Effect of coppicing cycle and season on stock volume and new sprouting of Eucalyptus globulus plantations in the northern Ethiopian highlands

Ethiopian farmers have long practised coppicing to maximise the yield of Eucalyptus globulus Labill., yet the response of different coppicing cycles on productivity and sprouting of new shoots has not been recorded or evaluated scientifically. To address this gap, a randomised complete block design was applied, incorporating two harvesting seasons (November and March) and four coppicing cycles (not coppiced/planted, first coppicing, second coppicing, and third coppicing cycle). We hypothesised that the coppicing cycle influences stand density, basal area, wood volume and stools. Our findings revealed significant variation in wood volume, ranging from 71.36 ± 16.67 m3 ha−1 to 153.63 ± 13.48 m3 ha−1, with the coppicing cycle and their seasonal interactions showing statistical significance (p < 0.001 and p < 0.05, respectively). The basal area varied statistically from 12.67 ± 2.54 m2 ha−1 to 22.68 ± 1.39 m2 ha−1. Analysis of variance revealed significant effects of coppicing cycles, harvesting seasons and their interactions on stand density, diameter, height, stools per hectare and the number of stems per stool. Stem density ranged from 10 642.86 ± 724.44 to 18 414.29 ± 747.25 stems ha−1. The highest density was observed in the first coppicing cycle during both November (18 385.71 ± 987.87 stems ha−1) and March (18 414.29 ± 747.25 stems ha−1) harvests. A clear trend emerged: increasing coppicing intensity resulted in a gradual decline in stand density after the first coppicing cycle, with the lowest stem count observed in non-coppiced stands. The mean diameter and mean height followed a different trend, with the largest stem diameters recorded in the third coppicing cycle (3.98 ± 0.11 cm in November and 4.27 ± 0.14 in March). Increasing the coppicing level resulted in more new shoot sprouts. These findings provide valuable knowledge for Eucalyptus management, emphasising the significance of harvesting continuously with long-term sustainability.