Experimental Thinning Trials in a Douglas-fir Stand in the Calabrian Coast Range

1989

S. 155-194

1 Abb., 5 Tab., 20 Lit. Ang.

Unselbständiges Werk

200033987

The following thinning methods were compared in a 19 year old Douglas-fir stand in the Calabrian Coast Range: - thinning from below with 3 different grades (quantified by Hart-Becking distance factor): light (A): s% = 17; medium (B): s% = 18; heavy (C): s% = 19; - row thinning, cutting one row every 3 (D); - combined thinning: one row cut every 4 or 5 rows and thinning from below in the remaining 3 (4) rows, cutting 8 and 13% of trees (E and F) . Basal area and total production after 4 years are not significantly different. Current and percent annual increment for the main parameters are instead significantly different between control plots (lowest values) and thinned areas. Best results, for the whole stand, are from thesis (A), and, at a slightly lower level, from thesis (B). Individual tree basal area increment is higher with thesis (B), (C), (D) and (E), all at the same level. Thinning sensibly reduces mortality losses compared to control: practically no mortality has occurred in thesis (A), (B) and (C); some mortality has occured in (E) and (F), and mostly in (D).