Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Communautés de sous-bois des peupleraies artificielles : relation entre phytomasse, richesse spécifque. | 607 Ann. For. Sci. 56 1999 607-614 Inra Elsevier Paris Article original Communautés de sous-bois des peupleraies artificielles relation entre phytomasse richesse specifique et perturbations Marc Laquerbe Centre d ecologie des systèmes aquatiques continentaux Cnrs UMR c 5576 29 rue Jeanne Marvig BP 4349 31055 Toulouse cedex France Reẹu le 23 octobre 1998 accepté le 25 mars 1999 Abstract - Understory plant communities of cultivated polar groves relationship between phytomass species richness and disturbance. Understory plant communities of cultivated poplar groves are submitted to strong disturbances essentially due to mechanical upkeep. Upkeep consists of disking . weeding by a metallic disk which totally destroys and buries vegetation. This upkeep differs among poplar groves the intensity decreases with tree age and it totally disappears during the years preceding clearing. With canopy closure these differences lead to a modification in species communities. The four poplar groves chosen for this study showed different upkeep levels. Phytomass and species richness were studied by sampling vegetation at its stage of maximal growth just before upkeep periods. As the intensity of upkeep treatment decreases with time communities exhibited different suc-cessional stages from annual pioneer meadow perennial and woodland ligneous species. The results show that species richness increases with upkeep intensity whereas phytomass values decrease. Most of these phytomasses were between 250 and 1 000 g tn-2 with a maximum at 2 000 g ITT2 in the oldest and less maintained poplar groves. For strong disturbance levels species richness was high and reached a maximum for moderate phytomasses. However the steady state existing in abandoned poplar groves exhibited strong phytomass accumulation near trees. On the one hand community species enrichment mainly depended on disturbance levels induced by upkeep. On the other hand the flora enrichment was due to maturation of plantation. We
