![]() ![]() (HI is the measurement from the ground to your eye). Then stand at the mark and sight the top of the tree, finding its elevation angle. You can find a lot of information about using Clinometers on the internet.īriefly, you stand at a point as far from the centre of the trunk of the tree as its estimated height, so that the elevation angle is somewhere around 45°, this gives the best "geometry." Measure the distance (D) from the tree with a tape. Since buying a clinometer, our method of measuring trees has changed. Obviously all these factors are inter-dependant. Happily, this coincides with the need to be a long way back to minimise perspective errors! Finally, avoid using the outer 15% or so of the image. Avoid using the wide-angle setting on zoom cameras - try to use a degree of telephoto setting. There are several things that can be done to minimise the inaccuracy due to these effects. ![]() In other words, a 1m rule at the edge of a photograph may well appear to be a slightly different length than a 1m rule at the centre. We are, however, relying on the linearity of the lens and most will introduce a varying degree of distortion to the image, particularly when zoom cameras are used in their wide-angle setting. Though this sounds a little Heath-Robinson, this method should be able to produce fairly reasonable (if not scientific) results. Paste the image of the measure as many times as necessary all the way up the tree (see picture on left) and then you can calculate the height. Also, remember to include the top of the tree - it's easy to miss this when setting up the camera.Īt your computer, use the selection tool in a photo manipulation package (unfortunately Paint will not do) to select and copy a small rectangle including the exact length of the measure. Any closer and "perspective" error will become significant - do a scale drawing as an example and you will see what we mean. The camera needs to be placed a long way back from the tree for the most accurate measurement ideally at least twice the height of the tree. (3 metres would be better but the tape may buckle and fall). Standing to one side, hold a steel tape measure extended up 2 metres ensuring that the bottom of the measure is level with the bottom of the tree. Set the camera to timer mode and run back to the tree. You will need to place the camera a good distance away from the tree on a tripod or some other suitable object. Where the ground slopes the usual practise is to use the side of the tree with the highest ground level.Ī camera is needed to attempt this method of measuring the height of a tree. You might have to scrape away some of the detritus to get to the actual ground level. To measure the girth it is usual to position the tape measure at 1.5 metres from the ground (around chest height, but refer to chart on the left). Remember that it is important to make a note of the date that you measure, and feel free to contact us if you would like us to include a record of your findings and/or measurements of Redwood Trees, (preferably with photographs). ![]() Here are some tips on how to measure the Girth and Height of trees. ![]() Giant Redwood / Giant Sequoia / Wellingtonia This site refers to the three types of Redwood by the names commonly used in the U.K:
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |