ZLV Online

Abstrakt

In four mixed selection forests of northwestern Carpathians we analysed the structure and height growth of Norway spruce (Picea abies /L./ Karst.) and Silver fir (Abies alba Mill.) natural regeneration. In the period 2002–2004, the diameter structure of the stands (all living trees of dbh > 8 cm) was assessed in each research object. Moreover, in the series of 104 square sample plots with the size of 100 m2, the density of natural regeneration (individuals of dbh ≤ 8 cm) was recorded. For the older saplings (h > 1.3 m, dbh ≤ 8 cm) the following characteristics were measured: height (H), crown width (CW), length of living crown (CL), diameter at breast height (dbh) and height increments of the last 10 years (HI). Subsequently, the derived characteristics were calculated: relative crown length (RCL), crown width ratio (CWR), mean increment during the last three years (MHI) and relative growth ratio (RGR). The influence of temperature and precipitation on the height growth of Norway spruce and Silver fir was analysed using the modified standard index chronology. The average density of natural regeneration in particular research objects ranged between 9,054 ± 4,012 ha-1 and 23,720 ± 11,705 ha-1. The proportion of older saplings was only 6–17% (11% on average) from the total regeneration density. Compared to Norway spruce, Silver fir reached significantly higher (p < 0.01) values of MHI and RGR in most cases. Correlation and regression analysis confirmed moderate to strong correlation between the standardized indices and mean temperature or precipitation in selected periods (Rmax = 0.34–0.66 and 0.15–0.75, respectively).