2/20/2023 0 Comments Download treesize![]() ![]() ![]() ![]() Conversely, the density of annual species was significantly higher in the open area than under tree canopy (F=16.5 p<0.01 under small tree crown and F=8.65 p<0.05 under large tree crown) (Fig. However, no significant difference was found between the two crown blocks. In fact, a higher perennial density was recorded both under large (F = 5.28, p<0.05) and small (F=4.95 p<0.05) tree crown versus the open area (Fig. Plant density: The density of perennial species was significantly increased by tree presence. Multiple-comparison and one-way analysis of variance (ANOVA) procedures were used to compare the differences among the treatments. Data analysis: All data were analysed using SPSS software package. RNE ranges from-1 to 1with positive values indicating facilitation and negative values indicating competition. To facilitate the interpretation of the results, we have multiplied RNE values by-1 (Callaway et al. raddiana on herbceous strata under different tree size, we calculated the Relative Neighbour Effect (RNE) index as follow: RNE = (So-Sc)/X, where Sc and So are H’, plant cover, plant biomass, or density under tree canopy and in the open area, respectively, and X is either Sc (when SC >So) or So (where So>Sc) (Markham & Chanway, 1996). To evaluate the change of the effect of A. To assess the DM of aboveground parts of vegetation, we used the formula proposed by Le Houérou (1987): DM (kg ha - 1) = r*43.1☓.6 (r: perennial species cover in %). RNE The density of perennial and annual species per square meter was determined within 48 quadrats of 7.5 m 2 under tree canopies and 12 in the open area. Pi = ni/n To facilitate where ni: the the average interpretation cover of the of species the results, i, and n we the have total multiplied cover of all RNE species. plant cover, plant biomass, or density H’ = - ∑ under pi log 2 tree pi The canopy Shannon and index in the (H’ open Shannon area, & respectively, Weaver 1949), and X is either Sc (when SC >So) or So (where Pi: the So>Sc) relative (Markham frequency & of Chanway, the species: 1996). Diversity indices RNE Shannon = (So-Sc)/X, & Weaver 1949 (H’) were where used to Sc measure and So species are H’, diversity. Observations were made every 5 cm, for a total of 150 points along each transect to determine total plant cover (in %) and cover (in %) of each herbaceous species sampled. A total of 24 transects were placed under the large crown tree canopies, 24 transects were placed under the small crown tree canopies and 12 transects in the open area. The average crown diameter of the large and the small crown is about 9.167☓.54m and 3.524☑.076m, respectively. The average crown diameter was deducted from the longest length of the vertically projected canopy surface. In each block, we randomly selected six individuals. Transect data were collected in two blocks of tree size (large crown and small crown). ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |