Line Weights for Plants in Plan View
Proper line weights give your drawing depth and clarity. Whether you are drawing by hand or on the computer, line weights are important for visual communication.
LINE WEIGHT | The relative thickness of a drawn line
Thicker lines tend to be taller trees (those closer to you in plan view), while thinner lines are shorter plants (those farthest away in plan view). Apply the line weight variety to the outside edge of the plant, not the dot or cross-hair in the middle. The center symbol should always be thinner and typically the same for all plants (unless you are depicting the size of a trunk on an existing plant). On a side note: I use cross-hairs for proposed plant materials, while a dot represents existing.
The illustration below demonstrates a variety of line weights on a planting plan. Feel free to click on the image to download a .pdf for yourself.