An explanation and demonstration of using a wedge prism to estimate basal area. Filmed by Patrick Culbert, University of British Columbia - Faculty of Forestry
man, whoever this Forester is, he needs to be teaching in a lot more videos. So many foresters give WAAAY too much information. His way of almost speaking in laymen's terms works well. keep up the good work Patrick
When I heard that you can measure the basal area with a prism, the first thing in my mind was ' That doesn't sound very precise or true' but... it actually works. Worth to always keep an open mind I guess
When you purchase a prism, you select the desired BAF (there are also metric prism in m^2/ha and standard in ft^2/acre). They are usually labelled on the edge.
@@alinawaz7256 A number of devices that work on a similar principle as prisms (e.g., an angle gauge or Cruz-All) need to be held a specific distance from your eye, but a prism does not (though it must be held over the center point of the plot). From Forestry Supplier's: "Hold prism at any convenient distance from the eye, directly over the sampling point. Hold in a vertical position and at a right angle to the line of sight." (www.forestry-suppliers.com/Documents/1435_msds.pdf)
man, whoever this Forester is, he needs to be teaching in a lot more videos. So many foresters give WAAAY too much information. His way of almost speaking in laymen's terms works well. keep up the good work Patrick
Thanks for the video, just started my first job working in timber and this is really helpful
When I heard that you can measure the basal area with a prism, the first thing in my mind was ' That doesn't sound very precise or true' but... it actually works. Worth to always keep an open mind I guess
very informative!!! thanks a lot sir!!
So, the number of trees in x the factor on the prism equals basal area in square meters per hectare?
Basal area times height equals volume? How does this work for an oak tree?
How can you tell what factor your prism is?
When you purchase a prism, you select the desired BAF (there are also metric prism in m^2/ha and standard in ft^2/acre). They are usually labelled on the edge.
At what distance prism should be hold?
The distance from your eye doesn't actually matter with a prism, but you need to keep the prism itself over your plot center.
No! It should be at 25 cm distance from your eyes. This will done by thread ,one at end of thread in your mouth and other end will attached to prisms
@@alinawaz7256 A number of devices that work on a similar principle as prisms (e.g., an angle gauge or Cruz-All) need to be held a specific distance from your eye, but a prism does not (though it must be held over the center point of the plot). From Forestry Supplier's: "Hold prism at any convenient distance from the eye, directly over the sampling point. Hold in a vertical position and at a right angle to the line of sight." (www.forestry-suppliers.com/Documents/1435_msds.pdf)