<p>e extinction of a large part of the existing forest and ornamental trees in forestry is observed under the inuence of pests, which leads to the depletion of biodiversity. factors. is, in turn, depends on several environmental e article highlights the studies conducted in 2017–2018 in the territory of the Chatkal-Ugam state reserve of the Tashkent region, on the main types of pests of the forest and ornamental trees, the number of healthy and a ected trees, and species of trees. e researches show the number of damaged trees in the areas where the ecological balance is disturbed. e authors made a detailed survey of trees a ected by stem pests and diseases; identi ed stem pests of trees and conifers species, which are the part of the assortment of forest plantations of the Ugam-Chatkal state reserve. e article is devoted to a topical issue of conservation and e cient use of forest resources and their protection om massively propagating pests and diseases of the forest plantings.</p>