Influence of soil and organic residue management on biomass and biodiversity of understory vegetation in a Eucalyptus globulus Labill. plantation

Abstract

The objective of this study was to assess the effect of different options of soil preparation and management of harvesting debris on biodiversity and biomass of understory vegetation in plantations of Eucalyptus globulus of Central Portugal. The experiment consisted of six treatments in a replanted area and four treatments in a coppice area with five replicates, following a randomised block design. Surveys of vegetation were performed for 6 years. The proportion of soil cover by plant species was estimated and the Shannon-Wiener diversity and equitability indexes determined for each treatment and year. After the 2nd year, the understory vegetation was randomly sampled for above-ground biomass determination. Within the planted area, the removal of slash without soil preparation induced the highest number of species during the experimental period. A similar trend was observed in the coppice area, but less regularly. Significant differences in the proportion of soil cover only occurred within the planted area in the first year, when slash removal without soil preparation induced the highest understory cover. Species diversity was not clearly affected by treatments: significant differences only occurred occasionally and were apparently related to differences in the number of species. Therefore, differences in the equitability index between treatments never were significant. Removal of slash without soil disturbance and broadcast of slash over the soil usually shared the highest biodiversity. Differences between treatments in the amount of understory biomass were never statistically significant during the experimental period. Tendency for a negative influence of soil mobilisation on the amount of understory biomass was observed within the planted area, as well as a similar effect of the treatments consisting of broadcast of slash over the soil surface in the coppice area. In parallel to tree development and canopy closure biomass of that vegetation along the study period was reduced, especially in the planted area.

Impact of harvest residues, fertilisers and N-fixing plants on growth and nutritional status of young Eucalyptus globulus plantations, under Mediterranean conditions

“…This may contribute to extend fertiliser effects by nutrient cycling and soil carbon accumulation. Understory biomass seemed to have stabilised in all treatments between 3 and 4 years after planting, as reported for similar eucalypt plantations in the same area by Fabião et al (2002) and Carneiro et al (2009).…”

Do harrowing and fertilisation at middle rotation improve tree growth and site quality in Eucalyptus globulus Labill. plantations in Mediterranean conditions?

“…Understory biomass was within the range of values reported for eucalyptus plantations 5-6-year old in similar sites by Fabião et al (2002). Results of the present study show that harrowing in the middle of rotation had a clear short-term negative effect on understory biomass, still significant 86 months after treatments in the HF.…”

Eco-hydrological impacts of Eucalyptus in the semi humid Ethiopian Highlands: the Lake Tana Plain

“…In contrast, Eucalyptus species have less understory vegetation (Fig. S4, Fabiã et al, 2002). The good performance of Leucaena and Acacia species) is due to the absence of competition for resources with the understory plants (such as coffee) due to a deeper rooting system (Lehmann, 2003), nitrogen fixation (Ramadhanil et al, 2008) and a diverse and rich microbial habitat (Dupuy and Dreyfus, 1992;Parker and Brown, 1999).…”