1. Other criteria that should be considered to determine species replacement are: tree physiology such as growth, seed dispersal and maturity. Ecological characteristics should be taken into account. Feathers such as soil type, drainage, seedbed type and nutrients. The next phase of the current forest should also be considered. The physiology of trees is important in determining which species they would replace. The characteristics that allow tree species to grow quickly and tall allow the species to be shade intolerant (Bruns and Honkala, 1990, OMNR, 1998; OMNR, 2000; Homes, 2006; Matonis et al, 2011). This characteristic is found in many pioneer species such as: Fraxinus Americana, Betula papyrifera Populus tremuloides, Populus balsamifera, Populus grandidentata, all found in the South Drumlin Nature area. Furthermore, the physiology of shade-tolerant trees is equally important as shade-tolerant species such as Acer saccharum, Fagus grandifolia, Tusga canadensis and Ostrya virginiana are facilitator species (Bruns and Honkala, 1990, OMNR, 1998; OMNR, 2000 ). These species are able to facilitate the environment around them to be suitable for their species. A study by Woods (1984) found that the canopies of some species are capable of influencing the surrounding area. The canopies of species such as Tusga canadensis and Tilia Americana discriminate against other species, while the canopies of Acer saccharum favor Fagus grandifolia (Woods, 1984). Matonis et al (2011) suggest that there are multiple variations that influence gap regeneration and that large light availability would be more suitable for species such as Fraxinus Americana; Populus balsamifera, Populus grandidenta and Butula papyrifera.Many other studies (Poulson and Plati, 1...... half of paper ......on beavers and deer can result in the loss of the main stem. This can cause other stems and compete for the role of the main stem (Bruns and Honkala, 1990). The guideline used in this laboratory is not reasonable as it does not take density into account. As stated previously, density can greatly influence the diameter of the canopy I think a guideline that can determine the average canopy diameter should include other factors such as: average density, tree height, and proximity to the edge. The variable "proximity to the edge" is important in regards to trees found near the edges. exposed areas will therefore have larger canopies, as the tree will put more energy into lateral growth (toward the direction of most sunlight) than vertical growth. This can be seen in a study by Clark and Schlarbaum (2003) that has found that trees that were not sheltered and then exposed to light were taller than 65%..