Journal of Food, Agriculture and Environment

Thinning scenarios for Gmelina arborea plantations in south-western Nigeria using density management diagrams

Author(s):

Jonathan C. Onyekwelu ¹, Peter Biber ², Bernd Stimm ³

Recieved Date: 2003-01-16, Accepted Date: 2003-04-12

Abstract:

Thinning scenarios were developed for Gmelina arborea plantations in south-western Nigeria using density management diagram. Data were collected from even- aged plantations of 5 to 25 years. The youngest stand had well-developed crown canopies, indicating that canopy closure occurred at a younger age. Density (number of trees ha^-1) decreased with increase in tree size. Density management diagram, with upper and lower growing stock lines, was developed. With references to these lines, three thinning scenarios A (no-thinning), B (moderate thinning) and C (heavy thinning) were developed. At the end of 20 years rotation, volume production under scenarios A, B and C would be 1050.3, 784.2 and 751.7 m³ha^-1, respectively while mean diameter would be 29.8, 49.6 and 47.0cm, respectively. This result indicates that Gmelina would react strongly to thinning by way of diameter increase, which only applies if thinning commences at early ages. Net present value (NPV) at interest rates between 5 and 8% revealed scenarios B and C to be similar but superior to scenario A. Only scenarios B and C are judged for appropriate for timber production.

Keywords:

Gmelina arborea, plantation, density management diagram, scenario, thinning, density, net present value

---

Journal: Journal of Food, Agriculture and Environment
Year: 2003
Volume: 1
Issue: 2
Category: Environment
Pages: 320-325

---

Full text for Subscribers

---

Information:

Note to users

The requested document is freely available only to subscribers/registered users with an online subscription to the Journal of Food, Agriculture & Environment. If you have set up a personal subscription to this title please enter your user name and password. All abstracts are available for free.

Article purchasing

If you like to purchase this specific document such as article, review or this journal issue, contact us. Specify the title of the article or review, issue, number, volume and date of the publication. Software and compilation, Science & Technology, all rights reserved. Your use of this website details or service is governed by terms of use. Authors are invited to check from time to time news or information.

---

Purchase this Article:   20 Purchase PDF Order Reprints for 15

---

Share this article :