A plot of 225 m2 in the 1st generation Norway spruce (Picea abies [L.] Karst.) monoculture (age 77-92 years) in the research plot at Rájec nad Svitavou (altitude 625-640 m, 49° 20′ 37″ northern latitude (φ), 16° 42′ 1″ eastern longitude (λ), operated by the Institute of Forest Ecology was roofed for the period of 1983-1985. The roof was erected under the crowns of about twenty trees and its purpose was to induce drought stress. The paper presents a confrontation of biometric characteristics of shoots from top and basal crown parts, studied in three research phases as follows: 1. In 1980-1985: study of the roof impact (Vondřejc, 1986); 2. In 1984-1990: study of regeneration typo (Zvolánkovä, 1993); 3. In 1990-1997: evaluation of experimental results in comparison with results obtained under conditions of naturally occurring droughts. Drought stress led to the decrease in the size of transpiration and assimilatory compartments (area, surface, needle dry matter, etc.), to the restriction of shoot elongation and diameter growth, and to the general reduction of DM accumulation. Some of parameters were to a considerable extent predicted by the conditions of the preceding year (such as needle number per shoot), other were depending on whether the drought occurred in the period from May to June (stem length) or later (DM accumulation) with annual ring area depending on the conditions of the current year. Healthy individuals recovered and restored the original growth rate after two to three years after the water stress (roof) was removed. The methods of growth analysis made it possible to identify the stress impact and to find a different behaviour of the top and basal parts of crowns or that of the healthy and weakened individuals. Regarding the fact that the ratio between the annual precipitation amounts and annual average temperature was decreased in the course of several successive years down to values close to scmiarid regions (1989, 1992), or the precipitation were low (1993), or the temperatures high above average (1994), some biometric characteristics (in the third phase of research, i. c. in 1990-1997) reached the values close to those found at the artificially induced water stress by roofing the plot. In a non-autochthonous environment the tree species must face a repeated water stress (low precipitation and their fluctuation) and a temperature stress (supraoptimum or frost temperatures combined with insufficient snow cover). All this results in weakening, precocious ageing and development of fungal diseases.