The forest canopy is of critical importance for a variety of life processes in our biosphere. Defined as "the combination of all leaves, twigs, and small branches in a stand of vegetation, including the air and interstices of the foliage", elements of the forest canopy house the photosynthetic machinery of the forest, influence the exchange of energy and matter with the atmosphere, control the microclimate at various scales, and maintain habitat for wildlife. Forest canopy studies bear directly upon three of the most pressing environmental issues of the new millennium: the maintenance of biodiversity, the stability of world climate, and the sustainability of forests.

Studies from multiple scientific disciplines constitute the field of canopy research, e.g., forest ecology, meteorology, zoology, geography, and conservation biology. Recent technological applications for access to the canopy such as the "canopy raft" and the canopy crane have allowed researchers to record and interpret larger amounts of meaningful canopy data. In the last two decades, scientific interest in the canopy has burgeoned. Interdisciplinary research groups are now coalescing to approach canopy questions from different spatial scales. Heightened public interest in biodiversity, global climate change, and tropical deforestation has generated books, symposia, popular articles, and films about the canopy.

The types and amounts of canopy structure data are changing rapidly. In the past, scientists working alone with simple rope-climbing techniques generated studies that produced fairly small data sets. However, recent access innovations permit multiple teams of scientists to work within the same volume of the canopy. Canopy scientists have to deal with more data, new kinds of data, and the need to share data.

In 1993, our team of forest canopy ecologists and computer scientists received a planning grant from the National Science Foundation's (NSF) Database Activities Program. The project brought together forest canopy researchers, quantitative scientists, and computer scientists to establish methods to collect, store, display, analyze, and interpret three-dimensional (3-D) spatial data relating to forest canopies. We created a self-sustaining non-profit organization, the International Canopy Network (ICAN) to assure that network activity would continue beyond the life of the NSF grant. Over 750 forest canopy researchers from 62 countries now subscribe to the e-mail bulletin board and quarterly newsletter. Regional, national, and international meetings, workshops and symposia on canopy topics are regularly organized

We also conducted a survey of over 200+ canopy researchers and evaluated potentially applicable information models and software tools used in allied fields. We organized a multidisciplinary workshop for canopy scientists and database/computer scientists to identify important questions under study in the emerging field of canopy research and generate common ground for joint research by canopy researchers and database scientists.

The conclusions of both the survey and the workshop were that understanding forest canopy biota and processes was not limited by canopy access (as we had anticipated), but rather by two characteristics of canopy studies:

• Lack of quantitative tools that allow canopy researchers to analyze the complex three-dimensional spatial data associated with forest canopy studies
• Lack of harmonized data sets - forest canopy researchers have tended to collect data in non-comparable formats without common methods.
• Our research, software development, and communication activities address both of these issues for canopy and forest scientists.