DOI: 10.5063/aa/nceas.155.5
title: Productivity of forest ecosystems studied during the International Biological Programme (IBP): the woodlands data set

description: The IBP (International Biological Programme) Woodlands Data Set consists of contributions from 117 international forest research sites, all but a few associated with projects committed to the IBP. The data were collected in the 1960s and early 1970s and compiled into a single data set at the Oak Ridge National Laboratory to facilitate comparisons involving the diverse woodland ecosystems. The data set was originally published in DeAngelis et al. (1981) and was extracted from that reference to be presented here. Representatives of almost every kind of forest ecosystem are present in the data set (Burgess, 1981). A hierarchical scheme was used to assign a forest type to each site based on the climate, life-form, behavior, and status features of the site. Included are sites of the following types, with the number of each type in parentheses: Tropical (26), Mediterranean (3), Temperate (55), and Boreal (33). With respect to life-form, 72 sites were dominated by broad-leaved species and 45 were needle-leaved. There were 65 deciduous stands and 52 evergreen. Finally 89 sites consisted of natural forest and 28 were managed. Overall, the sites were classified as mediterranean broad-leaved evergreen (1), mediterranean broad-leaved deciduous (2), tropical broad-leaved evergreen (4), tropical broad-leaved deciduous (4), tropical broad-leaved deciduous plantation (18), temperate broad-leaved evergreen (1), temperate needle-leaved deciduous plantation (1), temperate needle-leaved evergreen (7), temperate needle-leaved evergreen plantation (2), temperate broad-leaved evergreen plantation (2), temperate broad-leaved deciduous (43), boreal needle-leaved evergreen (27), and boreal needle-leaved evergreen plantation (5). As published, the data for each site were organized into three general parts. The first part identified the investigator(s), selected citations, years of the study, forest type, soil and geology types, and principal plant types. The second part consisted of general site description data, including edaphic characteristics, average meteorological conditions, and basic descriptive and quantitative data on the vegetation. In the last part, data for up to 38 biomass compartments are presented. Tables present the measured amounts and increments in these compartments, as well as the fluxes between them. Disclaimers: The projects submitting data to the Woodlands Data Set were diverse, both internationally and in the scope and emphasis of their research. Because of this, the data did not always conform easily to the uniform format in which it is presented here. According to the compilers (DeAngelis et al. 1981); "Repeated communications with members of various projects were often employed before deciding on appropriate values. We have tried to follow faithfully the wishes of the projects in this regard." The meteorological and climatological measurements in the 'general site descriptions' in some cases represent values averaged over many years, and in other cases are values only for the years during which biomass measurements were made. In some cases the meteorological measurements were made directly at the site, while in other cases they were made at nearby stations. Lack of precise and generally agreed upon definitions is evident with respect to some quantities. Because of the variety of data forms submitted, with different compartmentalizations of the soil layers, values of the various soil compartments are not always consistent from site to site, Occasionally discrepancies occur between values which are listed as 'sums' of two or more compartments and the actual values in those compartments. The same holds true for net annual productivity; the value given for this is not always equal to the sum of fluxes and increments (see definitions above): Often, the reason for this is that the researchers have used their own insight to take into consideration other factors such as consumption, which could not be directly measured and, therefore, were not given in the biomass data. Rigorous comparisons among sites are complicated because of the above data constraints and because for each site there many be additional highly pertinent facts which could not be included in the data summaries. Those users of the data wishing to pursue similar analyses may find it useful to consult the literature publications relevant to each site, which are cited in the general site descriptions.