Another issue not mentioned in the paper is the selection of the plants. A typical way to select plants is to lay out quadrats (sampling sites). The shape and size of the quadrat are typically square although the literature does show quadrats that are rectangular and circular. Plants are often selected if the roots, trunks, or other plant parts lie inside of the quadrat. Every quadrat has edges. The rules that determine if a plant should be included in a sample are often biased. This means that selection of plants is not done based on their existence, but rather on their size, or shape.
At present I am only aware of one unbiased set of rules to decide if a plant should be included in a quadrat. I am not aware of the unbiased rule being used in plant journals. A typical biased rule is to state that if the plant touches 2 edges its in and it touches the other 2 edges it is out. Sounds like a nice rule, but it leads to a bias that over and under samples plants due to their size relative to the quadrat size.
At present I am only aware of one unbiased set of rules to decide if a plant should be included in a quadrat. I am not aware of the unbiased rule being used in plant journals. A typical biased rule is to state that if the plant touches 2 edges its in and it touches the other 2 edges it is out. Sounds like a nice rule, but it leads to a bias that over and under samples plants due to their size relative to the quadrat size.