Answer: Videos of the Green Belt Movement

It does not look promising for buying or renting films, unless you have time to feally plow through dozens or more likely hundreds of web sites, in search of practical sources to borrow or rent.

A few libraries DO have what may be what you are after, judging from a Worldcat search of keywords: "green belt movement" restricted to "visual materials":

1.
Title: Africa, search for common ground program 12 /
Author(s): Matshikiza, John. ; Deull, Jonathan S. ; Kaplan, Mark J. ; Good, Nic. ; Bensusan, Anthony. ; Ghetahun Teame. ; Brehane Tesfaye. ; Mutshekwane, Gloria. ; Hofmeyr, Nicolaas. ; Njoroge, Andrew. ; Edwards, Lee,; film sound engineer. ; Matsunyane, Kgomotso. ; Kobus, Kwezi.
Corp Author(s): Common Ground Productions. ; Ubuntu Television and Film. ; Media Peace Centre.
Publication: [Cape Town, South Africa] :; Common Ground Productions, 1997
Description: 1 videocassette (25 min.) :; sd., col. ;; 1/2 in.
Language: English; In English and various languages, with English translations and voiceovers.
Abstract: Part of a series profiling formal efforts by various Sub-Saharan African countries to peacefully resolve contemporary conflicts. The first film highlights the wartime experiences of women in one Eritrean family in Asmara and the issue of women's rights in an independent Eritrea. The second film profiles Wangari Maathai and the Green Belt movement, a tree-planting campaign organized by women in Kenya. Maathai's place in Kenyan opposition politics is emphasized.
Contents: Eritrea, three generations of women, three generations of struggle / director, Mark J. Kaplan ; associate producers, Ghetahun Teame, Brehane Tesfaye ; camera, Nic Good ; sound recording, Tony Bensusan ; narration Gloria Mutshekwane -- Kenya, entering the politicians den / director, Nicolass Hofmeyr ; camera, Nicolass Hofmeyr, Andrew Njoroge ; sound, Lee Edwards ; associate producer, Kgomotso Matsunyane ; narration, Kwezi Kobus.
SUBJECT(S)
Descriptor: Democracy -- Africa, Eastern.
Women's rights -- Eritrea.
Women in development -- Kenya.
Named Person: Maathai, Wangari.
Named Corp: Green Belt Movement (Society : Kenya)
Geographic: Eritrea -- History -- Revolution, 1962-1993.
Eritrea -- Politics and government -- 1993-
Kenya -- Politics and government -- 1978-2002.
System Info: VHS format. Note(s): Originally produced as a television program./ Participants: Host, John Matshikiza.
Class Descriptors: LC: JQ2945.A91
Other Titles: Africa: search for common ground; Subtitle from cassette label:; Kenya: Democracy or disruption : Wangari Maathai and Greenbelt; Wangari Maathai and Greenbelt; Eritrea: three generations of women, three generations of struggle.; Kenya: entering the politicians den.
Responsibility: a production of Common Ground Productions, Ubuntu Television and Film, The Media Peace Centre ; series producers, Jonathan S. Deull, Mark J. Kaplan.
Material Type: Videorecording (vid); Videocassette (vca); VHS tape (vhs)
Entry:19980327 Update: 20050618
Accession No: OCLC: 40685263
Database: WorldCat
Libraries worldwide that own item: 3
IL NORTHWESTERN UNIV INU
NY SAINT LAWRENCE UNIV XLM
WA UNIV OF WASHINGTON LIBR WAU

