We wish to thank Dr. Le Xuan Canh (Director, Institute of Ecology and Biological Resources, Hanoi), the director and staff of the following National Parks and Nature Reserves, and the authorities concerned for their kind arrangement of official permissions and provision of every facilities for our field surveys: Ba Be NP (Bac Can Province), Ba Na NP (Da Nang), Ba Vi NP (Ha Tay), Bac Ma NP (Hue), Bai Tu Long NP (Quang Ninh), Binh Chau-Phuoc Buu NP (Ba Ria-Vung Tau), Cat Ba NP (Hai Phong), Chua Yen Tu (Quang Ninh), Cuc Phuong NP (Ninh Binh), Ha Giang (Ha Giang), Hanoi (Hanoi), Ha Tay (Ha Tay), Hoang Lien Son NR (Sa Pa and Van Ban Districts, Lao Cai), Huong Son (Ha Tinh), Huu Lien NR (Lang Son), Kim Hy NR (Bac Can), Ky Thuong NR (Quang Ninh), Mai Chau (Hoa Binh), My Yen (Thai Nguyen), Moc Chau (Son La), Nui Chua NP (Ninh Thuan), Nui Ong NR (Binh Thuan), Phong Dien NR (Hue), Phu Quoc NP (Kien Giang), Pu Hoat NR (Nghe An), Pu Mat NP (Nghe An), S. Cat Tien NP (Dong Nai), Tam Dao NP (Vinh Phuc), Thanh Hoa (Thanh Hoa), Tuyen Quang (Tuyen Quang), W. Yen Tu NP (Bac Giang).

We are also thankful to Prof. Seiki Yamane (Kagoshima Univ., Japan), Prof. Kazuo Ogata (Kyushu Univ., Japan) and Dr. Hirofumi Okido (Fukuoka, Japan) who provide us valuable materials and useful comments and suggestions.

Foresters at the remote stations and people in local villages always welcome us and provide facilities for our successful and happy days. All of them are indispensable contributors to our project and our friends. Eguchi also wish to thank friends working along the "Hoang Quoc Viet" road, Hanoi.

Eguchi's research activities were supported by the Research Fellowships of the Japan Society for the Promotion of Science for Young Scientists. Viet's research activities were supported by the Basic Research in Life Science Programme of Vietnam.