Documenting
the giants
Click the graphic above to visit GaLTT’s Big Tree Registry subsite—it documents the largest individual trees of each of Gabriola’s native species.
Our island’s location in the relatively dry Coastal Douglas-fir (CDF) ecological zone means that many of our native trees do not grow to the enormous sizes found in wetter coastal ecological zones, so our largest Douglas-fir, Western redcedar and Western hemlock do not match those found in other parts of Vancouver Island and the coastal mainland. For other native species that thrive on drier sites, such as arbutus and Garry oak, Gabriola likely has some of the largest specimens found anywhere.
How to nominate a big tree
Please let us know if you know of a Big Tree on Gabriola Island that you’d like entered into our registry. Email us at info@galtt.ca, or bigtrees@galtt.ca or bring your suggestion to our display table at the Saturday morning Farmers’ Markets. We’ll send someone out to verify or identify the species, measure it and take photos. GaLTT will confirm the species, sizes and locations of the trees, take photographs, and list them in our registry. Precise location information will allow other interested individuals to find and admire the tree. If a tree is located in a sensitive area, on private land or a site with access restrictions, the exact location can be withheld. The locations of big trees on private land are publicized only with the landowner’s permission.
Even better, you can actively participate by identifying, measuring, and photographing the tree yourself. The Tree Book is a useful on-line identification resource provided by the Ministry of Forests, Lands, and Natural Resource Operations. Another useful source is Plants of Coastal British Columbia compiled and edited by J. Pojar and A. MacKinnon (Lonestar Publishing).
Taking measurements
Always be respectful of the environment—don’t trample the tree roots or surrounding plants. Once you’ve identified the tree by species, simply measure the trunk circumference (the girth of the trunk) at a specified height—this is the easiest measurement to take accurately without specialized equipment.
- On flat ground, measure the trunk circumference at breast height (1.37 m or 4.5 ft above ground level). If a burl or obstruction makes this location unrepresentative, measure at the most suitable point and record the actual measurement height. If using a string or rope, make sure it is made of non-stretch material. Also ensure that the measuring tape remains horizontal as it wraps around the tree.
- If the tree forks at or below 1.37 m, measure the circumference at the narrowest place below the lowest fork. Record the actual measurement height.
- If the tree is on a slope, measure the circumference at 1.37 m up the trunk on both the high and the low side of the slope. Record the average of these two measurements. If the tree is on a steep slope, take one measurement at 1.37 m up from the midpoint of the trunk (the estimated germination point of the tree). If the slope is extreme, you may need to measure circumference higher up. Always make note of the measurement height.
- If the tree is leaning, measure the circumference at 1.37 m up from the axis of the tree base, following the lean of the trunk. Always measure circumference at a right angle to the trunk, otherwise circumference will be overestimated.
For trees of outstanding size, GaLTT will arrange for the measurement of tree height and crown spread.
Taking photographs
For photographs, you will need to provide the photographer/image owner’s first and last name, email address (kept confidential), and photo date. Before submitting a photograph you must obtained permission from the image owner and consent from all people captured in the photograph.
