Recreational Load and Mechanical Erosion on the Mountainsides in the Forests of Colchis
The goal of research is to study the impact of recreation on the mechanical erosion processes and to obtain data on the acceptable level of recreational load in the forests of Colchis. The following research methods are used: modeling of recreation loads; determination of the soil weight, fragments of forest litter and grass, moved down the slope by tourists. The dry weight of forest litter and grass on the average does not exceed 4.0 t/ha in the absence of recreational loads on the gorge slopes in the forests of Colchis. With the increase of recreational load the litter and grass are gradually destroyed and, together with the soil, move to the base of slope. Mechanical soil erosion under the influence of the feet of tourists is divided into the following stages: 1) (recreational load ≤ 1 person/ha.) the partial destruction of forest litter and grass cover with transportation of their fragments along the slope; 2) (1... 9 persons/ha) repeats the first stage and involves the complete destruction and transportation of fragments of litter and grass with the soil down the slope; 3) (> 9 persons/ha), repeats the second stage, involves the soil transportation without the fragments of forest litter and grasses. Average recreational loads, at which mechanical erosion is not observed, are established: at the slope inclination up to 10˚ recreational load is less than 5.1 persons/ha; at the slope inclination of 15˚ - 3.4 persons/ha; at the slope inclination of 20˚ -1.6 persons/ha. If the slope inclination is greater or equal to 25˚, mechanical erosion isevident for all levels of recreational load.