2.
Title: Women at work
Corp Author(s): Green Belt Movement (Society : Kenya) ; Belbo Productions. ; Television Trust for the Environment.
Publication: [London?] :; Television Trust for the Environment, 1990s
Description: 1 videocassette (051 min.) :; sd., col, ;; 1/2 in. Language: English
Abstract: The Kenyan Green Belt Movement, started by activist Wangari Maathai, is helping African women to protect their environment by growing trees and in the process improving their standard of living and their status.
SUBJECT(S)
Descriptor: Tree planting -- Kenya.
Conservation of natural resources -- Kenya.
Rural development projects -- Kenya.
Rural development -- Kenya -- Citizen participation.
Women -- Kenya.
Women in development -- Kenya.
Documentary films.
Named Corp: Green Belt Movement (Society : Kenya)
System Info: PAL format.
Responsibility: produced by Belbo Productions.
Material Type: Videorecording (vid); PAL (pal); Videocassette (vca); VHS tape (vhs)
Document Type: Visual Material
Entry: 19960912 Update: 19980528
Accession No: OCLC: 35525285
Database: WorldCat
Libraries worldwide that own item: 3
FL UNIV OF FLORIDA FUG
VT UNIV OF VERMONT, BAILEY LIBR VTU
BC UNIV OF BRITISH COLUMBIA LIBR UBC

3.
Title: Women at work a film /
Author(s): Van Run, Godfried. ; Winter, Steven de.
Corp Author(s): Green Belt Movement (Society : Kenya)
Publication: [Amsterdam] :; Belbo Films,; Vancouver :; Idera Films [distributor]
Edition: English version. 1989 Language: English
Abstract: Describing the village life in Machakos District, a semi desert area in Kenya, where women do most of the work. The "Green Belt Movement" is currently working on a project to get the women to plant trees in the area to improve the environment while deforestation is continued by men in the northern part of the country.
SUBJECT(S)
Descriptor: Forests and forestry -- Kenya.
System Info: VHS. Note(s): Title on container label: Woman at work./ With English subtitles.
Other Titles: Woman at work.
Responsibility: by Steven de Winter. Production and research: Godfried Van Run ; directed by Steven de Winter.
Material Type: Videorecording (vid); Videocassette (vca); VHS tape (vhs)
Document Type: Visual Material
Entry: 19940425 Update: 20040308
Accession No: OCLC: 30424400
Database: WorldCat
Libraries worldwide that own item: 1
OH OHIO UNIV OUN

4.
Title: Women at work
Author(s): Winter, Steven de Corp Author(s): Green Belt Movement (Society : Kenya) ; Belbo Film Productions. ; Media for Development Trust (Organization) .Publication: [S.l.] :; Belbo Film Productions ;; Harare, Zimbabwe :; Distributed by Media for Development Trust, 1989
Description: 1 videocassette (ca. 51 min.) :; sd., col. ;; 1/2 in.
Language: English; In English and Swahili (?) with English subtitles.
Abstract: Efforts of the Kenyan Green Belt Movement, an organization that helps women learn to farm trees in order to earn money as well as improve their status in society.
SUBJECT(S)
Descriptor: Women farmers -- Kenya.
Women in rural development -- Kenya.
Leadership in women -- Kenya.
Women -- Kenya -- Social conditions.
Documentary films.
System Info: VHS. Class Descriptors: LC: HQ1787
Responsibility: Belbo Films presents; a film by Steven de Winter. Director, Steven de Winter.
Material Type: Videorecording (vid); Videocassette (vca); VHS tape (vhs)
Document Type: Visual Material
Entry: 20051012 Update: 20051012
Accession No: OCLC: 62035177
Database: WorldCat

Google.com search: "Africa, search for common ground program 12" gets 8 hits but all seem to be talking about use of it only on site at Columbia University or other colleges, by students, etc.

Google search: "women at work" "green belt movement" is possibly more promising, if you want to rent or buy the video. http://omgsic.com/traditional_women.htm has "Women at Work" in a list of films, and has a "Request a Quote" link at the top. But even searches like: "women at work" "belbo productions" seem to get mostly lists, not sources to order or rent.

But I am having a lot of trouble finding more than 1 potential source (omgsic.com) to buy or rent these — it may well be that the only surviving copies are at a few libraries (See Worldcat printouts at top of this message)

Do these films from Worldcat even seem like what you are after?