Within the past few weeks digitizing the field collections was completed, this was accomplished by taking Jonathan and Evan's collected field data and creating a referenced shape file over the area of Herbert Run. The work was split by Mariah and I, in the picture above her points are green, mine are yellow. The data was in the form of hand-drawn grids and estimated point positions within the subplot were numbered including the species and estimated DBH of the described tree.
The method I used in creating this representative tree population distribution is fairly straight forward. Each subplot drawing was overlaid with a transparency in which I attempted to equally partition the cell into 25, 5x5 meter subcells. A 5x5 meter subgrid polygon file was supplied for the Herbert run area and the drawn points were transferred.
One of the main issues with the supplied data that may cause minor error was the case of trees that split at the trunk. These were denoted on the drawn grids as two dots, and frequently interpreted as two separate trees in very close proximity, rather than the same tree with two DBH's. This data can be fixed but its overall error effect on canopy data may be negligible.
It's useful to note again that these points are NOT the true locations of the trees, but this set gives a representation of where the species occur. The next major step of this dataset will be collecting the heights of the given trees with the laser hypsometer, or collecting the data in 5 x 5 meter cells or both....we'll see which technique proves fit in the coming weeks!