, estimated from plantation surveys as inventory or survival percentage (FAO 2001a). Division according to different levels was made as in Gross area. The definition of net area aimed to similar to that used in the Global Synthesis of FRA 1990 (FAO 1995a).
Planting rate was the announced area of plantings at certain period (determined with Starting and Ending years), by Forest action and was classified with the same division as Gross area. Planting rate was announced in literature at species or genera at sub-national level or for the whole country.
Starting year was the first year of announced Planting rate.
Ending year was the last year of announced Planting rate. If one year Planting rate was filled, then Starting and Ending year were the same. In many cases announced one year planting rates were combined to five year totals.
Mean annual increment (MAI, m3 ha-1 year-1) was the total volume yield including yield from thinning divided by rotation length. Theoretically, optimum rotation length of a stand growing on a certain site is determined when current annual increment (volume increment of actual year) and MAI reach the same value.
Minimum mean annual increment was the announced average or absolute minimum value for individual tree species or genera on sub-national or country level, or globally. If possible this was classified according to the purpose of planted forests.
Average mean annual increment was the announced average value for individual tree species or genera on sub-national or country level, or globally. If possible this was classified according to the Purpose of planted forests.
Maximum mean annual increment was the announced average or absolute maximum value for individual tree species or genera on sub-national or country level, or globally. If possible this was classified according to the purpose of planted forests.
Minimum rotation length of planted forests was minimum amount of years that was used in growing individual tree species or genera on sub-national or country level, or globally. If possible this was classified according to the purpose of planted forests.
Average rotation length of planted forests was the average amount of years that was used in growing individual tree species or genera on sub-national or country level, or globally. If possible this was classified according to the Purpose of planted forests.
Maximum rotation length of planted forests was maximum amount of years that was used in growing individual tree species or genera on sub-national or country level, or globally. If possible this was classified according to the Purpose of planted forests.
In some cases MAIs and rotation lengths were reported for different sites. If so, site indexes were recorded with the same classes as in original literature.
Sometimes MAIs were announced for commercial volume only. In these cases minimum diameter of commercial volume was recorded.
In some cases MAIs were announced as under bark volume. This was recognised and thus separated from over bark values.
In many cases yield experiments of planted forests were so young that they had not yet reached the rotation age. In these cases the values of MAIs were recorded as not related to rotation age. These observations can be used to evaluate the development of volume growth over age.
References were collected form different sources. The largest single collection was that used in estimating FRA 2000 gross areas and annual plantings. This collection consisted of all countries besides Europe, former CISs and North America. All relevant data related to gross areas, net areas, MAIs and rotation lengths were used. They comprised some figures for each country mostly connected to some year at 1990s, or in some cases to earlier periods.
Other sources contained FAO working papers, conference proceedings, books and other material as well as other relevant books. A literature search for MAIs and rotation lengths was made.
All the literature sources information, including country sourced documents as official documents and field reports, was stored in EndNote bibliographic reference database (ISI ResearchSoft 2000). Although the original data were stored in PFDB notes of countries, tree species and table contents info were filled in EndNote, too, for the classification purposes of the data. This enabled a quick search of literature during the process. The references used are listed by countries in Country references chapter and sources referring to particular countries in Appendix 1.
The planted forests database was designed by using Microsoft Access database program. It contains three main input tables (see figures below):
• Gross and Net Area
• Planting Rate
• Production
Besides these main input tables seven classifying tables were created according to the classifications (chapter 2.1):
• Taxa
• Forest land use action
• Ownership
• Purpose
• Reliability
• Countries and sub-national units (equal to FRA 2000)
• Reference sources
The essential base of planted forests data are the former consecutive Global Forest Resource Assessments that were stored in different FAO databases. The FRA 1980 data contained country wise gross areas of planted forests for 139 developing countries (FAO 1981a, b, c, FAO 2001a). The division into industrial/non-industrial plantations were not stored in the FRA database.
The FRA 1990 data contained net areas for 143 developing countries (FAO 1995a, FAO 2001a) based on reported gross areas and estimated reduction factors (FAO 1995b). The division into industrial/non-industrial plantations was not available in FRA databases but these figures could be derived for 102 tropical countries from FAO (1995b) for both 1980 and 1990 gross areas.
The FRA 2000 data included the gross areas of FRA forest plantations in all developing countries by eight species and genera classes and in developed countries without species specification. The division of plantations into industrial/non/industrial and into ownership classes were expressed as percentages. These percentages were derived into hectare estimates for each country, and figures were incorporated to PFDB.
Different combinations of classifying variables (species, sub-national units, ownership, purpose and forest action) are possible. For example, gross areas can be found by:
• countries without any other classification (Species to be classified as Unspecified);
• countries and by tree species;
• sub-national units;
• countries, by species and by sub-national units;
• countries and by ownership;
• countries, by species and by ownership;
• countries and by purpose; or
• countries, by species and by purpose.
The same classification rules were used for planting rates, too. In addition, division of afforestation/reforestation was given in some cases.
Area information (Gross area, net area, planting rate) were always connected to a specific country. In many countries gross area estimates for individual tree species or genera were obtained from different sources. The combination and checking of different information was made by using Reference year and Reference identification number as qualifiers. MAIs and rotation lengths were sometimes given for individual tree species of genera without any country specification. In those cases “Country” was determined as General.
