THE WEATHERING ABILITY OF HIGHER-PLANTS - THE CASE OF AILANTHUS-ALTISSIMA (MILLER) SWINGLE

The growth of higher plants on monuments causes weathering of the substrata and can be one of the biggest problems for conservators. Deterioration can be: chemical-acidity of the roots; root exudation of organic acids that decompose the calcium bicarbonate, which is the main component of limestone used as building material. Mechanical-through the growth pressure of the roots, either on or near the monuments. This paper aims to point out the importance of studying the floristic and ecological aspect of higher plants growing on buildings, particularly the Tree of Heaven-Ailanthus Altissima (Miller) Swingle, on Asiatic plant, naturalised in Europe. This tree can be found growing in modern and ancient buildings, and its large root system causes severe damage to the structure of the buildings. The results of a biocide treatment (ammoniacal solution) are described.