Tree Growth Response of Pinus oocarpa Along Different Altitude in Dedza Mountain Forest Plantation

摘要

Understanding of the effects of altitude on tree growth is central to forest management, especially in the establishment of seed source stands. A study was conducted to investigate the effect of altitude on the growth height, diameter at breast height (dbh) and volume of Pinus oocarpa in Malawi. Stands of Pinus oocarpa at the altitude of 1500m, 1700m and 1900m above the sea level (asl) were measured for total height, dbh and volume at the age of 18 years. Data obtained were subjected to analysis of variance. The results shows that there were significant (P<0.001) differences in total mean height, dbh and volume among the different altitudes. Higher mean height (19.2m), dbh (24.5cm) and volume (0.417m~3) was observed at 1500m asl, while total mean height, dbh and volume at 1700m asl and 1900m asl were 17.1m, 22.9cm, 0.322m~3 and 15.4m, 20.8cm, 0.243m~3 respectively. Total mean height, dbh and volume decreased with an increase of altitude. This was attributed to differences in supply of soil nutrients and specific leaf area. It is therefore, recommended that seed sources stands for Pinus oocarpa in Malawi and the surrounding countries should be established at 1500m to 1600m above the sea level for better genetic growth parameters.