SURVIVAL AND GROWTH OF MAHOGANY SEEDLINGS UNDER A NURSE CROP WITH DIFFERENT CANOPY OPENINGS

Abstract

Swieicnia nuurophvl!« King is one of thc luxury class timbers of thc world, The survivaland growth of S, ntarcrophvlla when planted under the nurse crop, Atacia auriculifonniswith different canopy openings was determined. The study was carried out in a 9 year oldAcaci« plantation established by the Forest Department on a degraded. hilly land atNauiyapana ill Kcg.illc. Two experimental blocks (replicates) about I km apart wereselected for the study. In each block 3 plots (.'ix5 m) were selected on the basis or canopyopenings (open. moderate, closed) hy removal of trees and branches. Within each plot IXmahogany seedlings were planted. The photosynthetically active radiation at each canopyopening was measured using a data logger with PAR light sensors. The mean survivallevel of seedlings was found to be X3% (open gap-6FJ,; PAR). l)7'/r; (moderate gap-43%PAR) and 94% (closed gap- 24'!i; PAR). Height of seedlings measured monthly indicatedan increase in height with high light intensity. Similarly. the root collar diametermeasured 9 months after planting varied from 1.2 em (open canopy). O.9R em (moderatecanopy) to n,71 em (closed canopy). The mean number of leaves per plant under opencanopy was 15. and II under moderate and closed canopy. Data obtained so tnr indicatethat survival is low under open canopy with high light intensity, while growth is betterunder open canopy inferring that shade is important only during the initial establishmentphase of seedlings and not thereafter. However. there arc reports of high damage by themahogany shoot borer (/l\'jJsifi.\'/a roIJ/l.\'IO Moore) when grown in the open.