Is there a way of creating a buffer (elliptical I guess) in QGIS that has independent distances to the North, South, East & West (from the attribute table) so the buffer could be 5m wide to the North, 4m to the East, 6m to the South & 2m to the West? This is to show tree crown dimensions on a map.
You can consider to use the geometry generator to do this job for you. The geometry generator will only generate the geometry of your symbol. The example below has a point theme with 4 attributes: "n", "s", "e" and "w" for your values and makes a polygon symbol with this four values with the expression:
smooth( make_rectangle_3points( make_point($x-"w",$y-"s"), make_point($x-"w",$y+"n"), make_point($x+"e",$y+"n")), 3)
it takes the pointgeometries ($x and $y) and generates a rectangle with the values from "n", "s", "e" and "w", which will be smoothed afterwards: