The Diaries series is divided into two main subsections: daily diaries and travel diaries. The daily diaries record daily events and appointments, as well as notes on daily accomplishments and weather conditions. The travel diaries record Bruce and Barbara Zobel's trips throughout the United States and abroad doing forest consulting. Some of these trips were taken to attend the Wallenberg Prize meetings in Sweden, and many others were taken to do forestry work, many while consulting as part of Zobel Forestry Associates. The diaries are mainly arranged according to country; however, some are arranged according to the name of the corporation for whom Zobel consulted. Barbara Zobel prepared most of the diaries, which recorded not only their work but also the social and geographical conditions of the areas they visited.

In addition to the diaries, the Zobels prepared summaries, which include: (A) General Comments About the Area, (B) Exciting and/or Dangerous Situations, (C) Travel, (D) Social Situations, Including Hospitality, (E) Forest Management and Utilization and Scientific Activities, (F) Governmental Operations and Actions, (G) Visits with Historical Importance, (H) Special People Encountered As Colleagues or Friends, and (I) Special Visits. The summaries for each country immediately follow the corresponding travel diaries.

Additions were incorporated into this series in 2007.

The Correspondence series begins with correspondence between Bruce Zobel and Gunnar Nicholson, the well-known Swedish forester. Much of this correspondence is undated. The rest of the series contains general correspondence. Topics include research, meetings, letters between Zobel and North Carolina State University, invitations, correspondence with clients, and issues of forestry.

Additions were incorporated into this series in 2007.

The Speeches and Presentations Series includes the text of addresses made by Bruce Zobel throughout his career. Much of the series consists of correspondence, programs, and other materials related to the events at which Zobel spoke. Frequent topics include genetics, forest tree improvement, conservation, and wood utilization. Zobel made these addresses during lectures at other universities and at Society of American Foresters meetings, among others. The series is arranged chronologically.

Additions were incorporated into this series in 2007.

The Biographical Information and Awards series details major events and awards in Bruce Zobel's life. The series begins with Bruce Zobel's autobiography, a detailed account of his life and career. Zobel has also evaluated his own "background and characteristics" to see how aspects of his personality have influenced the course of his life. Also included are news articles about Zobel from the 1950s to the 1990s.

The series continues with materials such as diplomas, course outlines, and homework related from Zobel's education from elementary school onward. Included are some course work completed in his undergraduate career, as well as his Ph.D. dissertation. The series also includes many of the tributes Zobel received throughout his career. Materials include certificates, nomination documents, and letters of congratulations. (Researchers who are interested in Zobel's awards and prizes should also look in the Artifacts series, where many of the plaques and other oversized honors are stored.)

Additions were incorporated into this series in 2007.

This series contains publications written by Zobel. The first subseries, Books, does not actually contain Zobel's published books, but book contracts and correspondence with his publisher. The Publications subseries contains a "Publications Index," a list of Zobel's articles, which has been annotated by Zobel. All of the publications available in full text in the collection are marked with a red X on the Publications Index. The articles are arranged chronologically.

Additions were incorporated into this series in 2007.

The Professional Activities series contains materials related to Bruce Zobel's career, and is arranged roughly chronologically, according to the organization with which Zobel worked. Zobel worked on a number of tree improvement projects, and materials from these projects include correspondence, reports, newsletters, studies, and other materials.

Additions were incorporated into this series in 2007.