Relationship between diameter at breast height, canopy cover, and tree location

Methods

The study was performed at York
University, Boyer Woodlot; Latitude: 43.773116, Longitude: -79.501118 from 3:00
PM – 3:45.  This is a woodlot area,
containing many species of trees, varying from areas of dense tree
concentrations and areas of sparse tree concentrations. On the day of the
study, the weather was sunny with an average temperature of 25 degrees Celsius,
and a little bit of rain from 3:30 PM to 4:00PM.

Two individuals used transect
measuring tapes to measure the distance between adult trees and saplings of the
same species. One person would hold one end of the transect measuring tape at
the edge of the adult tree, while the other person would hold the other end of
the transect measuring tape at the edge of the sapling, then report the
measured distance.
The species of trees used for the
study were chosen at random. Adults of the chosen species ranged in diameter at
breast height values of 0.10 m to 0.5 m. The saplings ranged in diameter at
breast height values of 0.01 m to 0.03 m. The trees had thin branches with
few leaves near the top of the tree. The trunk of the trees were brown and the
trees were reddish in colour.

Adult trees were classified as
trees that were at least 6’ tall; saplings were classified as trees not meeting
this minimum height requirement. This minimum height requirement was measured
using the transect.

A measuring tape was used to
measure the diameter at breast height (DBH) of both the adult trees and the
saplings.

The same individual estimated the
canopy coverage by making a square with their fingers then estimating how much
sky they saw; the canopy coverage was reported as a percentage. The person collecting
the canopy coverage data was 5’5 with a thumb length of 6 cm and an index
finger length of 9 cm.   

Hypothesis

To compete for resources, plants
attempt to maximize height and surface area. This offers the advantage of
enabling the trees to increase their acquisition of resources essential for
survival, i.e., sunlight and water from rain. Trees that do not have this
advantage of height and high surface area will be smaller than those who have
the advantage. Thus, in a woodlot area, the trees that form the canopy coverage
will be larger than the trees in the nearby surroundings, that are beneath the
canopy coverage.  

Predictions:
1. The
greater the canopy coverage value, the                     lower the DBH value of the sapling.

2. The greater the canopy
coverage value, the higher the DBH value of the adult tree.

3. The greater the distance
between the sapling and the adult tree of the same species, the greater the DBH
value of the sapling.