Growth and Yield Estimation of the Stand of Cupressus lusitanica

Abstract

Cupressus lusitanica was introduced to Ethiopia before 1950 (Pukkala and Pohjonen, 1993; Negash et. al, 1995) and it has been planted in different parts o f the country through reforestation programs. Munesa Shashemene forest is among the plantation where this species has been planted widely as timber tree. Currently, it accounts for 61.67% of the total plantation area o f 6101 ha. Cupressus is the most important and fast growing exotic tree species in Ethiopia, suitable for construction and making of furniture, doors, windows etc (Web etal. 1984). Availability of growth and yield models is among the important forest management tools that give required information for planning. Predicting future growth and yield of plantations is absolutely essential in forest management. Adequate documented empirical models or yield tables of exotic as well indigenous species that help to estimate growth and yield o f plantation forests o f the country are lacking. As a result, foresters frequently try to make best guess and subjective estimates of growth and yield or use models of neighbouring countries. Therefore, this manual is meant to give insight on the basic concepts and definition of growth and yield and then look at the meaning and measurement o f growth in the context of plantation forest managed under even-aged silvicultural system at Munesa Shashemene. Stand growth is a change in a stand attributes such as volume, and basal area, over some specified time. Yield is the amount of wood that can be harvested and removed per period or the total amount of wood that could be removed at any time. Growth and yield can be explained in physical units such as volume (m 3 /ha) and basal area (m 2/ha). Naturally, trees accumulate growth over many years. Woody growth occurs in branches diameter, height, and roots. Commonly only the bole to some merchantable top is removed from the forest. The models presented in this manual give the quantitative relationship between measured growth characters, which are helpful to predict quadratic mean diameter, total height, tree volume, growth, and yield o f C. lusitanica stands growing at Munesa Shashemene. getting replies to question like: where, how much, and when to cut. These permit managers to understand the present and future status of the plantation and to make decision based on predicted yield. Therefore, models as well as yield tables presented in this manual helps for management planning o f C. lusitanica growing at Munesa Shashemene and could be used to estimate growth o f C. lusitanica growing in other similar agro ecology.