Determination of Growth Rate and Age Structure of Boswellia papyrifera from Tree Ring Analysis: Implications for Sustainable Harvest Scheduling
Abstract
Boswellia papyrifera is a multipurpose deciduous species that grows in Combretum – Terminalia deciduous woodlands of Ethiopia. It is widely known for its commercial frankincense production. The B. papyrifera woodland is under a problematic state of population decline due to heavy encroachment and unsustainable tapping. To sustainably manage such a sensitive ecosystem needs exact knowledge of growth rates and age structure of trees where such information on tropical trees under natural condition is rather poor. In this study growth rate and age of B. papyrifera was determined from tree ring analysis. The study was carried out in Lemlem Terara, Metema district, Ethiopia. The mean annual diameter growth rate of B. papyrifera derived from the mean ring-width is 2.32mm and varies among sample trees. All sampled trees showed a comparable general growth trend which can be divided into three phases – i) good growth in the beginning, ii) phase with depression in middle and iii) increase in ring width. The average age of B. papyrifera trees growing in the study site is estimated to be about 75 years. Although there is strong correlation between diameter of a tree and age, the result from this study highlighted that age-size relations should be used cautiously as the diameter may not reflect the true age. The result from this study is important input to develop strategic plan for the species regarding tapping frequency and intensity as per the annual increment of the species. For further dendrochronological studies of the species, it is recommended to take samples from different size classes and slope gradients for better and reliable results. In future, the use of tree ring analysis as a tool to understand growth dynamics and age structure of trees species, and their response to climate variability should be strengthen in Ethiopian.
Keywords: Boswellia papyrifera, Annual growth rings, Diameter growth rate, Age structure, Ethiopia.
The Momona Ethiopian Journal of Science accepts the manuscripts for consideration with the understanding that the manuscript has not been published and is not under consideration for publication elsewhere. Only original articles will be considered for publication if they have been published previously as abstracts, but not if they have been published previously as extended abstract (>1000 words). This applies to both electronic and print versions of the journal. The authors should assign copyright ownership to the Editorial Office of MEJS in the event that the manuscript is accepted for publication in the Momona Ethiopian Journal of Science. All accepted manuscripts must be accompanied by a copyright statement signed by all authors. A copy of the copyright form will be supplied along with the final reviewed version of the manuscript that is sent for final proof- reading. Authors may make multiple copies of the form if necessary and send to the Editorial Office with author’s signature(s) even individually.
All articles published by Momona Ethiopian Journal of Science (MEJS) are Open Access under the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0). Under this license, authors retain ownership of the copyright for their content, and anyone can copy, distribute, or reuse articles as long as the author and original source are properly cited. In all these cases for re-use, the authors will be given proper credit to the original publication in MEJS.