How to determine tree height – in that case, for example, if you need to dump for the purpose of safety old tree near the house, and you want to be sure that when falling it will not touch construction or wire of power line? There are electronic and laser altimeters by means of which height of trees is defined quickly and quite precisely. However it is not reasonable to buy the device for single use.

- - tape measure;
- - scissors;
- - sheet of cardboard or fibreboard;
- - calculator;
- - saw;
- - nails;
- - pole about 2 m long.

1. It is the simplest to determine tree height by shadow. Measure distance from the end of shadow of tree to its trunk. Write down it, having designated by letter S.

2. Thrust to the earth pole in the place lit with the sun. Measure length of its shadow. Designate height of pole and length of its shadow by letters h and s respectively. Proceeding from similarity of the triangles formed by tree, pole and their shadows, H/h = S/s where H – the required height of tree. Find tree height on formula H = h*S/s.

3. If it is impossible to use shadow for determination of height of tree (there is cloudy weather, or the tree is located in such place that it is not possible to measure its shadow), manufacture the simple device suitable for determination of height of any objects. Cut out from cardboard or fibreboard right triangle with equal legs – the sizes, approximately, about half a meter. Beat it to pole so that two legs of triangle were located in parallel and perpendicularly in relation to it, and its bottom sharp angle was approximately at height of your eyes.

4. Find such situation on the earth that at vertical position of pole your eye, the top of tree and hypotenuse of triangle were on one line. In other words, it is necessary to find the place from which you can look (to aim) on tree top through triangle hypotenuse at vertically standing pole. Having found the right place, measure distances from pole to tree and from bottom corner of triangle to the earth. If to designate them by S and h respectively, height of tree will be S + h. This way is also based on similarity of triangles – cardboard and formed by tree and the line of your look.