Canopy gaps and establishment patterns of spruce (Picea abies (L.) Karst.) in two old-growth coniferous forests in central Sweden

Abstract

The spatial pattern of seedlings, saplings and canopy trees was studied in two spruce (Picea abies (L.) Karst.) forests in central Sweden. Canopy and forest structure were determined in five 0.25 ha plots. Life stage classes were distinguished on the basis of age and size distributions. Ripley's K-function (1977) was used to analyze the spatial patterns within each class. A random distribution of seedlings gave way to a more aggregated pattern on a small scale during the establishment phase. Saplings and sub-canopy trees were strongly aggregated and canopy trees were again randomly distributed within the plots. The proportion of individuals growing in gaps was used as an index of association between the spatial pattern in saplings and sub-canopy trees and the occurrence of small (50-350 m 2) canopy gaps. Under the null hypothesis of independence the expected value of this statistic would equal the canopy gap ratio for the stand. Monte Carlo simulation of this statistic, using fixed sapling positions and randomly repositioned canopy gaps, confirmed the importance of canopy gaps for the final success of establishment of spruce. The association of understorey trees with gaps suggest that small gaps are typically closed by recruitment of new saplings from a sapling bank rather than by the release of larger suppressed trees.

Natural stand structures, disturbance regimes and successional dynamics in the Eurasian boreal forests: a review with special reference to Russian studies

“…Gap-phase disturbances caused by death of individual trees or small groups of trees drive the mosaic structure and regeneration dynamics of old-growth forests in the absence of catastrophic disturbances (Hofgaard, 1993;Hytteborn and Packham, 1985;Kuuluvainen et al, 1998;Leemans, 1991;Liu and Hytteborn, 1991;Skvortsova et al, 1983).…”

“…Aaltonen, 1919;Utkin, 1965;Verkhunov, 1970;Glagolev, 1975Glagolev, , 1976Dyrenkov, 1984;Zyabchenko, 1984;Fedorchuk et al, 1998;Shevelev, 1999 4. Bogushevsky, 1912;Ivashkevich, 1915;Sernander, 1936;Skvortsova et al, 1983;Dyrenkov, 1984;Hytteborn and Packham, 1985;Smolonogov, 1990;Leemans, 1991;Liu and Hytteborn, 1991;Hofgaard, 1993;Furyaev, 1996;Kuuluvainen et al, 1998;Fedorchuk et al, 1998;Volkov, 2003 * According to Figure 3. 201p16 Eurasian natural forest stands Ann. For.…”

Pienaukkohakkuun uudistumistulos Pohjois-Suomen korpikuusikossa 10 vuoden kuluttua hakkuusta

“…Lukkala 1946). Se perustuu kuusen kykyyn taimettua varjoisissa oloissa järeänkin puuston alla (Leemans 1991). Toinen syy on rahkasammalien edullinen vaikutus havupuun siementen itämiseen (esim.…”

Weak competitive ability may explain decline of Taxus baccata

“…It is often the result of larger or smaller natural gaps in the canopy of the stand (Leemans 1991). Geostatistical analysis in the Central Apennines found that yew occurred in patches and high density of mature yews suppressed regeneration (Piovesan et al 2009).…”

“…One of the most important ecological factors, especially important for natural regeneration, is light conditions on the forest floor (Szwagrzyk et al 2001). The analysis of the horizontal spatial organisation of the forest allows us to study the relationships between younger and older trees (Leemans 1991;Szwagrzyk et al 2001;Szymura et al 2007). Spatial relationships between different naturally regenerating species in a mixed forest are particularly interesting because such knowledge could help us to explain the natural species change in the mixed forest.…”