Some aspects of mechanical stability of centuries-old Pinus pinea L. trees growing in the Crimea

The paper considers the issues of assessing the mechanical stability and accident rate of the Italian pine, using the example of a 120 year-old tree growing in the conditions of the recreationally loaded territory of the A.P. Chekhov House-Museum in the city of Yalta, Republic of Crimea. It was found that the viability of the studied plant is 1 point – this is a healthy plant without damage to the trunk and crown. Biomechanical studies were carried out: the aboveground phytomass of the trunk of the tree under study and the main skeletal branches with needles were calculated, the physico-mechanical properties of tissues were determined and model calculations of the mechanical stability of the tree were performed. It was found that the dimensions of the main skeletal branches are separate independent trees, and the calculated weight is an additional static load on the trunk and under the action of a dynamic factor, which additionally reduces the critical load by ~ 20% and increases the accident rate of the entire tree. A large angle of inclination, taking into account the length of the branches, also increases the degree of accident. As a result, there is a shift in the center of mass and a tilt of the entire body with a high probability of falling out of the tree with the slab. To reduce the accident rate of a tree, it is necessary to trim the main branches and reduce the load on the trunk, taking into account the center of mass, and if it is impossible to carry out the necessary trimming, it is necessary to fix dangerous skeletal branches to metal structures.