I followed the property line for this set of observations, so the route can be assumed to be linear, which facilitates an estimate of the field of vision for Big Tree observations – those are Big Trees ‘readily observed’ from my walking route. (I would leave the walking route to make a measurement or estimate of tree dbh, then return to the track.)
The estimated field of vision, based on the rectangle above, is +/- 12.2 m, i.e. Big Trees visible within 12.2 meters of the walking route were included. This stand was more closed than the other stands. For other, more open stands, I am guessing the field of vision is 20 to 30 m, 20 m for mixed stands, 30 m for hardwoods. (I will be making estimates like those above in other situations.)
The estimated density of Big Trees in this stand (see legend to the image at the top of the page), 97 Big trees/ha, falls within the range of densities of Big Trees in Mature and Old Growth forest in 4 stands by Sandy Lake (38-183 Trees>50 cm diameter per hectare).
Regardless of the actual densities, these types of observations appear to give a good indication of the mix of big trees, in this case 12 of the 15 were hemlock, 2 were red spruce and only 1 was a hardwood (Mountain Birch).